Lect 6 - Block 3 - Tubuloglomerular Feedback Flashcards

1
Q

The macula dense is found in the _______ and is part of the juxtaglomerular apparatus

A

Distal tubule

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2
Q

If distal tubule NaCl delivery fails (lower GFR), 3 things happen to compensate

A

Dilate afferent
Constrict efferent
Release renin

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3
Q

Nephron GFR is regulated by what

A

It’s own juxtaglomerular apparatus. Each nephron regulates it’s own function

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4
Q

Renin release causes intrarenal formation of ________. This acts more on the ______ arteriole.

A

Angiotensin II
Efferent arteriole

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5
Q

GFR decreases, flow through tubule decreases, flow past macula dense decreases…
This causes 2 things that increase GFR

A

Release of renin, forming angiotensin II, by macula densa (JG cells) constricting efferent arteriole

Paracrine signals from macula dense to dilate afferent arteriole

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6
Q

Increased Na intake results in increased blood flow to this part of huge kidney

A

Cortex

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7
Q

________ preferentially dilates juxtamedullary nephrons. In diseased kidneys with low blood flow, this is important to ________ salt and water.

A

Prostaglandins

Blocking prostaglandin production in individuals with impaired renal function may cause a further decrease in renal function

Blocking prostaglandin production in individuals with impaired renal function may cause a further decrease in renal function.

What drug class does this?NSAIDs

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8
Q

Almost all Na in the body is in the ______ cellular space

Urinary Na regulation is where most of an control happens for body Na levels
120mmol/day (intake & excretion)

A

Extracellular space

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9
Q

2/3 of Na is reabsorbed in huge PT, more is reabsorbed in huge _____ by _______. The rest is reabsorbed by the DT and CD, dropping excreted amount to 1%

A

Thick ascending limb of hone loop of Henle, by NaK2Cl transporters

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10
Q

_______ cells (Lacis cells) can contract, causing a ______ in GFR, reducing amount of Na excreted.

2 agents that increase permeability _____ and _____
2 agents that decrease permeability _____ and _____

A

Mesangial cells contract, decreasing GFR

Increase permeability: ANP, NO (increase GFR)
Decrease permeability: norepi, epi, ADH

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11
Q

An increase in GFR causes an increase in protein concentration in the peritubular capillaries, increasing the reabsorption of fluid. This is called __________ _______

A

Glomerulotubular balance

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12
Q

Renal sympathetic nerves:

  1. directly contract _______, _____ GFR
  2. Cause release of renin, leading to formation of angiotensin II
  3. Norepi and angiotensin II increase Na reabsorption at the _______ _______. They act synergistically.
  4. _____ causes contraction of the glomerular capillary cells, which decreases permeability of glomerular capillaries and decreases GFR
A
  1. Contract afferent arteriole.e, decreasing GFR
    2.
  2. Proximal tubule cells
  3. Norepi
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13
Q

_______ increases Na reabsorption in the distal tubule
Its release is stimulated by an increase in plasma ______ levels and also by the hormone _____

A

Aldosterone
K levels and angiotensin II causes release of aldosterone

It acts on the electrogenic reabsorption channels in the distal tubule on the apical surface

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14
Q

ANP/urodilatin acts on ____ (part of nephron) to _____ Na reabsorption

It works through cyclic _____

A

Collecting duct, to decrease Na reabsorption

Cyclic GMP to decrease the entry of Na through channels in the medullary collecting duct

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15
Q

Angiotensin II increases Na reabsorption by:

  1. It is one of the stimuli causing release of ________
  2. A2 ________ the glomerular cap. cells, _______ glomerular cap. permeability, causing a ____ in GFR
  3. Constricts the ____ arteriole, and ________ the filtration fraction, enhancing the reabsorption of Na and water in the ________ capillaries, which decreases Na excretion
A
  1. aldosterone (Na retaining hormone)
  2. A2 contracts the glomerular cap cells, decreases glomerular cap perm, causing a decrease in GFR
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16
Q

Laying down all day results in what to water balance in the body?

A

Body secretes water because blood that is normally pooled in the legs from gravity is now circulating. This results in the body getting rid of the excess. The person is at risk of passing out if standing up suddenly.

17
Q

K+ intake is 100mmol/day
The major compartment in the body where K is found is _______

3 things cause K to move into the compartment from the previous blank

A

Intracellular Fluid
Insulin (quickest way to drop K), epi, aldosterone
90% of K is secreted in urine, 10% in feces

18
Q

2/3 of K is reabsorbed in the PT, nothing in the descending limb, most in the ______, with essentially none excreted. ______ causes some secretion of K in the DT

A

Thin ascending

19
Q

______ and ______ stimulate K secretion in the DT, by acting on ______ cells

A

Aldosterone and K+ increase K+ secretion in the DT
Principal cells

Aldosterone causes an increase in the expression of apical Na channels and an increase in expression and activity of basolateral Na/K-ATPase. Transepithelial reabsorption of Na creates a luman negative transepithelial potential, and this is what promotes secretion of K into the lumen.

20
Q

Acute renal regulation of plasma Na
Increase concentration: 4 things
Decrease concentration: 2 things

Chronic regulation of plasma Na:
Increase: 1 thing
Decrease: 1 thing

A

Acute increase in plasma Na: Aldosterone, Angiotensin II, SNS, Blood Pressure

Acute decrease in plasma Na: ANP, Urodilatin

Chronic increase in plasma Na: aldosterone
Chronic decrease in plasma Na: ADH (major control - dilutional)

21
Q

Acute renal regulation of plasma volume

increase: 1 thing
decrease: nothing

Chronic renal regulation of plasma volume

increase: nothing
decrease: 1 thing

A

Acute renal regulation of plasma volume

increase: ADH
decrease: nothing

Chronic renal regulation of plasma volume

increase: nothing
decrease: increased renal perfusion pressure

22
Q

_____ causes release of Ca from bone

A

Parathyroid hormone

23
Q

50-60% of plasma Ca is filtered, the rest is bound to albumin and other plasma proteins.
2/3 reabsorbed in PT via the ____ route.
Some reabsorbed in the TAL via ____ route
Distal tubule reabsorption of Ca is regulated by _____

A

Paracellular
Paracellular
PTH

24
Q

PTH acutely and chronically ______ Ca reabsorption
_________ on _________ surface of the _____
_____ on the _________ surface of the ______
PTH also causes a decrease in _____ reabsorption

A

increases
Ca-ATPase on basolateral surface of DT
Na/Ca exchange on the basolateral surface of DT
PTH causes a decrease in PO4 reabsorption

25
Q

Normal PCO2
Normal Bicarb
Every ____mmHg CO2 increase results in an increase of bicarb by ____mEq/L

A

40mmHg
26mEq/L

26
Q

The first thing to help buffer pH is _______, then ______, then ______

A

body proteins, respiratory CO2 changes (minutes), Renal HCO3 excretion (days)

27
Q

85% of bicarbonate reabsorption occurs in the ______ by ______ and _______ transporters and ______ enzyme

A

Proximal Tubule
Na/HCO3 symport

28
Q

________ cells of the DT regulates H+ excretion

A

Intercalated cells, some H ATPase facing lumen, some facing blood, depending on if blood is acidic or basic

29
Q

Hydrogen ATPase is on the apical surface of the ___ and ___
Urine pH can drop to _____

A

DT and CD
4.5 (1000 fold greater from cell to lumen - it is why you need H-ATPase)

30
Q

Ammonium trapping is when NH3 leaves the DT and CD cells as NH3 and becomes NH4+ in the lumen. The charged particle can’t cross back. The NH3 in the cell is made from _______

A

Glutamine

31
Q

3 renal responses to metabolic acidosis

A
  1. Decrease filtered load of bicarbonate (plasma bicarb low)
  2. Increase H secretion
  3. Increase NH3 production (from glutamine) to absorb H+ secreted
32
Q

What % of filtered bicarbonate is excreted in a normal kidney?

A

0% is secreted

33
Q

2 types of acids produced by the human body

A

volatile (co2 —> HCO3)
non-volatile (fixed acids) H + SO4 + PO4

34
Q

The negative feedback process of tubuloglomerular feedback helps maintain constant delivery of ______ to the distal tubule

A

NaCl