Lecture 38 Flashcards

1
Q

Function of glmoerular filtration is where…

A

Selected components of the plasma are allowed to enter the bowman caopsule to the nephron (first step in urine formation)

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

Which portion of the nephron contributes most to the reclaiming of useful substances

A

Proximal convoluted tubule

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

Tubular reabsorbtion

A

Water and other useful substances are reclaimed by the kidneys tubules

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

Specialisations of the PCT

A

Microvilli - ↑ surface area

Fenestrated capillaries around PCT to aid exchange of substance

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

Reabsorbed molecules and how

A

Water - conc gradients
Urea - passive diffusion
Glucose- Glut2 transporters- facilitated diffusion trans cellular
Glucose also has SGLT-1+2 receptors (Sodium conc gradient)- active transport
Potassium sodium- primary active transport

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

SGLT1 and 2 relationship to GLUT1 and 2

A

SGLT1+2 move glucose across from filtrate into tubular cell

Glut1+2 move glucose from cell to blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What limits the transport of glucose?

SGLT1 GLUT1

A

Too much glucose to reabsorbed through transporters = glucosuria eg diabetes

Disfunction of the SGLT1/2 receptors, due to drug inhibition

ONLY IN PCT

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

AMINO ACID REABSORPTION

A

PCT
Carried out by SLC (solute carrier proteins)

Aminoaciduria caused by

  • high plasma AA (metabolic disease)
  • disfunction of receptors (hartnup disease)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Reabsorption of sodium

A

Active transport transcellular
Secondary active transport (with glucose, AA or H+)
PCT initially
Further reabsorption in ascending loop via co transporters
DCT via co transporters

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

Benefit of sodium wasting and how

A

In times of hypertension or HF, this can ↓ BP by ↓ water levels in the blood
Sodium excretion = water loss via urine

Diuretics
- spironolactone =
prevents the effects of aldosterone ↓ sodium pump ↓ reabsorbtion

  • loop diuretics
    = inhibit co transporters in the ascending loop
  • thiazides
    = inhibit co transporter in the DCT
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Spironolactone use

A

Prevents sodium reabsorbtion by ↓ the effects of aldosterone on Na+/K+ pump expression which helps reabsorb sodium

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

Loop diuretics use

A

Inhibits the Na/Cl/K transporter in ascending loop

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

Thiazide Duirrtics use

A

Inhibits Na+/Cl- transporter in DCT

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

Water reabsorption

A

Movement across and through membranes as a result of the gradient produced by sodium

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

What facilitates water reabsorption

A

Aquapourins

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

H2O reabsorption in loop of henle

A

Counter multiplier

Sodium pumped out of ascending limb into the vasa recta
Blood very concentrated
Makes its way to the water permeable descending limb
Water drawn out into the vasa recta by conc gradients

Leads to v concentrated filtrate, keeping the process going

17
Q

Production of urea

A

Protein metabolism

18
Q

Reabsorption of urea

A
  1. Through bowman capsule
  2. Reabsorbed in the PCT (50%)
  3. Facilitated diffusion in ascending limb urea INTO THE FILTRATE
  4. Further reabsorption in the collecting ducts
  5. 20% excreted
19
Q

Uraemia is a sign of…

A

Renal failure as it is the only pathway for urea out of the body
Most likely have other conditions too.

20
Q

Why is reabsorption of urea so important in collecting ducts?

A

Adds to the hyper-osmolarity which allows for the osmotic uptake of water.

21
Q

Secretion in the kidneys

A

Movement from the blood plasma into the filtrate

Useful in excretion of toxins like… creatinine, uremic toxins, drug clearance, antibiotics NSAID and statins.