circulatory responses to exercise and special circulations- week 6

Question 1

what changes when change occurs to vessels?

Answer 1

change of flow and velocity

Question 2

what is hyperaemia ?

Answer 2

blood flow increases in relation to the metabolic activity of a tissue/ organ

Question 3

what is tissue hypoxia ?

Answer 3

not enough O2 causes dilation for O2 exchange

Question 4

what else causes blood flow to increase ? (increase in dilation) (5)

Answer 4

CO2 increase

pH decrease

increased lactate production

breakdown of products of ATP

osmolality

Question 5

how does endothelial cells effect vasodilation ? (3)

Answer 5

release of nitric oxide which goes into smooth muscle

releases CGMP

causing vasodilation

Question 6

give an example of the effect of CGMP

Answer 6

when viagra is taken

causes prolonged effect of CGMP

increased effect of vasodilation in the penis

Question 7

what is released from tissues during inflammation and what can reduce it ?

Answer 7

prostaglandins increase in inflammation

ibuprofen reduces PGs

Question 8

what are the changes to blood flow to skeletal muscle during exercise ?

Answer 8

during exercise 80-85% of CO is taken to muscles

Question 9

what happens to organs during exercise ?

Answer 9

reduced blood flow

redistribution depends on metabolic rate

Question 10

as _ increases, _ to skeletal muscle increases

Answer 10

VO2 max

redistribution

Question 11

_ of vasodilation is _ to the size of recruited muscle mass

Answer 11

magnitude

proportional

Question 12

what is autoregulation ?

Answer 12

blood flow regulation

Question 13

where does vasoconstriction occur during exercise ?

Answer 13

visceral organs and inactive tissues

Question 14

what happens to vascular resistance during vasodilation ?

Answer 14

decreases

Question 15

what happens to vascular resistance during vasoconstriction ?

Answer 15

increases

Question 16

in special regions during exercise where does sympathetic vasoconstriction occur?

Answer 16

inactive organs - resting skeletal muscles , skin etc

Question 17

in special regions during exercise where does metabolic vasodilation occur ?

Answer 17

in active organs

active skeletal muscles, coronary arteries etc

Question 18

in special regions during exercise what occurs in the skin ?

Answer 18

vasodilation for thermoregulation

Question 19

during splanchnic circulation in exercise blood flow decreases so what happens to compensate ?

Answer 19

oxygen extraction increases even with the same consumption at rest

Question 20

what is splanchnic circulation?

Answer 20

blood supply to trunk organs

Question 21

what does contraction of blood flow to the splanchnic region lead to ?

Answer 21

increased blood volume into he circulation back to the heart

aka increased venous return

Question 22

what does adrenergic mean ?

Answer 22

noradrenaline as neurotransmitter

Question 23

what does it mean by adrenergic vasoconstrictor in terms of sympathetic neural control of skin blood vessels?

Answer 23

decreased blood flow to non-hairy skin

Question 24

what does cholinergic mean?

Answer 24

acetylecholine as neurotransmitter

Question 25

what does it mean by cholinergic vasodilator in terms of sympathetic neural control of skin blood vessels?

Answer 25

increased blood flow to hairy skin

allows heat loss

Question 26

what does cold stress lead to ?

Answer 26

vasoconstriction - adrenergic

Question 27

what does heat stress cause ?

Answer 27

vasodilation- cholinergic

Question 28

how does blood pressure relate to skin(cutaneous) circulation ?

Answer 28

in heat blood flow shifted from core to surface

muscle pump can’t assist venous return as filling of heart is reduced

so vasoconstriction occurs to maintain blood pressure