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Flashcards in Physiology 4 Deck (40)
1

How much of the plasma that enters the glomerulus is filtered?

20%

2

Glomerular filtration rate?

125ml/min
= 180 litres per day

3

Roughy how many times a day is plasma filtered?

65

4

How much glucose reabsorbed?

100%

5

How much urea is reabsorbed?

50%

6

Percentage of amino acids reabsorbed?

100%

7

Rate of fluid getting reabsorbed into the proximal tubule?

about 80mil/min

8

Substances reabsorbed in the proximal tubule? (SAPSL)

Sugar
Amino acids
Phosphate
Sulphate
Lactate

9

Substances secreted into the proximal tubule?

H+
Hippurates
Neurotransmitters
Bile pigments
Uric acid
Drugs
Toxins

10

Energy is directly required to operate the carrier and move the substrate against its concentration gradient

Primary active transport

11

The carrier molecule is transported coupled to the concentration gradient of an ion (usually Na+)

Secondary active transport

12

Passive carrier-mediated transport of a substance down its concentration gradient

Facilitated diffusion

13

Diffusion through the lipid bilayer

O2, CO2

14

Diffusion through channels

Na+

15

Facilitated diffusion

Glucose

16

Primary active transport

Na+ K+ and the ATP thing

17

Secondary active transport

Na+ and glucose in their little transport thing

18

Percentage of salt and water reabsorbed in the proximal tubule?

67%

19

What drives Na+ rabsorption?

The basolateral Na+ K+ ATPase

20

Na+ reabsorption also drives reabsorption of what?

Cl-

21

How is water reabsorbed?

Reabsorbed by osmosis

22

How does glucose move from the lumen into the cell?

Cotransport (glucose and Na+)

23

How does glucose move from the cell into the interstitial space?

Facilitated diffusion

24

Transport maximum for glucose?

about 2mmol/min

25

Which part of the nephron generates a cortico-medullary solute concentration gradient?

The loop of henle

-This enables the formation of hypertonic urine

26

This segment does not reabsorb NaCl and is highly permeable to water?

Descending limb

27

Along the entire length of the ascending limb Na+ & Cl- are being reabsorbed

Ascending limb

28

Thick upper limb of AL, which type of transport?

Active transport

29

Thin (lower) AL, which type of transport?

Passive transport

30

What type of diuretics block the triple co-transporter?

Loop diuretics

31

ISO-OSMOTIC, enters or leaves the tubule?

ISO-osmotic LEAVES the proximal tubule

32

HYPO-OSMOTIC, enters or leaves the tubule?

Hypo-osmotic ENTERS the distal tubule

33

Urea: how does it pass into the loop of henle and is the distal permeable to it?

Passively diffuses into the loop of henle
Distal tubule is not permeable to urea

34

How much urea is absorbed in the collecting duct?
And what promotes this?

About 50% urea
ADH promotes this

35

Why is countercurrent multiplication important?

To enable the kidney to produce urine of different volume and concentration according to the amounts of circulating antidiuretic hormone (ADH = vasopressin)

36

Roughly how much urine do you make per minute?

Vu on normal fluid intake = ~1 ml/min
Can be 0.3-25 ml/min

37

Essential blood flow through the medulla tends to wash away NaCl and urea. How is this problem minimised? (3 reasons)

Vasa recta capillaries follow hairpin loops
Vasa recta capillaries freely permeable to NaCl and water
Blood flow to vasa recta is low (few juxtamedullary nephrons)

38

Which two components make up the countercurrent system?

Countercurrent multiplication and countercurrent exchanger and the VASA RECTA

39

In which type of nephrons does the vasa recta run alongside?

Vasa recta runs in JUXTAGLOMERULAR nephrons

40

The high medullary osmolarity allows the production of hypertonic urine in the presence of _____?

In the presence of ADH