Reg of BP

Question 1

Formula for BP

Answer 1

BP=CO*TPR

Question 2

Formula for CO

Answer 2

CO=SV*HR

Question 3

What regulates CO?

Answer 3

1. Volume (Na)
2. HR (symp/para)
3. Force of contraction (symp)

Question 4

What regulates Vascular Resistance?

Answer 4

1. Vasoconstriction (NE+, Angiotensin+, NO-)
2. Structural changes- remodeling/hypertrophy

Question 5

What systems regulate BP? 2 Major+4 minor

Answer 5

1. Autonomic Nervous System

2. Renin-Angiotensin System

3. Chemoreceptors in Carotid/Aortic bodies
4. Centrally located chemoreceptors
5. Antidiuretic hormone
6. Low pressure baroreceptors: veins, atria, PA

Question 6

How is the autonomic nervous system regulated?

Answer 6

Parasymp: decreases HR

Symp: increases CO & peripheral resistance via increase in HR and contractile force; increases renin from kidneys

Baroreceptors do feedback

Question 7

What is the baroreceptor reflex?

Answer 7

Located in internal carotids, senses stretch

increase in BP –> increase in stretch –> decrease symp/ increase para

Bleeding, standing –> decrease in stretch –> decrease para, increase symp

Question 8

What is the renin-angiotensin-aldosterone system?

Answer 8

Regulated by kidnes, leads to increased Na and H2O retention

Question 9

What are the effects of Angiotensin II?

Answer 9

1. Adrenal cortex: stimulates synthesis & secretion of aldosterone (which acts on renal distal tubule collecting duct to increase Na reabsorption)
2. Vasoconstriction of arterioles
3. Directly stimulates Na/H exchange in kidneys
4. Hypothalamus: increases thirst, antidiuretic hormone (ADH)
5. Increases contractility and ventricular hypertrophy

Question 10

What stimulates renin secretion?

Answer 10

Decreased renal perfusion (mechanoreceptors)

Decreased Na+

Sympathetic activity

Question 11

How is ADH stimulated? What are its effects?

Answer 11

Stimulated by angiotensin II & increase in serum osmolarity

Affects V1 receptors on vasc sm muscle–> vasoconstriction and V2 renal collecting ducts –> increased H2O reabsorption

Question 12

How do the low pressure baroreceptors work?

Answer 12

Activated by increase in blood volume which increases venous/atrial pressure

Effect is to increase ANP which leads to relaxation of vascular smooth muscle & increasing blood flow to kidneys so water and salt can be excreted

Low pressure baroreceptors also increase HR (bc increased CO –> increased renal perfusion & Na/H2O excretion) and decrease antidiuretic hormone