Lecture 16: Renal Tubular Physiology

Question 1

What do arcuate arteries do? What do they branch off of?

Answer 1

Arcuate arteries assist with renal circulation, and branch off of interlobar arteries.

Question 2

What is obligatory water reabsorption? Where does it mostly happen?

Answer 2

Occurs when water is dragged along by solutes moved from tubules. Mostly occurs in proximal convoluted tubule, descending loop of Henle.

Question 3

Describe facultative water reabsorption.

Answer 3

Remaining 10% of water reabsorption. Under control of ADH, making cells in collecting duct permeable to water so water can leave ducts.

Question 4

Differentiate between paracellular and transcellular transport.

Answer 4

Para = slip between cell junctions
Trans = THROUGH cells of tubules

Question 5

Differentiate between primary and secondary active transport.

Answer 5

Primary = strictly ATP.
Secondary = “backpack” transport, uses concentration gradient to bring along ex. glucose, amino acids

Question 6

Differentiate between symporter and antiporter (both secondary active transport)

Answer 6

Symporter = transport protein moves ion and solute in same direction
Antiporter = transport protein moves ion and solute in opposite directions

Question 7

What is significant about glucose and transport proteins?

Answer 7

Conditions ex. glucosuria occurs because the maximum bonding capacity of the protein transporter has been reached, glucose cannot be further reabsorbed.

Question 8

Where is the Na/Glucose symporter found in the nephron?

Answer 8

Proximal convoluted tubule

Question 9

If kidneys fail, what happens to waste products and pH?

Answer 9

Waste products ex. urea build up, pH goes down (H+ cannot be excreted).

Question 10

What causes massive edema? Acidemia? Hyperkalemia?

Answer 10

Massive edema = salt retention
Acidemia = inability to excrete acids
Hyperkalemia = high K, cardiac arrest

Question 11

What senses the filling of bladder? Where are these messengers sent?

Answer 11

Stretch receptors. Sacral portion of spinal cord.

Question 12

Which two internal muscles are involves in the micturition reflex?

Answer 12

1. contraction of detrusor smooth muscle
2. relaxation of internal urethral sphincter (males only)

Question 13

The ________ ______ __________ is a _______ muscle and can be consciously controlled. Which other 2 muscles help keep “in” urine?

Answer 13

External urethral sphincter, striated. Levator ani, deep perineal muscles.

Question 14

The _______ nerves holding the external sphincter closed are inhibited by the _________ ______.

Answer 14

Somatic, external urethral sphincter.