Origin of waste products

Question 1

What does ureotelic mean?

Answer 1

Excrete excess protein-derived nitrogen as urea

Question 2

What are the four stages to urea biosynthesis?

Answer 2

Transamination
Oxidative deamination
Ammonia transport
Urea cycle

Question 3

What happens in transamination?

Answer 3

Amino acids are converted to glutamate

Question 4

What happens in oxidative deamination?

Answer 4

Oxidative deamination occurs by glutamate dehydrogenase

Question 5

What happens in ammonia transport?

Answer 5

Catalysed conversion to non-toxic glutamine for transport

Question 6

What catalyses the conversion of ammonia to glutamine?

Answer 6

Glutamine synthase

Question 7

How do amino groups travel from the muscle to the liver?

Answer 7

Via the glucose-alanine cycle

Question 8

What is the amino carrier?

Answer 8

Alanine

Question 9

What removes an amino group from alanine?

Answer 9

Alanine transaminase

Question 10

What does alanine regenerate?

Answer 10

Glutamate

Gluconeogenic pyruvate

Question 11

Describe how ammonia is converted to urea

Answer 11

ATP-dependent process

Requiring 5 enzymatic reactions

Question 12

Describe urea

Answer 12

End product of nitrogen metabolism
Non-toxic
Uncharged, water soluble
Filtered and excreted by the kidneys

Question 13

What factors increase urea excretion?

Answer 13

Excess protein intake
Protein energy malnutrition
Uncontrolled type 1 diabetes
Infections, burns, wasting disease

Question 14

What factors decrease urea excretion?

Answer 14

Low protein diet
Severe liver disease
Glomerular nephritis
Acute tubular necrosis
Poor renal blood supply
Renal obstruction

Question 15

Where does uric acid come from?

Answer 15

Nucleic acid degradation yields purine and pyramidine bases

Purines breakdown enzymatically to uric acid

Question 16

What would cause increased creatinine clearance?

Answer 16

Excessive meat diet

Question 17

What would decrease creatinine clearance?

Answer 17

Wasting disease
Malnutrition
Poor renal function

Question 18

What is urobilin?

Answer 18

Converted from urinary urobilinogen

Question 19

What hormones would be seen in urine?

Answer 19

Hormonal end products
Deactivation of hormones
This makes them more polar and soluble

Question 20

What are the advantages of urine testing?

Answer 20

Non-invasive diagnosis
Easily obtained
Normal composition known

Question 21

What is red urine a sign of?

Answer 21

Blood

Question 22

What is pseudohematuria?

Answer 22

Free Hb in the blood, myoglobin, porphyrins, drugs

Question 23

What is red/brown urine?

Answer 23

Conjugated bilirubin

Question 24

What is black urine?

Answer 24

Melanin

Question 25

How would bacteria be detected in a urine sample?

Answer 25

Dipstick test for nitrite

Question 26

What would white cells in the urine be evidence of?

Answer 26

Kidney infection

Question 27

What would red cells in the urine be evidence of?

Answer 27

Damage

Question 28

What diseases would cause acidic urine?

Answer 28

Uncontrolled diabetes Starvation Respiratory disorders

Question 29

What diet would cause acidic urine?

Answer 29

Too much meat

Question 30

What stones would be at risk of forming with acidic urine?

Answer 30

Uric acid | Cystine

Question 31

What diseases would cause alkaline urine?

Answer 31

Urinary tract obstructions | Respiratory disorders

Question 32

What diet would cause alkaline urine?

Answer 32

Citrus fruit | Vegetables

Question 33

What stones are at risk of forming with alkaline urine?

Answer 33

CaPO4 MgPO4 CaCO3

Question 34

Abnormal solute excretion is due to what two things?

Answer 34

Pre-renal | Renal

Question 35

What things are excreted in small quantities?

Answer 35

Sugars

Question 36

What would amino acids in the urine indicate?

Answer 36

Generalised tubular damage Transporter defects Raised plasma amino acid levels

Question 37

What is the definition of proteinuria?

Answer 37

Over 200mg of protein excreted in 24 hours

Question 38

What are the mechanisms of proteinuria?

Answer 38

Overflow Glomerular Tubular Secreted