kidney as producer,excretor and regulator

Question 1

erythropoietin

Answer 1

fall in oxygen level in renal tissues
erythropoietin secretion by peritubular cells in the kidney
stimulates RBC precursors in bone marrow
EPO secretion in response to tissue PO2

Question 2

Vitamin D

Answer 2

raises serum Ca2+ by:

• promoting GI absorption
• decreasing renal excretion
• stimulating bone reabsorption

Question 3

tight junctions

Answer 3

fusion of adjacent cell membranes to create a barrier to passage of water and dissolved particles

Question 4

glomerulus

Answer 4

high pressure filtration of blood

loss of filtrate leads to a rise in oncotic pressure in efferent arteriole-useful to increase absorption gradients

Question 5

creatine

Answer 5

product of muscle metabolism

minor tubular secretion->over estimation

Question 6

cystitis C

Answer 6

small protein produced by most cells

no tubular secretion

Question 7

inulin

Answer 7

plant extra-infused to steady state

Question 8

autoregulation 1

Answer 8

afferent arteriole dilates improving RBF at a lower Pa

Question 9

autoregulation 2

Answer 9

efferent arteriole constricts, improving GFR at a lower RBF

Question 10

adenosine

Answer 10

produced in hydrated state
constricts afferent arteriole reducing GFR
switched off with decreased filtrate flow

Question 11

PGE2

Answer 11

produced in DCTin response to decreased filtrate flow
dilates afferent arterioles to maintain RBF
beware of NSAIDS in hypovolaemia
cytoprotective to tubule

Question 12

ADH

Answer 12

small polypeptide released from posterior pituitary

release primarily controlled by hypothalamic receptors

Question 13

V2 G-protein

Answer 13

renal collecting duct epithelium =aquaporin-2 insertion clotting factor release