Circulation

Question 1

systemic circulation pathway

Answer 1

oxygenation blood leaves left ventricle via aorta
blood deoxygenated through capillary beds
deoxygenated blood enters right atrium via vena cavae

Question 2

pulmonary circulation pathway

Answer 2

deoxygenation blood leaves right ventricle via pulmonary arteries
blood oxygenated through capillaries of the alveoli
oxygenated blood enters left atrium via pulmonary veins

Question 3

coronary circulation pathway

Answer 3

oxygenation blood from left ventricle enters aorta
small portion is diverted into the left and right coronary arteries via the coronary sinuses
- right: in posterior interventricular sinus
- left: in anterior interventricular sinus
deoxygenated blood brains directly into right atrium

Question 4

waves on cardiogram

Answer 4

P wave = atrial contraction from SA node depolarisation
plateau = delay from AV node
QRS complex = ventricular contraction beginning from apex due to AV node depolarisation
- repolarisation of SV node

Question 5

state of valves during:
ventricular filling

Answer 5

AV valves: open
SL valves: closed

Question 6

what induces AV valve closing post ventricular filling

Answer 6

when ventricular pressure exceeds that of the atria

Question 7

state of valves during:
isovolumetric contraction

Answer 7

AV valves: closed
SL valves: closed
- allows for increase in ventricular pressure to close AV valve

Question 8

state of valves during:
ejection

Answer 8

AV valves: closed
SL valves: open

Question 9

state of valves during:
isovolumetric relaxation

Answer 9

AV valves: closed
SL valves: closed
AV valve remains shut until atrial pressure exceeds ventricular pressure

Question 10

mean arterial pressure

Answer 10

1/3 systole pressure + 2/3 diastole pressure

Question 11

blood pressure reading

Answer 11

upper (larger) value = systolic pressure
lower (smaller) value = diastolic pressure

Question 12

central venous pressure

Answer 12

pressure in the vena cavae

Question 13

starlings law

Answer 13

increase in contractile energy is proportional to ventricular stretch

Question 14

cardiac baroreceptors locations

Answer 14

aortic arch (blood to body) and carotid (blood to brain)

Question 15

cardiac baroreceptors

Answer 15

detect stretch in walls of major arteries

Question 16

blood pressure for hypotension

Answer 16

<90mmHg

Question 17

blood pressure for hypertension

Answer 17

> 140mmHg

Question 18

what is shown by poiseuilles law

Answer 18

change in lumen radius alters resistance by a power of 4

Question 19

control of flow distribution during rest

Answer 19

metabolic rates in tissues and organs

Question 20

intrinsic control of flow distribution

Answer 20

myogenic response
endothelial secretion
vasoactive metabolites
temperature

Question 21

extrinsic control of flow distribution

Answer 21

overrides intrinsic controls
vasomotor nerves
vasomotor hormones
fight/flight responses

Question 22

affect of myogenic responses on blood flow

Answer 22

myocytes = functional muscle units
myocytes depolarise when stretched
increase in arterial pressure causes stretch inducing constriction
decrease in arterial pressure reduces stretch inducing dilation

Question 23

endothelin-1

Answer 23

vasocontrictor endothelial secretion

Question 24

nitric oxide

Answer 24

vasodilator endothelial secretion

Question 25

vasoactive metabolites

Answer 25

the amount of metabolites released during myocardial activity can indicate the amount of blood flow needed

Question 26

affect of temperature on flow distribution

Answer 26

vasodilation with heat vasoconstriction with cold

Question 27

vasomotor nerves

Answer 27

release of hormones sympathetic vasoconstrictors: - noradrenaline acts on alpha receptors on vascular myocytes sympathetic vasodilators: - noradrenaline - acetylcholine parasympathetic vasodilators: - acetylcholine

Question 28

vasomotor hormones

Answer 28

vasopressin = constrictor angiotensin = constrictor adrenaline = constrictor/dilator atrial natriuretic peptide = dilator insulin = dilator

Question 29

affect of flight/fight response on flow distribution

Answer 29

redistribution of blood from digestive system to muscular system adrenaline acts on both alpha (vascular) and beta (cardiac) adrenoreceptors

Question 30

cardiac output calculation

Answer 30

heart rate (bpm) x stroke volume (L)