N5 -U2 (MO) - KA7 Absorption of Materials

Question 1

Why do humans need transport system?s?

Answer 1

Humans require transport systems to supply their cells and remove waste products. Gas exchange occurs in the lungs and food molecules are absorbed by the digestive system.

Question 2

What waste materials must be removed from the body?

Answer 2

Waste materials such as carbon dioxide must be removed from cells into the bloodstream.

Question 3

Name necessary substance which must be absorbed by the body?

Answer 3

Oxygen and nutrients from food must be absorbed into the bloodstream to be delivered to cells for respiration.

Question 4

What structure allows the exchange of substances at a cellular level?

Answer 4

Capillaries

Question 5

Surfaces of the lungs, digestive system and capillaries have certain features in common to increase the efficiency of absorption. List these…

Answer 5

The surfaces involved in the absorption of materials have certain features in common:
* A large surface area
* Thin walls
* Extensive blood supply
These features increase the efficiency of absorption.

Question 6

Desolicribe the function of the lungs

Answer 6

The lungs are a mammal’s organs of gaseous exchange. Oxygen and carbon dioxide enter and leave the blood by diffusion through the lining of the lungs.

e. g.
* The cells in the body need oxygen to release energy from food efficiently by carrying out aerobic respiration. A waste product of aerobic respiration is carbon dioxide.
* Carbon dioxide must be removed from the body or it makes the blood dangerously acidic.

Question 7

Can you draw a diagram showing the structure of the lungs.

Answer 7

This should include the trachea including rings of cartilage, lung, bronchus, bronchiole and alveoli.

Question 8

Describe the movement of air from the mouth to the alveoli.

Answer 8

Air gets from the mouth and nose to the lungs through the windpipe (trachea). The trachea branches into two tubes called bronchi (one to each lung). The bronchi split into smaller and smaller tubes called bronchioles, which then end in microscopic alveoli (air sacs).

Question 9

Describe the alveoli in terms of their structure related to function.

Answer 9

The alveoli are

• lined with mucus and are surrounded by a network of blood capillaries.
• They have very thin walls for gases to be absorbed through.
• The layer of moisture in the alveoli allows gases to dissolve so that they can diffuse quickly.
• The alveoli have a very large total surface area and a very good blood supply, provided by the dense network of capillaries that surround them.

Question 10

Describe three features are particularly important to our lungs for efficient gas exchange. Remember these features also apply to other exchange surfaces such as the small intestine, body tissues and placenta.

Answer 10

• Thin lining: the lining of the alveoli is very thin so that gases can quickly diffuse through it.
• Large surface area: human lungs contain about 500 million alveoli. This speeds up diffusion because gases have more area over which to diffuse.
• Good blood supply: the alveoli have a dense capillary network so that large volumes of gases can be exchanged.