Respiratory Cycles & Lung Volumes & Capacities

Question 1

define respiratory cycle

Answer 1

inhalation and exhalation during a single breath

Question 2

what does the amount of air that flows in and out of the lungs depend on?

Answer 2

conditions of inspiration and expiration

Question 3

what are the 4 respiratory volumes

Answer 3

tidal volume (TV)
inspiratory reserve volume (IRV)
expiratory reserve volume (ERV)
residual volume (RV)

Question 4

Define Tidal Volume (TV)

Answer 4

This is the volume of air passing into and out of the lung with each breath during normal breathing

Question 5

How much is TV on average

Answer 5

500ml on a resting adult human

Question 6

Define IRV

Answer 6

This is the extra volume of air that can be forcibly inhaled beyond the tidal volume

Question 7

Define ERV

Answer 7

Extra volume of air which can be forcibly expelled from the lungs after a normal expiration

Question 8

Define RV

Answer 8

Volume of air that remains in the lungs even after a forceful expiration

Question 9

how much is RV on average

Answer 9

about 1200ml

Question 10

what is a respiratory lung capacity

Answer 10

specific combinations of respiratory volumes

Question 11

how many respiratory volumes do respiratory capacities consist of?

Answer 11

2 or more

Question 12

what does respiratory capacities help determine

Answer 12

the respiratory status of a person

Question 13

what are the 4 respiratory capacities

Answer 13

1. Inspiratory Capacity (IC)
2. Functional Residual Capacity (IRC)
3. Vital Capacity (VC)
4. Total Lung Capacity (TLC)

Question 14

Define IC

Answer 14

The total volume of air that can be inspired with maximum effort

Question 15

equation for IC

Answer 15

IC = TV + IRV

Question 16

Define FRC

Answer 16

The volume of air remaining in the lungs at the end of a normal expiration

Question 17

equation for FRC

Answer 17

FRC = RV + ERV

Question 18

Why is FRC important?

Answer 18

1. for the continuous exchange of gas in alveoli
2. to prevent the collapse of alveoli during expiration

Question 19

define VC

Answer 19

maximum volume of air which can be inhaled and exhaled

Question 20

how much is VC normally

Answer 20

4800ml in men
3100ml in women

Question 21

equation for VC

Answer 21

VC = TV + IRV + ERV

Question 22

define TLC

Answer 22

Maximum volume of air lungs can hold/ sum of all lung volumes

Question 23

how much is TLC

Answer 23

6000ml normally

Question 24

define anatomical dead space

Answer 24

some of inspired air fills the system of branching conducting tubes (trachea, bronchi, bronchioles)

this air never contributes to gas exchange in alveoli

this volume of air is anatomical dead space and its typically about 150ml

Question 25

how much is anatomical dead space typically

Answer 25

150 ml