Questions and Glossary from Course Book

4.1 The human respiratory system

1. Write down a sentence to describe the function of each of these parts of the human
respiratory system.
a. Trachea is a stiff and cartilage-flexible tube that carries air into and from the
lungs.
b. Bronchus is a branch from the trachea and it is joined to each lung. Its function
is to carry air to and from the lungs.
2. Glossary
a. Respiration: a chemical reaction that happens inside every living cell, in which
energy is released from glucose so that the cell can use it
b. Respiratory system : the organs that help oxygen to get into the body and carbon
dioxide to be removed from it
c. Gas exchange = exchange oxygen and carbon dioxide to and from the blood.
d. Larynx = voicebox
e. Trachea = (windpipe) the tube that carries air from the back of the throat to the
lungs.

4.2 Gas exchange

1. Name the red pigment inside red blood cells that helps to carry oxygen.
haemoglobin
2. Name the large blood vessel that carries blood from the heart to the lungs.
Pulmonary arteries
3. Explain how oxygen diffuses from an air sac into the blood.
The air inside the air sacs has come from outside the body. It contains a lot of oxygen
and very little carbon dioxide. Then oxygen diffuses from the air sac into the blood
capillary then into the red blood cells.
4. The walls of the air sacs and the capillaries are both very thin. Suggest how this helps
gas exchange to take place quickly.
Thin walls of air sacs and capillaries means diffusion of gases easily takes
place.This increases the rate of exchange of gases. Thinner the walls, faster the
diffusion occurs.
5. Glossary
a. Alveolus = (air sac) a tiny, air-filled space inside the lungs
Plural form = Alveoli
4.3 Aerobic respiration
1. Name the two new substances that are made when glucose reacts with oxygen inside a
cell.
Carbon dioxide and water
2. Use what you know about digestion and the human circulatory system to describe how
glucose gets to a cell in a muscle.
After digestion, nutrients are absorbed through the wall of the small intestine and
diffuse into the blood. Then the blood carries nutrients(glucose) and oxygen to all of the
body parts. In that way, the glucose gets to a cell in a muscle.

3. Use what you know about gas exchange and the human circulatory system to describe
how oxygen gets into a cell in a muscle.
The air inside the air sacs has come from outside the body. It contains a lot of oxygen
and very little carbon dioxide. Then oxygen diffuses from the air sac into the blood
capillary then into the red blood cells. The blood is carried back to the heart and the
heart transports the oxygenated blood to all of the cells in the body.

4. Explain the difference between respiration and breathing.

Respiration means breaking down glucose into energy with the presence of oxygen
that takes place in a cell. (or) is a chemical reaction that happens inside every living cell,
in which energy is released from glucose so that the cell can use it .
Breathing means taking in oxygen and removing carbon dioxide from the lungs.

Glossary
1. Aerobic respiration : respiration that use oxygen