Intro to Resp System

Question 1

why do we need a respiratory system? (4 things)

Answer 1

1. Cells require energy to function
2. Aerobic respiration requires O2 and produces CO2
3. The atmosphere provides a source of O2, and CO2 can be expelled.
4. Our bodies are too large to rely on simple diffusion of gases from the atmosphere to tissues- so a respiratory system overcomes this problem

Question 2

having an impaired airway function leads to what?

Answer 2

Insufficient ventilation

Question 3

alveoli have adaptations to maximise what?

Answer 3

maximise the rate of gas exchange

Question 4

name the 3 adaptations the alveoli have to maximise gas exchange:

Answer 4

1. they have a large SA
2. Wall = one cell layer thick + basement membrane fused with blood vessel
3. Richly innervated by capillaries (adequate blood supply)

Question 5

what 6 functions does the respiratory system have within the body?

Answer 5

1. provides a surface where gas exchange can take place between the atmosphere and blood
2. Contributes to acid-base balance (e.g. pH of the blood, making sure its not too acidic or alkaline)
3. Communication
4. Metabolism and production of specific mediators
5. The pulmonary circulation filters particulate matter and emboli reducing systemic circulation exposure
6. Immunological defence (factors that have antimicrobial properties)

Question 6

How does oxygen get from the atmosphere to cells?

Answer 6

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

Question 7

Is the total capacity of the lungs used during every breath?

Answer 7

No

Question 8

Lung volumes & capacities depend on factors such as…

Answer 8

• age, sex and height

- other factors like lung properties (eg. damage due to disease)

Question 9

what does ventilation depend on?

Answer 9

volume (depth) and rate of breathing)

Question 10

what is the equation involving minute volume, tidal volume and frequency?

Answer 10

minute volume=tidal volume x frequency

Question 11

what does minute volume mean?

Answer 11

the total volume of air inhaled in all breaths over one minute (mL)

Question 12

what does tidal volume mean?

Answer 12

the volume of air inhaled in each breath (mL)

Question 13

define frequency:

Answer 13

the number of breaths per minute (min-1)

Question 14

are alveolar air and inspired air the same?

Answer 14

no, as the lungs contain a mixture of ‘fresh’ & ‘stale’ air

Question 15

where it the 1 place gas exchange can occur?

Answer 15

the alveoli

Question 16

The respiratory system is a what?

Answer 16

a two-way system; air enters and leaves via the same path

Question 17

What remains in the airway & lungs at the end of expiration, and what does this mean?

Answer 17

• a residual volume of air
• this means that the final 150mL (dead space volume) of each inspiration never reaches the alveoli or takes place in gas exchange

Question 18

What is alveolar ventilation?

Answer 18

the amount of gas that reaches the alveoli during a breath

Question 19

what is dead space volume?

Answer 19

the volume of air remaining in the respiratory system at the end of expiration (mL)

Question 20

what is alveolar minute volume?

Answer 20

the total volume of fresh air entering the alveoli across all breaths over one minute (mL)

Question 21

gases naturally move from areas of higher pressure to lower pressure until what?

Answer 21

until an equilibrium is re-established.

Question 22

define Boyle’s Law

Answer 22

the pressure of a given mass of an ideal gas is inversely proportional to its volume at a constant temperature

Question 23

what do gases have in a gas phase mixture?

Answer 23

a partial pressure

Question 24

what is a mole fraction?

Answer 24

the % of total moles represented by the individual gas

Question 25

how can partial pressure can be calculated?

Answer 25

by multiplying the total pressure by mole fraction (% of total moles represented by the individual gas)