cardiovascular Flashcards
what is the #2 cause of death in Canada?
Atherosclerosis
what are the consequences of atherosclerosis?
myocardial infarct, stroke, aneurysm, peripheral vascular disease
what event initiates atherosclerosis?
endothelial injury and dysfunction
what is called the build-up in the intima in atherosclerosis?
buildup of atheroma
do veins have smooth muscle?
yes but thinner than arteries because they carry blood at lower pressure
do arteries or veins have valves? why?
veins: to maintain unidirectional blood flow against gravity
describe the 3 layers in the artery wall from inner to outer
intima: single layer of endothelial cells (all vessels)
media: smooth muscle
externa: connective tissue
describe the 3 layers of veins wall from inner to outer
endothelial cells
smooth muscle
external wall
what deposit on walls of the aorta?
cholesterol (fatty streak)
what is atherosclerosis?
harmful fibrous tissue accumulation in the intima
what are the 2 outcomes of atherosclerosis?
plaque rupture or grows until complete occlusion
what is an angina?
chest pain caused limited blood flow through coronary artery due to atherosclerosis
what is stenosis of the lumen?
narrowing of the lumen
what is a thrombus?
blood clot that can form on the plaque and cause vessel to rupture (stays there)
what can be caused by vessel occlusion in the periphery?
gangrene in extremities
what is the other term for angina?
transient ischemic attack
what causes the pain of angina?
inadequate blood flow during physical activity
what are the CNS symptoms of angina?
difficulty speaking and moving (happen transiently)
what is a myocardial infarction?
ischemic stroke: vessel occludes completely and causes death of cells in the brain or heart
what are the symptoms of peripheral arterial disease?
intermittent claudication (on and off blood flow to the legs causing pain during exercise)
what are the key components of atherosclerosis pathogenesis?
endothelial dysfunctions and chronic inflammation in the arterial intima
3 things that cause endothelial injury
hyperlipidemia, hypertension, smoking
how do vessels respond to injury of endothelial cells? what do these responses do?
retract (increase permeability) and release signaling molecules. this initiates atherosclerotic plaque formation
where is hemodynamic stress the most notable?
at branch points (area more susceptible to injury)
what are the 3 big sections of atherosclerosis pathogenesis?
hemodynamic stress, cell mediators/cytokines, lipoprotein accumulation
where is hemodynamic stress most notable?
at branch points
what induces smooth muscle proliferation after an injury?
mediators (macrophages, platelets, lymphocytes, fibroblasts, SM cells) and the growth factors they release
what kind of process is atherosclerosis development?
inflammatory process
what are foam cells?
modified macrophages formed after taking up LDL that release inflammatory cytokines/mediators
describe the function and structure of lipoproteins
carry lipids in blood.
inside = triglycerides and cholesterol
surface = phospholipids, free cholesterol, apoprotein
what type of lipoprotein has the most protein content? what does it do?
high-density lipoprotein HDL: brings lipids back to the liver
which lipoproteins are considered bad?
LDL and VLDL. they can deposit cholesterol to blood vessel walls
what are chylomicrons?
triglycerides from which we absorb lipids from intestines
how are LDLs a risk for atherosclerosis? (2 reasons)
their Apo B protein gets recognized by LDL receptor on cells -> LDL gets internalized and broken down in lysosome -> free cholesterol.
also, they activate inflammatory processes
what type of LDLs are most present in atherosclerosis plaques?
modified / oxidized LDLs
what are the 2 types of receptors that take up LDLs?
LDLR and scavenger receptors
what apoprotein is found on HDL surface?
Apo A
smooth muscle cells can form a fibrous cap on antheroplaque that has what function?
helps reduce risk of plaque rupture
how else do smooth muscle cells contribute to atherosclerosis?
accumulate lipids, synthesize collagen, elastin, glycoprotein, synthesize ECM -> enlarges the plaque / forms fibrous cap
what is an embolus?
something that moves through blood vessels and eventually blocks one that is too small to let it pass
name the cells involved in formation of a plaque
stem cells from bone marrow, foam cells
risk factors for atherosclerosis
hyperlipidemia, hypertension, smoking, toxins, obesity, metabolic syndrone, type 2 diabetes
what is caused by T2DM (type 2 diabetes mellitus)
high LDL, high triglycerides, high BP, low HDL
complications of atherosclerosis
ischemia (complete occlusion), renal ischemia, intermittent claudication, thrombus, embolus, plaque rupture (causes blood clot)
what is an aneurysm
weakening of vessel wall causes the vessel to bulge out because the artery is under pressure
how do cigarettes increase risk of atherosclerosis?
activates platelet aggregation, increased CO, impaired oxygen delivery, interferes with HDL production, hypertension,
what is familial hypercholesterolemia?
rare genetic defect in LDL receptors causing too much LDL in circulation, dengerous for atherosclerosis
what is PCSK9?
loss of function mutation that causes degradation of LDL receptors
what is the difference between saturated and unsaturated fat?
saturated = bad! lacks double bonds. decreases LDL receptors
unsaturated = good. protect you
which oil is the best?
canola; low saturated fat, high unsaturated
what is type 1 diabetes?
islets of langherhans are not making enough insulin
what is type 2 diabetes?
insulin resistance due to lifestyle (obesity)
what are metabolic syndrome symptoms?
abdominal obesity, hyperinsulinemia, high glucose levels, hypertriglyceridemia, low HDL, high HDL, hypertension
what does the activation of insulin receptors cause?
uptake of glucose, free fatty acids, and amino acids
how does diabetes affect LDL levels?
increases LDL in circulation
what % of people with T2DM die of coronary heart disease?
80%
how can insulin resistance affect endothelium?
glucose derivatives damage endothelium and ECM and can generate free radicals.
also increases vessel permeability.
can cause edema, ischemia, neovascularization
how are plasma C reactive proteins (CRP) related to coronary vascular disease?
higher CRP levels = more inflammation = diabetes
what is thrombosis?
formation of blood cloth in the vasculature
how is thrombosis developped from atherosclerosis?
platelets aggregate, adhere, and degranulate -> thrombosis
what is PGI2?
prostacyclin, an antithrombotic released by healthy endothelium
what does prostacyclin do?
promotes vasodilation and blocks platelet aggregation
3 contributors to thrombosis
endothelial injury -> abnormal blood flow and hypercoagulability
what can cause hypercoagulability?
changes in blood composition after childbirth or surgery (increased platelets, prothrombin, and fibrinogen)
what causes thrombosis in different vessels?
arteries: endothelial injury and plaque rupture
veins: slow blood flow, hypercoagulability & injury
what is deep vein thrombosis
DVT: stasis of blood flow in legs after sitting for long. possibility of thrombus forming
what can cause a thrombus in the heart?
infarct (damage to heart surface promotes platelets)
3 common sites of thrombus formation
heart, brain, periphery
what is the classical case of embolism
embolus form around the valves in deep vein in the legs, goes to heart then lungs -> pulmonary embolus
what can help in a small pulmonary embolus?
collateral circulation from bronchial artery
where will an embolus cause instant death?
if it’s stuck at the bifurcation to the heart
what happens if there is no collateral circulation?
infarct
what is blood flow proportional to?
the 4th power of the diameter of a vessel
what are the 2 main forces acting on artery?
BP and resistance to distension
where can micro-aneurysms be seen?
brain and retina
describe the 2 types of aneurysms
fusiform: bulges all around
saccular: localized on one side
where is berry aneurism?
in circle of Willis
what is cardiac tamponade?
tear in aortic wall and blood accumulates in pericardial sac; heart can’t pump properly
what causes varicose veins?
increased pressure in feet when standing up causes valves to not close properly