THE RESPIRATORY SYSTEM:

Question 1

Functions of the respiratory system:

Answer 1

• Deliver oxygen from the atmosphere to the lungs
• Provide a method of gaseous exchange within the lungs to allow oxygen to enter and carbon dioxide to leave the blood, and to remove carbon dioxide from the lungs into the atmosphere
• Create speech as air is breathed through the vocal cords
• Facilitate our sense of smell

Question 2

The air passage:

Answer 2

Mouth and nose > Pharynx > larynx > Trachea > Bronchi (left and right bronchus) > bronchioles > alveoli

Question 3

The lungs:

Answer 3

The lungs contain the bronchi, bronchioles and alveoli: gaseous exchange occurs in the alveoli

Question 4

Gaseous Exchange:

Answer 4

• Oxygen enters the alveoli as air is breathed into the lungs
• The venous blood in the capillaries that surround each alveolus is low in oxygen and high in carbon dioxide
• The pressure of oxygen within each alveolus is higher than the pressure of oxygen in the blood of the capillaries
• A gas will move from an area of high pressure to an area of high pressure to an area of low pressure. Therefore, the oxygen moves from the alveoli into the venous blood
• Similarly, the pressure of carbon dioxide in the blood is higher than that in the alveoli, therefore, the carbon dioxide moves from the blood to the alveoli where it can then be breathed out
• Diffusion can occur in the lungs due to the one-cell thickness of the walls of the alveoli and capillaries
• The blood in the capillaries is now rich in oxygen and is returned to the heart to be transported throughout the body

Question 5

The diaphragm

Answer 5

An involuntary smooth muscle which forms the base of the chest cavity and contracts and relaxes to control breathing

Question 6

BREATHING PROCESS

Answer 6

occurs to renew the air in the lungs and consists on the principle that gases move from areas of high pressure to areas of low pressure

Question 7

Inspiration

Answer 7

the pressure of air on the outside is higher than that in the lungs. High pressure will always go to low, therefore, the air enters the lungs and the diaphragm contracts to become flattered (external intercostal muscles contract to lower rib cage)

Question 8

Expiration:

Answer 8

As the diaphragm relaxes to become domed shaped, pressure is built up in the lungs as they get more condensed. High pressure will go to low pressure and therefore, the air in the lungs is breathed back out (internal intercostal muscles contract to lower rib cage)

Question 9

Lung volumes:

Answer 9

The resting lung volume of the average sized person is about 3 litres and can be increased by half during an inspiration and a forced maximum expiration lowers the remaining volume as little as 1 litre.

Question 10

Total lung capacity

Answer 10

is the amount of air in the lungs following a maximum inspiration and is calculated by adding the vital capacity of the lungs to the residual volume

Question 11

Vital capacity:

Answer 11

is the greatest volume of air that can be expired after a maximum inspiration
Inspiratory reserve volume: the amount of air that can be inspired during a forced inspiration following a normal inspiration
Expiratory reserve volume: the amount of air that can be expired during a forced expiration, following a normal expiration

Question 12

Residual volume

Answer 12

is the volume of air that remains in the lungs after a forced maximum expiration

Question 13

Tidal volume:

Answer 13

the amount of air that is inspired and expired with each normal breath during rest or any given exercise