Lecture 10 Flashcards

1
Q

Cholesterol

A

A steroid alcohol
critically important component of cell membranes
Not digested into CO2 + H2O

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2
Q

Steroid hormones

A

derived from cholesterol
Hormones derived from the same 4-ring structure as cholesterol

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3
Q

Triglycerides

A

Formed from one glycerol molecule with three fatty acid molecules attached via ester bonds

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4
Q

How are triglycerides transported?

A

through the body by chylomicrons and VLDL (very-low-density-lipoproteins)

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5
Q

Phospholipids

A

Composed of one glycerol molecule with a phosphate group and two fatty acid molecules attached via ester bonds
Create phospholipid bilayer membrane

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6
Q

Chylomicrons

A

Has largest diameter, but lowest density
enter the circulation and are metabolized into remnant particles for uptake and further modification by the liver

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7
Q

Chylomicron composition

A

68% triglycerides, 5% cholesterol, 7% phospholipid, and 2% apolipoprotein (B-48)

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8
Q

Very-low-density lipoproteins (VLDL)

A

secreted into the blood by the liver for metabolism in peripheral tissues

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9
Q

Very-low-density lipoproteins (VLDL) composition

A

55% triglycerides, 19% cholesterol, 18% phospholipid, 8% apolipoprotein (c-100)

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10
Q

Intermediate-density lipoproteins (IDL)

A

transitional form, it is made from VLDL and further modified in the liver to LDL

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11
Q

Low-density lipoprotein(LDL)

A

primary carrier of cholesterol
brings cholesterol to peripheral cells for membrane synthesis and formation of adrenal and reproductive hormones

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12
Q

What is LDL known as?

A

Known as “bad” cholesterol,”
easily taken up by cells
high levels are associated with increased risk for atherosclerosis

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13
Q

LDL composition

A

50% cholesterol, 22% phospholipids, 6% triglycerides, and 22% protein and have apoprotein B-100

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14
Q

High-density lipoprotein (HDL)

A

synthesized in the intestines and liver cells
Smallest Diameter, largest density

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15
Q

What is HDL known as?

A

Healthy cholesterol
removes excess cholesterol from peripheral tissues and transports it to other catabolic sites
This function has an anti-atherogenic effect

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16
Q

HDL composition

A

50% protein, 28% phospholipids, 19% cholesterol, and 3% triglycerides
apolipoproteins A-I, mainly, and A-II

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17
Q

Lipids and Lipoproteins: Clinical significance

A

Abnormal lipid metabolism can be due to genetic defects, or it can be acquired
associated with risk of coronary heart disease and other disorders

18
Q

Ranges of Cholesterols

A

Total: Normal: <200, high >240
HDL: Normal: >60, Risk: >40
LDL: Normal <100, Risk: >190
Triglyceride: Normal: <150, Risk: >500

19
Q

Type I hyperlipoproteinemia

A

Elevated chylomicrons
Serum appearance: Creamy layer of chylomicrons
Total cholesterol: Normal to moderately elevated
Triglyceride: Extremely elevated
Apo-B-48 increased, Apo A-IV increased

20
Q

Type IIa hyperlipoproteinemia

A

Increased LDL
Serum appearance: Clear
Total cholesterol: Generally elevated
Triglyceride: Normal
Apo-B 100 increased

21
Q

Type Iib hyperlipoproteinemia

A

Increased LDL and VLDL
Serum appearance: Clear or slightly turbid
Total cholesterol: Elevated
Triglyceride: Elevated
Apo B-100 increased

22
Q

Type III hyperlipoproteinemia

A

Increased IDL
Serum appearance: Creamy layer sometimes present over a turbid layer
Total cholesterol: elevated
Triglyceride: elevated
Apo E-II increased, Apo E-III decreased, and Apo E-IV decreased

23
Q

Type IV hyperlipoproteinemia

A

Increased VLDL
Serum appearance: Turbid
Total cholesterol: Normal to slightly elevated
Triglyceride: Moderately to severely elevated
Apo C-II either increased or decreased, and Apo B-100 increased

24
Q

Type V hyperlipoproteinemia

A

Increased VLDL with chylomicrons
Serum appearance: Turbid with creamy layer
Total cholesterol: Slightly to moderately elevated
Triglyceride: Severely elevated
Apo C-II increased or decreased, Apo B-48 and Apo B-100 increased

25
Q

Bilirubin

A

Principal pigment in bile that is derived from hemoglobin breakdown

26
Q

Delta bilirubin

A

Bilirubin forms a complex with albumin for transport to the liver
bilirubin is unconjugated

27
Q

Unconjugated bilirubin

A

carboxylic acids not derivatized to esters
Not soluble in water

28
Q

Conjugated bilirubin

A

Form of bilirubin with two ester groups
soluble in water

29
Q

Urobilin

A

an orange-brown pigment that gives stool its characteristic color

30
Q

Jaundice

A

a yellow discoloration that occurs when the bilirubin concentration in the blood rises
bilirubin is deposited in the skin and sclera of the eyes

31
Q

Kernicterus

A

Elevated bilirubin deposits in brain tissue of infants
affecting the central nervous system and resulting in mental retardation

32
Q

Pre-Hepatic Jaundice

A

excessive anemias, spherocytosis, toxic conditions, HDN caused by Rh or ABO incompatibility
increased level of conjugated bilirubin in the serum

33
Q

Neonatal Jaundice

A

Level of UDP-glycuronyltransferase is low at birth
takes several days for the liver to synthesis an adequate amount of the enzyme to catalyze bilirubin conjugation
causes increased serum level of unconjugated bilirubin

34
Q

Hepatic Jaundice

A

when the liver cells malfunction and cannot take up, conjugate, or secrete bilirubin

35
Q

Post-Hepatic Jaundice/obstructive jaundice

A

slow flow of bile due to a partial or complete obstruction of the extrahepatic biliary passage between the liver and duodenum

36
Q

Gilbert syndrome

A

Defect in the ability of hepatocytes to take up bilirubin

37
Q

Crigler-Najjar disease

A

Partial or complete deficiency of UDP-glycuronyltransferase

38
Q

Dubin-Johnson syndrome

A

Defective liver cell excretion of bilirubin due to impaired transport in the hepatocytes of conjugated bilirubin
increased serum level of conjugated bilirubin with a mild increase in unconjugated bilirubin

39
Q

Bilirubin Ranges

A

Infants: Total bilirubin 2-6 mg/dL
Adults: Total bilirubin 0.2-1.0 mg/dL
Indirect bilirubin 0.2-0.8 mg/dL
Direct bilirubin 0.0-0.2 mg/dL

40
Q

Urobilinogen

A

is the collective term for stercobilinogen, mesobilinogen and urobilinogen

41
Q

In post-hepatic obstruction, urobilinogen formation is decreased because of what?

A

impaired bilirubin excretion into the intestines
evidenced by: clay-colored/chalky white stool