Gas Exchange System

Question 1

General adaptations of gas exchange system:

Answer 1

-clean and warm the air that enters during breathing
-maximise the surface area for diffusion of oxygen and carbon dioxide between the blood and atmosphere
-minimise the distance for this diffusion
-maintain adequate gradients for this diffusion.

Question 2

Alveolus(plural:alveoli):

Answer 2

a small air sac in the lungs composed of a single layer of squamous epithelium and some elastic fibres; each alveolus is surrounded by capillaries that transport blood from the pulmonary artery to the pulmonary vein

Question 3

The alveoli has large surface area because:

Answer 3

1) large number of oxygen and carbon dioxide molecules can diffuse through the surface at any one moment giving a high rate of gas exchange.

2) large surface area is also required because oxygen is not very soluble in water.

Question 4

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Answer 4

The lungs are in the thoracic (chest) cavity surrounded by the pleural membranes, which enclose an airtight-
Lao
space.

Question 5

….. in the lungs form the gas exchange surface in mammals.

Answer 5

Alveoli

Question 6

The……and the……. Maintain concentration gradient between blood and air for oxygen and carbon dioxide.

Answer 6

Constant blood flow
And continuous ventilation of the lungs.

Question 7

b
How many times does an oxygen molecule cross a cell surface membrane as it moves from the air into a red blood cell?

Answer 7

5 times
In and out of squamous epithelia cells in alveolar wall
In and out of endothelial cell
And into a red blood cell

Question 8

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Answer 8

The walls of the alveoli also contain some collagen fibers to provide support and help prevent alveoli from bursting

Question 9

Goblet cell:

Answer 9

a cell shaped like a drinking goblet that secretes mucus; goblet cells are found in epithelia lining parts of the gas exchange system and other organ systems, e.g. reproductive and digestive

Question 10

Ciliated epithelium:

Answer 10

an epithelium that consists mainly of ciliated cells; may also contain goblet cells

Question 11

Mucin:

Answer 11

any glycoprotein that forms part of the mucus secreted by goblet cells and mucous cells,

Question 12

Benefits of cartilage in trachea and bronchi:

Answer 12

keeps these airways open and air resistance low, it prevents them from collapsing or bursting as the air pressure changes during breathing.

Question 13

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Answer 13

In the trachea, there, is a regular arrangement of C-shaped rings of cartilager in the bronchi, there are irregular blocks of cartilage.