Chapter 19 ( role of kidneys in long term arterial pressure)

Question 1

elevated arterial pressure does what to the kidneys?

Answer 1

causes them to excrete more fluid and return the pressure back to normal

Question 2

pressure diuresis-

Answer 2

increase of only a few mm Hg can cause the renal output to more than double the output of water

Question 3

Pressure natriuresis-

Answer 3

same as diuresis but with salt

Question 4

equilibrium point

Answer 4

intake =output

Question 5

2 determinants of long term arterial pressure

Answer 5

1. degree of pressure shift of renal output curve for water and salt
2. level of water and salt intake

Question 6

what does reduced blood pressure do?

Answer 6

activates the sympathetic nervous system and formation of antinatriuretic hormones are increased. The decrease in renal output increases the arterial pressure back to normal

Question 7

salt insensitive people

Answer 7

large amounts of salt changes blood pressure by a little

Question 8

salt sensative people

Answer 8

moderate increases in salt cause significant changes in pressure

Question 9

arterial pressure

Answer 9

cardiac output times peripheral resistance

Question 10

mechanism by which increased fluid volume can elevate arterial pressure by increasing cardiat output or total peripheral resistance

Answer 10

1. increased extracellular fluid volume
2. increases blood volume
3. which increases mean circulatory filling pressure
4. which increases venous return of blood to the heart
5. which increases cardiac output
6. which increases arterial pressure

Question 11

2 ways in which cardiac output can increase arterial pressure

Answer 11

1. ( direct) increased cardiac output increases pressure. 2. ( indirect) effect to raise total peripheral vascular resistance.

Question 12

how does salt incread extracellular fluid volume?

Answer 12

excess salt in the extracellular fluid stimulates the brain for thirst. This causes someone to drink water to return the extracellular salt concentration back to normal.
increased salt levels also stimulates the hypothalamic-posterior pituitary gland to secrete antidiuretic hormone ( ADH). ADH causes the nephron to re-absorb large amounts of water which increases the bodys temperature.

Question 13

chronic hypertension

Answer 13

mean arterial pressure is greater than a upper range of a normal measure ( greater than 110 mmHg)

Question 14

effects of hypertension

Answer 14

excess work load on the heart which leads to coronary disease and heart attacks. Damaging of blood vessels in the brain followed by cerebral infarct ( stroke)., Paralysis, dementia, blindness, kidney problems.

Question 15

reduced kidney mass effects

Answer 15

basically when part of your kidney doesn’t work you retain more salt and increases your blood pressure

Question 16

aldosterone

Answer 16

causes hypertension because it causes the kidneys to reabsorb more water

Question 17

Renin

Answer 17

protein enzyme released by the kidneys when arterial pressure falls too low. It helps correct the pressure level in many ways

Question 18

Prorenin

Answer 18

inactive form of renin and is made in the JG cells

Question 19

JG cells

Answer 19

juxtaglomerular cells. They are modified smooth muslce cells located in afferent arteriole walls

Question 20

Is renin a vasoactive substance?

Answer 20

no its just an enzyme

Question 21

what does renin act on?

Answer 21

angiotensinogen which releases angiotensinogen 1

Question 22

angiotensin 1

Answer 22

mild vasoconstrictor properties but not enough to cause significant changes in circulatory function. Renin persists in blood for 30 minutes to 1 hour and continues to cause formation of still more angiotensin 1 during this entire time

Question 23

angiotensin 2-

Answer 23

powerful vasoconstrictor. It persists in the blood only for 1 to 2 minutes because it is rapidly inactivated by multiple blood and tissue enzymes called antiotensinases

Question 24

effects of angiotensin 2

Answer 24

vasoconstriction , decreases excretion of salt and water from kidneys

Question 25

how long does the renin-angiotensin process take to be fully active?

Answer 25

20 min.

Question 26

retaining salt by angiotensin

Answer 26

acts on kidneys to retain salt and water. Causes adrenal glands to secrete aldosterone

Question 27

mechanism of retention by angiotensin 2

Answer 27

restricts the renal arterioles, which diminishes blood flow through kidneys, acts on tubular cells to increase reabsorption of sodium and water, it stimulates aldosterone from adrenal glands.

Question 28

neurogenic hypertension

Answer 28

caused by strong stimulation of sympathetic nervous system which causes vasoconstriction to occur

Question 29

genetic causes of hypertenstion

Answer 29

in humans is caused by a single gene mutation

Question 30

primary hypertenstion

Answer 30

in 90-95 % of hypertension cases. ITs an unknown origin but lifestyle plays a major role.

Question 31

charecteristics of primary hypertension

Answer 31

cardiac output is increased to additional blood flow required for adipose tissue. Sympathetic nerve activity iis increased. Angiotensin 2 and aldosterone levels are increased twofold to threefold in obese folks. Renal pressure natriuresis mechanism is impaired