Respiratory system

Question 1

What is breathing??

Answer 1

The exchange of gases through taking air into and out of the lungs.

Question 2

Where are your lungs?

Answer 2

In the upper part of your chest.

Question 3

What separates the lungs from the digestive organs?

Answer 3

The diaphragm.

Question 4

What gasses are inhaled?

Answer 4

Carbon dioxide, nitrogen, oxygen and argon.

Question 5

What gasses are exhaled?

Answer 5

Carbon dioxide, nitrogen, oxygen and argon.

Question 6

How much of each gas do you breathe in and out?

Answer 6

• Breath in less carbon dioxide.
• The same amount of nitrogen is inhaled and exhaled.
• Breath in more oxygen.
• The same amount of argon is inhaled and exhaled.

Question 7

What happens to lung volume during inhalation?

Answer 7

It increases.

Question 8

What happens to lung volume during exhalation?

Answer 8

It decreases.

Question 9

What happens to lung pressure during inhalation?

Answer 9

It decreases.

Question 10

What happens to lung pressure during exhalation??

Answer 10

It increases.

Question 11

What happens to the intercostal muscles during inhalation?

Answer 11

They contract.

Question 12

What happens to the intercostal muscles during exhalation?

Answer 12

They relax.

Question 13

What happens to the ribs during inhalation?

Answer 13

They move up and out.

Question 14

What happens to the ribs during exhalation?

Answer 14

They relax.

Question 15

What happens to the diaphragm during inhalation?

Answer 15

It contracts downwards, flattening.

Question 16

What happens to the diaphragm during exhalation?

Answer 16

It relaxes.

Question 17

How is the trachea strengthened?

Answer 17

It has rings of c-shaped cartilage.

Question 18

What connects one rib to the next?

Answer 18

The intercostal muscles.

Question 19

Where does gas exchange take place?

Answer 19

The alveoli.

Question 20

What is breathing also known as?

Answer 20

Ventilation.

Question 21

What adaptions does the alveoli have for gas exchange?

Answer 21

• The wall of an alveolus is a single layer of epithelial cells. The wall of a capillary is a single layer of endothelial cells. This means that there is a short diffusion distance for oxygen from the air in the alveoli to the red blood cells in the capillary. Therefore, making it easier for oxygen to get into the red blood cells.
• The many alveoli mean there is a large surface for gas exchange. About 75m (squared) in an adult.
• Ventilation of the lungs maintains a high concentration of oxygen and low concentration of carbon dioxide in the air in the alveoli.
• A good blood supply ensures that carbon dioxide is continually brought to the lungs and oxygen is carried away, which also helps maintain the high concentration gradient.

Question 22

How do the respiratory and circulatory systems work together?

Answer 22

The red blood cells in the capillaries can pick up oxygen that was inhaled to deliver it throughout the body and bring Co2 to the lungs to get exhaled.

Question 23

How does gas exchange happen?

Answer 23

• Oxygen and carbon dioxide are constantly being supplied and removed via breathing.
• Oxygen can diffuse across the membrane of the cells that line the alveoli, to the outside of the cell. The same applies for the lining of the capillaries, until oxygen eventually diffuses into the red blood cells, where it can bind with haemoglobin to make oxyhemoglobin.
• Carbon dioxide can also diffuse across these membranes and enter the alveoli sacks to then exit the body via the alveolar duct.
• While oxygen is being supplied, it’s also being taken away due to blood flow. This means we’re constantly maintaining a concentration gradient which allows gas exchange to continue.

Question 24

Define gas exchange.

Answer 24

Taking in oxygen and releasing carbon dioxide.

Question 25

Explain the structure of the respiratory system.

Answer 25

• The two lungs fill the thorax.
• The mouth and nose lead to the trachea.
• The trachea splits into two bronchi, one leading to each lung.
• Bronchi divide into many bronchioles.
• Bronchioles lead to alveoli.

Question 26

What keeps the trachea open?

Answer 26

C-shaped rings of cartilage.

Question 27

What are the alveoli?

Answer 27

Small air filled sacs that have a wall consisting of a single layer of thin epithelial cells.

They are the site of gas exchange.

Question 28

What do the walls of the bronchioles and alveoli contain?

Answer 28

Elastic tissue to allow for the expansion of the lungs during breathing.

Question 29

What are the lungs surrounded by?

Answer 29

Pleural membranes, which contain the lungs and allow for expansion when breathing.

Question 30

What encloses the chest cavity?

Answer 30

The ribs.

Question 31

What connects the ribs to eachother?

Answer 31

They are connected to eachother by intercostal muscles.

Question 32

What is the diaphragm?

Answer 32

A sheet of muscle that forms the floor of the chest cavity.

It separates the chest cavity from the abdominal cavity.

Question 33

What does the process of ventilation involve?

Answer 33

Inspiration and expiration.

Question 34

What does ventilation ensure?

Answer 34

That fresh air high in oxygen is brought into the alveoli when we breath in and carbon dioxide is removed when we breath out.

Question 35

What 2 muscles does the process of inspiration involve?

Answer 35

• The diaphragm contracts causing it to move down.
• The external intercostal muscles contract causing the rib cage to move up and outwards.

Question 36

How does elastic tissue assist in expiration?

Answer 36

It recoils, increasing the pressure in the lungs, helping to force air out.

Question 37

What muscles are involved in forced expiration?

Answer 37

The internal intercostal muscles contract causing the rib cage to be pulled in and down more forcefully, expelling air more rapidly from the lungs.

Question 38

What 2 muscles are involved in expiration?

Answer 38

• The rib cage relaxes causing it to move in and down.
• The diaphragm relaxes causing it to move up.

Question 39

Define recoil.

Answer 39

The process where elastic tissues return to their original length after having been stretched/expanded.

Elastic tissue only recoils, it does not contract.

Question 40

What are two other factors that help maximise the rate of diffusion?

Answer 40

• Alveoli walls are coated in a film of moisture. Oxygen dissolves in the water before diffusing across the epithelium of the alveoli. Pulmonary surfactant, produced by some cells in the wall of the alveoli, coats the epithelial cells and reduces the surface tension of water. This makes it easier for the lungs to inflate and stops the surfaces of the alveoli sticking together.
• Rate of diffusion increases with temperature, so body temperature helps to ensure maximum rate of diffusion.