Unit 4.3 Review PBS

What is cholesterol? What roles does cholesterol play in our cells and in the body

• Cholesterol is an important lipid that is made in the liver

• It acts as a stabilizer for cell membranes and used for cell to cell communication.

• It is a precursor to steroid hormones and Vitamin D

• It helps for bile acids, which are important in fat digestion.

• It also makes up the myelin sheath around nerve cells to improve the speed of nerve impulses

What are LDL and HDL?• HDL – High Density Lipoprotein (made of mostly protein). – Job is to carry cholesterol from the arteries to the liver to be

digested• LDL – Low Density Lipoprotein (made of mostly lipids).

– Job is to carry cholesterol to the cells

How are LDL, HDL, and cholesterol related to heart disease? How do doctors interpret the

results of a cholesterol test?

• High LDL levels carry too much cholesterol to the cells, which then builds up in the arteries.

• Low HDL levels means not enough HDL to clear the arteries of the excess LDL.

• Build of LDL causes Atherosclerosis, which reduces blood flow and can cause high blood pressure and heart attacks

What is familial hypercholesterolemia and how is it inherited?

• Mutation of the LDL receptors on the cell membrane, which leads to a build of LDL in the blood stream.

• It is an autosomal dominant trait so heterozygotes will still be affected

How can techniques of molecular biology be used to analyze DNA for the presence of the FH mutation?

• PCR – is used to make many copies of the FH gene

• Restriction Enzymes are used to cut the FH Gene. Depending on the bases the enzyme will cut at different places, making different sized fragments, called RFLPs

• Gel electrophoresis is used to separate the fragments by size. The negatively charged DNA moves towards the positive end and shorter fragments move farther.

• The bands from each person can be compared to controls to identify the genotype that person has.

What lifestyle changes may help a patient

obtain healthy cholesterol levels?

• Limit Trans and Saturated Fat as they increase LDL

• Eat unsaturated fats to increase HDL

• Exercise daily• Maintain healthy weight• Manage stress and do

not smoke• Take medications, like

statins if needed

What are the pros and cons of using cholesterol lowering medications?

• Common cholesterol medication, statins, will decrease LDL, triglycerides, and even CRP (involved in strokes), while slightly elevating HDL

• However it can lead to side effects, such as muscle weakness and pain, even in the heart (since it is a muscle)

• They can also cause amnesia for minutes to hours, headaches, dizziness, and liver dysfunction

How does the heart work as a pump ?

• As the heart contracts it pushes on the blood, causing enough pressure to push it through the arteries.

What is atherosclerosis? How can cholesterol plaques affect the overall function of the heart?

• Atherosclerosis is the build up of plaque, which can be due to excess LDL along the arterial walls, reducing blood flow

• Atherosclerosis of the coronary artery can cause lack of oxygen to fuel the heart

• It can cause lack of blood flow to the extremities, including the brain, causing strokes