Comparative AnatomyComparative AnatomyRespiratory SystemRespiratory System

KardongKardongChapter 11 Chapter 11

Part 12

Respiratory SystemRespiratory System

Gas exchange systemGas exchange system Oxygen and carbon dioxideOxygen and carbon dioxide

Fish - internal gills or lungsFish - internal gills or lungs Some amphibians - permanent external gills Some amphibians - permanent external gills

(perennibranchiate)(perennibranchiate) Others possess lungsOthers possess lungs

Accessory respiration organsAccessory respiration organs Amphibian skinAmphibian skin

Figure 12.1. Adaptations for cutaneous respiration (left, book figure 11.7; right, figure 11.6).

Fish Respiratory SystemFish Respiratory System Gills associated with walls of pharyngeal archesGills associated with walls of pharyngeal arches Internal gillsInternal gills Operculum- flap of skin covering gillsOperculum- flap of skin covering gills Spiracle- reduced 1Spiracle- reduced 1stst pharyngeal arch opening pharyngeal arch opening

NonfunctionalNonfunctional Not in higher fishNot in higher fish

Figure 12.2. Gills of shark and teleost (see book figures 11.17 and 11.19).

Swim Bladder & LungsSwim Bladder & Lungs Every vertebrate has lung diverticulumEvery vertebrate has lung diverticulum

Pneumatic sacPneumatic sac Which came first?Which came first? PhysoclistousPhysoclistous

Esophagus not connected to swim Esophagus not connected to swim bladderbladder

PhysostomousPhysostomous Trachea to lungs or pneumatic sacTrachea to lungs or pneumatic sac

Figure 12.3. Fish swim bladders and urodele lungs (see book figure 11.5).

Lung diverticulum came firstLung diverticulum came first Then pneumatic duct in teleostsThen pneumatic duct in teleosts Swim bladder was secondary modification of lungSwim bladder was secondary modification of lung

Primitive Fish Have Primitive LungPrimitive Fish Have Primitive Lung

Figure 12.4. Evolution of lungs and swim bladders (book figure 11.5).

Swim BladderSwim Bladder Red glands - network small arteriesRed glands - network small arteries

Provide oxygen to swim bladderProvide oxygen to swim bladder

Figure 12.6. Rete mirabile in fish, red indicates high oxygen concentration.

Figure 12.5. Swim bladder (red) of fish.

Figure 12.7. Relationship between rete mirabile and the swim bladder (book figure 11.22).

Swim Bladder Swim Bladder (cont’d.)(cont’d.)

Weberian ossiclesWeberian ossicles Swim bladder may act as sound chamberSwim bladder may act as sound chamber

Figure 12.8. Weberian apparatus for transmitting swim bladder vibrations to ear.

Figure 12.9. Weberian ossicles.

Figure 12.10. Lower respiratory tract of bird (see book figure 11.35, 36, and 37).

LungsLungs Birds - modified lungs and ductsBirds - modified lungs and ducts

Air sacs associated with lungsAir sacs associated with lungs Increase respiratory capacity for flightIncrease respiratory capacity for flight

TracheaTrachea Passageway to lungsPassageway to lungs Larynx- voice box at headLarynx- voice box at head

Laryngeal cartilagesLaryngeal cartilages Sound produced- vocal sacSound produced- vocal sac

Snake hissing- expulsion of air from Snake hissing- expulsion of air from lungslungs

Figure 12.11. Human trachea and larynx.

TracheaTrachea Birds - A syrinx instead of larynxBirds - A syrinx instead of larynx

Lower end of tracheaLower end of trachea Not homologous to larynxNot homologous to larynx Produces sound without vocal cordsProduces sound without vocal cords

Mammals - man has larynxMammals - man has larynx Different cartilages presentDifferent cartilages present Epiglottis over glottis (slit) to larynxEpiglottis over glottis (slit) to larynx Diaphragm Diaphragm

Figure 12.12. Asymmetrical bronchotracheal syrinx of duck.