Question

3. Explain how book lungs and book gills are similar and different.

 4. Fish gills utilize counter-current gas exchange. Explain what this process is and how it helps fish get enough O2

 5. How do reptile lungs differ from amphibian lungs?

 6. Explain how unidirectional air flow allows for great O2 extraction

Answer 1

1.Book Lungs are couple of respiratory organ used for excahange of gases and is found in arachnids. They are situated in abdomen. This is best described by its structure, air pockets and tissues filled with hemolymhp neatly arranged into piles, thus this structure is similar to "folded book". This structure is found internally.

Book gills are similar to book book lungs in thier structure as well as function. Book lungs are said to be evolved from book gills. Book gills are flap-like appendages that help in gas exchange but appers like legs of the organism. In the inner side of this appendage there are over 100 thin sheets of membrane called lamella that gives this structure a book shape. Respiration is the core purpose of book gills but also take up the role, to help in swimming in smaller and younger organisms. Book gills are found externally.

3.Fish gills are highly specialized to absorb more amount of oxygen from water.

This is achieved through counter current mechanisam which is also seen in human kidneys. counter current mechanisam always involve two fluids moving in oppsite direction. Here blood and water flow in opposite direction,this is to facilitate maximum absorption. as the blood flows through the gills it encounter fresh water with more and more oxygen which allow continous absorption.

consider 2 different areas

A.Entry of water into gills- highly saturated with O2 & blood in opposite directionwith depleted oxygen concentration

leads to continious absorption of oxygen into blood

B. Exiting:low O2 water after flowing through gill while exiting encounter low O2 blood entering gill

leads to absorption of remaining oxygen into the blood

5. there are several differences between repetial lung and amphibian lung.

reptile lungs amphibian lung

(a) reptiles breath through lungs    (a) amphibians can breath through both ways using gills and lungs

(b) they have more complex structure and greater surface (b) smiple sack like structure

area than amphibians (c)

(c) breathing patter is not regular, they take series of active (d) buccal acvity is the mechanisim used for   inspirations and expirations that follow a long pause. inflamation of lungs.

(d) mechanism of lung inflamation is by aspiration pumb or

suction pumb

(e) alvoli present (e) alvoli absent

(f) more efficient (e) less efficient

question 6

unidirectional air flow is more efficeint. Air move in and pass out through distant points there is no mixing up of air. Air flow bidirectional in mammals, air flow in and out of the lungs as aresult air coming in to the lung mix up with the air that goes out and this mixing reduces the oxygen avialbility of the air moving into the lungs. in unidirectional flow there is lagre amount of oxygen avialabiltity compared to bidirectional.