Renal Function Flashcards

1
Q

what are the functions of kidney?

A
  • Excretion of metabolic waste + small solutes (urea+proteins)
  • Excretion of drugs
  • Acid/Base balance
  • Electrolyte Balance- K/Mg/Ca
  • Regulation of blood pressure
  • Production of EPO (promotes RBC formation)
  • Vitamin D Hydroxylation
  • Toxin Metabolism:
    Insulin- Low BG
    Beta 2 microglobulin- product of inflammation metabolism
    Medicines
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2
Q

what are the body compartments

A
intracellular space (inside cell)
intravascular space (inside blood vessels + circulatory system)
interstitial space (space between blood vessels + cells)
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3
Q

what is extracellular fluid made of

A

interstitial and intravascular

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4
Q

what are the most abundant cation in extracellular and intracellular fluid

A

Extracellular fluid- Na (sodium)

Intracellular fluid- K (Potassium)

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5
Q

what are the most abundant anion in extracellular and intracellular fluid

A

Extracellular fluid- Cl (chlorine)

Intracellular fluid- Proteins

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6
Q

what are nephron functions

A
  • Glomerular filtration (filtration of blood to form the glomerular filtrate)
  • Tubule Reabsorption (selective reabsoprtion of substances from GF back into blood)
  • Tubule Secretion (secretion of substances from blood into filtrate)
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7
Q

what properties does the glomerular filtration have

A

Fenestrated endothelium
Glomerular basement membrane (thick unique collagen)
Podocyte foot processes

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8
Q

what is the Glomerular filtration rate in a minute or a day

A

100ml/min

144L/day

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9
Q

describe the tubular reabsorption and secretion in the PCT

A

PCT:

  • Majority reabsoprtion (70% of glomerular filtrate reabsorbed)
  • water follows Na/NaCl
  • All glucose + amino acids reabsorbed
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10
Q

what is the epithelium found in the PCT

A

Cuboidal epithelium

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11
Q

what are the channels found in the PCT

A

AQP1- Transports water
SGLT1/2- Glucose Transport
Both found in microvilli- optimises surface area

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12
Q

Mitochondria found in the PCT provides energy for _____

A

Na/K ATPase

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13
Q

what is the principle aim of LOH

A

Principle method by which conc of urine is varied to deal with water depletion and excess

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14
Q

What is the thin descending limb of LOH permeable and impermeable to

A

Permeable to water

Impermeable to solutes

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15
Q

what epithelium is the thin descending LOH made of

A

simple squamous epithelium which has AQP1 for water transport

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16
Q

What is the thick ascending limb of LOH permeable and impermeable to

A

Permeable to solutes

Impermeable to water

17
Q

Describe the reabsoprtion of solutes in the thick ascending LOH and the channels involved

A
  • Filtrate moves up the lumen
  • Gradient created by Na/K ATPase
  • Filtrate meets Na/K/2Cl channel
  • Channel Opens and Na/K/2Cl move in
  • K leaks back out down the conc. gradient if K channel open
  • this creates a + gradient in the lumen
  • Ca and Mg moves in between the cells and back into circulation
18
Q

Describe the role DCT plays in reabsorption

A
  • Only 5% of glomerular filtrate reaches DCT
  • site for Ca reabsorption
  • Na and Cl cotransporter
  • Also has Na/K ATPase which sets up gradient
19
Q

Describe the role collecting duct plays in reabsoprtion

A

Intercalated and principal cells found here

- Secretes H+

20
Q

what are the channels found in collecting duct

A

Epithelium Na channels and K channels

21
Q

What is the kidney response to increased tubular flow

A

Sensed by macula densa
MD releases adenosine
Adenosine causes constriction of afferent arteriole- reduces volume of blood going into glomerulus- prevents excess urine
Adenosine also inhibits renin release -> inhibits efferent constriction

22
Q

where is macula densa found

23
Q

what is the kidney response to decreased tubular flow

A
Sensed by macula densa 
MD releases NO and PGE2, causing dilation of afferent arteriole = Increases glomerular blood flow 
Lack of adenosine causes renin release from juxtaglomerular cells 
Renin makes angiontensin II
Angiotensin II:
- Increases ADH production
- Vasoconstricts efferent arteriole
- Increases aldosterone production
- Increases  Na reabsorption in the PCT
24
Q

what is kidneys response to reduced sense of volume due to renin

A

Efferent glomerular arteriolar constriction preserves waste excretion
Avid tubular sodium and water reabsoprtion preserves extracellular fluid volume

25
what is the effect on urine solute conc when there is reduced sense of volume
Oliguria (low urine) Concentrated urine Low urine Na conc High urine K conc