3.1 Exchange Surfaces and Breathing

Question 1

What is a spirometer?

Answer 1

A device that measures the volume of air moving in and out of the lungs.

Question 2

What is the tidal volume?

Answer 2

The volume of air in one resting breath.

Question 3

What is the vital capacity?

Answer 3

Greatest volume of air that can be exhaled.

Question 4

What is the residual volume?

Answer 4

The volume of air that remains in the lungs after maximum possible exhalation.

Question 5

How does the spirometer get rid of the carbon dioxide exhaled?

Answer 5

It is absorbed by soda lime.

Question 6

How can oxygen uptake be calculated from a spirometer trace?

Answer 6

By finding the gradient of the decrease in volume

Question 7

What is inhaling also known as?

Answer 7

Inspiration

Question 8

What is exhalation also known as?

Answer 8

Expiration

Question 9

In what order does air enter the lungs?

Answer 9

Trachea
Bronchi
Bronchioles
Alveoli

Question 10

What are the two muscles that allow mammalian ventilation?

Answer 10

Diaphragm and Intercostal Muscles

Question 11

Describe the process of inspiration

Answer 11

• diaphragm and external intercostal muscles contract
• ribcage moves upwards and outwards
• volume of chest cavity increases
• pressure in chest cavity decreases
• air enters lungs

Question 12

Describe the process of expiration

Answer 12

• diaphragm and external intercostal muscles relax
• ribcage moves downwards and inwards
• volume of chest cavity decreases
• pressure in chest cavity increases
• air moves out of the lungs

Question 13

What is the most essential thing for efficient diffusion in gas exchange?

Answer 13

A steep concentration gradient of oxygen and carbon dioxide between the alveoli and capillaries.

Question 14

Why is the surface area of the lung so large?

Answer 14

Because there are so many alveoli (folds of lung epithelium).

Question 15

What helps to maintain a steep concentration gradient?

Answer 15

Good blood supply.

Question 16

What is the thickness of capillary walls?

Answer 16

1 cell thick

Question 17

What is the thickness of alveoli walls?

Answer 17

1 cell thick

Question 18

How long is the diffusion distance between capillaries and alveoli?

Answer 18

Very short

Question 19

What is a countercurrent flow?

Answer 19

When blood flows through capillaries in the opposite direction to water flowing over lamellae.

Question 20

Which animals have a countercurrent flow?

Answer 20

Bony fish

Question 21

What is the operculum?

Answer 21

A bony flap that covers the gills of fish.

Question 22

What are gill filaments?

Answer 22

Branches of fish tissue that make up the gill

Question 23

What are lamellae?

Answer 23

Folds of the gill filament to increase surface area.

Question 24

What is the function of smooth muscle in breathing?

Answer 24

It is found in the bronchi and bronchioles and it regulates the flow of air by dilating or constricting.

Question 25

What are goblet cells?

Answer 25

Cells in the ciliated epithelium that secret mucus. The mucus traps dust and microorganisms

Question 26

What is the ciliated epithelium?

Answer 26

A specialised tissue found along the trachea. Each cell has cilia on the surface which sweep mucus away from the lungs. The ciliated epithelium also has goblet cells in it.

Question 27

What is the squamous epithelium?

Answer 27

A very thin and permeable tissue that lines the alveoli.

Question 28

What are the purpose of elastic fibres in the lungs?

Answer 28

To allow the lungs to stretch and recoil.

Question 29

What is the purpose of cartilage in breathing?

Answer 29

Cartilage forms rings to hold open trachea and support it.