Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Renal > Physiology 4, 5 & 6 > Flashcards

Physiology 4, 5 & 6 Flashcards

(61 cards)

Start Studying
1
Q

What is primary active transport?

A

Energy is directly required to operate the carrier and move the substrate against it’s concentration gradient.

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

Secondary active transport.

A

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

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

Define facilitated diffusion.

A

Passive carrier-mediated transport ofa substance down it’s concentration gradient

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

What is the transport maximum?

A

Refers to a point where increases in concentration do not result in an increase in movement of a substance across a membrane.

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

What is the renal threshold?

A

The concentration of a substance dissolved in the blood above which the kidneys begin to remove it into the urine

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

What is the renal threshold for glucose?

A

10-12mmol/l

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

How does sodium move acros the tubular epithelium?

A

By primary active transport throught the Na+/K+ ATPase pump at the basolateral membrane

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

What % of glucose in the filtrate is reabsorbed in the proximal tubule?

A

100%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What %s of salt, water and amino acids in the filtrate are reabsorbed in the proximal tubule?

A

salt - 67%
water - 67%
amino acids - 100%

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

The tubular fluid is what when it leaves the proximal convoluted tubule?

A

Iso-osmotic (300mosmol/l)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the function of the loop of Henle?

A

Generates a corticomedullary gradient which enables the formation of hypertonic urine

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

In terms of reabsorption of NaCl and water, what is the descending limb of Henle like?

A

Does not reabsorb NaCl

Highly permeable to water

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

In terms of reabsorption of NaCl and water, what is the ascending limb of Henle like?

A

NaCl is absorbed

Impermeable to water

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

The selective permeabilities of the ascending and descending limbs allows what to be established?

A

An osmotic gradient is established in the medulla

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

What is the maximum rtico-medullary gradient in humans?

A

1200

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

What is the purpose of countercurrent multiplication?

A

The conentrate the medullary interstitial fluid

To enable the kidney to produce urine of different volumes and concentrations according to the amount of circulating ADH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does blood osmolality change as the vasa recta follows the loop of Henle?

A

Blood osmolality rises asit dips down into the medulla

Blood osmolality falls as it rises back up into the cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What mechanisms are in place to stop the vasa recta washing away the solute gradient?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What 2 mechanisms make up the medullary osmotic gradient?

A

Countercurrent multiplier and urea cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

The high medullary osmolarity of the loop of Henle allows what?

A

The production of hypertonic urine in the presence of ADH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

The tubular fluid is what when it leaves the loop of Henle and enters the distal tubule?

A

Hypo-osmotic

100mosmol/l

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How does the presence of ADH control water reabosrption?

A

Increases water reabsorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does the presence of aldosterone do?

A

Increases Na+ reabsorption

Increases H+/K+ secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

ANP does what to Na+ reabsorption?

A

Decreases it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are the effects of parathyroid hormone?
Ca2+ reabsorption increased | (PO4)3- reabsorption decreased
26
The distal tubule has what permeabillity to water and rea?
Low permeability | Urea is concentrated in the tubular fluid of the distal tubule which increases the cortico-medullary gradient
27
What happens in the early distal tubule?
Na+-K+-2Cl- transport (NaCl reabsorption)
28
In the late distal tubule and early collecting duct what happens?
Ca2+ reabsorption H+ secretion Na+ reabsorption - basal state K+ reabsorption - basal state
29
The late collecting duct is permeable to what and what. What is it the main site of?
The late collecting duct is permeable to water and urea | Main site of ADH action
30
Where is ADH synthesised and stored?
Synthesised - supraoptic and paraventricular nuclei in the hypothalamus Stored - in granules in the posterior pituitary
31
How does ADH increase the luminal permeabillity of the collecting duct to water?
By inserting new water channels (aquaporins)
32
In the presence of maximal [ADH]plasma what kind of urine is produced?
``` Small volume of concentrated urine Hypertonic urine (max 1400mosmol/l) ```
33
In the presence of minimal [ADH]plasma what kind of urine is produced?
``` Large volume of dilute urine Hypotonic urine (<50mosmol/l) ```
34
Summarise the properties of the proximal tubule and descending loop of Henle.
Na+ reabsorbed by transcellular mechanisms (**PT only) Water moves between inter-cellular junctions These produce net fluid reabsorption Na+ and water coupling
35
Summarise the properties of the ascending loop of Henle and distal tubule.
Low water permeability of epithelium (ADH-dependent) Na+ & Cl- reabsorption These produce dilution of urine Na+ & Cl- coupling
36
Summarise the properties of the collecting duct.
Modulation of water / urea permeability | This contributes to determination of final urine osmolarity
37
The distal tubule and collecting duct are the site of action of what?
Hormones - ADH, aldosterone, ANP
38
What are the 2 stages of micturition?
Micturition reflex | Voluntary control
39
What is the micturition reflex?
bladder can accommodate up to 250-400 ml of urine before stretch receptors initiate the micturition reflex. This reflex causes involuntary emptying of the bladder by simultaneous bladder contraction and opening of both the internal and external urethral sphincters.
40
What is voluntary control when discussing urination?
Micturition can be voluntarily prevented by deliberate tightening of the external sphincter and surrounding pelvic diaphragm – up to a point.
41
What are the basic functions of ADH, Aldosterone and ANP?
ADH - water balance Aldosterone - Na+ reabsorption and K+ secretion ANP - Na+ balance
42
Why is the priority to regulate ECF osmolarity higher then that to regulate ECF volume?
The need for optimun [ion] and cell volume for cellular function ECF volume is also regulated by CV reflexes
43
What controls the release of ADH from the posterior pituitary gland?
Hypothalamus
44
What stimulates and inhibits ADH secretion?
Stimulated by water deficit | Inhibited by water excess
45
What is the most important stimulus for ADH secretion?
Hypothalamic osmoreceptors - detect and initiate the prioroy mechanism for regulation of ECF osmolarity - signal to ACH and thirst
46
What exogenous compounds inhibit and stimulate ADH secretion?
Stimulate - Nicotine | Inhibits - Alcohol
47
What alters the mount of Na+ reabsorbed and filtered?
Filtered - altered by regulation of GFR | Reabsorbed - regulated by RAAS
48
What is aldosterone and where is it produced?
Steroid hormone | Produced by the adrenal cortex
49
What is aldosterone secreted in response to?
Increased [K+]blood or decreased [Na+]blood | Activation of renin-angiotensin system
50
What dos aldosterone do in terms of secretion and reabsorption of other ions? Be specific.
Stimulates Na+ reabsorption | Stimulates K+ secretion
51
An increase in [K+]plasma does what to the adrenal cortex?
Directly stimulates it
52
A decreased [Na+]plasma does what to the secretion of aldosterone?
Promotes the indirect secretion of aldosterone by means of the JGA (unknown mechanism)
53
What 3 mechanisms help to control the renin release from granular cells of JGA?
decreased pressure in afferent arteriole macula densa cells sense amount of NaCl in distal tubule and can control the release of renin to counteract this Increased sympatehtic activity as a result of decreased arterial BP
54
The granular cells of the JGA are directly innervated by..?
The sympathetic nervous system
55
Does the presence of aldosterone increase or decrease the Na+ reabsorption in the DT and collecting duct?
Increases
56
Problems with the RAAS can lead to what pathologies?
HTN | Fluid retention in congestive heart failure
57
Where is Atrial Natriuretic peptide produced and stored?
Produced by the heart and stored in atrial muscle cells
58
When is ANP released?
When the atrial muscle cells are mechanically stretched (increased circulating plasma volume)
59
What is the function of ANP?
Promotes excretion of Na+ and diuresis (thus decreasing PV) | Alos exerts effet o CV system to decrease BP
60
What is water diuresis?
Increased urine flow but not an increased solute excretion
61
What is osmotic diuresis?
Increased urine flow as a reult of primary increased salt excretion

Renal (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions