CVS - CHD and Thromoembolic CV Pathologies Flashcards
Atherosclerosis
narrowing of the arteries
Ischemia
less oxygen
Coronary system
get blood when heart relaxes
Coronary circulation:
pressure excreted to aortic arch, when aorta relaxed there is a backflow to the blood
hyperlipidaemia/ atherosclerotic lesions
narrow coronary arteries and reduce ability to dilate
lesions rupture and stimulate platelet aggregation/thrombus formation LEADS to
occludes the artery and PREVENTS blood flow/suppy
How does NO dilate the blood vessel? (vascular smooth muscle)
- NO stimulates cytoplasmic guanylyl cyclase
- Elevation of intracellular [cGMP]
- Activation of protein kinase G
- Smooth muscle relaxation (vasodilation)
- PDE isoform breaks down cGMP
Antianginal drugs - what are the 1st line options?
- BB = beta blockers (‘lol’) drugs
for pateints w angina or HF - CCB = Calcium channel blocker
what are the 2nd line options?
- sodium-channel blocker
- potassium channel activator
Progressive coronary heart disease;
myocardial infarction
What does myocardial infarction require?
thrombolytics or surgical
PC heart disease effect on vessels?
severe coronary artery narrowing, transient occlusion or microembolization of thrombis or atheromatous material
NSTEMI
Non-ST segment elevation MI
NSTEMI explained
myocardial ischaemia and necrosis - still functional (some blood flow)
changes in TROPONIN & no change in ECG
why is STEMI worse than NSTEMI?
complete and prolonged occlusion of an epicardial coronary blood vessel
ST segment elevation of Mi (STEMI)
Dysfunction and death (necrosis) of cardiac myocytes in the ventricular wall
explain the troponin and ECG levels in an occurance of STEMI?
troponin level RISE
elevation of ST segment in ECG
thrombosis
blood clotting in artwery
embolism
b,ood clot/ endogenous materials (embolus) moving in blood the vessel and obstruct blood flow
What are the charicteristics of thrombocytes/ fragments/ platelets?
- no nucleus
- mitochondria in them
- play a role in blood clotting
what is the process of maemostasis of blood clotting
physiological process to stop bleeding - staying still
Blood clotting - haemostasis. explain in 3 steps:
1) vasular spasm
2) Platelet activation
3) Coagulation- patch (fibrin mesh)
1) vasular spasm
pain reflux, constriction of vasuclar smooth muscle , trigger clotting chemicals/ factors needed & directed to site of injury
2) Platelet activation
+ive feedback mechanism
Endothelial Damage
Exposed Collagen
Platelets stick to exposed collagen (swell like star shaped cells)
Platelets stimulate ADP, Thromboxane A2 and Serotonin
Von Willebrand Factor- Stabilise collagen-platelet adhesion
- Coagulation- Patch
Clotting factors/procoagulants in Liver
Vitamin K, the biosynthesis clotting factors
Plasma proteins I to XIII
What is the last process of blood clotting ? forming a mesh?
Intrinsic (blood) and exrinsic (tissue) > PROthombin activation > PROthombin > thrombin > fibrinogen (soluble) > fibrin (INsoluble) > fribrin (MESH)
What happens in the clotting process in ATHEROSCLEROSIS?
the thrombin-mediated platelet activations becomes abrupt and accelerated due to the endothelial dysfunction/damage
What is the HEALTHY thrombin mediated process?
Protease-activated receptor causes THROMBIN to activate the platelets via PAR
AT-III binds to HEPARIN (released from endothelial cells)
Anti-thrombin III- heparin complex inhibit throbin activity
ATHERSCLEROSIS, hwo does, how does ADP- mediated platelet plug formation work?
becomes abrupt and accelerated due to endothelial dysfunction or damage
PLATELETS stimulate ADP, thromboxane A2 and serotonin
Explain the process of pltelet-endothelial interaction (ADP-mediated process- healthy)
ACTIVATED platelets stimulate the release of ADP whioch acts on P2Y receptors in platelets to actiavte +ive feedback
in healthy ADP binds to P2Y receptor and stimulate the release of prostacycin and NO from endothelial cells to prevent plug formation
Platelet-Fibrin Plug Formation (GPIIb/IIIa-mediated process- Healthy)
Von Willebrand factor acts as a bridge between collagen, exposed in damaged blood vessels, and the glycoprotein receptors, GPIIb/IIIa expressed in activated platelets
Glycoprotein receptors, GPIIb/IIIa binds to fibrinogen and form platelet-fibrin plug
Clot retraction concurrent with vessel repair
The actin and myosin in platelets contract and pulls on fibrin strands
Platelet-derived growth factor (PDGF)
Stimulate smooth muscle and fibroblast division
Vascular endothelial growth factor (VEGF)
Rebuild endothelial lining by multiplying endothelial cells
What is Fibrinolysis?
Plasminogen, plasma protein trapped in clot- converted Plasmin-digest Fibrin