Lipids

Question 1

Predominate lipids measured

Answer 1

Cholesterol and triglycerides

Question 2

Cholesterol

Answer 2

Key component of cell membrane, myelin sheaths, and is precursor for steroid hormones and bile acid

Question 3

Triglycerides

Answer 3

Major constituent of adipose tissue. Represents body’s energy reserves

Question 4

Lipoproteins

Answer 4

Transport cholesterol and TG in aqueous environment. Transport as complexes and have specific proteins known as apoproteins

Question 5

Density of the lipoproteins from least to high

Answer 5

Chylomicron, VLDL, IDL, LDL, HDL
Determines where they sit in the sample

Question 6

Apoproteins

Answer 6

Structural and functional attributes and serve as regulators of lipid metabolism

Question 7

A1 Apoprotein

Answer 7

Activate lecithin: Cholesterol acyl transferase (LCAT)

Question 8

C-II Apoprotein

Answer 8

Activator of lipoprotein lipase

Question 9

Major steps of metabolism

Answer 9

-Production
-IV processing
-Clearance

Question 10

Lipases

Answer 10

Catalyze lipolysis of TG to FAs

Question 11

Lipoprotein lipase

Answer 11

Insulin causes LPL to migrate to cell surface of endothelial cell and enables uptake of TG

Question 12

Hormone sensitive LPS

Answer 12

Activated by epinephrine/glucagon/ cortisol causes mobilization of energy stores

Question 13

Exogenous or dietary lipid metabolism

Answer 13

Produced in SI enterocytes and get TG lipolysis to MG and FA-> reassembled as a chylomicron in enterocyte-> enters lymphatics and then blood-> obtain apoproteins C and E and C-II activates LPL in presence of insulin catalyzes lipolysis of TG-> FA to be taken up by adipocytes or muscle

Question 14

VLDL

Answer 14

Apoprotein C-II activates LPL with insulin and the density increases due to lipolysis and FA liberation from TG-> VLDL loses TG to become IDL-> LDL and then LDL deliver cholesterol and LDL cleared by liver

Question 15

HDL

Answer 15

Accept cholesterol and transport it to hepatocytes

Question 16

Cholesterol in fasting serum

Answer 16

Within lipoproteins

Question 17

Increased cholesterol

Answer 17

-Increased cholesterol production: hepatocytes and enterocytes
-Decreased lipolysis or intravascular processing of lipoproteins: hypothyroidism, PLE or nephrotic syndrome
-Multiple mechanisms: cholestasis, DM, Hyperadrenocorticism

Question 18

Decreased cholesterol

Answer 18

Decreased cholesterol production: PSS, PLE (lymphangectasia)
Multiple causes : hypoadrenocorticism

Question 19

Hypertriglyceridemia

Answer 19

-Increased production by hepatocytes or enterocytes: fasted state or postprandial hyperlipidemia
-Decreased lipolysis or intravascular processing of lipoproteins: Hypothyroidism, nephrotic syndrome, LPL deficiency
-Multiple mechanisms: DM, acute pancreatitis