Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

The BIG Test > Renal > Flashcards

Renal Flashcards

(74 cards)

Start Studying
1
Q

When talking about regulating osmolality, we are talking about regulating ______ concentration.

A

Sodium

*Sodium salts represent 90% of total osmolality

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

What is normal osmolality?

A

300 mOsm/kg

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

Why is the patient with chronic renal disease hypocalcemic?

A

Kidney converts Vit D to its active form

Calcium absorption from the intestines is impaired when there is a Vit D deficiency

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

What % of CO flows to the kidneys?

A

25%

1.25 L/min

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

What are the 2 types of nephrons?

A
  1. Cortical - short loops of Henle, glomeruli located near the surface
  2. Juxtamedullary - long loops of Henle, glomeruli located deep
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the name of the peritubular capillaries of the loops of Henle of the juxtamdullary nephrons?

A

Vasa recta — constitutes a countercurrent exchange system

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

What 2 structures are found in the medulla?

A
  1. Loops of Henle

2. Collecting ducts

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

What part of the nephron is most vulnerable to ischemia?

A

Inner stripe of the outer medulla

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

From tubule to capillary…
From capillary to tubule…
From glomerulus to Bowman’s capsule…

A

Reabsorption
Secretion
Filtration

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

Function of the PCT

A

Reabsorption! 67%

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

Function of the LOH

A

Establishes and maintains an osmotic gradient in the medulla
Descending - permeable to water
Ascending - impermeable to water
*Countercurrent multiplier

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

Function of DCT and CD

A

Final adjustments

ADH (water) and Aldosterone (Na and K)

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

Osmolality in the medulla increases from 300 mOsm (croticomedullary junction) to ______ mOsm deep in the medulla.

A

1200-1500

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

ALL of the filtered glucose is normally completely reabsorbed from the _______ by active transport mechanisms.

A

PCT

*The amount of filtered glucose normally does NOT exceed the transfer max.

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

What happens with the renal tubular handling of glucose in DM?

A

Amount of glucose filtered exceeds the transfer max
Glucose that escapes reabsorption from the PCT is excreted - ALL segments of the renal tubule beyond the PCT are impermeable to glucose

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

Why does urine flow increase in the untreated patient with DM?

A

Unreabsorbed glucose causes an osmotic diuresis

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

The rate of ADH release is directly related to what?

A

Osmolality of the extracellular fluid

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

Extracellular fluid osmolality (sodium concentration) is regulated by…

A

ADH

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

Where is ADH synthesized?

Where is ADH stored?

A

Synthesized in paraventricular and supraoptic nuclei of the hypothalamus
Stored in posterior pituitary (neurohypophysis)

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

Which is more potent: angiotensin II or ADH?

A

ADH

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

What is the most sensitive to changes in extracellular fluid osmolality?

A

Paraventricular and supraoptic nuclei

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

What is the most powerful stimulus triggering release of ADH?

A

Increase in extracellular fluid osmolality

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

In the absence of ADH, the DCT and CD are _________ to water.

A

Impermeable

A large volume of dilute urine is formed

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

What are other triggers for ADH release?

A 
Hypotension
Decrease in plasma volume 
Stress
Pain 
Vomiting 
CPAP
PEEP
Volatile agents 
Morphine 
Nicotine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What % of the filtered water is reabsorbed in the... PCT Descending LOH Ascending LOH
PCT - 67% Descending LOH - 13% Ascending LOH - impermeable to water (NaCl is reabsorbed here!)
26
Responses Following a Decrease in Body Fluid Osmolality
``` Hypothalamic nuclei swell Decrease in nerve impulse frequency Decrease in ADH release DCT and CD become impermeable to water Large volumes of dilute urine ```
27
A __% increase in osmolality is sufficient to stimulate the release of large quantities of ADH.
2%
28
Are sodium intake and excretion important in regulating extracellular fluid osmolality?
NO b/c significant changes in body sodium content take a long time to be achieved *The control of water is involved in the control of body fluid osmolality (and sodium concentration)
29
+ ADH Urine osmolality Urine volume
+ ADH Urine osmolality: 1200-1500 Urine volume: 0.5 mL/kg/hr
30
- ADH Urine osmolality Urine volume
- ADH Urine osmolality: 50-100 Urine volume: 2-25 mL/kg/hr
31
What are causes of DI?
Failure of ADH synthesis Failure of ADH release (most common) Insensitivity of the DCT and CD (nephrogenic)
32
What are causes of SIADH?
``` Surgery Intracranial tumors Hypothyroidism Porphyria Small (Oat's) cell carcinoma of the lung ```
33
What is the diagnosis? Inappropriately increased urine sodium concentration and urine osmolality in the presence of hyponatremia and decreased plasma osmolality
SIADH
34
What is the major determinant of extracellular fluid volume?
Amount of sodium
35
What is the most important hormone for regulating extracellular fluid volume?
Aldosterone
36
Does sodium excretion increase or decrease when glomerular filtration rate increases?
Increases
37
List 3 determinants of sodium excretion.
1. GFR - direct 2. ANP - direct 3. Aldosterone - indirect
38
Where is aldosterone produced? Where does aldosterone act? What are the actions of aldosterone?
Zona glomerulosa of the adrenal cortex Acts on the late DCT and CD* Increases Na reabsorption + Increases K excretion
39
``` What % of the sodium is reabsorbed in the... PCT Descending LOH Ascending LOH DCT + CD ```
PCT - 67% Descending LOH - impermeable to Na (water is reabsorbed here!) Ascending LOH - 25% DCT + CD - 7% in the presence of aldosterone *Na reabsorption is an active process
40
With aldosterone present, < ___% of the filtered sodium load may be excreted.
1%
41
Result of High Sodium Intake
``` Body fluids become concentrated ADH output increases Thirst mechanism activated Expanded fluid volume Hypervolemia + HTN Corrected by increasing the renal excretion of sodium: increase GFR, decrease renin, increase ANP ```
42
Where does aldosterone work?
Late DCT and CD | Primarily on the principal cells of the CD
43
What % of the potassium is reabsorbed in the... PCT Descending LOH Ascending LOH
PCT - 67% Descending LOH - passive K secretion Ascending LOH - 25% *About 92% of the filtered K is reabsorbed prior to DCT and CD
44
List 3 determinants of K excretion.
1. Aldosterone - direct 2. DCT flow rate - direct (how diuretics deplete K) 3. Bicarb concentration in DCT - direct (why Bicarb administration works in the setting of hyperkalemia)
45
``` Loop Diuretics Furosemide Bumetanide Ethacrynic acid Torsemide ```
Ascending LOH Inhibit the Na-K-2Cl symporter (reabsorption is blocked) Destroys the super salty medulla Water excretion increases SE: damage to CN 8, hypokalemic metabolic alkalosis
46
Why does Furosemide cause BP to drop?
Triggers the release of prostaglandins | Venodilation
47
Thiazides -thiazide Chlorthalidone Metolazone
Early DCT | Inhibit Na reabsorption
48
Potassium-Sparing *Spironolactone Triamterene Amiloride
Late DCT and CD* *Competitively inhibits aldosterone Inhibit Na reabsorption and K excretion SE: hyperkalemia
49
Carbonic Anhydrase Inhibitor | Acetazolamide
PCT Inhibits carbonic anhydrase Inhibits Bicarb + Na reabsorption SE: hyperchloremic metabolic acidosis
50
How does acetazolamide decrease intraocular pressure?
Inhibition of carbonic anhydrase decreases the rate of formation of aqueous humor
51
Osmotic Diuretic | Mannitol
Freely filtered in Bowman's capsule - BUT then remains trapped in the renal tubule (polar molecule) Exerts an osmotic force preventing the reabsorption of water SE: pulmonary edema, CHF *Does NOT depend on rental tubular concentrating mechanisms to produce diuresis - benefit
52
Explain the SE of hypokalemia as a result of Mannitol administration.
K secretion is increased secondary to increase flow through the DCT
53
How does the fractional excretion of filtered sodium (FEna) compare in prerenal vs. renal failure? *In acute renal failure, the renal tubule reabsorbs sodium poorly, so sodium appears in the urine.
Prerenal < 0.01 (1%) *Flow through tubule is slow - considerable time for Na reabsorption Renal failure > 0.03 (3%) *This test is 90% specific and sensitive
54
What is the normal GFR? Decreased renal reserve? Renal insufficiency - S/S appear? Lab issues? Uremia?
Normal - 125 mL/min Decreased renal reserve - 80 mL/min Renal insufficiency - 50 mL/min * Uremia - < 12 mL/min
55
What is the best test of renal reserve?
Creatinine clearance | *This measures GFR
56
Chronic Renal Failure Anemia Why? Tx?
Decreased production or erythropoietin | Administer recombinant erythropoietin - SE: HTN
57
Chronic Renal Failure Pruritus Tx?
Administer erythropoietin - this lowers the plasma concentration of histamine - decreases itching
58
``` Chronic Renal Failure Coagulopathies What is normal? What is abnormal? What is the most frequent site of bleeding? Tx? ```
``` Normal PT, PTT, plt Abnormal bleeding time (plt dysfunction!) Release of defective vWF Most frequent uremic bleed - GI tract Tx - dialysis, DDAVP, cryoprecipitate ```
59
Chronic Renal Failure Electrolyte Disturbances What goes up? Down?
HYPER: K, Mag, Phos HYPO: Ca - secondary hyperparathyroidism (triggers bone resorption of Ca - vulnerable to fractures) *Metabolic acidosis (retention of acids)
60
What % of ESRD patients have HTN?
80%
61
What is the most serious electrolyte abnormality in chronic renal failure?
HYPERkalemia | *AVOID LR (4 mEq/L K)
62
Nervous System abnormalities in chronic renal failure include peripheral motor and sensory polyneuropathies. What 2 nerves are most often involved?
1. Median | 2. Common peroneal
63
What is the most common cause of death in patients with renal failure?
Sepsis
64
Are kidneys autoregulated? What structure is responsible?
Yes - 80-180 mmHg Myogenic response - afferent arteriole Tubuloglomerular feedback - juxtaglomerular apparatus - afferent arteriole
65
Name the 3 major renal functions. Do they require energy?
1. Filtration 2. Reabsorption - active 3. Secretion - active
66
What is an example of a countercurrent multiplier? Exchanger?
Multiplier - LOH Exchanger - vasa recta *Allows for adjustments in the osmolality of the urine
67
State 2 actions of ADH.
1. Increase water reabsorption in CD | 2. Vasoconstrictor - increases BP
68
List 3 stimuli for renin release.
1. Decreased renal perfusion pressure* 2. Hyponatremia 3. SNS stimulation of beta-1 receptors of the juxtaglomerular cells
69
Which electrolyte promotes renin release from the juxtaglomerular apparatus?
Changes in Cl ion flow past the macula densa
70
Does angiotensin II have a greater constrictor effect on afferent or efferent arterioles?
Efferent arterioles | This is good b/c GFR is not decreased
71
What % of nephron mass loss correlates with s/s of renal dysfunction?
60%
72
What are hallmarks of nephrotic syndrome?
``` Bloody, protein urine HYPOalbuminemia HTN, Na retention, edema, hypovolemia HLD Thromboembolism ```
73
Creatinine Clearance Mild Mod Severe
Mild 60 mL/min Mod 40 mL/min Severe < 25 mL/min
74
Describe the MOA of most diuretics simply.
Inhibit Na reabsoprtion Water follows *Plasma volume decreases, while plasma osmolality does NOT change

The BIG Test (21 decks)

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