Atherosclerosis and Heart Disease

Question 1

Atherosclerosis characterization

Answer 1

characterized by raised fibrofatty plaques in intimal lining of medium and large-sized blood vessels

Question 2

atheromas

Answer 2

fatty material that builds up inside arteries

Question 3

what does atheromas consist of?

Answer 3

foam cells, proliferating smooth muscle cells, extracellular lipids, fibrous tissue

Question 4

atherosclerosis symptoms

Answer 4

process is usually asymptomatic until vessel is approximately 75% occluded

• at this time, heart can show signs of ischemia (eg. angina) particulary during times of physical exertion

Question 5

lipid metabolism pathway

Answer 5

1. chylomicron
2. lymph
3. subclavian veins => chylomicron circulates in blood
4. adipose tissues => release triglycerides for storage
5. liver => absorbed and broken down -> triglycerides, cholesterol, vitamins

Question 6

what is liver responsible for

Answer 6

producing cholesterol for cells of the body

Question 7

chylomicron

Answer 7

lipids absorbed from GI tract bound to a lipoprotein

Question 8

how can lipids be metabolized

Answer 8

have to be transported by being bound to lipoprotein

since lipids CANNOT be readily dissolved in blood plasma

Question 9

types of lipoprotein

Answer 9

• VLDL
• LDL
• HDL

Question 10

cholesterol pathway

Answer 10

1. VLDL (synthesized cholesterol and cholesterol from chylomicron)
2. adipose tissue - release triglycerides for storage
3. VLDL -> LDL

Question 11

what does LDL do once converted from VLDL

Answer 11

circulate around body and deliver cholesterol to tissues
or
taken up by liver and recycled

Question 12

what occasionally happens to LDL

Answer 12

can get consumed by macrophages
- plays a role in development of atherosclerosis

Question 13

HDL

Answer 13

high-density-lipoprotein

• produced in liver
• released into blood and is reponsible for picking up access cholesterol from tissues and plays a scavenger role

Question 14

what does HDL do to cholesterol

Answer 14

“drops-off” cholesterol at liver and is returned to circulation

Question 15

what happens in cholesterol removed by HDL?

Answer 15

excreted from body in bile

Question 16

Atherogenesis

Answer 16

“Response to Injury Theory”
- mechanism of atherosclerosis development believed to begin w/ endothelial damage and inflammation

Question 17

two types of how intima of artery can be damaged

Answer 17

mechanical stress
oxidative stress

Question 18

mechanical stress

Answer 18

ie. shear stress
- ↑BP or ↑blood viscosity

Question 19

oxidative stress

Answer 19

certain metabolic processes result in generation of high levels of ROS
eg. ↑LDL, diabetes, smoking

Question 20

ROS

Answer 20

reactive oxygen species
- can damage lipids, proteins, DNA, intima or coronary arteries

Question 21

what does damage to endothelium induce

Answer 21

induces an inflammatory response
activates adhesion molecules, growth factors and ↑angiotensin II, ACE levels

Question 22

what does inflammation in atherogenesis result

Answer 22

accumulation of macrophages

Question 23

what does macrophages do in inflammation

Answer 23

consumes LDL and become foam cells that forms initial fatty streak

Question 24

foam cells

Answer 24

type of macrophage that localize to fatty deposits on blood vessel walls

Question 25

angiotensin II in atherogenesis

Answer 25

=> vasoconstriction (vasospasm) and ↓NO levels

Question 26

what does vasoconstriction and ↓NO levels r/t angiotensin II cause?

Answer 26

vascular smooth muscle proliferation enhanced inflammation vasoconstriction promotion of thrombosis

Question 27

what does angiotensin II in atherogenesis promote

Answer 27

cardiac cell growth and contributes to cardiac hypertrophy

Question 28

thrombi easily forms where

Answer 28

lesions

Question 29

what happens to lesions as it grows?

Answer 29

- occludes lumen of vessel - may form a thrombus => complete occlusion quickly - weakens blood vessel wall => ↓activity - may calcify => further rigidity of blood vessel wall

Question 30

as lesions grow what can it lead to?

Answer 30

aneurysms, rupture or hemorrhage in wall

Question 31

stability of plaques is affected by what?

Answer 31

amount of lipid in plaque

Question 32

stability of plaque w/ lots of lipid

Answer 32

very unstable, progress quickly and attract more macrophages and platelets

Question 33

stability of plaque w/ more fibrous tissue and little lipid

Answer 33

more stable and less likely to rupture => ↓predisposition to thrombosis