Nephron structure Flashcards

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1
Q

What arteriole enters the nephron?

A

Afferent

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2
Q

What is the glomerulus?

A

a bundle of lots of capillaries, made up when the afferent arteriole branches out forming lots of capillaries

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3
Q

Where is the glomerulus found?

A

the renal capsule

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4
Q

What branches out from the renal capsule?

A

the proximal convoluted tubule

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5
Q

What is the function of the nephron?

A

filter the blood to remove waste and selectively reabsorb useful substances back in to the blood

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6
Q

What does urine not contain? (in a healthy person)

A

proteins and blood cells- too big
glucose - is selectively reabsorbed

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7
Q

What does urine contain?

A

mineral ions
water
urea
small substances

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8
Q

What happens in the glomerulus?

A

ultrafiltration forces out water and small molecules due to high hydrostatic pressure. These enter the renal capsule

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9
Q

What happens at the loop of Henle?

A

Na+ gradient maintained, so water can be reabsorbed by the blood

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10
Q

What arteriole leaves the renal capsule?

A

efferent

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11
Q

How are the cells lining the proximal convoluted tubule adapted to it’s function?

A
  • cells have microvilli that create large SA for reabsorption of glucose
  • cells have lots of mitochondria which produce the ATP needed for active transport
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12
Q

Why is the [Na+] low in the PCT cells?

A

Na+ is actively transported into the blood

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13
Q

Why does a low concentration of Na+ ions in the cells lead to glucose being absorbed?

A

Na+ can diffuse down its conc. gradient through a co-transport protein. The co-transport protein carries glucose also

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14
Q

Why cant water move out in the ascending limb of the loop of Henle?

A

the walls are impermeable

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15
Q

What happens in the ascending limb?

A

Na+ ions are actively transported out, into the interstitial space

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16
Q

What does the increase in Na+ ions do?

A

lowers water potential in interstitial space

17
Q

What happens at the base of the loop of Henle?

A

some Na+ ions diffuse into the interstitial space

18
Q

Describe the liquid that enters the distal convoluted tubule

A

very dilute (as Na+ ions moved out, however still has higher WP than medulla so moves out by osmosis

19
Q

How is glucose reabsorbed in the PCT?

A
  • Na+ actively transported out of Epithelial cells lining PCT (into blood)
  • forms conc. gradient, so Na+ diffuse down conc gradient into epithelial cells from the lumen
  • through co-transport protein, which takes glucose with it
  • diffuses into blood via facilitated diffusion
20
Q

How is water reabsorbed in the Loop of Henle?

A
  • Na+ actively transported out of ascending limb, which is impermeable to water
  • low water potential in the medulla
  • water moves out of descending limb, into the medulla by osmosis
  • water potential in the medulla decreases as you go down the loop of Henle so WP gradient maintained
21
Q

How is the PCT adapted for its function?

A
  • microvilli; large SA for reabsorption
  • infoldings; large SA to transfer substances into capillaries
  • lots of mitochondria for AT
22
Q

How might length of loop of Henle change depending on the environment they live in? why?

A

drier environments = longer loop of Henle
so more water absorbed along the whole length

23
Q

What is the gross structure of the kidney? (go from the outside in)

A
  • capsule
  • cortex
  • medulla
  • pelvis
  • ureter