w2 nitrogen balance

Question 1

how is the majority of nitrogen is excreted from his body

Answer 1

urea

Question 2

what urinary excretion products produced in the kidney would change in response to this metabolic condition

Answer 2

Ammonium

Question 3

Administration of which of the following would be most beneficial in treating a child with a defect in the urea cycle

Answer 3

Benzoate and Phenylbutyrate interact with glycine and glutamine, respectively, and increase excretion

Question 4

what explains an elevated BUN

Answer 4

Reduced excretion of nitrogen compounds

Question 5

Which of the following dietary recommendations would be most beneficial in treating a chronic kidney disease patient’s azotemia ( high levels of nitrogen based compounds)

Answer 5

Decreased protein intake with sufficient carbohydrate

Question 6

what is glutamine converted to in the kidney

Answer 6

ammonium

Question 7

what is heme converted to

Answer 7

Heme is converted to bilirubin which is converted to urobilinogen

Question 8

what role does alanine play in the liver

Answer 8

important in transporting amino acids from muscle to liver

Question 9

what is the primary site for the urea cycle

Answer 9

liver mitochondria and cytosol

Question 10

where do the N compounds for the urea cycle derive from

Answer 10

N contributed from aspartate and glutamate (see pic)

Question 12

what process turns glutamate to ammonia

Answer 12

oxidative deamination

Question 13

what process turns an alpha amino acid to an alpha keto acid

Answer 13

transaminase

Question 14

describe the urea cycle

Answer 14

Question 15

name 2 things that can increase the urea cycle

Answer 15

fasting and a high protein diet

Question 16

what changes occur in arginine with CKD

Answer 16

Arginine: synthesized in kidneys from citrulline, precursor for NO, creatine, agmatine, other polyamines

CKD: other organs must synthesize arginine that would normally be made in kidneys

Question 17

role of epo

Answer 17

Erythropoietin– stimulates the production of proerythroblasts from hematopoietic stem cells (increases the # of RBC’s in the blood in response to hypoxia)

Question 18

Outline the main effects of erythropoietin on the red cell mass.

Answer 18

Red Cell Mass– the part of the total blood volume (BV) occupied by the RBCs

· Erythropoietin increases the red cell mass of total blood volume until sufficient oxygenation is restored, then the rate of erythropoietin production decreases to a lvl that maintains a good lvl of required # of RBC’s for adequate oxygenation to all tissue

So long as plenty of iron, Vit B12, and folic acid (with other nutrients) are available, the rate of RBC production can rise to ~10x or more

· When kidneys are unable to secrete erythropoietin, the quantity of RBC’s drops and severe anemia develops

o Few RBCs are formed by the bone marrow

o Liver can compensate for 1/3 of the RBC load, but not enough so anemia is inevitable