Renal Physiology Practice Questions

Question 1

Which renal tubule parts functions more in secretion?

Answer 1

Distal convoluted tubule, because it does not contain microvilli

Question 2

where is the Macula Densa located & what is its function?

Answer 2

located in the juxtaglomerular Apparatus specifically in the distal tubule.

Function as chemoreceptors (Detect changes in chemical composition) or as osmoreceptors (Detect change in osmolarity)

They produce signals that promote renin secretion by Juxtaglomerular cells

Question 3

Which cells of the JGA act as mechanoreceptors?

Answer 3

Juxtaglomerular cells

Question 4

Which cell in the collecting tubule of the renal tubules functions in maintaining acid-base balance?

Answer 4

Intercalated cells.

Question 5

Which cell in the collecting tubule of the renal tubules functions in maintaining water and salt balance?

Answer 5

Principal cells.

Question 6

Where are the podocytes located and what are they?

Answer 6

Found in visceral layer of glomerular capsule.

Podocytes are modified branching epithelial.

Question 7

What is the filtration membrane, where is it located and what is it made of?

Answer 7

A filter that lies between the blood and interior of the glomerular capsule.

• Made of 3 layers:
  
  • A) Fenestrated endothelium.
  • B) Visceral membrane of glomerular capsule.
  • C)Basement membrane (which is composed of fused basal laminae of the other 2 layers)

Question 8

What is the difference between the glomerular filtrate and the plasma?

Answer 8

Glomerular filtrate has much less proteins in its composition than the plasma.

Question 9

What is the definition of the tubular secretion?

Answer 9

It’s the selective transfer of substances from Peritubular Capillary → tubular lumen.

Question 10

56 year-old patient came to the clinic with a severe shock and drop in blood pressure known to also have hypertension and diabetes mellites, has a glomerular hydrostatic pressure of 30mmHg, oncotic pressure of glomerular blood 25mmHg, capsular hydrostatic pressure of 15mmHg. Calculate the Net Filtration Pressure

Answer 10

NFP = HPg – (OPg+ HPc)

NFP = 30 – (25+15) = -10mmHg

Question 11

What does A NFP of -10 mmHG indicate?

If this condition is left untreated what is the most expected outcome?

Answer 11

Indicates that there is no filtration.

Acute Renal Failure (Acute Renal Injury)

Question 12

What is the function of Prostaglandin F in the regulation of GFR?

Answer 12

It causes renal vasoconstriction that results in decrease in RBF and GFR.

Question 13

What is the function of Prostaglandin D/I/E in regulation of GFR?

Answer 13

They cause renal vasodilation that results in increase in RBF and GFR.

Question 14

37 year old man came into the clinic for a routine checkup, blood tests showed that the blood glucose was 900 mg/dL, knowing that the tubular transport maximum (Tmax) is 380mg/min, what is the expected amount of glucose that will be found in the urine?

Answer 14

First you need to calculate the glucose filtration rate, that is done by multiplying the blood glucose level by 1.25

Glucose filtration rate = 900 * 1.25 = 1125mg/min

Then we deduct the Tmax from the glucose filtration rate to give us the amount excreted 1125 – 380 = 745mg/min

Question 15

Sodium is mostly reabsorbed by:

Answer 15

Primary Active Transport

Question 16

Glucose is mostly reabsorbed by:

Answer 16

From tubular lumen to tubular cell by Carrier Mediated secondary active transport.

From Tubular cell to peritubular capillary by Carrier-mediated passive transport.

Question 17

Where does the ADH dependent reabsorption occur?

Answer 17

In the medullary connecting duct.

Question 18

Which part of the Loop of Henle is more permeable to water?

Answer 18

Thin Descending Limb.

Question 19

Specify 4 factors affecting sodium reabsorption.

Answer 19

1) GFR: and increase in GFR causes an increase in Na filtration
2) Aldosterone: Causes sodium retention
3) Estrogens: Cause reabsorption of sodium. (pregnant women more at risk of developing edema)
4) Natriuretic Hormone: Causes decreased Sodium absorption

Question 20

Describe the different sensations from the urinary bladder at different urine volumes.

Answer 20

From 150-300ml → The first urge to void urine.

From 300-400ml → sense of fullness of the bladder.

From 400-600ml → sense of discomfort.

From 600-700ml → sense of pain

Question 21

What is the cause of the distention of the urinary bladder and what does its distension produce?

Answer 21

The cause is the
increase in the intra-vesical pressure, the distension of the urinary bladder produces reflex contraction of its
wall and relaxation of the internal & external urethral sphincter which is known as the micturition reflex.

Question 22

What is the denervation of the afferent supply to the urinary bladder characterized by?

Answer 22

Loss of Urinary bladder sensations and reflex micturition, retention of smooth muscle intrinsic responses, tonic bladder (unable to contract) & retention with overflow (dribbling).

A good example Tabes Dorsalis which is an inflammation of the spinal cord.

Question 23

What is the denervation of the afferent & efferent supply to the urinary bladder characterized by & what is it associated with?

Answer 23

Increase in smooth muscle intrinsic response, hypertonic bladder (spasmatic bladder) & abolishment of reflexes.

Associated with uncontrolled periodic micturition.

A good example is an injury to the cauda equine or a tumor in that area.