Chapter 7 - Exchange Surfaces and Breathing

Question 1

Why are gaseous exchange surfaces moist?

Answer 1

so oxygen dissolves in the water before diffusing into the body tissue.

Question 2

What is the membrane surrounding the thorax?

Answer 2

Pleural membrane.The space between them, the pleural cavity, is usually filled with a thin layer of lubricating fluid so the membranes slide easily over each other as you breathe.

Question 3

What are the features of the nasal cavity?

Answer 3

• Large surface area with good blood supply = moist air in lungs
• Hairs, goblet cells for mucus
• Moist surface = increase humidity = reduce evaporation

Question 4

What are the alveolli composed of?

Answer 4

Flattened epithelial cells, along with some collagen and elastic fibres (composing of elastin) = allow alveoli to stretch in and out =squeeze air out = elastic recoil

Question 5

What is the inner surface of the alveoli covered by?

Answer 5

A thin layer of a solution of water, Salts and lung surfactant. It is the surfactant that makes it possible for the alveoli to remain inflated

Question 6

How does an asthma attack work?

Answer 6

The cells lining the bronchioles release histamines, chemicals that make the epithelial cells become inflamed and swollen. Histamines stimulate the goblet cells to make excess mucus, and smooth muscles on bronchioles to contract = narrow airways filled with mucus.