6.4 - Gas Exchange

Question 1

What is ventilation?

Answer 1

The pumping of gas into the lungs and removal of stale air

Question 2

Why does ventilation occur?

Answer 2

To maintain the concentration gradient

Question 3

Where does ventilation occur?

Answer 3

In the cytoplasm and mitochondria of cells

Question 4

What does ventilation involve?

Answer 4

An increase in O2 intake and decrease in CO2 in the lungs helps maintain a high concentration of gases between alveoli and capillaries
This allows for faster diffusion

Question 5

Lungs (3)

Answer 5

• air enters the trachea which branches into bronchi
• both the trachea and bronchioles are protected by rings of cartilage
• they then divide into bronchioles and then alveoli

Question 6

What are alveoli?

Answer 6

The site of gas exchange

Question 7

Type I pneumocytes (2)

Answer 7

• extremely thin cells with thin cell walls

- adapted for gas exchange and have a short diffusion pathway

Question 8

Type II pneumocytes (2)

Answer 8

• secrete a solution containing a surfactant that creates a moist surface to prevent the alveoli sticking by adhesion to itself
• surfactant reduces surface tension

Question 9

Ribcage movement in inspiration

Answer 9

Upwards and outwards

Question 10

Diaphragm movement in inspiration

Answer 10

Contracts

Question 11

Floor of thorax movement in inspiration

Answer 11

Downwards

Question 12

Chest cavity volume in inspiration

Answer 12

Increases

Question 13

Internal intercostal muscles inspiration

Answer 13

Relax

Question 14

External intercostal muscles inspiration

Answer 14

Contract

Question 15

Pressure in lungs in inspiration

Answer 15

Decreases

Question 16

Air movement inspiration

Answer 16

In, because atmospheric air pressure is higher than lung air pressure

Question 17

Ribcage movement in expiration

Answer 17

Downwards and inwards

Question 18

Diaphragm movement in expiration

Answer 18

Relaxes

Question 19

Floor of thorax movement in expiration

Answer 19

Upwards

Question 20

Chest cavity volume in expiration

Answer 20

Decreases

Question 21

Internal intercostal muscles in expiration

Answer 21

Contract

Question 22

External intercostal muscles in expiration

Answer 22

Relax

Question 23

Pressure in lungs in expiration

Answer 23

Increase

Question 24

Air movement in expiration

Answer 24

Out

Question 25

Lung cancer causes (4)

Answer 25

• smoking, including passive smoking
• air pollution from exhaust fumes
• radon gas
• asbestos/silica particles inhaled

Question 26

How does smoking cause lung cancer?

Answer 26

Contains mutagenic chemicals

Question 27

Consequences of lung cancer

Answer 27

• difficulty breathing
• persistent coughing
• fatigue
• weight loss

Question 28

Emphysema (4)

Answer 28

• fusing of alveoli
• reduces number of alveoli present and increases thickness of their walls
• slower gas exchange (large diffusion pathway and smaller surface area)
• lungs become more rigid and breathing becomes difficult

Question 29

Causes of emphysema (3)

Answer 29

• decreases in AIAT production by genetic factors
• increase in phagocytes in the lung increases digestion of lung tissue
• heavy metals and asbestos inhalation