SSEH3301 Lecture Notes - Lecture 2: Calcium Channel Blocker, Qrs Complex, Coronary Artery Bypass Surgery
Lecture 2: CVD
Cardiovascular disease:
-disease of heart and/or BV
- eg. CHD, stroke, peripheral vascular disease
Most common cause of death in Australia
-These deaths are preventable through lifestyle (CVD)
CV system:
-needed to transport O2 and nutrients and remove metabolic waste
SA node in RA: electrical signals spreads to
AV node, then AVB (BoH), then down BB,
ending at PF = where depolarises wave
spread to ventricles = contract = eject blood
into circulation
Layers: pericardium = fluid filled
sac surrounding the heart (as
heart contracts = movement in
chest cavity = without getting
friction)
-muscle layer = myocardium,
contracts to allow blood to be
ejected
-Inner lining of chambers of heart
= endocardium = consistent with
inner lining of BV
3 layers of artery wall:
Tunica intima, media and adventitia
-intima: inner most (consistent with endocardium) =
single layer of endothelial cell (blood flow past easily)
-Media = muscle layer = primarily smooth muscle cell
for vasoconstriction
-Adventitia = network of CT which gives structure to
artery and allow it to be anchored to surrounding
structures
Atherosclerosis
-disease of artery walls = thickening and loss of
elasticity
-Thickening and loss of elasticity is build up of fat and
cholesterol in intima and media in large and medium
sized arteries
-Diagram: healthy to completely blocked
-Lumen not as wide, higher BP because less blood
flow through, less oxygen flowing
-If progress far enough = complete blockage
Don't generally see atherosclerosis in brachial artery, usually in arteries that
supply the heart (coronary arteries) ad carotid, iliac and femoral, etc
Coronary arteries provide oxygen,
nutrients, etc
Atherosclerosis: process of development
-starts with endothelial layer (intima)
-When endothelial healthy = it is protective
against athero
-Endothelial line entire CV system when
healthy
-Barrier: blood & artery wall
-Permeable selectively (wont let through
dangerous substances)
-Hormones produced (keep healthy)
-Receptors
Healthy endothelium helps BV stay wide and open for blood flow and makes sure no clots
accumulate on endothelial layer, it is thrombo resistant, anti-inflammatory properties. Makes sure
sm muscle cell stays within
Whole process kicks off when endothelial gets injured = athero
process begins
-injured by chemicals in blood (blood-borne chemicals)
-High fat diet (cholesterol)
-Homocysteine is an AA elevated in some individuals
-High BG
-Hypertension (HBP) - blood constantly flowing past endothelial
layer, if too high, damage cell
-Some drugs (cause vessels to vasoconstrict)
-herpes/chlamydia
When damaged, doesn’t normally protect
against atherosclerosis
-no longer selectively permeable, lets certain
substances through
-Endothelial becomes more sticky = high risk
of clot
-Start to get lately adhere to
vessels wall (inflammatory), and
lipids from LDL enter intimate
layer (normally doesn’t), when fat
and cholesterol gets to
endothelial response, monocytes
released, adhere to endothelial
layer, becomes macrophages =
swallow debris = swallow fats/
cholesterol -> becomes foam
cells = plaque formation = athero
begins
Phases of plaque formation:
-fatty streak
-Fibrous plaques
-Complicated lesion
Fatty streak:
-when foam cells start to accumulate under
endothelial layer
-Endothelial layer below has fat, cholesterol
accumulating, monocytes come in ->
macrophages -> swallow up now become
foam cells @ sub-intimal space (below intima)
-Not dangerous because accumulated fat/
cholesterol is not significant (not protruding to
vessel lumen yet so doesn’t affect blood flow)
-@ this stage, can reverse it/stabilise/progress
to fibrous plaque
Document Summary
These deaths are preventable through lifestyle (cvd) Needed to transport o2 and nutrients and remove metabolic waste. Sa node in ra: electrical signals spreads to. Av node, then avb (boh), then down bb, ending at pf = where depolarises wave spread to ventricles = contract = eject blood into circulation. Layers: pericardium = fluid filled sac surrounding the heart (as heart contracts = movement in chest cavity = without getting friction) Muscle layer = myocardium, contracts to allow blood to be ejected. = endocardium = consistent with inner lining of bv. Intima: inner most (consistent with endocardium) = single layer of endothelial cell (blood flow past easily) Media = muscle layer = primarily smooth muscle cell for vasoconstriction. Adventitia = network of ct which gives structure to artery and allow it to be anchored to surrounding structures. Disease of artery walls = thickening and loss of elasticity.
