Cholesterol metabolism and health and disease

Question 1

what pathway are cholesterol and fatty acids absorbed

Answer 1

exogenous pathway

Question 2

what happens to cholesterol and fatty acids in the exogenous pathway

Answer 2

Triglycerides are formed in the intestinal cells from free fatty acids and glycerol
Cholesterol is esterified

Question 3

what do Triglycerides and cholesterol combine to form

Answer 3

chylomicrons

Question 4

Once Chylomicrons enter the circulation where do they travel

Answer 4

travel to peripheral sites

Question 5

In peripheral tissues, free fatty acids are released from the chylomicrons to be used as what

Answer 5

energy, converted to triglyceride or stored in adipose

Question 6

In peripheral tissues, free fatty acids are released from the chylomicrons to be used as what

Answer 6

energy, converted to triglyceride or stored in adipose

Question 7

what is the main site of LPL activity

Answer 7

adipose & mammary tissue, skeletal muscle, myocardium.

Question 8

what do Endocytosed chylomicrons that are catabolized
by lysosomes do

Answer 8

release cholesterol for excretion as bile acids in bile
or incorporated into VLDL

Question 9

what do Endocytosed chylomicrons that are catabolized
by lysosomes do

Answer 9

release cholesterol for
excretion as bile acids in bile
or incorporated into VLDL

Question 10

what happens in the endogenous pathway

Answer 10

VLDL FORMS IDL or VLDL remnants.

Question 11

What do LDL particles contain

Answer 11

a core of cholesterol esters and a smaller amount of triglyceride.

Question 12

What is LDL is internalized by

Answer 12

hepatic and non-hepatic tissues.

Question 13

In the liver, what is LDL converted into

Answer 13

bile acids and secreted into the intestines.

Question 14

In non hepatic tissues, what is LDL used in

Answer 14

hormone production, cell membrane synthesis, or stored.

Question 15

LDL is also taken up by macrophages and other cells which can lead to what

Answer 15

excess accumulation and the formation of foam cells which are important in plaque formation.

Question 16

What is HDL

Answer 16

HDL is a heterogenous group of macromolecules with different physical properties and chemical components

Question 17

What are the 2 subclasses of HDL

Answer 17

HDL2 and HDL3

Question 18

What is the function of HDL

Answer 18

to reverse transport of cholesterol from different tissues to the liver for excretion

Question 19

What is the function of HDL

Answer 19

to reverse transport of cholesterol from different tissues to the liver for excretion

Question 20

What does Reverse cholesterol transport begins with

Answer 20

the removal of cholesterol from arterial foam cells

Question 21

what happens to Cholesterol from non-hepatic peripheral tissues

Answer 21

is transferred to HDL by the ABCA1(ATP-binding cassette transporter).

Question 22

what does ApoA-1 act as

Answer 22

an acceptor and the phospholipid component of HDL acts as a reservoir for the cholesterol.

Question 23

what enzyme coverts cholesterol to cholesterol esters

Answer 23

The cholesterol is converted to cholesteryl estersby the enzyme LCAT (lecithin-cholesterol acyltransferase).

Question 24

what does LCAT do

Answer 24

Cholesterol → cholesteryl esters catalysed by lecithin cholesterol acyltransferase (LCAT) in peripheral tissues

Question 25

Where is ACAT2 found

Answer 25

found in both intestine and liver

Question 26

Where is ACAT1 found

Answer 26

in all tissues

Question 27

what is cholesterol

Answer 27

Most abundant steroid It is amphipathic Can be found in large concentrations in the brain, spinal cord, and liver Liver is the most important site of cholesterol biosynthesis, although other sites include the adrenal glands and reproductive organs

Question 28

what is the function of cholesterol

Answer 28

Serves as the major precursor for the synthesis vitamin D3 steroid hormones (cortisol, cortisone, and aldosterone in the adrenal glands) sex hormones (progesterone, estrogen, and testosterone).

Question 29

what is CVD

Answer 29

CVD includes all the diseases of the heart & circulation including coronary heart disease, angina, heart attack, congenital heart disease and stroke CVD is responsible for a ¼ of all deaths in the UK About half of all deaths from CVD are from CHD and about a quarter are from stroke CHD by itself is the most common form of heart disease, and the most common cause of death for both men and woman globally The cost of CVD to the UK healthcare system in 2020 was £22.5 billion

Question 30

what arteries relate to CHD

Answer 30

Disease involving the network of blood vessels (coronary arteries) surrounding and serving the heart

Question 31

What plaques effect the coronary arteries

Answer 31

the accumulation of atherosclerotic plaques in coronary arteries that lead to a reduction in blood flow to the myocardium.

Question 32

what does CHD lead to

Answer 32

myocardial infarction (MI) and sudden death

Question 33

what is Atherosclerosis

Answer 33

Risk factors: unhealthy blood Chol; high BP; smoking etc Thickening of the arterial wall; artery becomes occluded (blocked) Begins in childhood with clinical symptoms in middle age or later Leads to ischaemia (lack of nutrients and oxygen) to cells supplied by the artery

Question 34

how do you lower blood cholesterol

Answer 34

Regular exercise Reducing Chol & Sat fat Drugs - HMG-CoA reductase inhibitors - statins -lovastatin (Mevacor) & atorvastatin (Lipitor)

Question 35

what is a major cause of CHD

Answer 35

atherosclerosis

Question 36

What are the 3 stages of plaque formation

Answer 36

1. fatty streak 2. plaque progression 3. plaque disruption-unstable plaques will rupture leading to thrombus and possible thrombosis

Question 37

what is angina

Answer 37

A narrowing of one or more coronary arteries, restricting the flow of blood to the heart Pain occurs during physical activity and sometimes at rest Crushing pain which may move to left arm or to the jaw

Question 38

how is stroke manifested

Answer 38

cerebral arteries

Question 39

how is myocardial infarction manifested

Answer 39

coronary arteries

Question 40

how is leg pain, DVT, gangrene manifested

Answer 40

peripheral arteries

Question 41

what is heart attack

Answer 41

1. Acute Myocardial Infarction 2. death, long term complications 3. happens when one or more of the coronary arteries supplying blood to the heart muscle becomes suddenly blocked and Shortage of blood supply to heart muscle leads to tissue death

Question 42

what is Arrhythmia

Answer 42

1. Disturbance in heart rhythm leading to ineffective pumping 2. Common cause of death in early stage heart attack 3. Bradycardia describes a rate of less than 60 beats per minute 4. Tachycardia usually refers to a heart rate of more than 100 beats per minute

Question 43

what tool diagnoses arrhythmias

Answer 43

An electrocardiogram

Question 44

what treats issues with the heart

Answer 44

pacemaker

Question 45

what is heart failure

Answer 45

when the pumping mechanism is ineffective and can be sudden or over a long time

Question 46

what are the symptoms of heart failure

Answer 46

Chest discomfort Shortness of breath Nausea Light headed

Question 47

what is cardiac arrest

Answer 47

1. Heart stops pumping 2. Ventricular fibrillation most common cause and can be related to CHD, cardiomyopathy, electrocution, lack of oxygen, drug misuse 3. CPR and defibrillation used to treat

Question 48

what is a stroke

Answer 48

disturbance to brain function caused by inadequate blood supply (cerebral infarction) or by direct damage by bleeding into the brain (cerebral haemorrhage)

Question 49

what is vascular dementia

Answer 49

1. Narrowing of small blood vessels in the brain 2. Mini strokes – transient ischaemic attacks (TIA) Degenerative condition causing confusion, memory loss, difficulty with speech and balance and personality change 3. >65 years most common

Question 50

what are common medications for cholesterol issues

Answer 50

Probucal: increases conversion of cholesterol to bile acids Cholestyramine: sequesters bile acids for excretion. As the body loses bile acids, it replaces them by converting blood cholesterol to bile acids

Question 51

what are statins

Answer 51

A class of drugs used to lower cholesterol levels Inhibit the enzyme HMG-CoA reductase, which plays a role in the production of cholesterol in the liver

Question 52

what diet should you follow to reduce CVD

Answer 52

Replace SFA with unsaturated fats, Avoid trans fats Eat 2 portions of fish per week Increase fibre intake