Integration Of Cardiovascular Mechanisms

Question 1

Overview of circulation and functions of different vessels:

Answer 1

Arterioles - Major resistance vessels
Capillaries - Gas, nutrients and water exchange
Veins - Holds most blood volume

Question 2

Factors influencing MAP:

Answer 2

Regulating HR SV and SVR regulates MAP

MAP = DBP + 1/3pulse pressure

Question 3

Factors influencing vascular resistance:

Answer 3

Regulated by smooth muscles
- Vasoconstriction increases SVR and MAP
- Vasodilation decreases SVR and MAP
- Can change radius of arterioles (larger radius, higher SVR)

Arterioles are main site of SVR

Question 4

Extrinsic and intrinsic mechanisms that influence vascular smooth muscle and systematic vascular resistance (SVR):

Answer 4

Extrinsic:
- Control by nerves and hormones
- E.g. noradrenaline acting on alpha receptors
- Smooth muscle partially constricted at rest (Vasomotor Tone - caused by tonic discharge of sympathetic nerves)
- Increased vasomotor tone = vasoconstriction
- Decreased vasomotor tone = vasodilation
- Adrenaline acts on alpha = vasoconstriction
- Adrenaline acts on Beta2 = vasodilation

Question 5

Factors influencing venous return (VR):

Question 6

Acute and chronic cardiovascular response to exercise: