Circulatory responses

Question 1

Hyperaemia

Answer 1

blood flow increases in relation to metabolic activity of a tissue/organ
CO2 increase
pH decrease
lactate production

Question 2

Factors regulating blood flow

Answer 2

sympathetic vasoconstriction
metabolic vasodilation
endothelial derived relaxing factors - nitric oxide/prostaglandins

Question 3

Redistribution blood flow during exercise

Answer 3

increase to working skeletal muscles
80-85%
decrease to less active organs
e.g., liver/kidney

Question 4

Redistribution of local blood flow during exercise

Answer 4

skeletal muscle vasodilation (decrease vascular resistance)
autoregulation
due to changes in local factors (increase nitric oxide, prostaglandins, ATP, adenosine)
inactive muscle vasoconstriction (increase vascular resistance) - reduced to 20-30%

Question 5

Cardiac output redistribution during exercise

Answer 5

skeletal muscles 90% CO
skin
coronary circulation

Question 6

Circulation special regions during exercise

Answer 6

sympathetic vasoconstriction inactive organs (resting muscles, skin)
metabolic vasoconstriction in active organs
thermoregulatory vasodilation in skin

Question 7

Splanchnic circulation duirng exercise

Answer 7

liver, GI tract, pancrease, spleen

oxygen consumption stay same
oxygen extraction increase to compensate
blood flow decrease through symapthetic vasoconstriction

constriction = +blood volume into circulation back to heart = increase SV
more during heat = more CO for skin

Question 8

Skin circulation

Answer 8

rest = 1-3 L.min-1 m2 body surface
max = 7-8

Question 9

Sympathetic neutral control of skin blood vessels

Answer 9

adrenergic vasoconstrictor (noradrenaline) - non-hairy skin
cholinergic vasodilator (acetylcholine) - hairy skin

Question 10

Cold stress

Answer 10

vasoconstriction
sympathetic constrictor activity increases (adrenergic)

Question 11

Heat stress

Answer 11

vasodilation
sympathetic dilator activity increase (cholinergic)

Question 12

Exercise onset

Answer 12

initial vasocontriction
followed by vasodilation

Question 13

Dynamic exercise

Answer 13

vasodilation occur at high threshold than during heating at rest
to lose heat

vasoconstriction during prolonged to maintain central blood volume and venous return

sympathetic cholinergic nerves
nitric oxide

Question 14

Blood pressure regulation

Answer 14

heat = blood shifted from core to surface
muscle pump to aid venous return
filling heart reduced

=vasoconstriction occur to maintain BP

Question 15

Renal blood flow during exercise

Answer 15

flow decrease
oxygen extraction increase

as renal blood flow increase HR decrease

Question 16

Endothelial derived relaxing factors

Answer 16

endothelial cells = release nitric oxide
made from l-arginine (amino acid)
into vascular smooth muscle
release CGMP = vasodilation

Question 17

Prostaglandins

Answer 17

arachidonic acid –> PGs
PGs released from tissues during inflammation or infection

Question 18

Sympathetic vasoconstriction

Answer 18

conduit artery

Question 19

EDRFs

Answer 19

NO/PGs
feed artery

Question 20

Metabolic vasodilation

Answer 20

arterioles

Question 21

Adrenergic vasoconstrictor

Answer 21

non hairy
neurotransmitter = noradrenaline

Question 22

Cholinergic vasodilator

Answer 22

hairy skin
neurotransmitter = acetylcholine

Question 23

Blood flow to skin during rest

Answer 23

100-300 ml.min-1.m2 of body surface

Question 24

Blood flow to skin during exercise

Answer 24

7-8L.min.m2 of body surface

Question 25

Blood flow to splanchnic during rest

Answer 25

1500ml.min-1.m2 of body surface

Question 26

Blood flow to splanchnic during exercise

Answer 26

350ml

Question 27

Blood flow to renal during rest

Answer 27

1200ml

Question 28

Blood flow to renal during exercise

Answer 28

360ml