Ventilation

Question 1

Describe process of inspiration

Answer 1

1. The external intercostal and diaphragm muscles contract.
2. This causes the rib cage to move upwards and outwards, and the diaphragm to flatten increasing the volume of the thorax.
3. As the volume of the thorax increases, the lung pressure decreases below atmospheric pressure
4. This causes air to flow into the lungs- requires energy

Question 2

Describe the process of expiration

Answer 2

1. The external intercostal and diaphragm muscles relax
2. The rib cage moves downwards and inwards and the diaphragm becomes curved again.
3. The thorax volume decreases, causing the air pressure to increase to above atmospheric pressure.
4. Air is forced out of the lungs and the internal intercostal muscles contract to pull the rib cage down and in

Question 3

Define Tidal volume

Answer 3

Volume of air in each breath (usually 0.4 dm cubed )

Question 4

Define vital capacity

Answer 4

Maximum volume of air that can be breathed in or out

Question 5

Define oxygen consumption or oxygen intake

Answer 5

The rate at which an organism uses of oxygen ( e.g. the number of decimetre cubed to used per minute)

Question 6

Define residual volume

Answer 6

Volume of air that always remains in the lungs-prevents lungs collapsing; prevents inner surfaces sticking together; continual gas exchange

Question 7

Define inspiratory and expiratory reserve volume

Answer 7

Inspiratory- how much more air can be breathed in over and above the normal tidal volume when you take in a big breath
Expiratory - how much more air can be breathed out over and above the normal tidal volume

Question 8

Define total lung volume

Answer 8

Vital capacity plus residual air in lungs

Question 9

Define breathing rate

Answer 9

Number of breaths per minute