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

A

DCT

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
Q

what is the effect on urine solute conc when there is reduced sense of volume

A

Oliguria (low urine)
Concentrated urine
Low urine Na conc
High urine K conc