Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

G.I & Nutrition > Bile and Bile Salts > Flashcards

Bile and Bile Salts Flashcards

1
Q

80% of bilirubin comes from ____

A

red cells –> heme –> iron, CO, biliverdin –> bilirubin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Unconjugated bilirubin is polar/nonpolar

A

polar –> but insoluble b/c polar groups are hidden in tertiary structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How is insoluble unconjugated bilirubin transported?

A

by hydrogen bonding to albumin –>separates at the hepatocyte membrane in the space of disse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where in the cell does bilirubin become conjugated?

A

in endoplasmic reticulum –> e.g. if pt has elevated unconjugated bilirubin, we know the defect is at the conjugation step or after

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the rate limiting step in bilirubin production?

A

ATP mediated pumping into canaliculus against a large concentration gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Most bilirubin is secreted as a ______

A

diglucoronide, few as monoglucoronide, <1% unconjugated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Is conjugated bilirubin water soluble?

A

yes –> glucuronidation opens up the molecule and exposes hydrophilic moieties

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where in the body is conjugated bilirubin normally found?

A

bile but not blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where in the body is unconjugated bilirubin normally found?

A

bile and blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Mechanisms body employs to protect against neurotoxicity of unconjugated bilirubin

A

binding to albumin, blood brain barrier, conjugation, excretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

T/F all the body’s protective mechanisms against unconjugated bilirubin may be somewhat defective in the newborn.

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is delta bilirubin and when does it show up?

A

conjugated bilirubin COVALENTLY bonded to albumin (vs. H bonds in unconjugated bilirubin) –> serum of pts with long-standing hyperbilirubinemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why does it take a while for bilirubin levels to normalize after treatment?

A

delta bilirubin bound to albumin is too big to pass into urine and takes a while to get cleared

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Bacteria convert bilirubin to colorless water soluble _____

A

urobilinogen –> some is absorbed, some reaches urine via serum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are pyrroles?

A

bacteria act on urobilinogen to produce pyrroles to give stool its color

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Unconjugated hyperbilirubinemia results in direct/indirect jaundice and conjugated hyperbilirubinemia results in direct/indirect jaundice.

A

indirect and direct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does unconjugated hyperbilirubinemia lead to jaundice?

A

H bonds to albumin make molecules too large to pass into urine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How does conjugated hyperbilirubinemia lead to jaundice?

A

conjugated bilirubin is actually mixed –> conjugated part is water soluble and passes into urine, unconjugated part and delta part get stuck in circulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the urine color differences in (un)conjugated bilirubin?

A

tea/red color = conjugated == + on dipstick

20
Q

3 causes of unconjugated hyperbilirubinemia

A

overproduction, reduced uptake, defects in conjugation

21
Q

2 etiologies of reduced hepatic uptake resulting in unconjugated jaundice

A
  1. altered circulation (portal shunting, right heart failure)
  2. effect of drugs (rifamycin)
22
Q

Name a few etiologies of overproduction of bilirubin leading to unconjugated jaundice

A

hemolysis, extravasation/bruising, ineffective erythropoeisis/pernicious anemia

23
Q

Lab findings in overproduction of bilirubin leading to unconjugated jaundice

A

normal liver histology/tests, serum bilirubin < 3X b/c of effective liver clearance AKA really high bilirubin is probably not due to overproduction

24
Q

Name a few etiologies of conjugation defects leading to unconjugated jaundice

A

inherited: crigler najjar I and II (rare) and gilberts (benign, common)
acquired: testosterone, novobiocin, wilson’s/chronic heptatitis, hyperthyroidism, jaundice of newborn

25
Q

What kind of crigler najjar is more dangerous?

A

type I

26
Q

What is kernicterus?

A

bilirubin mediated injury to CNS –> phototherapy to prevent in jaundice of newborn

27
Q

MOA of phototherapy

A

exposure of unconjugated bliirubin to UV breaks H bonds and makes it water soluble

28
Q

Gilbert’s syndrome

A

benign, common, defect in promoter gene for G-transferase, slightly elevated serum unconjugated bilirubin

29
Q

How does bilirubin change during fasting?

A

increases slightly –> increases greatly in Gilbert’s/fasting can cause jaundice

30
Q

Gilbert’s: Is there bilirubin in the urine?

A

no –> remember, it’s mostly unconjugated

31
Q

Gilbert’s: liver chemistries

A

normal

32
Q

How do we normally get conjugated bilirubin in the blood?

A

injury to cell or biliary obstruction leads to reflux (even during severe liver disease, conjugation continues) –> most of the serum bilirubin is conjugated and only some of it is unconjugated

33
Q

What two rare syndromes are inherited secretory defects leading to conjugated hyperbilirubinemia?

A

Dubin-Johnson (black pigment in liver) and Rotor (no black pigment) –> both have normal liver enzymes and normal excretion of bile salts

34
Q

PBC is intra/extrahepatic

A

intrahepatic –> no dilated ducts

35
Q

PSC is intra/extrahepatic

A

intra but also extrahepatic –> dilated biliary duct obstruction

36
Q

Cholestasis: liver chemistries

A

alkphos >3X (could also be bone disease), GGT increase, increase in conjugated bilirubin

37
Q

Symptoms of cholestasis

A

pruritis (opiates, bile salt resin irritation), jaundice, fatigue, anorexia, xanthelasma (cholesterol deposit near eye)

38
Q

Tx of pruritis

A

cholestyramine

39
Q

Malabsorptions in cholestasis

A

Vit A: night blindness
Vit D: osteomalacia/osteopenia
Vit K: prothrombin impairment
Vit E: cerebellar and peripheral nerves

40
Q

Tx of PBC

A

ursodeoxycholic acid –> protects against hydrophobic bile salts –> can be used in many kinds of cholestasis

41
Q

Liver chemistries: acute biliary obstruction

A

early elevation in transaminases, after passage of stone, delayed increase in bilirubin, alkphos

42
Q

Gallstones- 3 predisposing factors

A

cholesterol or bilirubin precipitation –> supersaturation, stasis, nucleation factors

43
Q

Detection of gallstones

A

ultrasound

44
Q

What is the difference between (un)pigmented stones?

A 
unpigmented = cholesterol
pigmented = unconjugated bilirubin (black form in gallbladder, brown form in bile ducts)
45
Q

Risk factors for cholesterol gallstones

A

females, >30, multiparity, obesity, lack of exercise, rapid weight loss, genetic (native americans), estrogens, TPN, western diet

46
Q

What kind of gallstones show on xray?

A

cholesterol in gallbladder

47
Q

What kind of gallstones show on xray?

A

all

G.I & Nutrition (43 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions