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Comparative anatomy
Respiratory system
Question | Answer |
---|---|
Organs of gas exchange | skin,external gills(exposed-get O2 well but can get damaged),internal gills(H2O flow not as good but well protected),lungs |
Skin | cutaneous respiration(must have low amount of keratin),low metabolic rate,Low O2 requirement.amphibians |
External gills | Larval form,few adult-Salamanders(neoteny) |
Internal gills | Most common,fish,develop on pharyngeal bars.unidirectional water flow(mouth->gills->out).more efficient than bidirectional or tidal |
Types of internal gills | pouch gills,septal gills,opercular gills |
pouch gills | internal and external pores |
septal gills | chondricthyes.internal and external slits.large gill chamber,gas exchange lamella on septa. |
opercular gills | bony fish.gill bars,lamella free floating,operculum(protects delicate gill tissue,used as pump,used in communication).counter current(2 fluid streams will pass each other in different direction-very efficient) |
Septum | supports gills in cartilage fish |
filament | each individual gill |
afferent artery | bringing blood from heart |
efferent artery | pick up O2 and blood and brings it to body. |
Gill SA | Tiny folding, secondary lamellae on gill filaments.Secondary lamellae per mm.80-90% of O2 in water is extracted by gills. very efficient |
Blood flow in gills | heart,ventral aorta,afferent branchial arteries(5in shark),capillaries of gill filament(pick up O2 in collection loop),efferent branchial arteries(now O2rich blood(4in sharks)),dorsal aorta.**single circuit |
Other functions of gills | Nitrogen excretion as ammonia,salt and water excretion,salt and water up take,heat exchange. |
General lungs | air filled,respiratory,grow from digestive tract,ventral paired |
Gas bladder | air filled,buoyancy,grow from digestive tract,dorsal(mostly),single |
What would happen if the gas bladder was dorsal? | expand energy to keep upright,adapt like upside down catfish(they also have reverse counter shading) |
Swim bladder mechanisms | reservoir for gases,add or release gases for neutral buoyancy.special cases are lung fish(seasonal ponds dry up, switch to lungs) |
Lungs | paired,huge SA,joins gut tube via trachea,only respiratory,blood supply from 6th aortic arch |
amphibians respiration | first vocal cords,short trachea,small sac like lungs, little internal partitioning,positive pressure ventilation(forces air into lungs(almost swollow air)). |
Reptiles respiration | lungs are larger, Larger SA.bronchi enter further caudad,larynx,negative pressure ventilation(well developed ribs) |
Mammal respiration | Large lungs,very large SA.Trachea is C shaped cartilage.negative pressure(muscular diaphragm).Tidal flow,need to match ventilation and perfusion for things to work properly,alveoli is very thin. |
Respiration path in mammals | nose(2nostrils to increase SA),glottis,larynx,trachea(bifurcates),primary bronchi,2nd bronchi,3rd bronchi,bronchioles(smooth muscle),alveoli,gas exchange,epiglottis. |
Negative pressure ventilation | diaphragm contracts, lowers,air enters,diaphragm relaxes,raised,air pushes out,muscle fibers radial in diapgragm,only mammals have fully muscular diaphragm. |
Diving mammals | Increase pressure,lots of nitrogen dissolves in blood (this is bad).therefore dive fast,dissolved gas released.seal case study showed that lungs collapse(lot more cartilage) so nitrogen doesnt diffuse in, lungs open back up when at surface. |
Bird respiration | syrinx(larynx).most efficient.lungs and air sacs stores air.one way air flow,parabronchi=alveoli.parabronchi are in the main lung.cyclical more efficient. |