wk 4 - haemodynamics Flashcards
how can infarcts occur in the vascular system 2
- blockage of arterial system- ischaemia- necrosis - infarct
- blockage in venous system - congestion - haemorrhge - necrosis - infarct
define congestion
passive build up of blood in the vessel
define oedema
increased fluid in interstitial tissue
define effusion
increased fluid in body cavity
define exudate
high in plasma poteins- occurs in acute inflammation
define transudate
low in plasma proteins odema - usually occurs in most pathology
define ischaemia
lack of blood supply, partial or complete
define haemorrhage
damage to a vessel and release of all blood
accumulation of blood which if large it is referred to as haematoma
define thrombus
Blood clot attached to the wall (vessel/heart chamber)
define embolus
Undissolved mass travelling in the blood
define aneurysm
localised, abnormal ballooning out of an artery or ventricle of heart
define antheroma
sclerotic (hardening) plaque in an artery. referred to this when dead
lesion in the artery
define atherosclerosis
chronic inflammatory process within the wall of an artery. typically affects the intima of an artery.
-ongoing injury
-attempts to reparir
-hardening of lipids and calcium
referred to this when alive
define hypertension
raised blood pressure
define anaemia
decreased number or quality of RBCs
define stasis
lack of blood flow
define hypercoagulability
blood with a higher tendency of clotting
what are blood flow and blood pressure differences in the systemic, pulmonary and venous circuits
systemic - high blood pressure (hard to get congestion to occur)
pulmonary - low blood pressure
venous - low blood pressure (easy for congestion to occur)
what causes venous thrombi vs arterial thrombi
venous- stasis and coagulation
arterial- endothelial injury and atherosclerosis
compare superficial and deep vein thrombi
same risk factors but different in:
superficial-
pain, ulceration, oedema
rarely embolise.
deep-
asymptomatic often, maybe swelling
often embolise
list the 2 main risk factors for DVT and track their path if they embolise
stasis- lack of movement
hypercoagulation- promotes blood clotting
list the 8 main risk factors for the development of atherosclerosis
age
male gender (oestrogen is protective)
Smoking
Diabetes (both)
Systemic Hypertension
Hyperlipidaemia (high LDL, low HDL)
/dyslipidaemia
Visceral adiposity
how do the kidneys contribute to systemic hypertension
kidneys regulate blood volume and pressure and they activate the RAAS system
what 3 vascular pathologies does atherosclerosis predispose towards
- thrombus
- embolus
- aneurysm
what are consequences of having atherosclerosis in the abdominal aorta, coronary arteries carotid and cerebral arteries
abdominal aorta- embolise and infarct downstream. it could kill if you get an aneurysm and a haemorrhage
coronary- ischemic heart disease
cerebral - cerebral vascular disease
infarction is
area of necrosis
thrombus is
bloot clot attached to the wall of a vessel or heart chamber
embolus
anything undissolved travelling in the blood
aneurysm
localised abnormal ballooning out or dilation of part of a vessel/ventricle wall
antheroma
sclerotic plaque which represents an area of chronic inflammation within the wall of an artery
atherosclerosis is
the process of atheroma formation
congestion is
passive build up of blood within a vessel, which increased hydrostatic pressure
transudate
low protein oedematous fluid caused by increased hydrostatic pressure and/or reduced collodial osmotic pressure
what is the main site for haemopoiesis in the adult
the red marrow in the axial skeleton- produces red blood cells in response to erythropoietin
can you live without a spleen?
yes, in cases when theres trauma. however, because its role is to look for antigens and recycle RBC’s there is an increased risk of infection when removed
how do the normal functions of the kidneys impact blood pressure and composition?
- kidneys produce EPO which stimulates RBCs
2.renin angiotensin - aldosteron system (RAAS):
aldosterone increases amount of water and salt reabsorbed and increases the blood volume as a result. through renin and angiotensin 2 causes vascular constriction increasing blood pressure. - regulate ions and blood pH
how do the normal functions of the liver impact blood composition?
- sythensis of plasma proteins which is responsible for increased collodial osmotic pressure and discouraging oedemea (transudate) occuring
- also has a role in RBCs formation
in what ways do superficial and deep vein thrombi differ?
super- dont embolise, symptomatic
deep-embolise, asymptomatic
what is the route of a deep vein thrombi that has embolised
femoral/iliac vein - inferior vena cava - right atria - right ventricle - pulmonary arteries - lungs
what do aneurysms form in vessels and ventricles?
in arteries, they form in areas of atheroslcerosis (high pressure, weakened areas)
in heart ventricles, areas of scarring
why do thrombi form on atherosclerotic lesions or within aneurysms?
atherosclerosis encourages turbulent blood flow where there is a bashing against the endothelial lining causing further injury. When endothelium is lost there are pro clotting factors released.
aneurysms the same reason applies because they form in areas of atherosclerosis but also because cells and proteins can get entrapped in them.
an ebolus released from a thrombus in the addominal aorta can cause an infarction where
Anywhere downstream like lower limbs, bowels etc
what is the difference between angina and a heart attack?
both caused by ischaemia but angina the blood is restored to the tissue before necrosis occurs
what are the 4 ways atherosclerosis can cause death? -example of location as well
- BRAIN- aneurysm bursting or giving rise to thrombi/emboli (if it bursts in the brain it will lead to a haemorrhage stroke that increases intracranial pressure)
- CAROTID/BRAIN - thrombi/emboli leading to ischaemic strokes (in the carotid or cerebral arteries can be life threatening)
- HEART- atherosclerosis/thrombi can cause chronic ischaemia through blockage, if this is within the coronary arteries then it will cause a myocardial infarction
- ABDOMINAL AORTA- bursting of aneurysm causing hypovolemic shock
cause myocardial infarctions
what is the difference between a myocardial infarction and a brain infarction?
the heart undergoes coagulative necrosis where the dead tissue is walled off until inflammatory cells remove the dead tissue. Whereas the brain often encompasses a large area of necrosis and because of the difference in tissue like other organs, it turns into liquefaactive necrosis. mush.
what are the scars in the brain formed from?
Glia, glial scars
why are there symptoms to infarctions in the heart and brain compared to other organs?
they are both permanent therefore they must heal by scarring, meaning loss of functional tissue and because both work as a complete unit, this will cause symptoms to occur. compared to organs that have multiple functions and able to separate these functions, less symptomatic.
atherosclerosis in what vessels could lead to a stroke?
cerebral or carotid arteries
atherosclerosis in what vessels could lead to a myocardial infarct
coronary arteries
atherosclerosis in what vessels could lead to ischaemic heart disease
coronary arteries
atherosclerosis in what vessels could lead to cerebral atrophy?
cerbral or carotid arteries
what is colloidal pressure governed by?
concentration of plasma proteins
