Download The Vasomotor Control Centre

The Vasomotor Control Centre
Learning Objectives…
1) To understand how the VCC affects the
cardiac cycle.
2) To understand how vascular shunting affects
SV/Q/HR.
The vasomotor control centre found in the
medulla oblongata of the brain.
What else is located in the medulla oblongata?
The Vasomotor Control Centre
Chemoreceptor's and baroreceptors
stimulate the VCC.
The Vasomotor Control Centre
VCC stimulates the sympathetic
nervous system which control blood
vessel lumen diameter of organs and
muscles.
Why would your blood vessels need to get bigger?
The Vasomotor Control Centre
Vasodilatation = The widening of blood vessels lumen
Vasoconstriction = The narrowing of blood vessels lumen
Vasoconstriction
Question…
How does the Vasomotor control
centre link to the cardiac control
centre, conduction system and
cardiac cycle?
The Vasomotor Control Centre
Vascular Shunting…..
Describes the redistribution of blood
How would this be different at rest
and during the onset of exercise?
Vascular Shunting
At rest 20 % (approx) of your blood is located
at your muscles and 80% is located in your
organs.
During exercise (depending on the intensity) 80
% (approx) of your blood is located at your
muscles and 20% is located in your organs.
Plot this information on your graph
80%
Muscles
20%
Cardiac Output
Vascular Shunting
Organs
At rest
Exercise
Vascular Shunting
So we now know that blood is moved around
our body when we go from rest to exercise.
Use your textbooks…can you find out what
controls the blood flow in/out of muscles and
organs?
Vascular Shunting
Blood flow to the organs/muscles is controlled
by the VASOCONSTRICTION/VASODILATION
OF ARTERIOLES & PRE CAPILLARY
SPHINCTERS.
The precapillary sphincter is a band of smooth
muscle that adjusts the blood flow into each
capillary.
The arteriole is a smaller version of an artery.
VASCULAR SHUNT MECHANISM
During the onset of exercise
What happens at
your
ORGANS
INCREASED STIMULATION OF
SYMPATHETIC NERVES
VASOCONSTRICTION OF
ARTERIOLES & PRE CAPILLARY
SPHINCTERS
DECREASED BLOOD FLOW (Q)
TO CAPILLARIES OR NON
ESSENTIAL ORGANS
What happens at
your
MUSCLES
DECREASED STIMULATION OF
SYMPATHETIC NERVES
VASODILATION OF ARTERIOLES
& PRE CAPILLARY SPHINCTERS
INCREASED BLOOD FLOW (Q)
TO CAPILLARIES OR WORKING
MUSCLES