Nitrogen Metabolism/Urea Cycle Flashcards Preview

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Flashcards in Nitrogen Metabolism/Urea Cycle Deck (64)
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1

What are the dietary fuels

1. Carbohydrates - sugars and starches ( store glycogen in skeletal muscle and liver)
2. Lipids (store as triglycerides in adipose tissue)
3. Proteins - amino acids

2

We dont store amino acids ; we ____them down

break

3

No ____ in carbohydrates of lipids

nitrogen

4

Have to convert nitrogen to ____

urea

5

where does urea cycle occur

liver

6

When are aa oxidized for energy?

1. normal protein turnover
2. starvation/diabetes (uncontrolled)
3. protein rich diet (Atkins)

7

what is nitrogn balance

what you take in vs what you excrete; if intake and excretion are equal it is called N balance; healthy adults

8

What is + nitrogen balance

Holding all the nitrogen you take in (intake> loss); growing children, pregnancy, illness/trauma recovery

9

What is - nitrogen balance

loss is greater than your intake; excreting a lot of Nitrogen in urine; you get edema

10

What is kwashiorkor

The condition of the first born when the second child arrives. the first child who was on breast milk that had all the essential aa's is put on grain diet thats missing essential aa: muscle waisting metabolism!

11

what maintains fluid in bloodstream vs going into tissues

colloid osmotic pressure; proteins of blood maintain colloid osmotic pressure that draws water in but if your lose protein from your blood bc your using it for energy production the main protein you lose is albumin which prov bulk of colloidic osmotic pressureAs osmotic pressure dec fluid leaves blood and goes into tissues. You get edema.

12

What is ureotelic

excrete urea- terrestrial animals. 86%

13

what is ammonotelic

excrete ammonia directly - bony fishes. 2.8%

14

what is uricotelic

excrete uric acid- birds and reptiles. You dont want a bird with a big bladder; birds conserve water in this way. 1.5%

15

what does the other 4% nitrogen come from

Creatine. Which comes from muscle

16

What is peristalsis and stomach acid important for

open up proteins and dentature them; make them more accesible to proteases and cleave them into ind aa that can be asorpeed by brush border in intestine.

17

What do mucosal cells produce

Gastrin; hormone that binds to receptors on T cells that cause them to secrete pepsinogen (inactive precursor protein) and it also makes histamine which makes HCl via parietal cells.

18

What is the end result of the digestive system

liquid chyme

19

How does pepsinogen turn to pepsin

Pepsinogen-->pepsin-->active and auto cleaves itself which starts process of protein digestion slightly

20

Secretion initiated by CNS input is via

acetylcholine

21

What does atropine, probanthine do

blocks acetylcholine interaction with muscarinic receptors.

22

What does cimetidine or ranitidine block

histamine interaction with H2 receptors

23

What are the two hormones that the intestinal mucosa produces

cholecyskokinin: causes gall bladder to secrete bile salts to emulsify fats.
secretin: targets exocrine pancreas; secretes things into intestine which secretes zymogens and bicarbonate.

24

What is the enzyme that the intestinal mucosa produces:

enteropeptidase which activates trypsinogen-->trypsin--> pancreatic zymogens: pro carboxypeptidase

25

What are the enzymes involved in gall bladder and bile salts

chymotrypsinogen, procarboxypeptidase and proelastase

26

what do secretory cells secrete and what is the end result of it

zymogens and bicarbonate. End result is a single amino acids!

27

What are the different classes of aa that the intestine uses for active transport systems

1. neutral
2. basic and Cys
3. imino and Gly
4. acidic
5. beta amino acids: beta alanine, taurine

28

What is Hartnup's disease

similar to pellagra; niacine deficiency; bc this transporter transports tryptophan. you get dermatitis, diarrhea and dementia and inflammation of tongue and oral cavities.

29

how do you get amino acids

from intracellular protein or dietary proteins

30

what do the carbon skeletons do

Go into diff pathways: TCA cycle for energy production, ketone bodies which break down into acetyl coA for fatty acid synthesis, or glucose synthesis or glycogen storage