structures and functions of mammal components

Question 1

describe the trachea and its function in the mammalian gaseous exchange system

Answer 1

• wide tube supported by C-shaped cartilage to keep the air passage open during pressure changes
• lined by ciliated epithelium cells which move mucus, produced by goblet cells, towards the throat to be swallowed, preventing lung infections
• carries air to the bronchi

Question 2

describe the bronchi and their function in the mammalian gaseous exchange system

Answer 2

• similar to the trachea, they are supported by rings of cartilage and are lined by ciliated epithelium cells and goblet cells
• however, they are narrower and there are two of them, one for each lung
• allow passage of air into the bronchioles

Question 3

describe the bronchioles and their function in the mammalian gaseous exchange system

Answer 3

• narrower than the bronchi
• do not need to be kept open by cartilage, therefore mostly only have smooth muscle and elastic fibres so that they can contract and relax easily during ventilation
• allow passage of air into the alveoli

Question 4

describe the alveoli and their function in the mammalian gaseous exchange system

Answer 4

• mini air sacs, lined with epithelium cells, site of gas exchange
• walls only one cell thick, covered with a network of capillaries, 300 million in each lung, all of which facilitates gas diffusion