Atheroma, thrombosis and embolism Flashcards
(59 cards)
is ischaemia reversible?
yes depending on multiple factors including speed of onset, local demand and duration
is infarction reversible
no, you get repair by scarring .
In the liver though you may get regeneration
what are the 2 functions of haemostasis?
1 – maintain blood in a fluid, clot free state in normal vessels;
2 – induce rapid, localised haemostatic plug at site of vascular injury.
what is thrombosis ?
pathological corruption of haemostasis. The formation of a solid or semi-solid mass from the constituents of blood, within the vascular system, during life.
what is the role of platelets?
to close small breaches in vessel walls
what are the haemostatic contents of platelet alpha granules
adhesion components e.g. fibrinogen, fibronecton, PGDF, anti-heparin. Also vWF and factor V
what are the haemostatic contents of platelet dense granules
they are important for aggregation and contain ADP and 5HT
what are the 8 main functions of endothelial cells
- maintain a permeability barrier
- elaborates anticoagulant, antithrombotis, fibrinolytic regulators
- elaborates prothrombotic molecules
- produces EC matrix
- modulates blood flow and vascular reactivity
- regulates inflammation and immunity
- regulates cell growth
- role in LDL oxidation
give some examples of the anticoagulant, antithrombotic, fibrinolytic regulators produced by endothelial cells?
Prostacylcin, Thrombomodulin, Heparin-like molecules, Plasminogen activator
give some examples of the prothrombotic molecules produced by endothelial cells?
VWF, Tissue Factor, Plasminogen activator inhibitor
how do endothelial cells modulate blood flow and vascular reactivity?
by secreting:
- Vasoconstrictors – endothelin, ACE
- Vasodilators – NO, prostacylcin
how do endothelial cells Regulates inflammation and immunity?
by
IL-1, IL-6, chemokines
Adhesion molecules – VCAM-1, ICAM-1, E-selectin, P-selectin
how do endothelial cells Regulates cell growth?
Growth stimulators
Growth inhibitors
name examples of growth stimulators?
PDGF, CSF, FGF
name examples of growth inhibitors?
heparin, TGF-beta
what are some causes of endothelial injury ?
Hyperlipidaemia Hypertension Smoking Toxins Vasculitis Viruses - cytomegalo virus e.g. Immune reactions- coagulation cascade, antibody complexes
what effects does stasis and turbulence have? 4 things
- platelets come into contact with the endothelium
- activated clotting factors are not dilutes by the normal rapid flow of blood
- inflow of anticoagulant factors is slowed, allowing thrombi to persist
- activation of endothelial cells in promoted
what are some examples of situations in which turbulence and stasis are important factors in thrombosis ?? name 4
- DVT
- non -contractile areas of myocardium following an MI
- aneurysm
- AF
what is hypercoagulability?
any alteration in the coagulation pathway which predisposes to thrombosis.
hypercoagulable states can be acquired or genetic. what are the high risk acquired states?
Myocardial infarction Immobilisation Tissue damage Cancer Prosthetic heart valves DIC Heparin induced thrombocytopenia Antiphospholipid syndrome
what is disseminated Intravascular coagulation (DIC) ?
is a serious disorder in which the proteins that control blood clotting become over active. Causes.
what is Heparin-induced thrombocytopenia (HIT) ?
development of thrombocytopenia (a low platelet count), due to the administration of heparin.
HIT is caused by the formation of abnormal antibodies that activate platelets.
hypercoagulable states can be acquired or genetic. what are the lower risk acquired states?
Atrial fibrillation Cardiomyopathy Nephrotic syndrome Hyperoestrogenic states Oral contraceptive use Late pregnancy Sickle cell anaemia Smoking
hypercoagulable states can be acquired or genetic. What are the genetic states?
- Factor V mutations (2-15% of Caucasians)
- Defects in anticoagulant pathways – antithrombin III deficiency, protein C or S deficiency
- Defects in fibrinolysis
- prothrombin 20210 mutation and others
there is a synergy in these
