Theme 20: Respiration 2

Question 1

True or False: Water is a favorable membrane for getting oxygen.

Answer 1

False, it is unfavorable because its not as easy (this applies to all animals which can get oxygen from either)

Question 2

What is diffusion helped by?

Answer 2

Convection (ventilation) - stirring around of the gas exchange

Question 3

Why must the body convecte?

Answer 3

otherwise you will eventually be left with no oxygen

Question 4

What are the three mediums for oxygen to be transported?

Answer 4

blood
air
water

Question 5

what do blood, air, and water have in common?

Answer 5

they are the three mediums for oxygen to be transported in

Question 6

why were gills developed?

Answer 6

because the larger the area the more gas flow and they are also proportional to the partial pressure gradient

Question 7

What two things can you do to help the gradient move along?

Answer 7

Breathing (ventiation)

circulation

Question 8

What will making the thickness of the alveoli wall thinner do?

Answer 8

help large molecules dissolve better

Question 9

true or false: CO2 can be diffused more easily than O2.

Answer 9

True, oxygen is almost insoluble in water so you need hemoglobin to get O2 in

Question 10

What are the four mechanism that vertebrates use for gas exchange?

Answer 10

Fish gills
bird lungs
mammalian lungs
amphibian skin

Question 11

How do amphibians diffuse oxygen?

Answer 11

through their skin (salamander)

Question 12

What does the Cutaneous Gas Exchange represent?

Answer 12

an “open model” where amphibians have thin, well vascularized, moist, naked skin

Question 13

Which has the most cutaneous gas exchange?

a) Mudpuppy
b) trout
c) human

Answer 13

mudpuppy

Question 14

Why is the bullfrogs metamorphosis a good model for evolution of air breathing?

Answer 14

it starts out using its skin for diffuison, then skin and gills then skin and lungs

Question 15

What are the advantages and disadvantages of external gills?

Answer 15

Ad: lots of ability to get oxygen
Dis: vulnerable, can be eaten, if taken out of water they collapse

Question 16

What are the differences between fish gills and external gills?

Answer 16

fish gills are internal

Question 17

What is the flow of water and oxygen through gills called?

Answer 17

Counter current flow

Question 18

What is counter current flow?

Answer 18

an efficient system where the blood leaves oxygenated more than the outer oxygen concentration in water

Question 19

what is the double pumping mechanism in body and cartilagious fish?

Answer 19

a valve that lets water in the mouth, through the gills and closes so the water has to go out the opercular cavity

Question 20

What is ram ventilation?

Answer 20

Fish like sharks and mackerel that have to oxygenate their body by moving to oxygenate their blood, if they stop moving, then no oxygen

Question 21

what does the operculum act like in fish?

Answer 21

a suction pump to pull the water in and then a pressure pump to expel the water out

Question 22

What are lamellae and what do they do?

Answer 22

secondary gill filaments that increase surface area for the gases and act as sieves for water flow

Question 23

What is Counter current arrangement?

Answer 23

blood flow from tail to head (hence counter current), and this is efficient for getting the oxygen to the blood

Question 24

Why are counter current gas exchangers so efficient?

Answer 24

• pressure of dissolved oxygen starts at venous partial pressure then is oxygenated at the secondary lamellae and moves the opposite direction
• pressure is kept constant so the oxygen constantly is flowing in
• arterial blood has a higher gradient than the expired water

Question 25

What is the Fick equation?

Answer 25

basic physics of gas exchange, diffusion of oxygen is driven by the pressure gradient

Question 26

What are the four vertebrate gas exchanges?

Answer 26

open
pool
countercurrent
crosscurrent

Question 27

What is Open gas exchange?

Answer 27

through the skin (cutaneous gas exchange) external gills are a method of expanding surface area (important in tadpoles)

Question 28

What is counter-current gas exchange?

Answer 28

fish gils
most efficient gas exchange organ in terms of transfer of gas into blood
- PaO2( oxygen concentration in arterial blood) is greater than PEO2 (oxygen concentration in expired water)

Question 29

What does amphibian metamorphosis represent (transition)?

Answer 29

skin
to external gill
to internal gill
to lung as gas exchange organ