10: Physiology 6 Flashcards Preview

Renal Week 2 2017/18 > 10: Physiology 6 > Flashcards

Flashcards in 10: Physiology 6 Deck (67)
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1

The fluid which enters the Loop of Henle has a ___ osmolarity.

The fluid which leaves the Loop of Henle has a ___ osmolarity.

entering - low osmolarity

leaving - still a low osmolarity, but ADH sorts that in distal tubules and collecting duct

Tubular fluid becomes highly concentrated in the Loop of Henle to set up the cortico-medullary concentration gradient and then becomes less concentrated again as it leaves

2

What is the osmolarity of the interstitium of the renal cortex?

300 mosmol/L

same as most of the body

3

What is the concentration gradient going from the renal cortex to medulla?

Increasing

(300 - 1200 mosmol/L)

4

As fluid goes down the collecting ducts, the osmolarity of the interstitium around it (increases / decreases).

osmolarity increases

So the water from the fluid moves to the interstitium, increasing fluid osmolarity

Leading to the production of a low volume of hypertonic urine

5

Where do the distal tubules drain?

Collecting ducts

6

What occurs in the distal tubules and collecting ducts?

Water balance

Ion balance

7

What regulates the absorption of ions and water in the distal tubules and collecting ducts?

Hormones

8

What hormones regulate water and ion reabsorption in the distal tubules and collecting ducts?

ADH

Aldosterone

ANP

PTH

9

What does ADH cause?

Increased water reabsorption

10

What does aldosterone cause?

Increased SODIUM REABSORPTION

Increased K+ and Hsecretion

11

What does ANP cause?

Decreased sodium reabsorption

opposite of aldosterone

12

What affects the permeability of the distal tubules to water?

[ADH]

13

In the absence of ADH, the permeability of the distal tubules to water is ___.

low

14

How does the early distal tubule absorb ions?

Triple transporter

15

How does the late distal tubule reabsorb ions?

Action of ALDOSTERONE (Na+) and PTH (Ca2+)

16

In the basal state, how permeable is the early collecting duct to ions?

Impermeable

17

Which gland produces ADH?

Hypothalamus

stored and secreted by posterior pituitary

 

18

Which ion triggers __cytosis of peptide hormones from cells?

Ca2dependent exocytosis

19

What is the half life of ADH?

10 - 15 minutes

20

When is ADH released by the posterior pituitary?

Reduced blood volume e.g dehydration, haemorrhage, sepsis

21

Which vessels have ADH receptors?

Which type of receptor are they?

Distal tubules

Late collecting ducts

G-protein coupled receptors

22

What is produced by G-protein-coupled ADH receptors when they are activated?

What does this cause in the apical membrane of the distal tubule and late collecting duct?

Cyclic AMP

Opening of aquaporins 

Reabsorption of water

23

What is ADH also known as?

Vasopressin

24

The movement of water through ___ of the distal tubules and late collecting duct creates what between the tubules and capillaries?

aquaporins

osmotic gradient

25

High levels of ADH lead to the production of ___ urine.

Low levels of ADH lead to the production of ___ urine.

hypertonic / concentrated

hypotonic / dilute

26

As water is reabsorbed, the osmolarity of tubular fluid ___.

increases

27

Is the ascending limb of the Loop of Henle permeable to water?

No

NaCl only

28

In high concentrations of ADH, the distal tubules and collecting ducts are ___ to water.

permeable

29

In low concentrations of ADH, the distal tubule and collecting ducts are ___ to water.

impermeable

30

Why does fluid leaving the Loop of Henle always have a low osmolarity?

Corticomedullary concentration gradient, loses all its salt as it travels back up, reducing its osmolarity

Remember ascending limb is impermeable to water so osmosis INTO the ascending limb doesn't occur to reduce the osmolarity