Chapter 22 Gas exchange

Question 1

What are the 3 phases of gas exchange?

Answer 1

1. Breath in/out air: O2 in air diffuses to the blood vessels in the lungs and CO2 in the blood vessels diffuses out into the lungs. Exhale the CO2 rich air
2. Transport: The O2 diffused into the blood is transported to the cells and CO2 concentrated blood is brought back to the lungs by the circulatory system.
3. Gas exchange at the cells: O2 is absorbed by the cells from the blood and CO2 is released by the cells into the blood stream

Question 2

Why would many animals die if they don’t get enough oxygen?

Answer 2

Oxygen is needed for respiration that produce ATP for proper functioning of the body

Question 3

What is the purpose of gas exchange?

Answer 3

Take in O2 and give out CO2

Question 4

What are the characteristics of the respiratory surfaces?

Answer 4

1. They are moist
2. They are large in surface area to enable sufficient gase exchange
3. They have an abundant supply of blood vessels to exchange gases

Question 5

What are the characteristics of earthworms gas exchange system?

Answer 5

1. Entire outer skin is used as the respiratory surface
2. O2 diffuses in to and CO2 diffuses out of the blood that is brought closer to skin by a set of densely populated capillaries
3. Skin must remain moist

Question 6

Why are skin breathers long and small in size?

Answer 6

Small in size because skin breathing cannot carry out enough gas exchange to sustain large animals
They are long to increase the surface area of the respiratory surface

Question 7

What are the types of respiratory surfaces specially adapted for gas exchange in animals?

Answer 7

1. Gills: Aquatic animals
2. Tracheal systems: Insects
3. Lungs:Terrestial animals

Question 8

What are gills?

Answer 8

Extensions of the body surface specialized for gas exchange in aquatic animals. Gills are specialized for diffusion of gases between the water outside the gills and blood inside the gills

Question 9

Why are gills exposed in fish?

Answer 9

Respiratory surfaces such as gills must be moist. Keeping gills moist in water is not a problem.

Question 10

What is a tracheal systems?

Answer 10

Extensive network of internal tubes made of moist epithelial tissue in insects. Since these smallest branches exchange gases directly with the cells the insects do not count on a circulatory system for gas exchange

Question 11

What are lungs?

Answer 11

Sacs of air lined with moist epithelial tissue

Question 12

How does the structure of the respiratory system like a lung or a gill fit its function?

Answer 12

1. Respiratory surfaces are thin and moist so that gases can easily diffuse
2. They are highly branched or sub divided to increase the surface area of the gas exchange

Question 13

Why should gills be very efficient in gas exchange?

Answer 13

The amount of gases dissolved in water is very low compared to the atmospheric gases

Question 14

How do fish direct water through the gills?

Answer 14

1. They swim open mouthed so that water flows in through the mouth
2. The operculum or gill cover regulates the water flow through the gills to maximize gas exchange

Question 15

Where does gas exchange take place in a Gill?

Answer 15

In the gill filament

Question 16

What is counter current exchange?

Answer 16

Blood and water flow in the opposite directions in the gills