Theme 3: Lecture 10 - Drug treatments for CVD 1

Question 1

Definition of hypertension

Answer 1

Persistently higher than normal blood pressure

Question 2

How do guidelines say BP should by measured

Answer 2

Using ABPM (ambulatory blood pressure monitoring) or HBPM (home blood pressure monitoring)

Question 3

When is high BP treated

Answer 3

If the mean BP is above 150/95

Question 4

What is a normal BP

Answer 4

120/80

Question 5

BP equation

Answer 5

BP =CO x TPR (total peripheral resistance)

Question 6

Cardiac output equation

Answer 6

CO = stoke volume x HR

Question 7

What is stoke volume regulated by

Answer 7

The ventricles

Question 8

What is total peripheral a measure of

Answer 8

The degree of constriction of the arterioles

Question 9

How does the sympathetic NS increase cardiac output

Answer 9

• It releases noradrenaline and adrenaline which act on alpha 1 receptors on smooth muscle cells causing arterioles to constrict, this leads to an increase in afterload and total peripheral resistance
• Noradrenaline and adrenaline also act on beta 1 receptors on the SAN and ventricular muscle to increase heart rate and force of contraction respectively
• It causes the venules to constrict by acting on alpha 1 receptors of the smooth muscle cells which causes an increase in preload which causes an increase in the force of contraction

Question 10

Which neurotransmitter does the parasympathetic nervous system mainly use

Answer 10

Acetyl choline

Question 11

Describe the biochemical pathway that enables the sympathetic nervous system to increase the force and rate of contraction of the heart

Answer 11

• Sympathetic NS releases adrenaline and noradrenaline
• These act on beta 1 receptors
• Causing an increase in cAMP
• Causing an increase in intracellular Ca2+
• Causing an increase in the force and rate of contraction

Question 12

describe the biochemical pathway that allows the parasympathetic nervous system to decrease the frequency of the heart rate

Answer 12

• Parasympathetic NS releases acetyl choline
• This acts on muscarinic 2 (M2) receptors
• Causing a decrease in cAMP
• Causing a decrease in the frequency of the heart rate

Question 13

Describe the biochemical pathway that enables the sympathetic NS to cause vasoconstriction

Answer 13

• SNS releases noradrenaline
• This acts on alpha 1 receptors
• This causes an increase in inositol triphosphate (IP3)
• This causes an increase in Ca2+ influx into the cell and releases Ca2+ from the intracellular stores
• This leads to vasoconstriction

Question 14

Describe the biochemical pathway that enables the sympathetic NS to cause relaxation of blood vessels

Answer 14

• SNS releases adrenaline
• This acts on beta 2 receptors
• This causes an increase in cAMP
• This leads to relaxation

Question 15

What does angiotensin II do

Answer 15

• Causes an increase in sympathetic activity
• Tubular absorption of Na+ and Cl-, as well as K+ excretion leading to water retention
• Causes aldosterone secretion
• Constriction of arterioles
• The pituitary gland to release ADH

Question 16

How is BP regulated by RAAS

Answer 16

• Decreased cardiac output causes reduced renal flow
• This activates RAAS causing the release of angiotensin II and aldosterone
• Aldosterone causes Na+ and water retention through AT1 receptors which causes an increase in preload causing an increase in BP
• Angiotensin II causes veno constriction through AT1 receptors which causes an increase in preload causing an increase in BP
• Angiotensin II also causes arterio constriction through AT1 receptors causing an increase in afterload which causes an increase in BP

Question 17

AT1 receptor

Answer 17

• Angiotensin II type 1 receptor

- Involved in the RAAS pathway

Question 18

Describe the biochemical pathway that causes an increase in angiotensin II to cause constriction of blood vessels

Answer 18

• Increase in angiotensin II
• Acts on AT1 receptors
• Leads to an increase in IP3 (inositol triphosphate)
• Leads to and increase in intracellular Ca2+
• Causes constriction of arterioles

Question 19

What does the choice of drug depend on

Answer 19

• Age
• Race
• Co existing diseases

Question 20

How does aldosterone aid Na+ and water retention

Answer 20

• Aldosterone activates cytoplasmic receptors which bind to the nucleus to increase expression of Na+ channels
• ENaC (epithelial Na+ channels) sit in the membrane of distal convoluted tubule allowing Na+ to be reabsorbed
• An increase in Na+ retention causes an increase in water retention