Physiology

Question 1

Internal Respiration definition

Answer 1

oxygen from blood to tissues -> metabolism -> CO2 from tissues to blood

Question 2

External Respiration definition

Answer 2

exchange of O2 and CO2 from atmosphere to blood across the lungs

Question 3

Boyle’s law

Answer 3

at constant temp. P ∝ 1/V

Question 4

Innervation to the diaphragm

Answer 4

C3, 4, 5 - phrenic nerve

Question 5

LaPlace’s Law

Answer 5

inward collapsing P = 2surface tension/radius

so smaller alveoli are more likely to collapse

Question 6

Active expiration muscles

Answer 6

abdominal muscles and internal intercostals

Question 7

Accessory muscles of forceful inspiration

Answer 7

scalenus and sternocleidomastoid

Question 8

Spirometry pattern for obstructive disease

Answer 8

FVC normal(or low) FEV1 low FEV1% low

Question 9

Spirometry pattern for restrictive

Answer 9

FVC low FEV1 low FEV1% normal

Question 10

Pulmonary ventilation =

Answer 10

in litres per minute TVxRR

Question 11

Alveolare ventilation =

Answer 11

vol air exchanged between envnt and alveoli, in litres per min : (TV- dead space)xRR

Question 12

Anatomical dead space =

Answer 12

airway - air not available for gas exchange

Question 13

Alveolar dead space =

Answer 13

Ventilated alveoli not adequately perfused

Question 14

Dalton’s Law of partial pressures

Answer 14

Ptotal = sum of PPs in mixture

Question 15

Fick’s law of diffusion

Answer 15

rate of gas transfer across a membrane ∝ SA/thickness

Question 16

Henry’s Law

Answer 16

amount of gas dissolved in a liquid ∝ P gas in equilibrium (between gas and liquid) with liquid

Question 17

Bohr effect

Answer 17

Conditions in the tissues shift the O2 Hb dissociation curve to the right - more O2 released at tissues

Question 18

Factors in tissues that shift O2 Hb dissociation curve to right

Answer 18

Metabolites: increased CO2, H+, temp., 2,3 - biphosphoglycerate

Question 19

Foetal Hb compared to adult’s

Answer 19

curve is shifted to left and so O2 moves from mother to foetus even if PO2 low

Question 20

Part of brainstem for Rhythm modification of ventilation

Answer 20

Pons

Question 21

Pneumotaxic centre in pons:

Answer 21

dorsal firing stimulates -> inhibits inspiration

Question 22

Apneustic centre in pons:

Answer 22

excites dorsal -> prolonged inspiration

Question 23

Main rhythm control of ventilation in medulla:

Answer 23

Pre-Botzinger Complex

Question 24

Neural area that causes inspiration and passive expiration

Answer 24

Dorsal group in medulla (firing = insp - ceases = exp)

Question 25

Neural area that causes active expiration

Answer 25

Ventral group (excited by increased dorsal firing in hyperventilation)

Question 26

Hering Breuer reflex

Answer 26

stretch receptors in bronchi/oles walls activated in inspiration -> afferent that inhibits insp. preventing hyperinflation

Question 27

Peripheral chemoreceptors

Answer 27

carotid and aortic bodies - sense O2 and CO2 tensions and H+ concn in blood

Question 28

Central chemoreceptors

Answer 28

near surface of medulla - sense concn of H+ in CSF

Question 29

Blood brain barrier is permeable to

Answer 29

CO2 - not H+ but if CO2 increases then H+ increases in CSF as is produced due to the equilibrium

Question 30

hypercapnia stimulates

Answer 30

mainly central chemoreceptors (H+) and peripheral chemoreceptors (CO2) a little -> increase ventilation

Question 31

hypoxic drive occurs at a PO2 of____ which stims____chemoreceptors

Question 32

H+ drive

Answer 32

Peripheral chemoreceptors affected - adjust for acidosis by hyperventilation to blow off CO2

Question 33

Predominant autonomic control of airway SM

Answer 33

parasympathetic