Respiratory

Question 1

Tidal volume =

Answer 1

Volume of air drawn in and out of the lungs during NORMAL breathing

Usually 500ml (0.5L)

Question 2

Inspiratory reserve volume =

Answer 2

Volume of air that can be inspired at the end of a normal inspiration (difference between resting inspiration and maximum inspiration)

Question 3

Expiratory reserve volume =

Answer 3

Volume of air that can be expired at the end of a normal expiration (difference between resting expiration and maximum expiration)

Question 4

Residual volume =

Answer 4

Volume of air remaining in the lungs after maximal expiration

Question 5

Vital capacity =

Answer 5

Maximum tidal volume when an individual breathes in and out as far as possible

IRV + TV + ERC

Question 6

Total ventilation =

Answer 6

tidal volume x respiratory rate

Question 7

Anatomical deadspace =

Answer 7

Anatomical dead space is represented by the volume of air that fills the conducting zone of respiration made up by the nose, trachea, and bronchi.

(anything not aveoli)

Question 8

Alveolar dead space =

Answer 8

Refers to alveoli incapable of gas exchange

(minimal in health)

Question 9

Physiological dead space =

Answer 9

sum of anatomical and alveolar dead space

Question 10

Ventilation (V) =

Answer 10

flow of gas

Question 11

Perfusion (Q) =

Answer 11

flow of blood

Question 12

Dead space V/Q mismatch

Answer 12

Lung region with normal alveolar ventilation but absent perfusion e.g. PE

Q = 0, V/Q = infinity

Question 13

True shunt V/Q mismatch

Answer 13

Lung region with normal perfusion but absent alveolar ventilation

Caused by complete collapse or consolidation of a lung region

V = 0, V/Q = 0

Question 14

Difference between type I & type II alveolar pneumocytes?

Answer 14

Type II secrete surfactant

Question 15

At all volumes which bit of the lung has greatest compliance?

Answer 15

Base

Question 16

Actions of surfactant in the lungs (3)

Answer 16

Prevent alveolar collapse, increase lung compliance and prevents transudation of fluid into alveoli

Question 17

Receptors that mediate brochoconstriction

Answer 17

Muscarinic receptrs

Question 18

Receptors that mediate bronchodilation

Answer 18

B2 adrenoreceptors

Question 19

Partial pressures of PO2 and PCO2 in inhaled air

Answer 19

21.2

0.0(4)

Question 20

Partial pressures of PO2 and PCO2 in inspired air in the airways (humidified)

Answer 20

19.1

0.0

Question 21

Partial pressures of PO2 and PCO2 in alveolar air (after equilibrium with pulmonary capillaries)

Answer 21

13.3

5.3

Question 22

Partial pressures of PO2 and PCO2 in exhaled air

Answer 22

15.5

4.3

Question 23

Rate of gas transfer is limited by what? (2)

Answer 23

Diffusion or perfussion

Question 24

Respiratory centre(s) in which parts of the brain stem

Answer 24

Pons & medulla

Question 25

3 major respiratory groups of neurons

Answer 25

dorsal respiratory group (medulla) , ventral RG (medulla) & pontine RG

Question 26

Which respiratory group of neurones initiates respiration?

Answer 26

dorsal respiratory group

Question 27

Which respiratory group of neurones determines the rhythm of breathing?

Answer 27

dorsal respiratory group

Question 27

What excites the DRG during exercise?

Answer 27

Apneustic centre in the pons

Question 28

What does the DRG stimulate? (2)

Answer 28

Phrenic nerve -> diaphragm

Thoracic nerves -> Ex. ICMs

Question 29

What inhibits the DRG?

Answer 29

Pneumotaxic centre

Question 30

When is the VRG activated?

action

Answer 30

Forced expiration

Inhibits the apneustic centre

Question 31

Respiratory voluntary control comes from?

Answer 31

Via cortical motor neurones in pyramidal tract

Question 32

Central respiratory chemoreceptors are detecting?

Answer 32

pH of CSF (controlled by pCO2, which is diffusing into the CSF)

Question 33

Where are peripheral respiratory chemoreceptors found?

Innervated by?

Answer 33

Carotid body which lies at the bifurcation of the common carotid arteries

&

Aortic bodies at the aortic arch

Glossopharyngeal nerve

&

Vagus nerve

Question 34

Where are central respiratory chemoreceptors found?

Answer 34

Medulla

Question 35

Stretch receptors in the lungs are located where?

Answer 35

Smooth muscle of bronchial walls

Question 36

What does activation of pulmonary stretch receptors do?

Answer 36

Delays next inspiratory cycle and causes short, shallow breaths

Question 37

Which receptors are involved in tachynpnoea due to odema, emboli or inflammation

Answer 37

J receptors

Question 38

Stimulation of pulmonary irritant receptors causes?

Answer 38

Reflex bronchial and laryngeal constriction