Kidney and Renal function

Question 1

Name 3 nitrogenous wastes

Answer 1

Urea, creatinine and uric acid

Question 2

Functions of renal system

Answer 2

Endocrine, metabolic, homeostatic, excretory

Question 3

What happens blood volume when there is many salts in the body

Answer 3

blood volume increases

Question 4

How many litres are filtered by kidneys per day

Answer 4

180L

Question 5

What molecular weight is forced out of glomerulus

Answer 5

<68,000

Question 6

What happens in the DCT

Answer 6

Exchange of Na+ for K+ under aldosterone control

Question 7

What happens in loop of henle

Answer 7

Descending H2O is lost, ascending Na+ is lost

Question 8

What is the average GFR

Answer 8

125ml/min

Question 9

What is GFR influenced by

Answer 9

Filtration pressure and filtration coefficient

Question 10

What hormones are synthesised by the kidney

Answer 10

Renin and erythropoietin

Question 11

Function of aldosterone

Answer 11

Regulate sodium and potassium levels and increase water retention

Question 12

Function of antidiuretic hormone

Answer 12

Water absorption in collecting ducts

Question 13

What does pre renal refer to

Answer 13

Any condition that results in reduced blood flow to the kidneys

Question 14

What does renal refer to

Answer 14

Damage to renal tissue, glomerular basement membrane/tubules

Question 15

What does post renal refer to

Answer 15

Obstruction to urine outflow

Question 16

Reference range for serum urea

Answer 16

1.7-8.3mmol/L

Question 17

How does urea end up in the blood

Answer 17

End product of protein and amino acid catabolism

Question 18

Suitable samples for serum urea testing

Answer 18

Serum, plasma, urine, amniotic fluid, other bodily fluids. Deprotinised whole blood

Question 19

Why is refrigeration of urea necessary

Answer 19

Urea can be destroyed by bacteria

Question 20

Principle of urea assay

Answer 20

Measure nitrogen content of urea and not urea directly

Question 21

Enzyme used in urea hydrolysis

Answer 21

Urease

Question 22

What is nesselers reagent

Answer 22

Iodine salt of mercury and potassium

Question 23

What occurs in nesseleres reaction

Answer 23

Nesselers reagent is reacted with the amonia formed in the urease reaction. Forms brown colour which can be measured enzymatically

Question 24

Name the catalyst in the berthelot reaction

Answer 24

sodium nitroprusside

Question 25

What occurs in the berthelot reaction

Answer 25

Amonia formed in urease reaction reacts with phenol and sodium hypochlorite to form blue indophenol.

Question 26

Name 2 enzymes used in kinetic method

Answer 26

Urease and glutamate dehydrogenase

Question 27

Pre renal causes for increased urea

Answer 27

low blood pressure, decreased blood flow, increased dietary protein

Question 28

Renal causes for increased urea

Answer 28

renal disease with decreased glomerular filreation. Glomerular nephritis, renal failure from diabetes

Question 29

Post renal causes for decreased urea

Answer 29

UTI's, kidney stones, bladder tumour

Question 30

Pre renal causes for decreased urea

Answer 30

liver disease, high fluid intake, decreased dietary protein, increased protein synthesis.

Question 31

Where is creatine formed

Answer 31

Liver and pancreas

Question 32

What is creainine

Answer 32

A waste product of creatine formed during normal muscle metabolism

Question 33

Reference range for creatinine serum

Answer 33

Men 62-115umol/L Women 53-97 umol/L

Question 34

What happens in the Jaffe reaction

Answer 34

Creatinine is reacted with alkaline picrate solution to form a complex which is read

Question 35

What produces falsely elevated creatinine values in the Jaffe reaction

Answer 35

Interferences. Presence of noncreatine chromogens or Jaffe positive substances

Question 36

Examples of Jaffe positive substances

Answer 36

Acetoacetic acid, pyruvic acid and hydantoin

Question 37

What is different in the modified jaffe reaction

Answer 37

Absorbance is measured at two different pH levels

Question 38

Urea:creatinine ratio

Answer 38

10:1 to 20:1

Question 39

When would you see an increase in the ratio

Answer 39

Following GIT bleeding, fever and burns

Question 40

When would you see a decrease in the ratio

Answer 40

Protein intake, severe liver disease

Question 41

Rate that plasma is filtered in glomeruli

Answer 41

140ml/min

Question 42

How is GFR measured

Answer 42

Clearance test, eGFR

Question 43

What is clearance

Answer 43

The number of mls of blood cleared of a substance by per unit time

Question 44

Formula for clearance

Answer 44

C=(UxV)/P

Question 45

Limitations of clearance test

Answer 45

Expensive, difficult assay, invasive