Long term control of BP Flashcards
What are the 2 main factors which lead to total peripheral resistance?
- Arteriolar radius
- Blood viscosity (haematocrit)
What factors lead to increased ECF volume?
- Fall in GFR
- RAAS
- Salt reabsorption
- Sympathetic activation
What factors lead to vasoconstriction?
- Sympathetic activation
- Endothelin
- Renal prostaglandins (+ other vasodilators) decrease
What factors lead to Renin release?
- Sympathetic nerve activation (mediated by baroreceptor feedback)
- Renal artery hypotension (independant of baroreceptor feedback)
- Decreased Na+ in kidney distal tubules
Why do people with kidney disease get high blood pressure?
- Activation of RAAS
- Retention of salt and water with reduced excretory function
What percentage of the UK adult population have hypertension?
25%
What percentage of people over 60 have hypertension?
50%
What is the effect of hypertension on K+ intake?
Decreased
What drugs can increase BP?
- Oral contraceptive pill
- Steroids
- NSAIDs
What is usually the primary problem which causes hypertension?
Reabsorption of too much sodium
What are the causes of secondary hypertension?
- Renal disease Renal artery stenosis Polycystic kidney disease Glomerulonephritis - Coarcation of aorta - Endocrine disorder Cushing's Conn's Pheochromocytoma
What is cushing’s syndrome due to?
Excess cortisol
Where is cortisol produced?
zona fasciculata of adrenal cortex
Where is aldosterone produced?
zona glomerulosa
What does the zona reticularis produce?
Androgens
What are the three zones of the adrenal cortex from outer to innermost?
- Zona glomerulosa
- Zona fasciculata
- Zona reticularis
WHat can the effects of hypertension be on the eyes?
- Retinal blood vessels become damaged by high pressure
- Arteries become narrowed and tortous
- Subsequently veins occluded and oedema and haemorrhage occurs
What are the effects of hypertension on the kidneys?
Autoregulation tries to protect the glomerulus
Albuminuria
Continued high pressure
- Arterial walls thicken and narrow
- Kidney function declines irreversibly (sclerosis due to fibroblast activity)
Urine formation falls
- Volume overload
- Decreased clearence of creatinine, urea and waste products
