6.4 gas exchange

Question 1

Ventilation

Answer 1

• Breathing in and out
• Maintains concentration gradients of oxygen and carbon dioxide between air in alveoli and blood flowing in adjacent capillaries

Question 2

Pulmonary circulation

Answer 2

Oxygen = Alveoli –> capillaries

Co2 = capillaries –> Alveoli

Question 3

Systemic circulation

Answer 3

Oxygen = Cappilaries –> body cells

Co2 = cells –> Capillaries

Question 4

Order oxygen travels to body cells

Answer 4

1. Mouth/ nose
2. Trachea
3. Bronchi
4. Bronchioles
5. Alvioli
6. Pulmonary circulation
7. Systemic circulation

Question 5

The 2 cells in alveoli

Answer 5

Type 1 pneumocytes

Type 2 pneumocytes

Question 6

Type 1 pneumocytes

Answer 6

Thin & longer

Helps gas exhange occur across alveolus.

Question 7

Type 2 pneumocytes

Answer 7

Clumped

Produces Surfactant:

Prevents alveoli and capillries from sticking together, but allows them to contract and expand.

Allows faster diffusion of air to and from alveoli and capillary.

Question 8

Cell respiration

Answer 8

Chemical reaction inside the cell, converting energy (glucose)into ATP.

Aerobic: Cell respiration with o2 (Long exercise)

Anaeobic: Without o2 (Short exercise)

• Can occur from holding breath, muscles using o2 faster than you can get through ventilation.

Question 9

Alveoli features

Answer 9

Large SA/V ratio

One layer of flattened cells

Moist lining (surfactant)

Dense network of capillaries (Gas exchange, SA/V)

Question 10

Inhalation

Answer 10

Diaphragm contracts and flattens

External intercostal muscles pull rig cage outward and foward

Internal intercostal muscles relax & makes chest cavity larger, causing pressure to drop allowing air to flow in

Question 11

Exhalation

Answer 11

Diaphragm relax into ‘∩’ shape

External intercostal muscles: Relax

Internal intercostal muscles: Contract, causing ribs to move down & backward

–> chest cavity gets smaller, creating higher pressure forcing the air out.

Question 12

Antagonistic muscles pairs that encourage Inspiration and Expiration

Answer 12

• Intercostal muscles (External & Internal)
• Diaphragm & Abdominal muscels

Question 13

Causes and consequences of lung cancer

Answer 13

• uncontrolled proliferation of lung cells, leading to the abnormal growth of lung tissue (tumour)
• The tumours can remain in place (benign) or spread to other regions of the body (malignant)

Question 14

Causes and consequences of emphysema

Answer 14

• a lung condition whereby the walls of the alveoli lose their elasticity due to damage to the alveolar walls
• The major cause of emphysema is smoking, as the chemical irritants in cigarette smoke damage the alveolar walls