Block C Lecture 3: The Hepatic System Part 2 - Electric Boogaloo

Question 1

What percentage of cholesterol is synthesised by the body and what percentage comes from diet?

Answer 1

75% is synthesised with 25% coming from diet
(Part 1, Slide 2)

Question 2

Where in the body is cholesterol synthesised primarily?

Answer 2

The liver
(Part 1, Slide 3)

Question 3

Where in the cell does cholesterol synthesis occur?

Answer 3

The cytoplasm and ER
(Part 1, Slide 3)

Question 4

What reaction in cholesterol synthesis is the rate limiting reaction and is usually the target of pharmacological intervention to lower cholesterol levels?

Answer 4

The HMG-CoA reductase reaction
(Part 1, Slide 3)

Question 5

What are 5 functions of cholesterol?

Answer 5

Component of cell membranes
Precursor molecule for sex hormones
Precursor molecule for hormones released by the adrenal glands
Precursor molecule for bile acids
Precursor for vitamin D
(Part 1, Slide 5)

Question 6

What is the risk of high cholesterol levels?

Answer 6

Atherosclerosis
(Part 1, Slide 6)

Question 7

What is atherosclerosis?

Answer 7

Where the bodies arteries become narrowed, making it difficult for blood to flow through them- caused by a buildup of plaque
(Part 1, Slide 6)

Question 8

What 3 things does atherosclerosis increase the risk of happening?

Answer 8

Coronary heart disease (such as a heart attack or angina)
Stroke
Peripheral vascular disease
(Part 1, Slide 6)

Question 9

What are the 5 classes of lipoprotein?

Answer 9

Chylomicrons
Very low density lipoproteins (VLDL)
Intermediate-density lipoproteins (IDL)
Low density lipoproteins (LDL)
High density lipoproteins (HDL)
(Part 1, Slide 7)

Question 10

What are the “good” and “bad” types of cholesterol?

Answer 10

Low density lipoproteins are considered “bad” cholesterol whereas high density lipoproteins are considered “good” cholesterol
(Part 1, Slide 7)

Question 11

What is hyperlipidemia?

Answer 11

An elevated level of lipids (such as cholesterol or triglycerides) in the blood
(Part 2, Slide 3)

Question 12

What are 5 risk factors for hyperlipidemia?

Answer 12

Answers Include:
Diet
Medical conditions (such as diabetes or hypertension)
Genetics
Sex
Age
Smoking
Inactivity and Obesity
(Part 2, Slide 2)

Question 13

What are 3 drugs that can be used in drug therapy of hyperlipidemia?

Answer 13

Answers Include:
Statins
Bile-Acids Sequestrants
Niacin (Nicotinic Acid)
Fibric Acid Derivatives
Ezetimibe (to inhibit the delivery of cholesterol)
(Part 2, Slide 3)

Question 14

Generally, what effect do drug therapies for hyperlipidemia have on HDL, LDL and triglyceride concentrations?

Answer 14

Generally, they increase HDL concentration, decrease LDL concentration and can either decrease or have no effect on triglyceride concentration
(Part 2, Slide 5)

Question 15

What reaction of cholesterol synthesis do statins inhibit?

Answer 15

The rate limiting reaction (The HMG-CoA -> Mevalonic acid reaction)
(Part 2, Slide 6)

Question 16

What does statins inhibiting the HMG-CoA -> Mevalonic acid reaction do?

Answer 16

It increases expression of LDL receptor gene (which reduces free cholesterol levels and increases synthesis of LDL receptors) and it reduces the degradation of LDL receptors, which in turn reduces LDL levels
(Part 2, Slide 6)

Question 17

What are statins competitive inhibitors of?

Answer 17

HMG-CoA reductase
(Part 3, Slide 2)

Question 18

What are statins used for?

Answer 18

To decrease coronary heart disease events, strokes and total mortality
(Part 3, Slide 2)

Question 19

What is hepatotoxicity?

Answer 19

When a drug causes damage to the liver
(Part 3, Slide 5)

Question 20

How are statins hepatotoxic?

Answer 20

They elevate hepatic transaminase levels
(Part 3, Slide 5)

Question 21

What does hepatic transaminase do?

Answer 21

Help the liver break down, detoxify and remove toxins from the body
(Part 3, Slide 5)

Question 22

On top of hepatotoxicity, what else can can statins cause?

Answer 22

Rhabdomyolysis (the destruction of striated muscle cells)
(Part 3, Slide 5)