Atherosclerosis and Exercise + CVD risk factors Flashcards
How does a fibrous plaque form?
Size of fatty streak increases, cap of CT may cover core of fat/cellular debris, forming fibrous plaque
The site of lesion can become calcified, causing..?
Reduced artery elasticity.
When lesion restricts blood flow by ?% do symptoms develop.
~45%. Threshold described as clinical threshold
What happens when vulnerable plaques rupture?
- Thrombus formation (leading to stroke or heart attack)
- Aorta (aneurysm) or brain artery (haemorrhagic stroke)
What are the triglyceride-rich lipoproteins?
Chylomicrons and VLDL
What mechanism may explain the blood pressure lowering effect of exercise?
Reductions in total peripheral resistance due to reduced sympathetic nerve activity and increased responsiveness to vasodilators like NO.
May also be increase CSA of veins and arteries.
What is endothelial function?
Ability of endothelium to interact with vascular smooth muscle to influence blood flow.
How do endothelial cells exert their effects?
By secreting various agents which diffuse to the adjacent vascular smooth muscle and induce vasodilation/constriction.
Name an important vasodilator released by endothelial cells.
Nitric Oxide (NO)
How is NO released?
Continously in basal state, but secretion can rapidly increase in response to chemical stimulants (e.g., exercise).
Secretion also elevated in response to increase in sheer stress (force exerted by blood flow).
When does endothelial dysfunction occur?
Early stages of atherosclerosis (triggers myocardial ischemia).
