CVS - Exercise & Recovery Flashcards
where is the cardiac control centre located
medulla oblongata
what is the cardiac control centres primary responsibility
regulating the heart (heart rate)
what nervous system is cardiac control centre controlled by & what this means
- automatic nervous system
- under involuntary control
what are the 3 types of neural control
- chemo-receptors
- baro-receptors
- proprio-receptors
what do chemo-receptors detect (2)
- increase in CO2
- decrease in blood pH (increased acidity - lactic acid)
what do baro-receptors detect
increase in blood pressure
what do proprio-receptors detect
increase in muscle movement
what is the type of hormonal control
adrenaline
what does adrenaline do
released before exercise to increase heart rate (fight or flight)
what is the type of intrinsic control
thermo-receptors
what do thermo-receptors detect
increase in body/muscle temperature - result of onset of exercise
where are messages from receptors sent to
medulla oblongata
where do messaged from medulla oblongata go to
cardiac control centre
what nervous system does messages from cardiac control centre go down + what as
- sympathetic nervous system
- electronic impulse
(CCC) where does message down sympathetic nervous system go to
SA node
what does message to SA node do + name of system
- increases impulses from SA node to increase heart rate
- conduction system
what does the parasympathetic nervous system do + why
- decreases heart rate
- cardiac control centre stops receiving messages from receptors
3 factors affecting cardiac control centre
- neural control
- hormonal control
- intrinsic control
what does adrenaline do to SA node
directly stimulates it to increase heart rate & stroke volume
where is the vasomotor control centre found
medulla oblongata
what does the vasomotor control centre control
vascular shunt
what is vascular shunt
redistribution of blood around the body when starting to exercise
which nervous system does the vasomotor control centre stimulate & what does this do
- sympathetic nervous system
- vasodilator or vasoconstrict pre-capillary sphincters & arterioles supplying blood to muscles & organs
what does vasodilation of pre capillary sphincters do
more blood to working muscles when exercising
what does vasodilation of arterioles do
increase blood flow to working muscles when exercising
what is vasodilation of pre-capillary sphincters
opening of them
what is vasoconstriction of pre-capillary sphincters
closure of them
what does vasoconstriction of pre-capillary sphincters do
decrease blood flow to non vital organs when exercising
what does vasoconstriction of pre-capillary sphincters do
decrease blood flow to non vital organs when exercising
where does vasomotor control centre receive information from (5)
- chemo-receptors
- baro-receptors
- proprio-receptors
- adrenaline
- thermo-receptors
what are pre-capillary sphincters
rings of smooth muscle at openings of capillaries
2 ways in which blood is redistributed during vascular shunt
vasodilation & vasoconstriction of:
- pre-capillary sphincters
- arterioles
where is vasomotor control centre & where does it receive message from
- medulla oblongata
- receptors
where is message from vasomotor control centre sent
doen sympathetic nervous system
(VCC) where does message down sympathetic nervous system go to & what does this do
- arterioles & pre-capillary sphincters leading to working muscles - vasodilate - more blood can go to WM when exercise
- arterioles & pre-capillary sphincters leading to non-vital organs - vastoconstrict - less blood to non-vital organs
5 mechanisms of venous return
- pocket valves
- muscle pump
- respiratory pump
- smooth muscle
- gravity
what do pocket valves d0 (2)
- valves in vein
- prevent back flow of blood & direct blood flow back to heart
what does muscle pump do (2)
- vein between muscle
- muscle contract & relax helps push blood through vein back to heart
what does respiratory pump do (4)
- exercise - breathing = deeper & faster
- causes pressure change in thorax & abdomen
- increases pressure in abdomen - large veins in that area squeezed
- this forced blood back to heart
what does smooth muscle do (venous return mechanism) (2)
- contraction & relaxation of smooth muscle within middle layer of veins walls
- pushes blood through veins towards heart
what does gravity do (venous return mechanism)
blood from above heart aided by gravity to help blood flow back to heart
what is starlings law
increase in venous return leads to increase in stroke volume when exercise
how does starlings law work (3)
- heart is muscle - when warms up = more elastic
- means can contain more blood & contract with more force
- means stroke volume increases when start to exercise
