W9 - The Circulatory System

Question 1

Elastic arteries function

Answer 1

Conducting vessels - use elastic recoil to conduct blood away from the heart (1.0-2.4cm)

Question 2

Muscular arteries function

Answer 2

Distributing vessels - change diametre to control blood flow to body regions and organs (0.3mm-1cm)

Question 3

Arterioles function

Answer 3

Resistance vessels - change diameter to control resistance to blood flow and flow into tissues and capillary beds (10um-0.3mm)

Question 4

List the types of resistance

Answer 4

viscosity, vessel length and vessel diameter

Question 5

Equation for Mean arteriole pressure

Answer 5

MAP = diastolic + (1/3 X pulse pressure)

Question 6

Equation for pulse pressure

Answer 6

PP = systolic pressure - diastolic pressure

Question 7

What is Systolic pressure?

Answer 7

The pressure in the arteries when the heart ventricles contract

Question 8

What is Diastolic pressure?

Answer 8

The pressure in the arteries when the heart ventricles relax

Question 9

What is autoregulation?

Answer 9

occurs within tissues and is dependent on local conditions (all about vessel diameter)
Intrinsic regulation:
Metabolic control  local arterioles dilate/constrict to increase/reduce blood flow
Myogenic control  high systemic BP will cause arteriole stretch, reflex constriction and decrease blood flow to capillary bed to prevent damage (BP drops = reduced stretch = dilation)

Question 10

What is neural regulation?

Answer 10

involves the cardiovascular centres, the autonomic system and baroreceptor reflex
Cardioinhibitory centre  parasympathetic input [via CN X] into SA and AV nodes, slows HR and decrease CO
Cardioacceleratory (cardiostimulatory) centre  sympathetic input into the SA and AV nodes, increases HR and CO
Cardioacceleratory (cardiostimulatory) centre  sympathetic input into the ventricular myocardium, increases the force of contraction and stroke volume and CO
Vasomotor centre  sympathetic innervation of vasomotor fibres (increased sympathetic activity = vasoconstriction and increased BP, decreased sympathetic division = vasodilation and decreased BP)
Baroreceptors (stretch receptors detect changes in pressure)

Question 11

What is renal regulation?

Answer 11

RAAS