Pathophysiology and Pharmacology

Running head: PATHOPHYSIOLOGY AND PHARMACOLOGY 1
Pathophysiology and Pharmacology
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PATHOPHYSIOLOGY AND PHARMACOLOGY 2
1.
a) What is cholesterol and why is it important?
Cholesterol is a steroid alcohol; it is an organic molecule with unsaturated alcohol and
steroid. The lipid, cholesterol, is found in all animal cells as it is a vital component of the cell
membrane; hence its importance it maintaining the integrity of cells (Feingold & Grunfeld,
2019). Also, cholesterol regulates membrane fluidity with respect to temperature changes. It is
serves a precursor in the biosynthesis of crucial substances such as bile acids, steroid hormones,
and vitamin D (Feingold & Grunfeld, 2019).
b) How is cholesterol transported in the blood?
Cholesterol is nonpolar in nature. It minimally dissolves in hydrophilic media, such as blood
or water. Therefore, it needs to be associated with lipoproteins for easy transportation in blood.
Lipoproteins are spherical assemblies that contain lipids and proteins; the outer parts are water-
soluble while the inward regions are lipid-soluble hence, its efficiency in cholesterol
transportation in blood (Feingold & Grunfeld, 2019). Plasma lipoproteins vary with density,
electrophoretic mobility, size, and the cholesterol content. As a result, the low density
lipoproteins (LDH) are favorable in transporting cholesterol from liver cells to other body parts
in blood.
c) What is a lipoprotein
A lipoprotein is a lipid-protein biochemical complex whose principal role is transporting
cholesterol in blood. They are globular in shape. Phospholipids, apoproteins, and unesterified
cholesterol enclose a nonpolar core lipid that comprises of esterified cholesterol and triglycerides
(TAGs) (Feingold & Grunfeld, 2019).
2.

PATHOPHYSIOLOGY AND PHARMACOLOGY 3
3.
a) What does the liver synthesise?
The uses free fatty acids and carbohydrates for the synthesis of triacylglycerides (TAGs).
TAGs are esters of glycerol and three fatty acid molecules, and are released into the blood in
association with very-low-density lipoprotein (VLDL) molecules (Feingold & Grunfeld, 2019).
Other molecules at the core of TAG secretion include apoprotein B-100, C, and E.
b) What are VLDL particles and what do they do?
Very-low-density lipoprotein (VLDL) is one of the types of lipoproteins made by the
liver: other types are chylomicrons, intermediate-density lipoprotein, high-density lipoprotein,
and low-density lipoprotein (Feingold & Grunfeld, 2019). VLDL facilitates the movement of
lipids in the water-component of blood. More also, with their 30 to 80 nanometre diameter,
VLDL carry endogenous substances. VLDL are rich in triacylglycerides. As a result, the
lipoprotein lipase found on the endothelial cells of capillaries hydrolyses the VLDL into TAGs,
which are then metabolized into fatty acids and monogylcerides for oxidation or storage in the
adipose tissues.
c) How are LDL particles created?
Low-density lipoproteins (LDL) are rich in cholesterol. A monolayer of phospholipid
makes up LDL particles: unesterified cholesterol on the outer layer and fatty acid esters forming
the hydrophobic core (Feingold & Grunfeld, 2019). The liver secretes VLDL that is then
metabolized by lipoprotein lipases that strip off triacylglycerol from the lipid to produce smaller
remnant particles, also known as intermediate-density lipoproteins (IDL). Subsequently, the
hepatic triacylglyceride lipase converts the IDL into low-density lipoprotein. However, the liver
clears these molecules from circulation through LDL receptors.