Long-term Regulation of Arterial Pressure

Question 1

How is blood pressure regulated long term?

Answer 1

By regulating blood volume

Question 2

Why is blood volume a major determinant of arterial pressure?

Answer 2

Influences: venous pressure, venous return, end-diastolic volume, stroke volume and cardiac output

Question 3

How are arterial blood pressure and blood volume related?

Answer 3

Increased blood volume = increased arterial pressure

Increased arterial pressure = decreased blood volume

Question 4

What factors effect blood volume and what controls these factors?

Answer 4

Changes in sodium ion and water concentration effect blood volume and this is controlled by the kidneys

Question 5

What is the normal value of plasma osmolarity?

Answer 5

-290 mosmol/kg

Question 6

What is plasma osmolarity sensed by?

Answer 6

Hypothalamic osmoreceptors

Question 7

What is the other name for ADH?

Answer 7

Vasopressin

Question 8

How does a decrease in blood pressure effect plasma osmolarity?

Answer 8

Blood osmolarity increases

Question 9

How does an increase in plasma osmolarity effect renin production?

Answer 9

Renin production increases

Question 10

What does renin do?

Answer 10

It cleaves angiotensinogen to form angiotensin I

Question 11

How is angiotensin I converted to angiotensin II?

Answer 11

By the enzyme angiotensin-converting enzyme (ACE)

Question 12

Where is angiotensin II primarily produced?

Answer 12

The lungs

Question 13

What effect does angiotensin II have on water retention and how does this effect blood volume?

Answer 13

Angiotensin II promotes water retention in the kidneys. And increases sodium and chloride ion reabsorption. Water follows solutes by osmosis so water is reabsorbed, increasing blood volume

Question 14

Increased levels of angiotensin II, increases the secretion of what molecule?

Answer 14

Aldosterone

Question 15

Where is aldosterone released from?

Answer 15

The adrenal cortex

Question 16

What effect does aldosterone have on blood volume and how does it achieve this effect?

Answer 16

Aldosterone increases sodium and chloride ion reabsorption and increases potassium ion secretion by altering the activity of the Na/K-ATPase. This promotes water retention and increases blood volume

Question 17

Where is ADH released from?

Answer 17

The posterior pituitary gland

Question 18

What effect does ADH have on blood volume and how does it produce this effect?

Answer 18

ADH increases water permeability of principle cells in the collecting ducts of the kidney by recruiting aquaporin-2 water channels to the surface of these cells. More water is reabsorbed and blood volume increases

Question 19

What effect does ANP have on blood volume and how does it achieve this effect?

Answer 19

It decreases blood volume by increasing water loss by increasing glomerular filtration rate and inhibiting the secretion of aldosterone and ADH.

Question 20

Where is renin released from?

Answer 20

Juxtaglomerular cells in the kidney

Question 21

What is ADH secretion stimulated by?

Answer 21

Angiotensin II

Increase in blood plasma detected by hypothalamus osmoreceptors