DCT

Question 1

Functions of DCT?

Answer 1

Fine regulation of Na+, K, Cl-, Pi, Ca and H2O reabsorption

Question 2

DCT

What channels does it have and these are found in?

Answer 2

NKCC2 channels too

Like Loop of henle

Question 3

DCT

What cells does it have on its outside?

Answer 3

Macula densa cells

Question 4

DCT is intimately related to the…

Answer 4

Glomerulus

Question 5

What is the function of the collecting duct?

Answer 5

Water reabsorption

Final acid/HCO3- regulation

Question 6

What 2 cell types are in the collecting ducts?

Answer 6

Principal cells

Intercalated cells

Question 7

What do principal cells have and are acted on by what 2 substances?

Answer 7

Have aquaporin 2 channels (APo II)
Have epithelial sodium channels in membranes (ENaC)
ADH
Aldosterone

Question 8

How does ADH affect principal cells?

Answer 8

Increased ADH 
Acts on V2R receptor
Cascade of reactions result in increased APo2
Increased APo expression
Increased H2O absorption

Question 9

How does aldosterone affect principal cells?

Answer 9

Increases transcription of ENaC and Na+/K+ ATPase

Result=increased Na+ reabsorption and K+ secretion

Question 10

What do intercalated cells do?

Answer 10

Reabsorb HCO3- and secrete H+

Question 11

What is intracellular pH?

Answer 11

7.0

Question 12

What is extracellular pH?

Answer 12

7.4

Question 13

What is the plasma osmolarity?

Answer 13

~300 mOsm

Question 14

How do u calculate plasma osmolality?

Answer 14

2x((Na+K)+glucose+urea)

Question 15

What is fluid volume regulated long term by?

Answer 15

RAAS and ADH

Question 16

What 2 things control K+ factors?

Answer 16

1. Diet (increased K+ = more secretion)

2. Aldosterone (increased = more K+ excreted)

Question 17

Where is most K+ reabsorbed?
How much K+ is excreted?
Where is it mostly excreted?

Answer 17

In PCT
Very little excreted
Mostly from cortical Collecting ducts (in medullary rays)