Vascular Shunting

Question 1

What is vascular shunting?

Answer 1

During exercise the cardiovascular system redistributes blood from inactive areas (digestive organs) to active areas (working muscles) via a vascular shunt mechanism

Question 2

Define vasomotor control

Answer 2

> The ability of arteries and arterioles to change their shape

Question 3

Explain vasomotor control

Answer 3

> During exercise, sensory receptors are stimulated - the vasomotor control centre receives this information
Sympathetic neves carry the impulses to muscle walls of arteries and arterioles
Causing them to vasoconstrict or vasodilate (regulating blood flow)

Question 4

Define venomotor control

Answer 4

> The limited capacity of veins to change their shape

Question 5

Explain the process that occurs at inactive tissue

Answer 5

> Impulses cause vasoconstriction (narrowing of the lumen) of arteries
Pre-capillary sphincters - (segments of smooth muscle that help to direct blood flow into capillaries) constrict
Blood flow is restricted into the capillary bed of the non-active tissue

Question 6

Explain the process that occurs at active tissue

Answer 6

> Impulses cause vasodilation (widening of the lumen) of arteries
Pre-capillary sphincters relax
Blood flow is increased into the capillary bed of the active tissue

Question 7

Explain vasoconstriction during exercise

Answer 7

> Artery constricts to narrow the lumen
Inner muscle contracts to do this
Reducing blood flow to inactive areas (digestive organs)
Reducing delivery of oxygenated blood

Question 8

Explain vasodilation during exercise

Answer 8

> Artery dilates to widen the lumen
Inner muscle relaxes to do this
Increasing blood flow to active areas ( working muscles)
Increasing delivery of oxygenated blood