Renal function tests and urinalysis

Question 1

The amount of urine excreted through the urethra each day

Answer 1

1.5 litres

Question 2

Glomerulus function

Answer 2

non-selective filtration across the semi-permeable membrane of capillary
All substances with low mw (

Question 3

Proximal convuluted tubule (PCT) function

Answer 3

reabsorption
control/response to acid-base homeostasis by H+, HCO3- reabsorption
remove waste product: urea, creatine

Question 4

Loop of Henle

Answer 4

concentrate/dilute urine
descending limb: highly permeable to water, passive reabsorption, concentration of urine occurs here
ascending limb: impermeable to water, active NaCl reabsorption, dilution of urine occurs here

Question 5

Distal Convoluted Tubule (DCT)

Answer 5

homeostatic regulation and secretion of waste/toxic substances from bloodstream into tubules
control/response to acid-base homeostasis

Question 6

Collecting ducts

Answer 6

direct urine flow into renal pelvis
responsive to hormones ADh and aldosterone
stimulates ADH secretion from posterior pituitary gland causing the DCT to reabsorb water
aldosterone stimulates sodium reabsorption and secretion of K+

Question 7

Functions of the kidney

Answer 7

1. Remove waste and toxins from the body
2. Regulation of homeostasis
3. Synthesize hormones

Question 8

Acute vs chronic kidney disease

Answer 8

Acute: result of injuries: post renal, renal, and pre-renal causes
Chronic: result of long-term disease, abnormalities of kidney structure or function present for >3 months with implications for health

Question 9

Azotemia

Answer 9

an elevated concentration of urea in the blood

Question 10

Uremia

Answer 10

high concentration of urea accompanied by renal failure

Question 11

Urease

Answer 11

hydrolyses urea to liberate ammonium ions

can be measured spectrophotometrically

Question 12

Chemical method for urea measurement

Answer 12

spectrophotometric measurement of coloured product as a result of reaction of urea with diacetyl monoxamine in presence of strong acid

Question 13

Increased urea is a sign of

Answer 13

increased protein intake
decreased kidney function
dehydration

Question 14

Decreased urea is a sign of

Answer 14

Decreased protein intake

decreased liver function

Question 15

Creatinine

Answer 15

a breakdown product of creatine phosphate in muscle
a good renal marker as it is produced at a fairly constant rate depending on body mass
shows little-no response to dietary changes
also a product of muscle function (confounding)

Question 16

Jaffe reaction

Answer 16

Creatinine + Alkaline Picrate –> orange red chromogen
lacks specificity
inexpensive, rapid, easy to perform

Question 17

Creatinase

Answer 17

catalyses the conversion of creatine –> creatinine
has potential to replace jaffe reaction as most widely used
less interference

Question 18

Clinical significance of creatinine

Answer 18

1. Increased serum creatinine –> impaired renal function

2. Decreased glomerular filtration rate results in less creatinine being filtered causing increased serum creatinine

Question 19

Uric acid

Answer 19

end product of purine metabolism by the liver

readily filtered by the glomerulus but undergoes a complex cycle of reabsorption and secretion by the tubules

Question 20

Caraway method

Answer 20

measuring uric acid
PTA reduction by uric acid
lacks specificity

Question 21

Enzymatic method using Uricase

Answer 21

measuring uric acid

measures H2O2 produced in primary step

Question 22

Clinical significance of Uric acid

Answer 22

increased uri acid production –> increased nucleic acid turnover , genetic enzyme defects, gout
decreased uric acid excretion: defetive reabsorption, overtreatment, decrease in renal functional mass

Question 23

Gout

Answer 23

monosodium urate (MSU) preceppitates form a supersaturated body fluid into joint fluid –> gouty arthritis

Question 24

Clearance test

Answer 24

the amount of plasma cleared of a substance per minute