document_title: Def Leppard

question_text: what is def leppard's new album called

question_tokens: what is def leppard 's new album called

root

text: Def Leppard

text: History[edit]

text: Early years (1977–1979)[edit]

text: Rick Savage, Tony Kenning, and Pete Willis, all students at Tapton School in Sheffield, South Yorkshire, formed a band called Atomic Mass in 1977. The band originally consisted of Willis on guitar, Savage on bass (after originally playing guitar), and Kenning on drums. Only 18 at the time, Joe Elliott tried out for the band as a guitarist following a chance meeting with Willis after missing a bus, in November 1977. During his audition it was decided that he was better suited to be the lead singer. Their first ever gig was in the dining hall in A Block in Westfield School in Mosborough, Sheffield.[14]

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text: The band adopted a name proposed by Elliott, "Deaf Leopard", which was originally a band name he thought up while writing reviews for imaginary rock bands in his English class (and in at least partial reference to Led Zeppelin).[15] At Kenning's suggestion, the spelling was slightly modified in order to make the name seem less like that of a punk band. In January 1978, Steve Clark joined the band. According to Elliott, he successfully auditioned for the band by playing Lynyrd Skynyrd's "Free Bird" in its entirety.[16]

text: In November, just prior to recording sessions for what would be a three-song release known as The Def Leppard E.P., Kenning abruptly left the band; he would later form the band Cairo. He was replaced for those sessions by Frank Noon. By the end of the month, Rick Allen, then only 15 years old, had joined the band as its full-time drummer. Sales of the EP soared after the track "Getcha Rocks Off" was given extensive airtime by renowned BBC Radio 1 DJ John Peel, considered at the time to be a champion of punk rock and new wave music.[17]

text: Throughout 1979, the band developed a loyal following among British hard rock and heavy metal fans and were considered among the leaders of the new wave of British heavy metal movement. Their growing popularity led to a record deal with the major label Phonogram/Vertigo (Mercury Records in the US). Def Leppard's original management, MSB, a local duo consisting of Pete Martin and Frank Stuart-Brown, were fired after Martin and Joe Elliott got into a fistfight over an incident on the road. The band approached Peter Mensch of Leber-Krebs management, who had booked them on a tour of the UK supporting AC/DC. Mensch, who admitted that he had had his eye on the band, became their manager.[18]

text: Rise to fame (1980–1983)[edit]

text: Def Leppard's debut album, On Through the Night, was released on 14 March 1980. Although the album hit the Top 15 in the UK, many early fans were turned off by the perception that the band was trying too hard to appeal to American audiences by recording songs such as "Hello America" and touring more in the US (supporting Pat Travers, AC/DC, and Ted Nugent). A performance at the Reading Festival in August was marred when audience members expressed their displeasure by pelting the band with beer cans and bottles filled with urine. This incident was partially blamed on a cover story in Sounds music newspaper by the journalist Geoff Barton entitled "Has the Leppard changed its spots?" accusing the band of selling out to the American market. In a documentary on the band recorded for BBC 2, Barton recalls feelings of guilt over the story and having a "stand-up row" with the band's manager, Mensch, backstage at the show.[18][19][20] In the documentary series Metal Evolution, Joe Elliott says that the media had exaggerated the event and all bands on the day had experienced the 'abuse' from the crowd.[21]

text: The band had by then caught the attention of AC/DC producer Robert John "Mutt" Lange, who agreed to work on their second album, High 'n' Dry, released on 11 July 1981. Lange's meticulous approach in the studio helped them begin to define their sound. Despite the album's unimpressive sales figures, the band's video for "Bringin' On the Heartbreak" became one of the first metal videos played on MTV in 1982, bringing the band increased visibility in the U.S.[22] The band continued to use the up-and-coming music television industry to reach fans over the years with their unique videos and the extravagance of their concerts.[23] After the album's release, European and American tours followed. The band opened for Ozzy Osbourne and Blackfoot.[24]

text: Phil Collen, former guitarist with the glam band Girl, on 12 July 1982 replaced Pete Willis, who had been fired the previous day because of excessive alcohol consumption on the job. (Willis would later resurface with the bands Gogmagog and Roadhouse.) This personnel change took place during the recording of their third album, Pyromania, which was released on 20 January 1983 and also produced by Lange. The cover artwork depicted an animated picture of a huge flame emerging from the top floor of a skyscraper, with a bullseye aimed at the flame. Though many stores would not carry the album due to the cover art, the band did not change the artwork. The lead single, "Photograph", turned Def Leppard into a household name, supplanting Michael Jackson's "Beat It" as the most requested video clip on MTV and becoming a staple of rock radio (dominating the US Album Rock Charts for six weeks), and sparked a headline tour across the U.S.[25]

text: Fueled by "Photograph" and subsequent singles "Rock of Ages" and "Foolin'", Pyromania went on to sell six million copies in 1983 (more than 100,000 copies every week in that year) and only was held from the top of the US album charts by Michael Jackson's Thriller. With the album's massive success, Pyromania was the catalyst for the 1980s pop-metal movement.[26] In 2004, Pyromania was certified Diamond having sold over 10 million copies in the US.[27] Def Leppard's US tour in support of Pyromania began opening for Billy Squier in March and ended with a headlining performance before an audience of 55,000 at Jack Murphy Stadium in San Diego, California in September. As a testament to the band's popularity at the time, a US Gallup poll in 1984 saw Def Leppard voted as favourite rock band over peers such as The Rolling Stones, AC/DC, and Journey. However, in their native England, Duran Duran secured the number one spot.

text: Hysteria era (1984–1989)[edit]

text: Following their breakthrough, the band moved to Dublin in February 1984 for tax purposes to begin writing the follow-up to Pyromania. Mutt Lange initially joined in on the songwriting sessions but then suddenly declined to return as producer due to exhaustion. Instead, Jim Steinman (of Meat Loaf's Bat Out of Hell fame) was brought in.

text: On 31 December 1984, drummer Rick Allen lost his left arm in a car crash on the A57 in the hills outside the band's home city of Sheffield. Allen was driving with his Dutch girlfriend, Miriam Barendsen, when his Corvette swerved off the road on a sharp bend and went through a drystone wall. Despite the severity of the accident, Allen was committed to continuing his role as Def Leppard's drummer, and realised that he could use his legs to do some of the drumming work previously done with his arms.[28] He then worked with Simmons to design a custom electronic drum kit.[29] The other members of the band supported Allen's recovery and never sought a replacement. Allen was placed in a separate studio to practice his new drums. After a few months, Allen gathered the band together and performed the intro to the Led Zeppelin version of "When the Levee Breaks" to showcase his progress to the band. Joe Elliott reports this as being a "very emotional moment." During this period, Mutt Lange returned as producer. Def Leppard brought in Jeff Rich in August 1986 to play alongside Allen during Def Leppard's warm-up mini tour of Ireland. When the band couldn't fit two drum kits on stage at a gig, he and the band realized Allen could drum alone.[30] Allen's comeback was sealed at the 1986 Monsters of Rock festival in England, with an emotionally charged ovation after his introduction by Joe Elliott.[31]

text: After over three years of recording, Def Leppard's fourth album, Hysteria, was released on 3 August 1987. One of the first singles from the album, "Animal", became the band's first Top 10 hit in the UK, reaching No. 6 on the UK Singles Chart.[32] "Animal" also started their run of ten consecutive U.S. Billboard Hot 100 Top 40 singles.[33] Hysteria immediately topped the UK Album Charts in its first week of release, and has since spent 105 weeks on the chart.[32] Initial US album sales were relatively slow (compared to Pyromania) until the release of the fourth single, "Pour Some Sugar on Me". The song hit Number 2, and Hysteria finally reached the top of the U.S. Billboard 200 in July 1988.[34] Often regarded as the band's signature song, "Pour Some Sugar on Me" was ranked No. 2 on VH1's "100 Greatest Songs of the 80s" in 2006.[35]

text: The band's UK success saw them nominated for the 1988 Brit Award for Best British Group.[36] In October 1988, the power ballad "Love Bites" reached number one on the Billboard Hot 100.[33] In January 1989, the band scored another US Top 5 hit with "Armageddon It", and by spring of 1989 the final single "Rocket" was in the Top 20.[33] Wanting to give fans something new after the massive radio and video airplay for not only the 7 singles but also the Album tracks that Radio DJs were playing off the album, the band performed "Tear It Down", a Hysteria B-side at the 1989 MTV Video Music Awards. Due to positive fan reaction the song was reworked for their following album Adrenalize.

text: Hysteria is one of only a handful of albums that has charted seven singles or more on the US Hot 100: "Women" (#80), "Animal" (#19), "Hysteria" (#10), "Pour Some Sugar on Me" (#2), "Love Bites" (#1), "Armageddon It" (#3), and "Rocket" (#12).[33] It remained on the charts for three years and has sold over 25 million copies worldwide.[7] Equally successful was the accompanying 16-month tour, in which the band performed in the round. This concept proved wildly popular with fans (as seen in the videos for "Pour Some Sugar on Me" and "Armageddon It") and was used again for the Adrenalize tour.

text: At the 1989 Brit Awards held at the Royal Albert Hall in London, Def Leppard were again a nominee for Best British Group, and the band performed "Pour Some Sugar on Me" at the ceremony.[37][38] At the 1989 American Music Awards, Def Leppard won Favorite Heavy Metal/Hard Rock Artist, as well as Favorite Heavy Metal/Hard Rock Album (for Hysteria).[39]

text: Adrenalize, Clark's death, and change in musical direction (1990–1999)[edit]

text: Following Hysteria, the band quickly set out to work on their fifth album, hoping to avoid another lengthy gap. Steve Clark's alcoholism worsened to the point that he was constantly in and out of rehab. Recording sessions suffered from this distraction, and in mid-1990, Clark was granted a six-month leave of absence from the band. Clark died from a mix of prescription drugs and alcohol on 8 January 1991, in his London home.[40]

text: The remaining band members decided to carry on and recorded the album as a four-piece, with Collen mimicking Clark's style on his intended guitar parts. Def Leppard's fifth album, Adrenalize, was finally released on 31 March 1992. The album simultaneously entered at number one on both the UK and US album charts, staying on the latter for 5 weeks.[34][41] The first single, "Let's Get Rocked", was an instant smash hit, and the band performed the song at the 1992 MTV Video Music Awards where it was nominated for Best Video of the Year.[42] In April 1992, Def Leppard appeared at The Freddie Mercury Tribute Concert at Wembley Stadium, London, performing a three-song set of "Animal", "Let's Get Rocked" and Queen's "Now I'm Here" with guitarist Brian May.[43] Joe Elliott later performed "Tie Your Mother Down" with the remaining members of Queen and Guns N' Roses guitarist Slash.[44]

text: In a period between late 1991 and early 1992, auditions for another guitarist commenced. Among the guitarists who auditioned included Adrian Smith, John Sykes, and Gary Hoey. Ultimately, the band chose Vivian Campbell in February 1992, formerly of Dio and Whitesnake. Another world tour followed but the band's fortunes began to be affected by the rise of alternative rock, including grunge. Amidst the increasing popularity of alternative rock, the band decided to balance their original image as rebellious rock stars with a slightly friendlier energy, combining heavy metal with melodies and hooks more reminiscent of pop music.[45][46]

text: A collection of b-sides and unreleased tracks recorded between 1984 and 1993, called Retro Active, was released in October 1993, preceded by the success of "Two Steps Behind" (from the Arnold Schwarzenegger film Last Action Hero). Another single, "Miss You in a Heartbeat", hit the Top 5 in Canada, becoming one of their biggest hits there. Retro Active has sold 3 million copies worldwide to date. Two years later, Def Leppard issued their first greatest hits collection, Vault: Def Leppard Greatest Hits (1980–1995), which reached number 3 in the UK, and sold over 5 million copies in the US.[32][47] Alternate track listings of the album were issued for North America, the UK, and Japan. The compilation included a new track, the power ballad "When Love & Hate Collide", which became their biggest ever hit in the UK, hitting No. 2 on the UK Singles Chart.[48]

text: On 23 October 1995, the band entered the Guinness Book of World Records by performing three concerts on three continents in one day (Tangiers, Morocco; London, England; and Vancouver, Canada).[49]

text: Slang, released in May 1996, marked a drastic musical departure for the band by featuring darker lyrics and a stripped-down alternative rock edge. The band rehearsed and played the songs together in the studio instead of recording parts separately, resulting in a much more live-sounding album.[50] The US audience reception for Slang and its subsequent tour was a major dropoff from a decade earlier, but Q Magazine nonetheless listed Slang as one of their Top Ten Albums of 1996.[51] This album was the first recorded performance of Rick Allen playing a semi-acoustic drum kit since his accident, and not his electronic set as was first used with Hysteria.

text: VH1 revived the band's fortunes in the US in 1998 by featuring them on one of the first episodes of Behind the Music. Reruns of the episode yielded some of the series' highest ratings and brought the band's music back into the public consciousness (following years of burial by the alternative rock climate). The episode was even parodied on Saturday Night Live. In an effort to capitalise on this new momentum, Def Leppard returned to its classic sound with the 1999 album Euphoria. The first single, "Promises", reunited the band with Mutt Lange and hit the US Mainstream Rock charts at No. 1 for 3 weeks. The album was certified gold in the US and Canada.

text: On 5 September 2000, Def Leppard were inducted into the Rock Walk of Fame on Hollywood's Sunset Boulevard by their friend Brian May of Queen. In 2001, VH1 produced and aired Hysteria - The Def Leppard Story, a biopic that included Anthony Michael Hall as Mutt Lange and Amber Valletta as Lorelei Shellist (Steve Clark's girlfriend). The docudrama covered the band's history between 1977 through 1986, recounting the trials and triumphs of Rick Allen and Steve Clark. 18 July broadcast still produced some of the channel's highest-ever ratings and is available on DVD.

text: Def Leppard's tenth album, X, saw the band's musical direction moving more towards pop and further away from the band's hard rock roots. X quickly disappeared from the charts, ultimately becoming the band's least successful release. However, the accompanying tour played to the band's strongest audiences since Adrenalize.

text: An expanded and updated best-of collection, Best Of, was released internationally in October 2004. The North America-only version, Rock of Ages – The Definitive Collection, was released the following May. Def Leppard participated at the Live 8 show in Philadelphia and toured in the summer with Bryan Adams. In 2005, the band left their longtime management team, Q-Prime, and signed with HK Management.

text: On 23 May 2006, Def Leppard released an all-covers album titled Yeah!. The disc pays homage to classic rock songs of their childhood, originally recorded by Blondie, The Kinks, Sweet, ELO, and Badfinger among others. It debuted at No. 16 in the US, their tenth consecutive Top 20 album.[34]

text: The band, along with Queen, Kiss, and Judas Priest, were the inaugural inductees of "VH1 Rock Honors" on 31 May 2006. During the show, The All-American Rejects paid homage to the band with a cover of "Photograph". Soon afterwards, they embarked on a US tour with Journey. That October, Hysteria was re-released in a two-disc deluxe edition format, which combined the original remastered album with b-sides, remixes, and bonus tracks from single releases. Def Leppard began their "Downstage Thrust Tour", on 27 June, which took them across the US and into Canada. Support bands were Foreigner and Styx.

text: Songs from the Sparkle Lounge (2008–2009)[edit]

text: On 28 April 2008, Def Leppard released their first album of new studio material in six years, Songs from the Sparkle Lounge. The album debuted at No. 5 on the Billboard 200 in the US. The first single was entitled "Nine Lives" and featured country singer Tim McGraw, who co-wrote the song with Joe Elliott, Phil Collen, and Rick Savage.

text: A tour in support of the album began on 27 March 2008 in Greensboro, North Carolina,[52] with Styx and REO Speedwagon joining the band on US dates. The band also played several European rock festivals. An arena tour of the UK took place in June in which the band co-headlined with Whitesnake and was supported by US southern rockers Black Stone Cherry. The band then returned to Europe before coming back for a second leg of the UK tour in June. The first of these dates was at the Glasgow SECC on 17 June. Again they were joined by Whitesnake; however, hard rock band Thunder supported at some of these shows. Black Stone Cherry continued to support most of the dates, including some of the Thunder ones. Six shows which were cancelled during the USA/Canada leg of their world tour due to illnesses affecting Joe Elliott and Phil Collen would be rescheduled and played in August of that year. On 11 June, Def Leppard announced further dates for their 2008 World Tour. The extension saw them visit Japan, Australia and New Zealand. Whitesnake continued to support Def Leppard for their Indian and Japanese dates. Def Leppard toured 41 US cities plus Toronto, Canada, during mid-2009 with Poison and Cheap Trick and also played the Download Festival with Whitesnake and ZZ Top.

text: In October 2008, Def Leppard played with country star Taylor Swift in a taped show in Nashville, Tennessee, in a show called CMT Crossroads: Taylor Swift and Def Leppard. This was released as a DVD on 16 June 2009 exclusively at Wal-Mart.[53] The release was the best-selling DVD of week, and the 10th best selling Wal-Mart music release.[54] A fan of the band since childhood, Taylor Swift chose Def Leppard to perform together for the show, and their crossover performance of "Photograph" was up for both Performance of the Year and Wide Open Country Video of the Year at the CMT Music Awards in 2009.[53] Taylor Swift said of the performance, "Performing with Def Leppard was awesome! They are the coolest guys on the planet! It was the coolest thing in the world to have my band on stage with them...It was the most amazing feeling in the world..."[55] Joe Elliott from Def Leppard said, "What an absolute pleasure it was to work with Taylor and her band who are a great set of musicians. Myself and Taylor blended really well together, I think, and everybody, both bands and the crowd, had a great time. I'm really glad we had the opportunity to do this."[56]

text: In October 2009 the band announced that they would be cancelling the last leg of the 2009 North American tour, a total of 23 shows. The band cited, "unforeseen personal matters", as the reason for the cancellations.[57] At the time, the band denied rumours about a breakup, saying, "We're not splitting. Not at all. We often joke, what else would we do? You just can't imagine doing anything else."[57][58]

text: Recent events and self-titled album (2010–present)[edit]

text: After taking a year off from touring in 2010, the band announced on 22 February 2011 that they would be releasing their first live album in the summer. Mirror Ball – Live & More, a two-disc live album, with three new studio tracks, was released in parts of Europe on 3 June, the rest of Europe on 6 June, and on 7 June in the US; it was announced at the same time that Def Leppard would perform at the Download Festival on 10 June 2011.[59] Of the three new studio tracks, two were released as singles, the first single being "Undefeated" released in April 2011, followed by "It's All About Believin'" released in May 2012.

text: Def Leppard embarked on a two-month U.S. tour in the summer of 2011, with Heart.,[60] as well as another seven shows in Australia in October with The Choirboys and Heart,[61] two shows in Japan in November,[62] and six shows in the United Kingdom in December with Steel Panther and Mötley Crüe.[63] The following year, they then toured with Poison and Lita Ford in the US during the summer of 2012 from 20 June through 15 September, dubbed the "Rock Of Ages 2012 Tour".[64][65]

text: The year after, Def Leppard played an eleven show residency at the Hard Rock Hotel and Casino in Las Vegas, Nevada from 22 March through 13 April 2013. The residency, referred to as Viva! Hysteria, featured a two part show, with the first half featuring Def Leppard opening for themselves, under the alias "Ded Flatbird", (jokingly called the best Def Leppard cover band in the world), when they would then play songs they very rarely play live, going all the way back to "Good Morning Freedom", a b-side from the single "Hello America" released in February 1980, an era usually left untouched by the band. The opening set varied each night, from playing the best hits from albums like On Through the Night, Slang, and Euphoria, to being the entire first half of High 'n' Dry. The second half, and "main event" was Def Leppard, as themselves playing their best-selling album, Hysteria, from start to finish. A live album, also titled Viva! Hysteria was released on 22 October 2013. This was the first time the band has played an album live from start to finish.[66][67]

text: The band has re-recorded several hits and even the entire album Hysteria in an effort to circumvent their record label from future royalties, though of these re-recordings, only "Rock Of Ages", "Pour Some Sugar on Me", and "Hysteria" have actually been released.[68][69][70]

text: In June 2013, Vivian Campbell announced that he had developed Hodgkin's lymphoma, a malignant form of cancer that affects the Reed-Sternberg cells, located in the lymph nodes.[71] He continued performing with Def Leppard, and no shows were cancelled or rescheduled. The sole idea of cancelling any shows and not doing anything disgusted Vivian, believing performing would be the best way to remain optimistic.[72] In November 2013, he announced he was in remission. However, the cancer has since reemerged, and he is now receiving chemotherapy once again. Should the cancer once again enter remission, he will undergo a stem-cell transplant.

text: On 11 February 2014, the band released a remastered deluxe edition of their 1996 album Slang after much delay. The album, still coveted by many loyal fans of the band, now features 30 tracks including demos, B-sides, and unreleased material.[73] From 23 June 2014 to 31 August 2014, Def Leppard and Kiss toured 42 cities, with a dollar per ticket donated to such military charities as Wounded Warrior Project.[74] Def Leppard contributed one song Helen Wheels to the Paul McCartney tribute album The Art of McCartney released on 18 November 2014. Joe Elliott also contributed another track Hi Hi Hi.

text: At certain recent points in time, the band had projects, such as a cartoon and a documentary in development. However, these projects seem to be shelved indefinitely. The band had originally planned to do another residency in Las Vegas, this time in honour of Pyromania (called Viva! Pyromania), but due to the "Heroes 2014" tour with Kiss, and the recording of their new studio album, the project had been pushed back indefinitely.[75][76] The new album was originally planned to be an EP, but the set-list increased to 15 songs by June 2014.[77] The album was released on October 30, 2015 with a tour following.[78]

text: In December 2014, the band announced a 13-date Canadian tour in April and May 2015.[79] This was followed in February 2015 with the announcement of a 2015 US summer tour with Styx and Tesla from June to October 2015.[80] The tour was then extended to include dates in Japan and Australia throughout November, and a tour of the UK and Ireland with Whitesnake in December. Def Leppard then returned to North America with Styx and Tesla in early 2016.

text: The eleventh studio album, titled Def Leppard, was recorded in 2014 and 2015, and released on 30 October 2015.[81] The band released the lead single from their self-titled album on 15 September 2015, titled "Let's Go", with a music video for the song being released on 30 October.[82] The 14 track album debuted at number 10 in the U.S. and number 11 in the UK.[83]

text: During the break following their 2015 tour, Def Leppard led the Hysteria on the High Seas concert cruise aboard the MSC Divina in January 2016. Originally supposed to be a cruise just for the concert goers, cabins were later opened up to others due to low sales. The cruise did not go according to schedule for various reasons: The cruise was not able to dock at the private island due to inclement weather, then Joe Elliott became ill with laryngitis on the night of their cruise performance. This led to the band performing without Elliott for the first time in their history. Vivian Campbell and Phil Collen sang lead vocals on two songs of the shortened seven song set in addition to two songs with vocals by Andrew Freeman and two more with Eric Martin and Kip Winger.[84] in addition to this, Campbell and Freeman's Last in Line bandmate Jimmy Bain, former bassist of Dio died of lung cancer aboard the ship the same night, causing Last in Line to cancel their show the following day.[85] Back on land, Elliott struggled through the first concert of the 2016 tour, resulting in Tesla's Jeff Keith joining Elliott on lead. The following day's concert was also postponed "due to illness", with Rick Allen reporting on Twitter "The Doctor basically said that if Joe continues to sing without resting his throat for a month he might do permanent damage.."[86] By July, the band were performing regularly again and intended to complete 48 dates.[87] When the tour stopped at DTE Energy Music Theatre in Clarkston, Michigan on 15 July, the show was recorded for future release. On 10 February 2017, the band released And There Will be a Next Time... Live from Detroit, a double live album and concert video.[88]

text: In August 2017 the band celebrated the 30th anniversary of Hysteria by releasing a collectors edition box. The singles were also re-released on vinyl.[89]

text: Musical style and legacy[edit]

text: Def Leppard's music is a mixture of hard rock, AOR, pop and heavy metal elements, with its multi-layered, harmonic vocals and its melodic guitar riffs. However, even though they were often considered one of the top bands of the new wave of British heavy metal movement of the late 1970s, in the mid-1980s the band were associated with the growing glam metal scene, mainly due to their mainstream success and glossy production.[91] Pyromania has been cited as the catalyst for the 1980s pop-metal movement.[26] Def Leppard, however, expressed their dislike of the "glam metal" label, as they thought it did not accurately describe their look or musical style.[92] By the release of the Hysteria album, the band had developed a distinctive sound featuring electronic drums and effects-laden guitar sounds overlaid with a multi-layered wall of husky, harmonised vocals. Def Leppard has been cited as an influence by a wide range of musical acts, from heavy metal and thrash metal bands such as Slayer,[93] Pantera,[94] and Metallica[95] as part of the new wave of British heavy metal movement as well as by popular contemporary artists Matt Nathanson[96] and Taylor Swift.[97]

text: With Pyromania and Hysteria both certified Diamond by the RIAA, Def Leppard are one of only five rock bands with two original studio albums selling over 10 million copies each in the US,[11] alongside the Beatles, Led Zeppelin, Pink Floyd and Van Halen.[11] Both Pyromania and Hysteria feature in Rolling Stone magazine's list of the 500 Greatest Albums of All Time.[6][28]

text: Def Leppard was among the most successful of the new wave of British heavy metal bands in the early 1980s. They combined the raw power of metal with a pop emphasis on melody, catchy hooks and vocal harmonies that, particularly later on, contrasted sharply with harsher contemporary metal and punk bands.[98] Their early albums such as On Through the Night (1980) appealed to metal fans and influenced the likes of Dimebag Darrell of Pantera[94] and Jeff Hanneman of Slayer.[93] Their hugely popular later albums, such as Hysteria (1987), appeared irregular due to their perfectionism in the studio, but appealed to a broad range of music fans.[98]

text: Despite their huge commercial success, Elliott has said in an interview that he feels the band does not receive its fair share of respect from the British music press and he claimed the band had been barred from the BBC's Later with Jools Holland series because they were "not cool enough".[99]

text: Band members[edit]

text:
Current members

Joe Elliott – lead vocals, occasional rhythm guitar (1977–present)
Rick Savage – bass, backing vocals (1977–present)
Rick Allen – drums, backing vocals (1978–present)
Phil Collen – lead and rhythm guitar, backing vocals (1982–present)
Vivian Campbell – rhythm and lead guitar, backing vocals (1992–present)

Former members

Tony Kenning – drums (1977–1978)
Pete Willis – rhythm and lead guitar, backing vocals (1977–1982)
Steve Clark – lead and rhythm guitar, backing vocals (1978–1991; died 1991)

tag: table

text: Side projects[edit]

text: Phil Collen played guitar, uncredited, on Sam Kinison's "Wild Thing" from 1988. The video featured members of bands such as Poison, Bon Jovi, Mötley Crüe, Guns N' Roses, Ratt, and Aerosmith. Collen also produced and played on the 1991 album On The Edge from Australian band BB Steal.

text: Joe Elliott sang lead vocals on two tracks on Rolling Stones guitarist Ronnie Wood's 1992 solo album, Slide on This. His then-wife Karla appeared in the videos for "Always Wanted More" and "Somebody Else Might". Various members of Def Leppard have played on tribute records for Jeff Beck, AC/DC and Alice Cooper.

text: A fan of his local football club Sheffield United F.C., Elliott performed on two tracks to the soundtrack of the 1996 Sheffield-set motion picture, When Saturday Comes (featuring fellow Sheffield native Sean Bean as a star football player), the title track and an instrumental, "Jimmy's Theme".[100] Elliott sang and co-wrote the opening track, "Don't Look Down" on Mick Ronson's farewell album Heaven and Hull. A promotional video was issued for the song as well.

text: Cybernauts was a side project consisting of Elliott and Collen teamed with members of The Spiders From Mars (David Bowie's former band), minus the late Mick Ronson. The group played several shows, covering Bowie's Ziggy Stardust-era songs and released one internet only album (since deleted).

text: Vivian Campbell has played with two side bands in recent years, Clock and the Riverdogs, and recorded a solo album, Two Sides of If, released in 2005. Campbell toured with Thin Lizzy in early 2011 before joining Def Leppard on their latest tour.

text: Collen sings lead vocals and plays guitar in a side band called Man Raze with Sex Pistols drummer Paul Cook and former Girl bandmate Simon Laffy. They released their debut album Surreal in 2008 and a second album, PunkFunkRootsRock, in 2008.

text: Joe Elliott founded and fronts the band Down 'n' Outz with members of The Quireboys. The band plays covers of Mott the Hoople and related artists such as British Lions and Ian Hunter. They have released two studio albums of covers and one live album since their incarnation in 2009.

text: Following the death of Ronnie James Dio, Vivian Campbell reunited with the rest of the original Dio lineup with vocalist Andrew Freeman to form Last in Line. The band pays tribute to Dio by playing songs from their original tenure in the band and will also be releasing a studio album of original material in 2016.

text: Joe Elliott, along with various other musicians including Glenn Hughes, Duff McKagan, Sebastian Bach, Matt Sorum, Gilby Clarke and Steve Stevens formed a supergroup called Kings of Chaos, whose catalogue consists of songs by Deep Purple, Def Leppard, Guns N' Roses and others. In 2012, Kings of Chaos recorded their version of Deep Purple's classic, "Never Before" featuring Elliott singing lead vocals. Kings of Chaos played Stone Fest in Australia along with a few dates in South America in 2013.

text: Phil Collen formed a blues project by the name of Delta Deep with vocalist Debbi Blackwell Cook which released an eponymous debut in 2015.[101]

text: Awards and nominations[edit]

text: Discography[edit]

text:
On Through the Night (1980)
High 'n' Dry (1981)
Pyromania (1983)
Hysteria (1987)
Adrenalize (1992)
Slang (1996)
Euphoria (1999)
X (2002)
Yeah! (2006)
Songs from the Sparkle Lounge (2008)
Def Leppard (2015)

tag: ul


document_title: Pro Football Hall of Fame Game

question_text: when do the dallas cowboys play the hall of fame game

text: Pro Football Hall of Fame Game

text: Team selection[edit]

text: The two teams that play in the Pro Football Hall of Fame Game are typically selected by the league in advance of the remainder of the preseason schedule. The participants are usually announced around the time that the new Hall of Fame members are announced, which coincides with Super Bowl week. Often if a particularly notable player will be entering the Hall of Fame that year a team they were strongly associated with may be selected to play in the game to help maximize attendance and publicity of the game itself. Since 1971, the opponents for each game have traditionally included one AFC team and one NFC team. In 2009, as recognition of the 50th anniversary of the American Football League, the game paired two AFC teams who were part of the "original eight" franchises of the AFL, the Tennessee Titans (dressed as their previous incarnation, the Houston Oilers) and the Buffalo Bills, whose owner, Ralph Wilson, was inducted into the Hall that year. An all-NFC matchup was scheduled for 2011,[1] but it was canceled due to the 2011 NFL lockout; the following year, another intra-conference matchup of two NFC teams took its place. Since 2012, both competing teams in the game has had at least one prominent alumnus being inducted into the Hall that year.

text: Because this game and the Hall of Fame's induction ceremonies are scheduled on the weekend before the league's regular four-week exhibition season begins, both teams end up playing five exhibition games instead of the normal four, and unlike the Canadian Football League, the league does not remove an exhibition game from another week.

text: Expansion clubs[edit]

text: The last four expansion teams to have been added to the league each played in the Hall of Fame Game as their first game. In 1995, expansion clubs Jacksonville and Carolina played one another, and in 2002, Houston was one of the participants. When the Cleveland Browns returned to the league with a rebooted roster in 1999, they too played in the Hall of Fame Game. (The Baltimore Ravens, while officially considered as being established in 1996, did not play in the Hall of Fame Game that year, nor have they played at any time in their existence.)

text: Scheduling[edit]

text: Prior to the AFL-NFL merger, the Hall of Fame Game was played in August or September, in some cases at the end of the preseason. In 1970, it was moved to the beginning of the preseason. Prior to 2002, it was not uncommon for the game to be played in July. Since 2002, when the league permanently moved the start of the season to the weekend after Labor Day, the game has always been played in early August.

text: The 2011 game was originally scheduled between the St. Louis Rams and the Chicago Bears, but the game was canceled due to an ongoing labor dispute that had disrupted nearly all league activity during the 2011 offseason. The two clubs had set a deadline of July 22 to ratify a resolution in enough time to prepare for the game. The league and players did not ratify the agreement until July 25, forcing cancellation of the game.

text: The 2016 edition, which was scheduled to be played between the Green Bay Packers and the Indianapolis Colts, was canceled due to unsafe playing conditions. Mike Silver of NFL.com reported that on the morning of game day, the logos at midfield and the end zones had been painted using paint which was not intended for use on artificial turf. When it was apparent the paint wasn't drying fast enough, the field was heated to speed up the drying process, but this caused the turf's rubber to melt. These issues led to unfavorable play conditions. The affected areas were described as being slick and "like cement," making it impossible to get decent footing. Stadium officials attempted to address this by applying a solvent, reportedly paint thinner, to the turf. A Packers employee noticed a label warning that this substance could result in burns when exposed to skin, and alerted others to the discovery. When officially cancelling the game, both the league and the Players Association cited safety concerns.[2][3][4]

text: Both teams were told at 6:40 p.m.--an hour and 20 minutes before kickoff--that the game was going to be canceled. However, fans in the stadium only learned of the pending cancellation via social media. No official announcement was made until just before the scheduled 8 p.m. kickoff.[5]

text: On December 28, 2016, the NFL announced that the 2017 edition of the game would be played on Thursday, August 3, 2017. The scheduling change makes the Hall of Fame Game the first event of the Hall of Fame Weekend. On February 23, 2017, it was announced the 2017 edition will be played between the Dallas Cowboys and the Arizona Cardinals.[6]

text: Television and radio[edit]

text: Unlike the majority of NFL preseason games, which air on local networks, the Hall of Fame Game airs nationwide. From 1999 to 2005, the game was held on Monday night, televised as part of ABC's Monday Night Football package. It had previously been held typically on Saturday afternoons, except from 1963 to 1965 on Sunday afternoons, televised as part of ABC's Wide World of Sports package (still using the MNF crew). In 1998, the game was put in the MNF package, and played on a Saturday night, which served as a test run for the move to Monday night. Starting in 2006, it was moved to Sunday night, coinciding with the new NBC Sunday Night Football[7] television package. The 2007 game was telecast on NFL Network as NBC was intending to televise the China Bowl game in Beijing, China (a game which was postponed to 2009 and later canceled). The Hall of Fame Game has since bounced between both networks. The 2012 game aired on NFL Network due to NBC's coverage of the Summer Olympics. After a two-year absence, the game returned to NBC in 2013 and remained on the network until 2015. The 2016 game was scheduled to air on ESPN as it was to be played two days into the 2016 Summer Olympics but the game was canceled due to field conditions, it returned to NBC in 2017 and will remain on the network until 2019.

text: Westwood One owns national radio rights; it is the only preseason game to air on a nationwide network. Each team's radio network is also allowed to broadcast the games (albeit usually with fewer affiliates since exhibition games are traditionally much lower priority to non-sports and non-flagship stations).

text: In 2007 and 2008, the game was broadcast live in both Ireland and the United Kingdom by Sky Sports. It was not shown in 2009 because of a dispute between Sky Sports and the NFL over TV rights. ESPN America (formerly North American Sports Network) broadcasts the game in the rest of Europe.

text: From 1998 to 2005, the Global Television Network aired the game in Canada, simulcasting ABC; upon the move to Sunday night in 2006, the CTV Television Network aired the game until 2010. With CTV airing the 2012 Summer Olympics, TSN broadcast the Hall of Fame Game in 2012. Azteca 7 aired Spanish-language coverage of the Hall of Fame Game in Mexico from 1998 to 2005; the Game moved to Canal 5 in 2006 and aired on that station until 2010. Due to the cancellation of the 2011 Hall of Fame Game and Televisa's Summer Olympics coverage, the Hall of Fame Game moved to Televisa Deportes in 2012 and then to Galavision in 2013.

text: Tom Benson Hall of Fame Stadium is part of the Cleveland market, and is also within 75 miles of numerous other television markets in northeast Ohio and western Pennsylvania. As such, the NBC affiliates (and before them, the ABC affiliates) are within league requirements to blackout the game in the rare event the game does not sell out. Because the stadium only holds 22,375 fans (less than half the NFL's minimum requirements for its stadiums) and the Hall of Fame induction ceremonies bring large numbers of outside fans to Canton, the game has, to date, always sold out (several NFL teams, as well as the Super Bowl, have similarly enjoyed long sellout streaks).

text: Game history[edit]

text:
Date
Away team
Away score
Home team
Home score
Recap

August 11, 1962
New York Giants
21
St. Louis Cardinals
21
Recap

September 8, 1963
Cleveland Browns
7
Pittsburgh Steelers
16
Recap

September 6, 1964
Baltimore Colts
48
Pittsburgh Steelers
17
Recap

September 12, 1965
Detroit Lions
3
Washington Redskins
20
Recap

August 5, 1967
Cleveland Browns
13
Philadelphia Eagles
28
Recap

August 3, 1968
Dallas Cowboys
24
Chicago Bears
30
Recap

September 13, 1969
Green Bay Packers
38
Atlanta Falcons
24
Recap

August 8, 1970
New Orleans Saints
14
Minnesota Vikings
13
Recap

July 31, 1971
Houston Oilers
6
Los Angeles Rams
17
Recap

July 29, 1972
Kansas City Chiefs
23
New York Giants
17
Recap

July 28, 1973
San Francisco 49ers
20
New England Patriots
7
Recap

July 27, 1974
Buffalo Bills
13
St. Louis Cardinals
21
Recap

August 2, 1975
Washington Redskins
17
Cincinnati Bengals
9
Recap

July 24, 1976
Denver Broncos
10
Detroit Lions
7
Recap

July 30, 1977
Chicago Bears
20
New York Jets
6
Recap

July 29, 1978
Miami Dolphins
3
Philadelphia Eagles
17
Recap

July 28, 1979
Dallas Cowboys
13
Oakland Raiders
20
Recap

August 2, 1980
San Diego Chargers
0
Green Bay Packers
0
Recap [A]

August 1, 1981
Atlanta Falcons
10
Cleveland Browns
24
Recap

August 7, 1982
Baltimore Colts
14
Minnesota Vikings
30
Recap

July 30, 1983
New Orleans Saints
14
Pittsburgh Steelers
27
Recap

July 28, 1984
Seattle Seahawks
38
Tampa Bay Buccaneers
0
Recap

August 3, 1985
New York Giants
21
Houston Oilers
20
Recap

August 2, 1986
New England Patriots
21
St. Louis Cardinals
16
Recap

August 8, 1987
San Francisco 49ers
20
Kansas City Chiefs
7
Recap

July 30, 1988
Cincinnati Bengals
14
Los Angeles Rams
7
Recap

August 5, 1989
Washington Redskins
31
Buffalo Bills
6
Recap

August 4, 1990
Cleveland Browns
0
Chicago Bears
13
Recap

July 27, 1991
Detroit Lions
14
Denver Broncos
3
Recap

August 1, 1992
New York Jets
41
Philadelphia Eagles
14
Recap

July 31, 1993
Green Bay Packers
3
Los Angeles Raiders
19
Recap

July 30, 1994
San Diego Chargers
17
Atlanta Falcons
21
Recap

July 29, 1995
Carolina Panthers
20
Jacksonville Jaguars
14
Recap

July 27, 1996
Indianapolis Colts
10
New Orleans Saints
3
Recap

July 26, 1997
Minnesota Vikings
28
Seattle Seahawks
26
Recap

August 1, 1998
Pittsburgh Steelers
6
Tampa Bay Buccaneers
30
Recap

August 9, 1999
Dallas Cowboys
17
Cleveland Browns
20
Recap

July 31, 2000
New England Patriots
20
San Francisco 49ers
0
Recap

August 6, 2001
St. Louis Rams
17
Miami Dolphins
10
Recap

August 5, 2002
Houston Texans
17
New York Giants
34
Recap

August 4, 2003
Kansas City Chiefs
9
Green Bay Packers
0
Recap[B]

August 9, 2004
Denver Broncos
17
Washington Redskins
20
Recap

August 8, 2005
Chicago Bears
27
Miami Dolphins
24
Recap

August 6, 2006
Oakland Raiders
16
Philadelphia Eagles
10
Recap

August 5, 2007
New Orleans Saints
7
Pittsburgh Steelers
20
Recap

August 3, 2008
Indianapolis Colts
16
Washington Redskins
30
Recap

August 9, 2009
Buffalo Bills
18
Tennessee Titans
21
Recap

August 8, 2010
Dallas Cowboys
16
Cincinnati Bengals
7
Recap

August 7, 2011
Canceled due to 2011 NFL lockout
Ref.

August 5, 2012
Arizona Cardinals
10
New Orleans Saints
17
Recap

August 4, 2013
Miami Dolphins
20
Dallas Cowboys
24
Recap

August 3, 2014
New York Giants
17
Buffalo Bills
13
Recap

August 9, 2015
Pittsburgh Steelers
3
Minnesota Vikings
14
Recap

August 7, 2016
Canceled due to poor field conditions
Ref.

August 3, 2017
Dallas Cowboys
20
Arizona Cardinals
18
Recap

August 5, 2018
TBA

TBA

text: Standings[edit]

text:
Team
W
L
T
PCT
Last appearance

Washington Redskins
5
0
0
1.000
2008

Chicago Bears
4
0
0
1.000
2005

Oakland/Los Angeles Raiders
3
0
0
1.000
2006

Carolina Panthers
1
0
0
1.000
1995

Minnesota Vikings
3
1
0
.750
2015

Pittsburgh Steelers
3
3
0
.500
2015

New England Patriots
2
1
0
.667
2000

San Francisco 49ers
2
1
0
.667
2000

Los Angeles/St. Louis Rams
2
1
0
.667
2001

Kansas City Chiefs
2
1
0
.667
2003

New York Giants
3
1
1
.625
2014

Dallas Cowboys
3
3
0
.500
2017

Indianapolis/Baltimore Colts
2
2
0
.500
2008

Philadelphia Eagles
2
2
0
.500
2006

New York Jets
1
1
0
.500
1992

Seattle Seahawks
1
1
0
.500
1997

Tampa Bay Buccaneers
1
1
0
.500
1998

Cleveland Browns
2
3
0
.400
1999

New Orleans Saints
2
3
0
.400
2012

Green Bay Packers
1
2
1
.375
2003

Cincinnati Bengals
1
2
0
.333
2010

Atlanta Falcons
1
2
0
.333
1994

Denver Broncos
1
2
0
.333
2004

Detroit Lions
1
2
0
.333
1991

Tennessee Titans/Houston Oilers
1
2
0
.333
2009

Arizona/St. Louis Cardinals
1
3
1
.300
2017

Los Angeles/San Diego Chargers
0
1
1
.250
1994

Baltimore Ravens
0
0
0
–
N/A

Houston Texans
0
1
0
.000
2002

Jacksonville Jaguars
0
1
0
.000
1995

Buffalo Bills
0
4
0
.000
2014

Miami Dolphins
0
4
0
.000
2013

text: Most appearances – 6: Pittsburgh Steelers (1963, 1964, 1983, 1998, 2007, and 2015) and Dallas Cowboys (1968, 1979, 1999, 2010, 2013, and 2017)

text: Most wins – 5: Washington Redskins (1965, 1975, 1989, 2004, and 2008)

text: Longest active drought without Hall of Fame Game appearance – 26 seasons: Detroit Lions (last appearance – 1991); 25 seasons: New York Jets (last appearance – 1992); 23 seasons: Atlanta Falcons and Los Angeles Chargers (last appearance – 1994); 22 seasons: Carolina Panthers and Jacksonville Jaguars (last appearance – 1995)

text: Active teams to have never made a Hall of Fame Game appearance – Baltimore Ravens

text: Notes[edit]

text:
Jump up ^ Game ended with 5:29 remaining in the fourth quarter due to severe lightning.
Jump up ^ Game ended with 5:49 remaining in the third quarter due to severe lightning.

tag: ol


document_title: Lung

question_text: where is the lungs located in our body

question_tokens: where is the lungs located in our body

text: Lung

text: Structure of the human lungs[edit]

text: Gross anatomy[edit]

text: The lungs are located in the chest on either side of the heart in the rib cage. They are conical in shape with a narrow rounded apex at the top, and a broad concave base that rests on the convex surface of the diaphragm.[1] The apex of the lung extends into the root of the neck, reaching shortly above the level of the sternal end of the first rib. The lungs stretch from close to the backbone in the rib cage to the front of the chest and downwards from the lower part of the trachea to the diaphragm.[1] The left lung shares space with the heart, and has an indentation in its border called the cardiac notch of the left lung to accommodate this.[2][3] The front and outer sides of the lungs face the ribs, which make light indentations on their surfaces. The medial surfaces of the lungs face towards the centre of the chest, and lie against the heart, great vessels, and the carina where the trachea divides into the two main bronchi.[3] The cardiac impression is an indentation formed on the surfaces of the lungs where they rest against the heart.

text: Both lungs have a central recession called the hilum at the root of the lung, where the blood vessels and airways pass into the lungs.[1] There are also bronchopulmonary lymph nodes on the hilum.[3]

text: The lungs are surrounded by the pulmonary pleurae. The pleurae are two serous membranes; the outer parietal pleura lines the inner wall of the rib cage and the inner visceral pleura directly lines the surface of the lungs. Between the pleurae is a potential space called the pleural cavity containing a thin layer of lubricating pleural fluid. Each lung is divided into lobes by the infoldings of the pleura as fissures. The fissures are double folds of pleura that section the lungs and help in their expansion.[4]

text:
Lobes and bronchopulmonary segments [5]

Right lung
Left lung

Upper

Apical
Anterior
Posterior

Middle

Medial
Lateral

Lower

Superior
Anterior
Posterior
Medial
Lateral

Upper

Anterior
Apicoposterior

Lower

Superior
Anterior
Posterior
Medial
Lateral

Lingula

Superior
Inferior

text: The main or primary bronchi enter the lungs at the hilum and initially branch into secondary bronchi also known as lobar bronchi that supply air to each lobe of the lung. The lobar bronchi branch into tertiary bronchi also known as segmental bronchi and these supply air to the further divisions of the lobes known as bronchopulmonary segments. Each bronchopulmonary segment has its own (segmental) bronchus and arterial supply.[6] Segments for the left and right lung are shown in the table.[5] The segmental anatomy is useful clinically for localising disease processes in the lungs.[5] A segment is a discrete unit that can be surgically removed without seriously affecting surrounding tissue.[7]

text: Right lung[edit]

text: The right lung has both more lobes and segments than the left. It is divided into three lobes, an upper, middle, and a lower, by two fissures, one oblique and one horizontal. The upper, horizontal fissure, separates the upper from the middle lobe. It begins in the lower oblique fissure near the posterior border of the lung, and, running horizontally forward, cuts the anterior border on a level with the sternal end of the fourth costal cartilage; on the mediastinal surface it may be traced backward to the hilum.[1]

text: The lower, oblique fissure, separates the lower from the middle and upper lobes, and is closely aligned with the oblique fissure in the left lung.[1][4]

text: The mediastinal surface of the right lung is indented by a number of nearby structures. The heart sits in an impression called the cardiac impression. Above the hilum of the lung is an arched groove for the azygos vein, and above this is a wide groove for the superior vena cava and right brachiocephalic vein; behind this, and close to the top of the lung is a groove for the brachiocephalic artery. There is a groove for the esophagus behind the hilum and the pulmonary ligament, and near the lower part of the esophageal groove is a deeper groove for the inferior vena cava before it enters the heart.[3]

text: Left lung[edit]

text: The left lung is divided into two lobes, an upper and a lower, by the oblique fissure, which extends from the costal to the mediastinal surface of the lung both above and below the hilum.[1] The left lung, unlike the right, does not have a middle lobe, though it does have a homologous feature, a projection of the upper lobe termed the "lingula". Its name means "little tongue". The lingula on the left serves as an anatomic parallel to the right middle lobe, with both areas being predisposed to similar infections and anatomic complications.[8][9] There are two bronchopulmonary segments of the lingula: superior and inferior.[1]

text: The mediastinal surface of the left lung has a large cardiac impression where the heart sits. This is deeper and larger than that on the right lung, at which level the heart projects to the left.[3]

text: On the same surface, immediately above the hilum, is a well-marked curved groove for the aortic arch, and a groove below it for the descending aorta. The left subclavian artery, a branch off the aortic arch, sits in a groove from the arch to near the apex of the lung. A shallower groove in front of the artery and near the edge of the lung, lodges the left brachiocephalic vein. The esophagus may sit in a wider shallow impression at the base of the lung.[3]

text: Microanatomy[edit]

text: The lungs are part of the lower respiratory tract, and accommodate the bronchial airways when they branch from the trachea. The lungs include the bronchial airways that terminate in alveoli, the lung tissue in between, and veins, arteries, nerves and lymphatic vessels.[3][10] The trachea and bronchi have plexuses of lymph capillaries in their mucosa and submucosa. The smaller bronchi have a single layer and they are absent in the alveoli.[11]

text: All of the lower respiratory tract including the trachea, bronchi, and bronchioles is lined with respiratory epithelium. This is a ciliated epithelium interspersed with goblet cells which produce mucus, and club cells with actions similar to macrophages. Incomplete rings of cartilage in the trachea and smaller plates of cartilage in the bronchi, keep these airways open.[12] Bronchioles are too narrow to support cartilage and their walls are of smooth muscle, and this is largely absent in the narrower respiratory bronchioles which are mainly just of epithelium.[12] The respiratory tract ends in lobules. Each lobule consists of a respiratory bronchiole, which branches into alveolar ducts and alveolar sacs, which in turn divide into alveoli.[3]

text: The epithelial cells throughout the respiratory tract secrete epithelial lining fluid (ELF), the composition of which is tightly regulated and determines how well mucociliary clearance works.[13][14]:Section 4 pages 7–8 (Page 4–7ff)

text: Alveoli consist of two types of alveolar cell and an alveolar macrophage. The two types of cell are known as type I and type II alveolar cells[15] (also known as pneumocytes).[3] Types I and II make up the walls and alveolar septa. Type I cells provide 95% of the surface area of each alveoli and are flat ("squamous"), and Type II cells generally cluster in the corners of the alveoli and have a cuboidal shape.[16] Despite this, cells occur in a roughly equal ratio of 1:1 or 6:4.[15][16]

text: Type I are squamous epithelial cells that make up the alveolar wall structure. They have extremely thin walls that enable an easy gas exchange.[15] These type I cells also make up the alveolar septa which separate each alveolus. The septa consist of an epithelial lining and associated basement membranes.[16] Type I cells are not able to divide, and consequently rely on differentiation from Type II cells.[16]

text: Type II are larger and they line the alveoli and produce and secrete epithelial lining fluid, and lung surfactant.[15] Type II cells are able to divide and differentiate to Type 1 cells.[16]

text: The alveolar macrophages have an important immunological role. They remove substances which deposit in the alveoli including loose red blood cells that have been forced out from blood vesels.[16]

text: The lung is surrounded by a serous membrane of visceral pleura, which has an underlying layer of loose connective tissue attached to the substance of the lung.[17]

text: Respiratory tract[edit]

text: The lower respiratory tract is part of the respiratory system, and consists of the trachea and the structures below this including the lungs.[15] The trachea receives air from the pharynx and travels down to a place where it splits (the carina) into a right and left bronchus. These supply air to the right and left lungs, splitting progressively into the secondary and tertiary bronchi for the lobes of the lungs, and into smaller and smaller bronchioles until they become the respiratory bronchioles. These in turn supply air through alveolar ducts into the alveoli, where the exchange of gases take place.[15] Oxygen breathed in, diffuses through the walls of the alveoli into the enveloping capillaries and into the circulation,[18] and carbon dioxide diffuses from the blood into the lungs to be breathed out.

text: Estimates of the total surface area of lungs vary from 50 to 75 square metres (540 to 810 sq ft);[15][16] roughly the same area as one side of a tennis court.[16][19]

text: The bronchi in the conducting zone are reinforced with hyaline cartilage in order to hold open the airways. The bronchioles have no cartilage and are surrounded instead by smooth muscle.[16] Air is warmed to 37 °C (99 °F), humidified and cleansed by the conducting zone; particles from the air being removed by the cilia on the respiratory epithelium lining the passageways.[20]

text: Blood supply[edit]

text: The lungs have a dual blood supply[15] provided by a bronchial and a pulmonary circulation. The bronchial circulation supplies oxygenated blood to the airways of the lungs, through the bronchial arteries that leave the aorta. There are usually three arteries, two to the left lung and one to the right, and they branch alongside the bronchi and bronchioles.[15] The pulmonary circulation carries deoxygenated blood from the heart to the lungs and returns the oxygenated blood to the heart to supply the rest of the body.[15]

text: The blood volume of the lungs, is about 450 millilitres on average, about 9 per cent of the total blood volume of the entire circulatory system. This quantity can easily fluctuate from between one-half and twice the normal volume.[21]

text: Nerve supply[edit]

text: The lungs are supplied by nerves of the autonomic nervous system. Input from the parasympathetic nervous system occurs via the vagus nerve. When stimulated by acetylcholine, this causes constriction of the smooth muscle lining the bronchus and bronchioles, and increases the secretions from glands.[22] The lungs also have a sympathetic tone from norepinephrine acting on the beta 2 receptors in the respiratory tract, which causes bronchodilation.[22]

text: The action of breathing takes place because of nerve signals sent by the respiratory centres in the brainstem, along the phrenic nerve to the diaphragm.[23]

text: Development[edit]

text: The development of the human lungs arise from the laryngotracheal groove and develop to maturity over several weeks in the foetus and for several years following birth.[24]

text: The larynx, trachea, bronchi and lungs that make up the respiratory tract, begin to form during the fourth week of embryogenesis[25] from the lung bud which appears ventrally to the caudal portion of the foregut.[26]

text: The respiratory tract has a branching structure like that of a tree.[27] In the embryo this structure is developed in the process of branching morphogenesis, and is generated by the repeated splitting of the tip of the branch. In the development of the lungs (as in some other organs) the epithelium forms branching tubes.The lung has a left-right symmetry and each bud known as a bronchial bud grows out as a tubular epithelium that becomes a bronchus. Each bronchus branches into bronchioles.[28] The branching is a result of the tip of each tube bifurcating.[27] The branching process forms the bronchi, bronchioles, and ultimately the alveoli.[27] The four genes mostly associated with branching morphogenesis in the lung are the intercellular signalling protein – sonic hedgehog (SHH), fibroblast growth factors FGF10 and FGFR2b, and bone morphogenetic protein BMP4. FGF10 is seen to have the most prominent role. FGF10 is a paracrine signalling molecule needed for epithelial branching, and SHH inhibits FGF10.[27][28] The development of the alveoli is influenced by a different mechanism whereby continued bifurcation is stopped and the distal tips become dilated to form the alveoli.

text: At the end of the fourth week the lung bud divides into two, the right and left primary bronchial buds on each side of the trachea.[29][30] During the fifth week the right bud branches into three secondary bronchial buds and the left branches into two secondary bronchial buds. These give rise to the lobes of the lungs, three on the right and two on the left. Over the following week, the secondary buds branch into tertiary buds, about ten on each side.[30] From the sixth week to the sixteenth week, the major elements of the lungs appear except the alveoli.[31] From week 16 to week 26, the bronchi enlarge and lung tissue becomes highly vascularised. Bronchioles and alveolar ducts also develop. By week 26 the terminal bronchioles have formed which branch into two respiratory bronchioles.[32] During the period covering the 26th week until birth the important blood–air barrier is established. Specialised type I alveolar cells where gas exchange will take place, together with the type II alveolar cells that secrete pulmonary surfactant, appear. The surfactant reduces the surface tension at the air-alveolar surface which allows expansion of the alveolar sacs. The alveolar sacs contain the primitive alveoli that form at the end of the alveolar ducts,[33] and their appearance around the seventh month marks the point at which limited respiration would be possible, and the premature baby could survive.[24]

text: After birth[edit]

text: At birth, the baby's lungs are filled with fluid secreted by the lungs and are not inflated. After birth the infant's central nervous system reacts to the sudden change in temperature and environment. This triggers the first breath, within about 10 seconds after delivery.[34] Before birth, the lungs are filled with fetal lung fluid.[35] After the first breath, the fluid is quickly absorbed into the body or exhaled. The resistance in the lung's blood vessels decreases giving an increased surface area for gas exchange, and the lungs begins to breathe spontaneously. This accompanies other changes which result in an increased amount of blood entering the lung tissues.[34]

text: At birth the lungs are very undeveloped with only around one sixth of the alveoli of the adult lung present.[24] The alveoli continue to form into early adulthood, and their ability to form when necessary is seen in the regeneration of the lung.[36][37] Alveolar septa have a double capillary network instead of the single network of the developed lung. Only after the maturation of the capillary network can the lung enter a normal phase of growth. Following the early growth in numbers of alveoli there is another stage of the alveoli being enlarged.[38]

text: Function[edit]

text: Breathing[edit]

text: The lungs are not capable of expanding themselves, and will only do so when there is an increase in the volume of the thoracic cavity.[39] This is achieved by the muscles of respiration, through the contraction of the diaphragm, and the intercostal muscles which pull the rib cage upwards as shown in the diagram.[40] During breathing out, at rest, the muscles of inhalation relax, returning the chest and abdomen to a resting position determined by their anatomical elasticity.[40] At this point the lungs contain the functional residual capacity (FRC) of air, which, in the adult human, has a volume of about 2.5–3.0 litres.[40]

text: During heavy breathing as, for instance, during exercise, a large number of accessory muscles in the neck and abdomen are recruited.[40] Exhalation, instead of being passive, is now caused by the rib cage being actively pulled downwards at the front and sides by the abdominal muscles. This has the effect of decreasing the size of the rib cage, and of pushing the abdominal organs up against the diaphragm which bulges into the thorax. The lung volume of air at the end of exhalation is now less than the resting FRC.[40] However, the lungs cannot be emptied completely and in an adult human there is always still at least one litre of residual air left in the lungs after maximum exhalation.[40] The FRC always remains in the alveoli after a normal out-breath.[40] With each breath only about 350 ml (i.e. less than 15%) of this alveolar air is expelled into the ambient air (with about 150 ml remaining behind in the airways, as "dead space" ventilation, as it is the first air to re-enter the alveoli on inhalation).[40] This is immediately replaced with the same volume of fresh, but moistened, atmospheric air. It is therefore obvious that the 350 ml inhaled fresh air is highly diluted by the 3 litres of functional residual capacity air (i.e. the air that remains in the lungs after a normal exhalation), and that the composition of the alveolar air therefore changes very little under normal circumstances: the alveolar partial pressure of oxygen remains very close to 14 kPa ( 105 mmHg ), and that of carbon dioxide varies minimally around 5.3 kPa ( 40 mmHg ) throughout the respiratory cycle (of inhalation and exhalation).[40]

text: Gas exchange[edit]

text: The major function of the lungs is gas exchange between the lungs and the blood.[41] The alveolar and pulmonary capillary gases equilibrate across the blood–air barrier, a very thin diffusion membrane which is only, on average, about 2 μm thick,[42] consisting of the walls of the pulmonary alveoli, consisting of the alveolar epithelial cells, their basement membranes and the endothelial cells of the pulmonary capillaries.[40][42][43] This membrane is folded into about 300 million small air sacs called alveoli[42] (each between 75 and 300 µm in diameter) branching off from the bronchioles in the lungs, thus providing an extremely large surface area (estimates varying between 70 and 145 m2) for gas exchange to occur.[40][42]

text: Since the blood gases in the alveolar capillaries equilibrate with those in the alveolar air, the arterial blood that is spread evenly throughout the body by the left ventricle, will have the same partial pressures of oxygen and carbon dioxide as persist in the alveoli.[40]

text: Control of breathing[edit]

text: The arterial partial pressures of oxygen and carbon dioxide in the arterial blood are homeostatically controlled. A rise in the arterial partial pressure of carbon dioxide, and, to a lesser extent, a fall in the arterial partial pressure of oxygen, will reflexly cause deeper and faster breathing till the blood gas tensions return to normal.[40] The converse happens when the carbon dioxide tension falls, or, again to a lesser extent, the oxygen tension rises: the rate and depth of breathing are reduced till blood gas normality is restored.[40]

text: It is only as a result of accurately maintaining the composition of the 3 litres alveolar air that, with each breath, some carbon dioxide is discharged into the atmosphere and some oxygen is taken up from the outside air. If more carbon dioxide than usual has been lost by a short period of hyperventilation, breathing will be slowed down or halted until the alveolar partial pressure of carbon dioxide has returned to 5.3 kPa ( 40 mmHg ).[40] The opposite occurs after breath-holding.

text: The partial pressures of oxygen and carbon dioxide in the arterial blood are measured by the peripheral chemoreceptors – the aortic and carotid bodies, and the central chemoreceptors of the medulla oblongata of the brainstem. The peripheral chemoreceptors are more sensitive to the arterial partial pressure of oxygen than they are to the arterial partial pressure of carbon dioxide.[40] The central chemoreceptor is particularly sensitive to the pH of the cerebrospinal fluid, which is directly influenced by the partial pressure of carbon dioxide in the arterial blood.[40][44]

text: Information from the peripheral chemoreceptors is relayed to a series of interconnected nuclei which comprise the respiratory centres in the medulla oblongata and the pons of the brainstem.[40] This information determines the average rate of ventilation of the alveoli of the lungs, to keep the partial pressures of oxygen and carbon dioxide in the arterial blood constant. The respiratory centre does so via motor neurons which activate the muscles of respiration (in particular the diaphragm).[23]

text: Exercise also increases the respiratory rate, partly in response to the movement of the limbs detected by proprioceptors in the muscles and joints, an increase in body temperature, the release of adrenaline (epinephrine) from the adrenal glands, and from motor impulses originating from the cerebral cortex.[45]

text: Protection[edit]

text: The lungs possess several characteristics which protect against infection. The lung tract is lined by epithelia with hair-like projections called cilia that beat rhythmically and carry mucus. This mucociliary clearance is an important defence system against air-borne infection. The dust particles and bacteria in the inhaled air are caught in the mucosal surface of respiratory passages and are moved up towards the pharynx by the rhythmic upward beating action of the cilia.[16][46][47] The lining of the lung also secretes immunoglobulin A which protects against respiratory infections;[46] goblet cells secrete mucus[16] which also contains several antimicrobial compounds such as defensins, antiproteases, and antioxidates.[46] In addition, the lining of the lung also contains macrophages, immune cells which engulf and destroy debris and microbes that enter the lung in a process known as phagocytosis; and dendritic cells which present antigens to activate components of the adaptive immune system such as T-cells and B-cells.[46]

text: The size of the respiratory tract and the flow of air also protect the lungs from larger particles. Smaller particles deposit in the mouth and behind the mouth in the oropharynx, and larger particles are trapped in nasal hair after inhalation.[46]

text: Other[edit]

text: In addition to their function in respiration, the lungs also have a number of other functions. They are involved in maintaining homeostasis, helping in the regulation of blood pressure as part of the renin-angiotensin system. The inner lining of the blood vessels secretes angiotensin-converting enzyme (ACE) an enzyme that catalyses the conversion of angiotensin I to angiotensin II.[48] The lungs are involved in the blood's acid-base homeostasis by expelling carbon dioxide when breathing.[39][49]

text: The lungs also serve a protective role. Several blood-borne substances, such as a few types of prostaglandins, leukotrienes, serotonin and bradykinin, are excreted through the lungs.[48] Drugs and other substances can be absorbed, modified or excreted in the lungs.[39][50] The lungs filter out small blood clots from veins and prevent them from entering arteries and causing strokes.[49]

text: The lungs also play a pivotal role in speech by providing air and airflow for the creation of vocal sounds.[39][51] Lungs also provide the airflow that enables the expression of many emotions such as sighing, yawning, sobbing, laughing in humans[40] and the vocal sounds in other animals.

text: New research suggests a role of the lungs in the production of blood platelets.[52]

text: Gene and protein expression[edit]

text: About 20,000 protein coding genes are expressed in human cells and almost 75% of these genes are expressed in the normal lung.[53][54] A little less than 200 of these genes are more specifically expressed in the lung with less 20 genes being highly lung specific. The corresponding specific proteins are expressed within different cellular compartments such as pneumocytes in alveoli, and ciliated and mucus secreting goblet cells in the respiratory mucosa. The highest expression of lung specific proteins are different surfactant proteins, such as SFTPA1, SFTPB and SFTPC, and napsin, expressed in type II pneumocytes. Other proteins with elevated expression in the lung are the dynein protein DNAH5 in ciliated cells, and the secreted SCGB1A1 protein in mucus secreting goblet cells of the airway mucosa.[55]

text: Clinical significance[edit]

text: Lungs can be affected by a variety of diseases. Pulmonology is the medical speciality that deals with diseases involving the respiratory tract,[56] and cardiothoracic surgery is the surgical field that deals with surgery of the lungs.[57]

text: Inflammatory conditions of the lung tissue are pneumonia, of the respiratory tract are bronchitis and bronchiolitis, and of the pleurae surrounding the lungs pleurisy. Inflammation is usually caused by infections due to bacteria or viruses. When the lung tissue is inflamed due to other causes it is called pneumonitis. One major cause of bacterial pneumonia is tuberculosis.[46] Chronic infections often occur in those with immunodeficiency and can include a fungal infection by Aspergillus fumigatus that can lead to an aspergilloma forming in the lung.[46][58]

text: A pulmonary embolism is a blood clot that becomes lodged in the pulmonary arteries. The majority of emboli arise because of deep vein thrombosis in the legs. Pulmonary emboli may be investigated using a ventilation/perfusion scan, a CT scan of the arteries of the lung, or blood tests such as the D-dimer.[46] Pulmonary hypertension describes an increased pressure at the beginning of the pulmonary artery that has a large number of differing causes.[46] Other rarer conditions may also affect the blood supply of the lung, such as granulomatosis with polyangiitis, which causes inflammation of the small blood vessels of the lungs and kidneys.[46]

text: A lung contusion is a bruise caused by chest trauma. It results in hemorrhage of the alveoli causing a build-up of fluid which can impair breathing, and this can be either mild or severe. The function of the lungs can also be affected by compression from fluid in the pleural cavity pleural effusion, or other substances such as air (pneumothorax), blood (hemothorax), or rarer causes. These may be investigated using a chest X-ray or CT scan, and may require the insertion of a surgical drain until the underlying cause is identified and treated.[46]

text: Asthma, chronic bronchitis, bronchiectasis and chronic obstructive pulmonary disease (COPD) are all obstructive lung diseases characterised by airway obstruction. This limits the amount of air that is able to enter alveoli because of constriction of the bronchial tree, due to inflammation. Obstructive lung diseases are often identified because of symptoms and diagnosed with pulmonary function tests such as spirometry. Many obstructive lung diseases are managed by avoiding triggers (such as dust mites or smoking), with symptom control such as bronchodilators, and with suppression of inflammation (such as through corticosteroids) in severe cases. One common cause of COPD and emphysema is smoking, and common causes of bronchiectasis include severe infections and cystic fibrosis. The definitive cause of asthma is not yet known.[46]

text: Some types of chronic lung diseases are classified as restrictive lung disease, because of a restriction in the amount of lung tissue involved in respiration. These include pulmonary fibrosis which can occur when the lung is inflamed for a long period of time. Fibrosis in the lung replaces functioning lung tissue with fibrous connective tissue. This can be due to a large variety of occupational diseases such as Coalworker's pneumoconiosis, autoimmune diseases or more rarely to a reaction to medication.[46]

text: Lung cancer can either arise directly from lung tissue or as a result of metastasis from another part of the body. There are two main types of primary tumour described as either small-cell or non-small-cell lung carcinomas. The major risk factor for cancer is smoking. Once a cancer is identified it is staged using scans such as a CT scan and a sample of tissue (a biopsy) is taken. Cancers may be treated by surgically removing the tumour, radiotherapy, chemotherapy or combinations thereof, or with the aim of symptom control.[46]Lung cancer screening is being recommended in the United States for high-risk populations.[59]

text: Congenital disorders include cystic fibrosis, pulmonary hypoplasia (an incomplete development of the lungs)[60]congenital diaphragmatic hernia, and infant respiratory distress syndrome caused by a deficiency in lung surfactant. An azygos lobe is a congenital anatomical variation which though usually without effect can cause problems in thoracoscopic procedures.[61]

text: A pneumothorax (collapsed lung) is an abnormal collection of air in the pleural space that causes an uncoupling of the lung from the chest wall.[62] The lung cannot expand against the air pressure inside the pleural space. An easy to understand example is a traumatic pneumothorax, where air enters the pleural space from outside the body, as occurs with puncture to the chest wall. Similarly, a scuba diver ascending while holding their breath with their lungs fully inflated can cause air sacs (alveoli) to burst and leak high pressure air into the pleural space.

text: Lung function testing[edit]

text: Lung function testing is carried out by evaluating a person's capacity to inhale and exhale in different circumstances.[63] The volume of air inhaled and exhaled by a person at rest is the tidal volume (normally 500-750mL); the inspiratory reserve volume and expiratory reserve volume are the additional amounts a person is able to forcibly inhale and exhale respectively. The summed total of forced inspiration and expiration is a person's vital capacity. Not all air is expelled from the lungs even after a forced breath out; the remainder of the air is called the residual volume. Together these terms are referred to as lung volumes.[63]

text: Pulmonary plethysmographs are used to measure functional residual capacity.[64] Functional residual capacity cannot be measured by tests that rely on breathing out, as a person is only able to breathe a maximum of 80% of their total functional capacity.[65] The total lung capacity depends on the person's age, height, weight, and sex, and normally ranges between 4 and 6 litres.[63] Females tend to have a 20–25% lower capacity than males. Tall people tend to have a larger total lung capacity than shorter people. Smokers have a lower capacity than nonsmokers. Thinner persons tend to have a larger capacity, and capacity can be increased by physical training as much as 40%.[65]

text: Other lung function tests include spirometry, measuring the amount (volume) and flow of air that can be inhaled and exhaled. The maximum volume of breath that can be exhaled is called the vital capacity. In particular, how much a person is able to exhale in one second (called forced expiratory volume (FEV1) as a proportion of how much they are able to exhale in total (FEV). This ratio, the FEV1/FEV ratio, is important to distinguish whether a lung disease is restrictive or obstructive.[46][63] Another test is that of the lung's diffusing capacity – this is a measure of the transfer of gas from air to the blood in the lung capillaries.

text: Other animals[edit]

text: Birds[edit]

text: The lungs of birds are relatively small, but are connected to 8 or 9 air sacs that extend through much of the body, and are in turn connected to air spaces within the bones. On inhalation, air travels through the trachea of a bird into the air sacs. Air then travels continuously from the air sacs at the back, through the lungs, which are relatively fixed in size, to the air sacs at the front. From here, the air is exhaled. These fixed size lungs are called "circulatory lungs", as distinct from the "bellows-type lungs" found in most other animals.[66][68]

text: The lungs of birds contain millions of tiny parallel passages called parabronchi. Small sacs called atria radiate from the walls of the tiny passages; these, like the alveoli in other lungs, are the site of gas exchange by simple diffusion.[68] The blood flow around the parabronchi and their atria forms a cross-current process of gas exchange (see diagram on the right).[66][67]

text: The air sacs, which hold air, do not contribute much to gas exchange, despite being thin-walled, as they are poorly vascularised. The air sacs expand and contract due to changes in the volume in the thorax and abdomen. This volume change is caused by the movement of the sternum and ribs and this movement is often synchronised with movement of the flight muscles.[69]

text: Parabronchi in which the air flow is unidirectional are called paleopulmonic parabronchi and are found in all birds. Some birds, however, have, in addition, a lung structure where the air flow in the parabronchi is bidirectional. These are termed neopulmonic parabronchi.[68]

text: Reptiles[edit]

text: The lungs of most reptiles have a single bronchus running down the centre, from which numerous branches reach out to individual pockets throughout the lungs. These pockets are similar to alveoli in mammals, but much larger and fewer in number. These give the lung a sponge-like texture. In tuataras, snakes, and some lizards, the lungs are simpler in structure, similar to that of typical amphibians.[69]

text: Snakes and limbless lizards typically possess only the right lung as a major respiratory organ; the left lung is greatly reduced, or even absent. Amphisbaenians, however, have the opposite arrangement, with a major left lung, and a reduced or absent right lung.[69]

text: Both crocodilians and monitor lizards have developed lungs similar to those of birds, providing an unidirectional airflow and even possessing air sacs.[70] The now extinct pterosaurs have seemingly even further refined this type of lung, extending the airsacs into the wing membranes and, in the case of lonchodectids, tupuxuara, and azhdarchoids, the hindlimbs.[71]

text: Reptilian lungs typically receive air via expansion and contraction of the ribs driven by axial muscles and buccal pumping. Crocodilians also rely on the hepatic piston method, in which the liver is pulled back by a muscle anchored to the pubic bone (part of the pelvis) called the diaphragmaticus,[72] which in turn creates negative pressure in the crocodile's thoracic cavity, allowing air to be moved into the lungs by Boyle's law. Turtles, which are unable to move their ribs, instead use their forelimbs and pectoral girdle to force air in and out of the lungs.[69]

text: Amphibians[edit]

text: The lungs of most frogs and other amphibians are simple and balloon-like, with gas exchange limited to the outer surface of the lung. This is not very efficient, but amphibians have low metabolic demands and can also quickly dispose of carbon dioxide by diffusion across their skin in water, and supplement their oxygen supply by the same method. Amphibians employ a positive pressure system to get air to their lungs, forcing air down into the lungs by buccal pumping. This is distinct from most higher vertebrates, who use a breathing system driven by negative pressure where the lungs are inflated by expanding the rib cage.[73] In buccal pumping, the floor of the mouth is lowered, filling the mouth cavity with air. The throat muscles then presses the throat against the underside of the skull, forcing the air into the lungs.[74]

text: Due to the possibility of respiration across the skin combined with small size, all known lungless tetrapods are amphibians. The majority of salamander species are lungless salamanders, which respirate through their skin and tissues lining their mouth. This necessarily restrict their size: all are small and rather thread-like in appearance, maximising skin surface relative to body volume.[75] Other known lungless tetrapods are the Bornean flat-headed frog[76] and Atretochoana eiselti, a caecilian.[77]

text: The lungs of amphibians typically have a few narrow internal walls (septa) of soft tissue around the outer walls, increasing the respiratory surface area and giving the lung a honey-comb appearance. In some salamanders even these are lacking, and the lung has a smooth wall. In caecilians, as in snakes, only the right lung attains any size or development.[69]

text: Lungfish[edit]

text: The lungs of lungfish are similar to those of amphibians, with few, if any, internal septa. In the Australian lungfish, there is only a single lung, albeit divided into two lobes. Other lungfish and Polypterus, however, have two lungs, which are located in the upper part of the body, with the connecting duct curving around and above the esophagus. The blood supply also twists around the esophagus, suggesting that the lungs originally evolved in the ventral part of the body, as in other vertebrates.[69]

text: Invertebrates[edit]

text: Some invertebrates have lung-like structures that serve a similar respiratory purpose as, but are not evolutionarily related to, vertebrate lungs. Some arachnids, such as spiders and scorpions, have structures called book lungs used for atmospheric gas exchange. Some species of spider have four pairs of book lungs but most have two pairs.[78] Scorpions have spiracles on their body for the entrance of air to the book lungs.[79]

text: The coconut crab is terrestrial and uses structures called branchiostegal lungs to breathe air.[80] They cannot swim and would drown in water, yet they possess a rudimentary set of gills. They can breathe on land and hold their breath underwater.[81] The branchiostegal lungs are seen as a developmental adaptive stage from water-living to enable land-living, or from fish to amphibian.[82]

text: Pulmonates are mostly land snails and slugs that have developed a simple lung from the mantle cavity. An externally located opening called the pneumostome allows air to be taken into the mantle cavity lung.[83][84]

text: Evolutionary origins[edit]

text: The lungs of today's terrestrial vertebrates and the gas bladders of today's fish are believed to have evolved from simple sacs, as outpocketings of the esophagus, that allowed early fish to gulp air under oxygen-poor conditions.[85] These outpocketings first arose in the bony fish. In most of the ray-finned fish the sacs evolved into closed off gas bladders, while a number of carp, trout, herring, catfish, and eels have retained the physostome condition with the sack being open to the esophagus. In more basal bony fish, such as the gar, bichir, bowfin and the lobe-finned fish, the bladders have evolved to primarily function as lungs.[85] The lobe-finned fish gave rise to the land-based tetrapods. Thus, the lungs of vertebrates are homologous to the gas bladders of fish (but not to their gills).[86]