Intro to the respiratory system

Question 1

Why do we need a respiratory system?

Answer 1

→Our bodies are too large to rely on simple diffusion of gases from the atmosphere to the tissues.

Question 2

What are the three functions the respiratory system has within the body?

Answer 2

→Provides (and ventilates) a specialised surface where gas exchange can take place between the atmosphere and blood.
→Contributes to acid-base balance (e.g. pH of the blood).
→Communication and metabolism.

Question 3

How does oxygen get from the atmosphere into cells?

Answer 3

→O2 inhaled from atmosphere into alveoli within lungs
→O2 diffuses from alveoli into blood within pulmonary capillaries.
→O2 transported in blood, predominantly bound to haemoglobin.
→O2 diffuses into cells/tissues for use in aerobic respiration.
→CO2 diffuses from respiring tissues to blood – exchanged at lungs.

Question 4

Why is ventilation of gas exchange structures necessary?

Answer 4

→Tissues continually demand O2 & produce CO2.

→An adequate concentration gradient between alveolar air and blood is required for efficient gas exchange (diffusion).

Question 5

Why is fresh air required from the atmosphere?

Answer 5

→fresh air required from atmosphere to ensure alveolar oxygen pressure (PAlvO2) = high
→alveolar CO2 pressure (PAlvCO2) = low, relative to the blood.

Question 6

Where do gases naturally move?

Answer 6

Gases naturally move from (connected) areas of higher pressure to lower pressure, until an equilibrium is re-established.

Question 7

What is the ideal gas law?

Answer 7

→PV=nRT

→P = pressure
→V = volume
→ n = number of moles
→R = gas constant 
→T = temperature

Question 8

What does Boyle’s law state?

Answer 8

pressure of a gas is proportional to the number of has molecules within a given volume.

P ∝ n/v

Question 9

What happens if the n remains constant in Boyle’s law and you increase the volume?

Answer 9

→If the n remains constant

→increasing the volume will decrease the pressure.

Question 10

How can we calculate partial pressure?

Answer 10

→Partial pressure can be calculated by multiplying the total pressure by the mole fraction.

Question 11

What is the equation for P gas?

Answer 11

P gas = (P barometric - P H2O) x n gas

P gas = partial pressure of the individual constituent gas

P barometric = atmospheric pressure

P H2O = water vapour pressure and n gas is the mole fraction.

Question 12

What do cells require to function?

Answer 12

→Cells require energy to function, and we need O2 to make that energy

Question 13

What does aerobic respiration require?

Answer 13

→ Aerobic respiration requires O2 and produces CO2. →The atmosphere provides a source of O2, and CO2 can be expelled.