Comparative Anatomy Respiratory System Note Set 10 Chapter 11

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

Accessory respiration organs Amphibian skin Figure 12.1: Adaptations for cutaneous respiration (hairy frog).

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.

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.

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.

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.

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.

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.

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.

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).

Trachea Birds- Syrinx instead of larynx Mammals- man has 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).

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

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/Lists/Glossary/GlossaryWZ.html#W Figure 12.6: http://www.palaeos.com/Vertebrates/Lists/Glossary/GlossaryC.html Figure 12.8: http://www.voiceproblem.org/anatomy/learning.asp Figure 12.10: http://www.voiceproblem.org/anatomy/learning.asp