Physiology

Question 1

how can plasma volume be measured

Answer 1

radiolabeling albumin

Question 2

how can extracellular volume be measured

Answer 2

by inulin or mannitol

Question 3

what type of collagen is present in the basement membrane

Answer 3

type IV collagen

Question 4

what barriers exist in the glomerular filtration barrier for preventing molecules to enter the glomerulus

Answer 4

charged barrier - GFB contains negatively charged ions which prevent negatively charged ions from crossing through i.e. albumin

size barrier - fenestrated capillary endothelium and podocytes prevent entry of certain sizes of molecules

Question 5

how can GFR be calculated

Answer 5

inulin clearance as it is neither absorbed nor secreted
GFR = (urine inulin X urine flow rate) / plasma inulin

Question 6

does Creatinine clearance under or overestimate GFR

Answer 6

slightly overestimates because a small amount of creatinine is secreted from the proximal renal tubules

Question 7

how can effective renal plasma flow be estimated

Answer 7

using para-amniohippuric acid (PAH) clearance

Question 8

how to work out filtration fraction

Answer 8

FF = GFR/RPF

Question 9

what effect does prostaglandins have on the arterioles in the kidney

Answer 9

prostaglandins Dilate Afferent arterioles
PDA

Question 10

what effect does ACE II have on the arterioles of the kidney

Answer 10

Angiotensin ii Constricts Efferent arterioles
ACE

Question 11

what effect does afferent arteriole constriction have on GFR and RPF ?

Answer 11

GFR decreases
RPF decreases

Question 12

what effect does efferent arteriole constriction have on GFR and RPF ?

Answer 12

GFR increases
PRF decreases

Question 13

what effect does and increase or decrease of protein concentration have on GFR and RPF ?

Answer 13

increased protein - decreases GFR, no change in RPF
decreased protein - increases GFR, no change in RPF

Question 14

what effect does constriction of ureters have on GFR and RPF ?

Answer 14

decrease GFR
no effect on RPF

Question 15

where is glucose reabsorbed n the kidney and through which transporter

Answer 15

proximal convoluted tubules by Na/glucose co-transport (GLUT)

Question 16

why can pregnancy cause glucosuria at normal plasma glucose levels

Answer 16

increased GFR and filtration of all substances inlcuidng glucose. the glucose threshold occurs at lower levels which results in urinary excretion of glucose even at normal blood levels

Question 17

what part of the kidney does fanconi’s syndrome affect

Answer 17

proximal convoluted tubule

Question 18

renal tubular defect syndromes and location of which they act on

Answer 18

Fanconi’s bagles
fanconi- PCT
Bartters syndrome - thick ascending loop of henle
Gitelman syndrome - DCT
little syndrome - collecting tubules
SAME - collecting tubules

Question 19

features of fanconi syndrome

Answer 19

reabsorption defect on the proximal convoluted tubule
increased excretion of glucose, HC03, PO4, and amino acids
results in renal tubular acidosis -> metabolic acidosis, low phosphate and low K

Question 20

causes of fanconi syndrome

Answer 20

Fanconi Has Multiple Interesting Drinks
hereditary i.e. wilsons
ischaemia
multiple myeloma
drugs i.e. cisplatin, lead poisoning

Question 21

features of primary hyperaldosteronism but with low aldosterone levels

Answer 21

Liddle syndrome or Syndrome of apparent minealocorticoid excess

Question 22

where is renin produced from?

Answer 22

juxtaglomerular cells

Question 23

where is ACE produced from

Answer 23

lungs and kidneys

Question 24

where are ANP and BNP produced from

Answer 24

ANP - atria
BNP - ventricles

Question 25

where is erythropoetin produced from

Answer 25

interstitial cells in peritubular capillary bed

Question 26

what effect does low and high doses of dopamine have on the kidney

Answer 26

low doses - dilates interlobular arteries, afferent arterioles and efferent arterioles to increase renal blood flow
high doses - vasoconstricts

Question 27

defect in renal tubular acidosis type 1

Answer 27

distal RTA = type 1
inability of alpha intercalated cells in DCT to secrete h which results in no new HCO3 being generated = metabolic acidosis

Question 28

defect in renal tubular acidosis type 2

Answer 28

proximal RTA = type II
defect in proximal convoluted tubule reabsorption of HCO3 = increased secretion = metabolic acidosis

Question 29

urinary PH of RTA type 1 and 2

Answer 29

type 1 urinary PH > 5.5
type 2 urinary PH < 5.5 but can be > 5.5 when filtered HCO3 exceeds resorptive threshold

Question 30

how does CKD affect calcium and phosphate

Answer 30

unable to excrete phosphate = hyperphosphataemia
this in turn causes low calcium which stimulates parathyroid gland = hyperparathyroidism
= osteodystrophy

Question 31

effects of IV 5% dextrose

Answer 31

the dextrose is quickly metabolised so is essentially like drinking water.
pure water causes serum osmolaliy to reduce which reduces ADH release. Reduced ADH would cause less aquaporin channels to be inserted into the collecting duct = dilute urine as less water is being reabsorbed. It would also reduce urea absorption as ADH causes reabsorption of urea to maintain interstitial conc gradient

Question 32

primary site of absorption of the following electrolytes;
Na, K, Cl, glucose, Ca, Mg, PH04

Answer 32

Na, Cl, glucose, K –> proximal convoluted tubule
Mg –> thick ascending loop of henle

Question 33

how is magnesium levels maintained

Answer 33

not regulated by hormones unlike other electrolytes. Mainly regulated by absorption in the thick ascening loop of henle.
Tight junctions due to caludin 16 and 19 allow for the paracellular movement of Mg required for reabsorption

Question 34

what part of the kidney is impermeable to water

Answer 34

ascending loop of henle

Question 35

what part of the kidney becomes permeable to water in the presence of ADH

Answer 35

collecting duct