Physiology of Hypertension Flashcards
Definition of hypertension
140> mmHg systolic / >90 mmHg diastolic
What are the causes of hypertension
Multifactorial causes - genetic/foetal Environmental facors - obesity -XS alcohol -XS Na + intake `
What happens to the following in chronic hypertension CO PR Lumen diameter Wall thickness
CO - normal
PR- increase
Lumen diameter- decrease
increase in wall thickness “resitance” vessels - sclerosis
What are the consequences of hypotension?
Increase in Na+
increase in ECF/ BV
Increase in CO
barorecptor adaptation
Where does secondary hypertension occur
Renal disease Coarctation of the aorta Endocrine disease Pregnancy drugs
What endocrine diseases can cause secondary hypertension
Primary hyperaldosteronism
Phaeochromocytoma
Cushings syndrome
What happens in renal disease
decrease in GF - leading to fluid retention
increase BV
increase in CO
increase in RAAS increases PR and increases CO
What happens in primary hyperaldosterone
Increase renal fluid absorption and increases BV and increases CO
What happens in phaeochromocytoma
Increase in catecholamines - vasoconstriction increasing PR
increase in catecholamines will also cause cardiac stimulation and increase CO
What is cushings syndrome
XS CG
increase in renal fuid absporption
increase in BV increase in CO
What does coarctation of the aorta mean
INcrease in BP proximal to stricture
decrease in BP/ perfusion distal to strcture
renally mediated general hypertension
What drugs can cause secondary hypertension
NSAIDs substance abuse herbal remedies steroids COC pill sympathomimetrics
What are the consequences of hypertension
LVH/cardiac failure
arterial wall thickening and reduced vascular compliance - increase in pulse wave veolcity
atheroma
What happens in endothelial dysfunction
Reduced dilators
Increase in constrictors
increase in risk atheroma/thrombosis
What happens in renal damage
Reduced perfusion/filtration
positive feedback from RAAS
further increase in blood pressure
What happens in cerebral vascular disease
Dementia
TIA
stroke
What happens in hypertensive retinopathy
Thickening of arterial walls
Haemorrhages
“soft” exudates
signs of hypertension
Headache/nosebleed
NONE
elevated BP
Hypersensitive retinopathy
Symptoms of hypertension
Cardiac cerebrovascular
renal disease
Peripheral vascular disease
Coronary vascular disease
How do we reduce cardiac output
Thiazide diuretics -
Beta adrenoreceptors
ACE inhibitors
All receptor inhibitors
What do thiazide diuretics do
Decrease cardiac output initially and decrease peripheral resistance long term
What do beta- adrenoreceptors blockers do
reduce cardiac sympathetic stimulation
What do ace inhibitors do
reduce aldosterone production
What do all receptor inihibitors do
reduced vasoconstriction
