circulatory responses to exercise and special circulations- week 6 Flashcards
what changes when change occurs to vessels?
change of flow and velocity
what is hyperaemia ?
blood flow increases in relation to the metabolic activity of a tissue/ organ
what is tissue hypoxia ?
not enough O2 causes dilation for O2 exchange
what else causes blood flow to increase ? (increase in dilation) (5)
CO2 increase
pH decrease
increased lactate production
breakdown of products of ATP
osmolality
how does endothelial cells effect vasodilation ? (3)
release of nitric oxide which goes into smooth muscle
releases CGMP
causing vasodilation
give an example of the effect of CGMP
when viagra is taken
causes prolonged effect of CGMP
increased effect of vasodilation in the penis
what is released from tissues during inflammation and what can reduce it ?
prostaglandins increase in inflammation
ibuprofen reduces PGs
what are the changes to blood flow to skeletal muscle during exercise ?
during exercise 80-85% of CO is taken to muscles
what happens to organs during exercise ?
reduced blood flow
redistribution depends on metabolic rate
as _ increases, _ to skeletal muscle increases
VO2 max
redistribution
_ of vasodilation is _ to the size of recruited muscle mass
magnitude
proportional
what is autoregulation ?
blood flow regulation
where does vasoconstriction occur during exercise ?
visceral organs and inactive tissues
what happens to vascular resistance during vasodilation ?
decreases
what happens to vascular resistance during vasoconstriction ?
increases
in special regions during exercise where does sympathetic vasoconstriction occur?
inactive organs - resting skeletal muscles , skin etc
in special regions during exercise where does metabolic vasodilation occur ?
in active organs
active skeletal muscles, coronary arteries etc
in special regions during exercise what occurs in the skin ?
vasodilation for thermoregulation
during splanchnic circulation in exercise blood flow decreases so what happens to compensate ?
oxygen extraction increases even with the same consumption at rest
what is splanchnic circulation?
blood supply to trunk organs
what does contraction of blood flow to the splanchnic region lead to ?
increased blood volume into he circulation back to the heart
aka increased venous return
what does adrenergic mean ?
noradrenaline as neurotransmitter
what does it mean by adrenergic vasoconstrictor in terms of sympathetic neural control of skin blood vessels?
decreased blood flow to non-hairy skin
what does cholinergic mean?
acetylecholine as neurotransmitter
what does it mean by cholinergic vasodilator in terms of sympathetic neural control of skin blood vessels?
increased blood flow to hairy skin
allows heat loss
what does cold stress lead to ?
vasoconstriction - adrenergic
what does heat stress cause ?
vasodilation- cholinergic
how does blood pressure relate to skin(cutaneous) circulation ?
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
