Renal 7 Flashcards

1
Q

What is secretion of K+ for

A

Acts directly on adrenal cortex protecting body from hyperkalemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are 4 causes of aldosterone release

A
  1. Decreased BP
  2. Increased osmolarity
  3. Large drops in plasma Na
  4. Increases in K
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does decreased BP release aldosterone

A

Initiate a pathway that results in production of angiotensin which triggers aldosterone release

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does increased osmolarity trigger release of aldosterone

A

Acts directly on adrenal cortex during dehydration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Renin angiotensin system (RAS)

A

Multi step pathway for maintaining BP
- day to day aldosterone secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the multi step pathway of the renin angiotensin system

A
  • Decrease BP causes release of renin from granular cells
  • renin cleaves angiotensin to ANG I then converted to ANGII by ACE
  • ANG II travels to adrenal cortex and stimulates production of aldosterone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does the renin-angiotensin pathway begin with

A

Renin secretion (enzyme)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What secretes renin

A

Granular cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is renin secretion indirectly stimulate

A

Sense when GFR decreases:
2. Sympathetic neurons activated by CVCC when BP decreased terminated on granular cells
3. Paracrine feedback (prostaglandins) from macula densa cells signal granular cells to secrete

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the direct stimuli that cause renin secretion

A

Low BP in renal arterioles cause granular cells to secrete in response to less stretch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are granular cells also known as

A

Juxtaglomerular cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is renin’s main role

A

Convert an inactive angiotensin, into angiotensin I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is angiotensin

A

Plasma protein constantly circulating in blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is ACE

A

Angiotensin converting enzyme
- enzyme produced in blood vessel endothelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are angiotensin II receptors

A

G protein coupled receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Effects of ANG II

A
  1. Increased sympathetic (increased CO + BP, vasoconstriction)
  2. Proximal tubule Na reabsorption
  3. Thirst
  4. AVP secretion, increased H20 absorption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does ANG II increase proximal tubule Na reabsorption

A

Stimulates an apical Na/H+ exchanger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What do pharmaceutical companies use ACE inhibitors for

A

Treatment of hypertension

19
Q

What does natriuretic peptide (ANP) promote

A

Na+ and water excretion
Less vasopressin

20
Q

Peptide produced and secreted by specialized myocardial cells in atria

A

Atrial natriuretic peptide

21
Q

What caused release of ANP

A

Increased blood volume causes increased stretch of atria causing myocardial cells to release

22
Q

What is the ANP receptor

A

Enzymatic membrane bound receptor acting through cGMP second messenger system

23
Q

Affects of ANP in kidney

A

Relaxes afferent arterioles to increase GFR
Reduce renin release from granular cells, reduce aldosterone and ANG II
Reduce Na reabsorption

24
Q

Affects of ANP at hypothalamus

A

Reduces AVP release
Inhibit thirst

25
Q

Affects of ANP at adrenal cortex

A

Inhibits aldosterone release

26
Q

Affects of ANP at medulla

A

Acts on CVCC to decrease BP

27
Q

Why is potassium balance complicated

A

Reabsorbed and secreted

28
Q

Where is K+ reabsorbed

A

Proximal tubule and ascending limb of loop

29
Q

Where is K+ secreted

A

Distal tubule and cortical collecting duct

30
Q

At normal K+ excretion

A

Reabsorption is less than filtered

31
Q

Low K+ does what to aldosterone

A

Decreases aldosterone
Reducing secretion which reduces excretion

32
Q

High K+ stimulates what

A

Aldosterone release
Increases secretion and excretion

33
Q

Alterations in body K levels affects what

A

The resting membrane potential of all cells

34
Q

Increased K+ in ECF

A

Hyperkalemia
Reduced efflux from cell, more K+ retained
Causes hyper excitation

35
Q

Low K+ around cell

A

Hypokalemia
Increased K+ leakage
Hyperpolarizes cell causing larger stimulus to reach threshold

36
Q

Where is potassium balance especially important

A

Excitable tissues such as heart and skeletal muscles

37
Q

What does hypokalemia cause

A

Muscle weakness because more difficult for hyperpolarized motor neurons and muscles to fire APs

38
Q

What is effects of hyperkalemia

A

More dangerous, initially leads to hyperexcitability
Eventually cells unable to repolarize and become less excitable
Arythmias in heart

39
Q

What can disturbances in K+ balance result from

A

Kidney dysfunction, eating disorders, diarrhea, diuretics

40
Q

Behavioural responses are critical for

A

Restoring to normal state, when ECF volume decreases or osmolarity deviates

41
Q

What are only way to replace los water and increase Na+ content

A

Drinking water and eating salt

42
Q

What causes relief of thirst

A

Act of drinking water, water does not have to be absorbed
Receptors in mouth/pharynx respond and decrease thirst and AVP release

43
Q

What stimulates thirst center in hypothalamus

A

Increase blood osmolarity, decreased blood volume, decreased blood pressure, dry mouth