Week 6- circulatory responses to exercise and special circulations Flashcards
What vessels does macrocirculation occur?
-conduit arteries
-feed arteries
What vessels does microcirculation occur?
-resistance arterioles
-terminal arterioles
-capillaries
What are the different potential influences of the vasculature?
-neural
-hormonal
-metabolic
-EDRF
What does myogenic mean?
everything stays in equilibrium
What is hyperaemia?
blood flow increases in relation to the metabolic activity of a tissue/organ
What happens when tissue hypoxia occurs?
vasodilation
What happens when there is an increase in carbon dioxide?
vasodilation
What happens when the pH decreases?
lactate production, protons produced, allows for vasodilation
What are other ways of metabolic regulation of resistance vessels?
-lactate production
-breakdown products of ATP
-potassium
-osmolarity
What do endothelial cells release?
nitric oxide which enters vascular smooth muscle
What occurs when nitric oxide enters the vascular smooth muscle?
CGMP release
What does Viagra allow for?
prolonged effects of CGMP, vasodilatory effects last for longer
What vessels allow for sympathetic vasoconstriction?
-conduit arteries
-feed arteries
What vessels allow for EDRFs (endothelial derived relaxing factor)?
-conduit arteries
-feed arteries
-arterioles
What vessels allow for metabolic vasodilation?
-arterioles
-feed arteries
What does the cardiac output to skeletal muscle change to during exercise?
80-85% from 15-20% at rest
What does skeletal muscle vasodilation cause?
decrease in vascular resistance
What is hyperaemia?
the magnitude of vasodilation in proportion to the size of recruited muscle mass
What percent of total blood volume is in the splanchnic region?
20-25%
What does constriction in the splanchnic circulation cause?
the addition of blood volume into the circulation back to the heart increasing venous return
What does the skin (cutaneous) detect?
pressure
temperature changes
touch
What controls skin blood vessels?
sympathetic neural control
What is an adrenergic vasoconstrictor?
-non-hairy skin
-noradrenaline as neurotransmitter
What is a cholinergic vasodilator?
-hairy skin
-acetylcholine as a neurotransmitter
What does cold stress lead to?
vasoconstriction
What does heat stress lead to?
vasodilation
When exercising in heat where is the blood flow shifted to and from?
from the core to the surface
What happens when filling of the heart is decreased?
vasoconstriction occurs to maintain blood pressure
