Ventillation

Question 1

Ventilation:

Answer 1

Ventilation: the refreshing of the air in the lungs, so that there is a higher oxygen concentration in the blood and lower carbon dioxide concentration.
- Ensures CO2 is higher in the blood and O2 concentration is higher in the alveoli.

Question 2

How is Ventilation produced

Answer 2

Ventilation is produced by the action of the external & internal intercostal muscles and the diaphragm.

Question 3

Inspiration (Inhalation)

Answer 3

•Diaphragm contracts to move down and become flatter – displaces digestive organs downwards.
•External intercostal muscles contract to raise ribs
•Volume of thoracic cavity increased.
•Pressure in chest cavity drops below Atmospheric.
•Air moved into lungs. Active process.

Question 4

Expiration (exhalation)

Answer 4

•Diaphragm relaxes and is pushed up by displaced organs beneath.
•External intercostal muscles relax, and ribs fall. Internal intercostal muscles can contract to push air out more forcefully (exercise/coughing/sneezing).
•Volume of thoracic cavity deceased.
•Pressure in the lungs rises above the pressure in the surrounding atmosphere.
•Air moved out of lungs. Passive process.

Question 5

Precautions:

Answer 5

•subject is healthy and asthma free
•soda lime is fresh and functioning, drum filled with fresh air {ensure no normal levels of O2 and no build up of CO2
•mouthpiece sterilised(avoid infection)
•no air leaks in apparatus, nose clips (valid measurements)