Integration of CV mechanisms

Question 1

Major resistance vessels?

Answer 1

Arterioles

Question 2

What two factors affect blood flow in vessels? (resistance)

Answer 2

1. Radius

2. Vessel length

Question 3

What are the extrinsic control mechanisms for BP?

Answer 3

1. Nerves

2. Hormones

Question 4

Explain nerve control mechanisms

Answer 4

1. Nerves- sympa/parasympahetic stimulation- causes vasoconstriction/ dilation respectively.

Question 5

Explain hormone control mechanisms

Answer 5

2. Hormones- Adrenaline: on alpha receptors- vasoconstriction
   on B receptors- vasodilation
   - Angiotensin II: Vasoconstriction
   - Vasopressin: “

Question 6

What are the intrinsic control mechanisms for BP?

Answer 6

1. Physical

2. Chemical

Question 7

What are the physical changes?

Answer 7

1. Temperature
   - Warmth- dilate
   - Cold- constrict
2. Mygoenic response
   MAP falls- vasodilate
   MAP Rises- vasoconstrict
3. Sheer Stress
   Dilatation of arterioles causes sheer stress in arteries upstream, making them dilate. Improves blood flow to local area