Physiological Function Of The Respiratory System

Question 1

What are the main physiological function of the lungs?

Answer 1

Has exchange between the blood and the external environment
Diffusion of oxygen and carbon dioxide between capillaries and cells
Transport of oxygen to and carbon dioxide from the body cells in the blood

Question 2

What is the secondary property of the respiratory system?

Answer 2

Host defence: mucocillary clearance system and immune response mech

Question 3

What is the mechanism of breathing?

Answer 3

Breathing in:
- diaphragm contracts and flattens
- intercostal muscle contract and raise
- decreasing Pa in the lungs so air rushes in
Breathing out:
- diaphragm relaxes
- intercostal muscles relax and fall
- increasing pressure in the lungs, and so air is pushed out

Question 4

What is the composition of atmospheric air?

Answer 4

79% nitrogen

0. 04% carbon dioxide
1. 96% oxygen

Question 5

The physiology of the alveoli which maximise gaseous exchange?

Answer 5

A very large SA (70m^2)
Dense network of capillaries with a thin alveolar-capillary membrane for easy nutrient passage
Produces surfactant to reduce surface tension

Question 6

What is the process of gaseous exchange?

Answer 6

Gases move by diffusion down gradients is partial pressure between alveoli and pulmonary capillary blood and between systemic capillary blood and interstitial fluid

Question 7

What are the changes in the respiratory system when it comes to exercise?

Answer 7

Diffusion capacity increases during exercise
Larger tidal volumes from inflated alveoli and increased (more pulmonary capillaries perfumes)
Rescues in diffusion capacity: thickening of air-blood barrier

Question 8

What carries the oxygen around the body?

Answer 8

97% of oxygen in blood carried by haemoglobin, and rest dissolved in plasma
Hb protein carries 4 O2

Question 9

What removes CO2 from the body?

Answer 9

The blood: - 70% in bicarb ions

• 23% in Hb blood
• and the rest is dissolved in the plasma

Question 10

What are the definitions of tidal col, inspiratory reserve vol, expiratory reserve vol, residual vol, inspiratory capacity, function residual capacity and vital capacity?

Answer 10

Tidal vol: - vol of air inspired or expired during normal insp or exp
IRV: vol of air inspired forcefully after inspiration of tidal vol
ERV: same as above but exp
Residual vol: vol of air still remain in resp passages and lungs after the most forceful exp
Inspiratory capacity: tidal vol plus IRV
Functional residual capacity: ERV plus residual vol
Vital capacity: IRV + tidal vol + ERV