Gas exchange in aquatic environments

Question 1

Why is the amount of oxygen in water different from the amount of oxygen in the air?

Answer 1

Water is more dense and more viscous, and lower oxygen solubility

Question 2

What else will affect the amount of oxygen dissolved in water?

Answer 2

Temperature and dissolved salts

Question 3

What are the 5 things that must be considered for respiratory anatomy to be effective?

Answer 3

Surface area, thickness of the respiratory surface, degree of vascularization, direct with external media, direction of media flow

Question 4

Why does body size affect the respiratory needs of animals?

Answer 4

A larger animal has a lower surface area to volume ratio, and diffusion distance also increases

Question 5

What is the relationship between time for diffusion and distance?

Answer 5

Time for diffusion increases with distance squared

Question 6

What happens to the surface area to volume ratio if the radius increases?

Answer 6

Decreases

Question 7

When is cutaneous respiration effective?

Answer 7

When the skin is small, thin, and moist

Question 8

How are metabolic rate and oxygen consumption related?

Answer 8

Higher metabolic rate = higher oxygen demand

Question 9

What would be the advantage of having thicker respiratory membranes if it reduces diffusion?

Answer 9

Reduces water loss in organisms like lower metabolic needs

Question 10

What is ventilation?

Answer 10

Movement of environmental medium over the respiratory surface

Question 11

What are the 3 types of respiratory systems?

Answer 11

Lungs, internal gills, and external gills

Question 12

What are lungs?

Answer 12

An invagination into the body

Question 13

What are internal gills?

Answer 13

An evagination out into a smaller body cavity protected by a flap of skin

Question 14

What are external gills?

Answer 14

An evagination directly out into the medium

Question 15

What are the 3 types of ventilation?

Answer 15

Non-directional, tidal, unidirectional

Question 16

What type of respiratory system uses non-directional ventilation?

Answer 16

External gills

Question 17

What is non-directional ventilation?

Answer 17

The medium comes into contact with the respiratory surface in many directions

Question 18

How does medium mixing affect the efficiency of respiration with external gills?

Answer 18

Lower efficiency when there is poor mixing and a boundary layer

Question 19

What is tidal ventilation?

Answer 19

Air or water flows to and from the respiratory surface through the same passage

Question 20

Do lungs empty between breaths?

Answer 20

No, there is always some still in there that the new air will mix with

Question 21

How do the internal partial pressure between the blood and medium compare in tidal ventilation?

Answer 21

Partial pressure in the blood is lower than in the ambient air

Question 22

What is unidirectional ventilation?

Answer 22

Air comes across the respiratory surface in one direction

Question 23

What are the 3 types of unidirectional ventilation?

Answer 23

Concurrent, countercurrent, cross-current

Question 24

What is concurrent ventilation?

Answer 24

Blood and medium flow in the same direction

Question 25

What is counter current ventilation?

Answer 25

Blood and medium flow in opposite direction

Question 26

What is cross current ventilation?

Answer 26

Blood flows at an angle to the medium

Question 27

What form of unidirectional ventilation is the best?

Answer 27

Countercurrent > cross current > concurrent