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Flashcards in the mechanism of breathing Deck (10):
1

what is inspiration (inhalation)?

when the air pressure of the atmosphere is greater than that of the lungs, and air is forced into the lungs.

2

what is expiration (exhalation)?

when the air pressure of the lungs is greater than that of the atmosphere, and air is forced out of the lungs.

3

what kind of process is inspiration?

an active process - it uses energy

4

describe the stages of inspiration/breathing in

the external intercostal muscles contract, the internal intercostal muscles relax.

the ribs are pulled upwards and outwards, increasing the volume of the thorax.

diaphragm muscles contract (it flattens), further increasing the volume of the thorax.

the increased volume of the thorax = reduced pressure in the lungs

atmospheric pressure > pulmonary pressure - air is forced into lungs

5

describe the stages of expiration/breathing out

the internal intercostal muscles contract, the external intercostal muscles relax.

the ribs are pulled downwards and inwards, decreasing the volume of the thorax.

diaphragm muscles relax, further decreasing the volume of the thorax.

the decreased volume of the thorax = increased pressure in the lungs

atmospheric pressure < pulmonary pressure - air is forced into lungs

6

what kind of process is expiration?

largely passive process - does not require much energy

7

what is pulmonary ventilation rate?

the total volume of air that is moved into the lungs in 1 minute

8

what is tidal volume?

the volume of air normally taken in when the body is at rest - usually around 0.5 dm^3

9

what is breathing rate?

number of breaths taken in one minute

10

pulmonary ventilation rate formula

tidal volume (dm^3) x breathing rate (per min)