14. When the Cardiovascular System Goes Wrong! Flashcards
What is Primary Hypertension?
Essential/ Idiopathic
“Of unknown medical cause”
Linked to: genetic predisposition, alcohol intake, obesity, lack of exercise, diabetes, intrauterine environment, etc
What is Secondary Hypertension?
“Of known medical cause”
- kidney disease - increase angiotensin II (vasoconstriction, expansion of extra cellular fluid).
- general endocrine disorders e.g. diabetes, Cushing’s, etc.
- adrenal medulla disease
(phaeochromocytoma) - excessive adrenaline secretion
What are the treatments for hypertension?
- Angiotensin II receptor blocker
- Thiazide diuretics
- Calcium-channel blocker
What do Angiotensin II receptor blockers do?
Inhibit the actions of angiotensin ll on aldosterone production
= preventing renal Na+/H2O absorption and blood volume increase, and prevents vasoconstrictor actions of angiotensin II.
What do Thiazide diuretics do?
They increase loss of Na+ and water in the kidneys
= decrease fluid volume = ↓ venous return, ↓cardiac output (CO)
What does an α-Andrenoceptor Antagonist (α-blockers) do?
Reduce TPR by inhibiting the action of noradrenaline.
What does an β-Andrenoceptor Antagonist (β-blockers) do?
- decreases CO
- decreases SNS activity centrally
- decrease renin release = favourable secondary actions
Hypertension increases the risk of:
- Atherosclerosis
- Stroke/ Cerebrovascular Accident
- Heart Failure
- Renal Failure
- Aneurysms
What is Atherosclerosis?
- Major cause of death in developed countries
- Can be treated by statins, fibrates and bile acid- binding resins
- Caused by damage to endothelium
- Fatty plaques are present on the blood vessel wall
- Fibrous cap of a dense extracellular matrix narrows lumen of vessels & restricts blood flow
- Lipid accumulation, macrophages, proinflammatory mediators, white cells, endothelial cells, smooth-muscle cells. Etc
- Fragments of plaques can detach and become lodged in small vessels causing thrombosis.
What is Arteriosclerosis?
- Hardening and thickening of artery walls
- Loss of tissue elasticity as part of the natural ageing process
- Narrowing of the vessel lumen in the absence of fatty plaques
- Build up of calcium deposits in the vessel wall
Define Angioplasty
Procedure that involves the insertion of a balloon catheter to enlarge the opening in the artery.
What is a DVT?
Most commonly found in the leg vein; deep vein thrombosis (DVT).
What is pulmonary embolism?
A blood clot in the lungs: pulmonary embolism (PE).
Define Regurgitation.
Valve Defect
Inadequate closure leading to backflow & turbulence; followed by a decrease in cardiac output.
Define Stenosis.
Valve Defects.
Inadequate opening; obstructs flow.
Caused by: thickening of the valve, papillary muscle or cordae tendinae following disease. Rheumatic fever can cause mitral valve stenosis up to 20 years after infection.
Severe occlusion: → hypertrophy to maintain CO, but will lead to increased blood pressure → oedema and dilatation of heart chambers → heart failure