Physiology 2: kidney structure + function

Question 1

what is the function of the hormone erythropoietin

Answer 1

EPO drives bone marrow production of RBC

Question 2

what effect does decreased GFR have on EPO and what can a low EPO indicate

Answer 2

decreased GFR can cause decreased EPO / a decreased EPO can indicate anaemia

Question 3

what effect does the kidney have on vitamin D

Answer 3

converts Vit D to it’s active form

Question 4

what is the primary function of the kidney

Answer 4

to regulate volume, composition and osmolarity of body fluids

Question 5

what is the functional unit of the kidney

Answer 5

nephron

Question 6

what is urine

Answer 6

a modifies filtrate of blood

Question 7

what are the 2 types of nephrons and which is more common

Answer 7

80% cortical and 20% juxtamedullary

Question 8

what is the difference between cortical and juxtamedullary nephrons

Answer 8

juxtamedullary have longer loops of henle that extend to the medulla to produce very concentrated urine

Question 9

what is the function of the juxtaglomerular apparatus

Answer 9

regulates the blood pressure and the filtration rate of the glomerulus

Question 10

what is the role of the macula densa in the juxtaglomerular apparatus and how Does it regulate BP and GFR

Answer 10

located in the distal tubule it detects sodium concentration of the tubular fluid and can secrete vasodilators/ vasoconstriction to the afferent arteriole - controlling how much blood enters the glomerulus and therefore the BP and GFR

Question 11

what would happen in response to high sodium in the tubular fluid being detected by the macula densa

Answer 11

vasoconstriction of the afferent arteriole which decreased GFR and the release of renin

Question 12

what % of blood that enters the glomerulus is filtered and what happens to the remaining blood

Answer 12

20% is filtered and 80% is returned to systemic circulation via the efferent arteriole

Question 13

what are peritubular capillaries and what is there role in secretion and reabsorption

Answer 13

capillaries that run alongside tubules - they secrete harmful substances into the tubules for excretion and reabsorb useful substances back into the blood eg glucose and water

Question 14

where to peritubular capillaries eventually drain to

Answer 14

venous system

Question 15

what is the rate one excretion of a substance in terms of filtration secretion and reabsorption

Answer 15

rate of filtration + rate of secretion - rate of reabsorption

Question 16

what is meant by the rate of filtration of a substance

Answer 16

mass of a substance (x) filtered into Bowman’s capsule per unit time

Question 17

how do you calculate the rate of filtration

Answer 17

rate(f) of X = [X]plasma x GFR

Question 18

what is meant by the rate of excretion of a substance

Answer 18

mass of substance X excreted per unit time

Question 19

how do you calculate the rate of excretion

Answer 19

rate(e) of X = [X]urine x Vurine

Question 20

what factors would indicate net reabsorption

Answer 20

rate of filtration > rate of excretion

Question 21

how do you calculate the rate of reabsorption

Answer 21

rate(r) of X = rate(f) of X - rate(e) of X

Question 22

what factors would indicate net secretion

Answer 22

rate of excretion > rate of filtration

Question 23

how do you calculate the rate of secretion

Answer 23

rate(s) of X = rate(e) of X - rate(f) of X