circulatory distubances Flashcards
Causes of oedema
- increased hydrostatic pressure (BP)
- decreased plasma oncotic pressure
- lymphatic obstruction
- increased vascular permeability
the thumb test
differentiating oedema (dough) from cell proliferation
ascites
oedema but in body cavities
infarction
the obstruction of the blood supply to a region of tissue
ischemia
condition where blood flow and oxygen are restricted/reduced to the body
tissues at higher risk of infarction
high metabolic activity and terminal blood vessels
types of infarction pathogenesis
hemorrhagic and anemic
causes of infarction
embolism, local vasoconstriction, compression of a vessel and torsion
similarities between hyperemia and congestion
- distended blood vessels
- increased hydrostatic pressure
- increased chance of oedema
how does congestion increase chance of oedema
from increased hydrostatic pressure only
how does hyperemia increase chance of oedema
from increased vascular permeability and increased hydrostatic pressure
what is hyperaemia
dilation of arterioles increasing blood into tissues –> arteriolar-mediated engorgement of vascular bed
causes of hyperaemia
- inflammation (redness and heat are cardinal signs)
- physiological: digestion, exercise, embarrassment
what is congestion
too little blood being removed from venules –> passive venous engorgement of vascular bed
what is a thrombus
a solid blood clot within the blood vessels or heart attached to the vessel wall
what is a thromboemnoli
an emboli that breaks loose
what stimulates the coagulation cascade
Tissue damage (collagen, basement membrane exposed)
what is the function of fibrin and what is it the polymer of
forms clots and from fibrinogen
tissue factor VII
activates clotting cascade
causes of thrombosis
- injury to endothelial cells
- disrupted blood flow disrupting normal laminar blood flow
- hypercoagulation of blood
outcomes of thrombosis
- fibrinolysis
- organisation and recanalisation
- phagocytic cells move in
- embolism and possible infarction
what is haemorrhage
the escape of blood through rhexis
haematomas
blood filled swelling
circumscribed extravascular collection of blood, usually clotted
haemopericardium
haemorrhage into pericardial space
haemothorax
haemorrhage into thoracic cavity
how can vessels become damaged and cause haemorrhage
- mechanical trauma
- necrosis or vessel wall destruction due to: neoplasia, toxins, vit C deficiency, anoxia, ulceration, deposition of immune complexes
Petechial haemorrhages
pinpoint haemorrhage (foci 1-2mm)
causes of petechial haemorrhages
vascular defect or platelet defect
enymoic haemorrhages
10-20mm in diameter
due to vascular, platelet or coagulation defects
disorders of haemostasis
platelet dysfunction (disease of platelets or congenital/acquired disorders) r clotting cascade disorder (inherited, acquired or clotting factors already used)
thrombocytopaenia
decreased number of platelets
thrombopanthua
platelet function disorder
resolution of haemorrhage
reabsorption and organisation of clotted blood
