Cholesterol
LDLs carry _______ and _______ synthesized cholesterol (most of which is made in the liver) to the cells of the body via ________________.
dietary; newly; blood cells
Atherosclerosis can lead to _____________.
heart attack
Some people naturally have fewer LDL receptors. In many individuals this is an ____________. In severe cases of this genetic disease called ________________, individuals have 6-8 times the normal cholesterol level and often have heart attack in early childhood.
inherited trait; hypercholesterolemia
The disease atherosclerosis build up in the ______ layers of the walls of _______.
inner; arteries
Recommended total cholesterol levels (Amer. Heat Assoc.) = [HDL] + [LDL]
200 mg/dl of blood or below = low risk cardiovascular disease 200-239 mg/dl of blood= borderline risk cardiovascular disease 240 mg/dl of blood or above= high rise of cardiovascular disease
LDLs contain _______ protein, and _______ cholesterol.
25%,50%
HDLS contain ______ protein, and _____ cholesterol.
33%; 30%
Individuals with hypercholesterolemia have ______ times the normal cholesterol level.
6-8
LDLs carry what percentage of cholesterol found in blood plasma?
60-80%
What disease is characterized by the build-up of yellowish plaques containing LDL cholesterol, triglycerides, and cellular debris in the inner layers of the walls of arteries?
Atherosclerosis
HDL cholesterol levels:
Average male: 40-50 mg/dl of blood Average female: 50-60 ""
What happens if there is a build up of LDL in the blood?
Cholesterol carried by LDL builds up on walls of arteries
What are statins?
Drugs that lower LDL
What are the two major types of lipoproteins?
HDLs, LDLs
Factors which tend to decrease HDL levels include:
Heavy drinking, obesity, & smoking
What leads to lower than expected numbers of LDL receptors on cell surfaces?
Inherited trait, and an oversupply of cholesterol
An oversupply of cholesterol due to diet high in saturated fats and/or a diet high in cholesterol may cause cells to produce fewer ____ cell surface receptors.
LDL
The plaques characterized with atherosclerosis contain:
LDL cholesterol, triglycerides, and cellular debris
Diets high in trans-fats appear to increase concentration of ________ and decrease the concentration of _____ in the blood.
LDL;HDL
Low density lipoproteins (LDLs):
Large particles, contain 25% protein, 50% cholesterol
LDL cholesterol levels:
Less than 100 mg/dl of blood- optimal 100-129 ""- near optimal 130-159 ""- borderline high 160-189 ""- high 190 ""- very high
Dietary sources of cholesterol:
Meat, egg yolk, cheese
Cholesterol is a component of animal cell _________.
Membranes
Is cholesterol found in plant tissue?
No
What do statins do to lower LDL?
Reduce production of cholesterol by liver cells Increase number of LDL cell surface receptors of liver cells --> increased removal of LDL cholesterol which is converted in into bile and excreted by small intestine.
Factors which tend to increase HDL levels include:
Regular exercise, eating veggies, & fish oils
What is a coronary bypass operation?
Restores blood flow to heart muscle by diverting the flow of blood around a section of a clocked artery in your heart.
High density lipoproteins (HDLs):
Small particles, contain 33% protein, 30% cholesterol
Animal fats are high in saturated fatty acids
True
To keep from being flooded with cholesterol, most cells including those in the liver, stop manufacturing LDL receptors.
True
Why is knowing only the total cholesterol concentration in your blood of little value?
You want to know the proportion of LDL to HDL
The removal of LDL cholesterol is converted into ______ and excreted by ____________.
bile; small intestine
HDLs pick up excess cholesterol from the _______, ________, and maybe from plaques coating the blood vessels. In the blood these HDLs are transformed into ______ which bind to the receptors on the surface of the liver cells and are converted into ___________ in the liver cells. The bile salts are dumped into the ___________ and eliminated with feces.
blood; tissues; LDLs; bile salts; large intestine
LDLs bind to special protein molecules located on the cell membrane called ____________________.
cell surface markers
One reason that LDLs build up in the blood is due to reduced number of LDL __________, especially on liver cells. As a result, LDLs are not efficiently taken up by cells; resulting in increased levels in the blood _______.
cell surface receptors; plasma
Since cholesterol is insoluble in the blood plasma, it is transported attached to carrier molecules called _________ which are soluble in the blood plasma.
lipoproteins
The ______ is the key organ in the regulation of the levels of cholesterol found in the blood.
liver
Cholesterol is synthesized in the ______ from _____________ taken in as part of your diet.
liver; saturated fatty acids
HDLs are produced in the ______ and __________.
liver; small intestine
LDLs bind to special _________ molecules located on the cell membrane called cell surface markers. They enter the cell by a process called ________________________. Once in the cells, the cholesterol is used for the synthesis of new cell membrane material, synthesis of _____________ (only in cells of sex organs).
protein; receptor mediated endocytosis; steroid hormones
Cell surface markers enter the blood through a process called ___________________.
receptor mediated endocytosis
Cholesterol is required for the synthesis of certain _______________ hormones in animals.
sex
The liver both _______ cholesterol when needed by the body and _____________ when in excess.
synthesizes; breaks it down
As plaques form in atherosclerosis walls become _______, fibrous and calcified, and the _____ (opening) narrows, reducing the flow of blood to the tissues the artery supplies. Plaques restrict blood flow, especially in __________, carrying blood to the heart. This results in a decreased ________ supply to the heart which in turn leads to death of the heart cells causing _____________.
thick; lumen; arteries; oxygen; heart attack
