Comparative Anatomy Respiratory System

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Comparative AnatomyRespiratory System

• Note Set 10
• Chapter 11

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Respiratory System

• Gas exchange system
• Oxygen and carbon dioxide
• Fish- internal gills or lungs
• Some amphibians- permanent external gills
  (perennibranchiate)
• Others possess lungs

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• Accessory respiration organs
• Amphibian skin

Figure 12.1 Adaptations for cutaneous
respiration (hairy frog).
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Fish Respiratory System

• Gills associated with walls of pharyngeal arches
• Internal gills
• Operculum- flap of skin covering gills
• Spiracle- reduced 1st pharyngeal
• arch opening
• Nonfunctional
• Not in higher fish

Figure 12.2 Gills of shark and teleost.
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Swim Bladder Lungs

• Every vertebrate has lung diverticulum
• Pneumatic sac
• Which came first?
• Physoclistous
• Esophagus not connected to swim
• bladder
• Physostomous
• Trachea to lungs or pneumatic sac

Figure 12.3 Swim bladders and urodele lungs.
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Primitive Fish Have Primitive Lung

• Lung diverticulum came first
• Then pneumatic duct in teleosts
• Swim bladder was possibly a secondary
  modification of lung

Figure 12.4 Evolution of lungs and swim bladders.
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Swim Bladder

• Red glands (gas glands)- network of small
  arteries
• Provide oxygen to swim bladder

Figure 12.5 Swim bladder (red) of fish.
Figure 12.6 Rete mirabile in fish, red indicates
high oxygen concentration.
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Swim Bladder (cont.)

• Weberian ossicles
• Swim bladder may act as sound chamber

Figure 12.7 Weberian apparatus for transmitting
swim bladder vibrations to ear.
Figure 12.8 Weberian ossicles.
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Tetrapod Lungs

• Diaphragmatic muscles pull the liver posteriorly
  via an attachment to the posthepatic septum in
  crocodilians
• Most turtles also use diaphragmatic muscles to
  alter volume of cavity within the shell.

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Avian Lungs

• Birds- modified lungs and ducts
• Air sacs associated with lungs
• Increase respiratory capacity for flight

Figure 12.9 Lower respiratory tract of bird.
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Trachea

• Passageway to lungs
• Larynx- voice box at head
• Laryngeal cartilages
• Sound produced- vocal sac
• Snake hissing- expulsion of air from lungs

Figure 12.10 Human trachea and larynx (see book
figure 13.13b).
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Trachea

• Birds- Syrinx instead of larynx
• Lower end of trachea
• Not homologous to larynx
• Incapable of producing sound
• Mammals- man has larynx
• Different cartilages
• Epiglottis over glottis to larynx
• Diaphragm

Figure 12.11 Asymmetrical bronchotracheal syrinx
of duck (book figure 13.16).
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Accessory Respiratory Organs

• Yolk sac
• In embryo
• Skin
• Many fish and amphibians
• Ex African Clawed frog (Xenopus)- chin barbels
• Rectum Cloaca
• Highly vascularized in some fish
• Ex Aquatic turtles

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Literature Cited

• Figure 12.1 12.4 Kardong, K. Vertebrates
  Comparative Anatomy, Function, Evolution. McGraw
  Hill, 2002.
• Figure 12.2, 12.3, 12.7, 12.9 12.11 Kent,
  George C. and Robert K. Carr. Comparative
  Anatomy of the Vertebrates. 9th ed. McGraw-Hill,
  2001.
• Figure 12.5 http//www.palaeos.com/Vertebrates/Li
  sts/Glossary/GlossaryWZ.htmlW
• Figure 12.6 http//www.palaeos.com/Vertebrates/Li
  sts/Glossary/GlossaryC.html
• Figure 12.8 http//www.voiceproblem.org/anatomy/l
  earning.asp
• Figure 12.10 http//www.voiceproblem.org/anatomy/
  learning.asp