7.2 The Mammalian Gaseous Exchange System

Question 1

Gaseous exchange system

Answer 1

Specialised exchange system found in all mammals, allowing the exchange of gases and minimising water loss

Question 2

Metabolic rate

Answer 2

Energy requirements reflected in level of activity

Question 3

Trachea

Answer 3

Main airway carrying warm moisture air into the chest from the nose. Flexible cartilage.

Question 4

Goblet cell

Answer 4

Secretes mucus between and below epithelial cells. Traps dust and microorganisms

Question 5

Epithelial cell

Answer 5

Cells lining surfaces of organs, sometimes have cilia

Question 6

Bronchus

Answer 6

Trachea divided into left and right bronchus, leads to the lungs. Similar structure to trachea but smaller

Question 7

Bronchioles

Answer 7

Bronchi leas to bronchioles. No cartilage, only smooth muscle. Lined with shattered epithelium, allowing some gaseous exchange

Question 8

Alveoli

Answer 8

Tiny air sacs, main gas exchange surface of the body. Consists of flattened epithelial cells along with collagen and elastic fibres.

Question 9

Elastic recoil

Answer 9

When alveoli return to their resting size after stretching out

Question 10

Lung surfactant

Answer 10

Decreases surface tension of alveoli, stopping them from collapsing

Question 11

Inspiration

Answer 11

Diaphragm contracts and flattens. Intercostal muscles contract moving ribs up and out. Thorax pressure reduced. Air is drawn in through nasal passages. Equalises pressure inside and outside of chest

Question 12

Expiration

Answer 12

Diaphragm relaxes, moving up. Intercostal muscles relax moving ribs down and in. Elastic fibres in lungs return to normal length. Pressure inside thorax is now higher than outside. Air moves out of lungs until equilibrium is reached.