chapter 21 pt 1- blood vessels Flashcards
short term control of BP- neural control
baroreceptors and chemoreceptors
what does neural control pg bp respond to?
changes in arterial pressure and stretch
what do receptors respond to in neural bp control
responds to changes in blood levels of CO2, H+, O2
what is neural bp control controlled by?
hypothalamus
short term control- hormonal control
adrenal medulla hormones (epi and NE), angitensin II (ridde bp), ANF( drops bv and bp) ADH (vasopressin)- all increase bp except ANF
long term bp control
renal mechanics alter blood volume via kidneys
BV increase
xs salt intake causes increase in BP via water retention
BV decrease
dehydration causes decrease in BP with vigorous exercise and blood loss
long term bp control directly
no hormones, BV or BP rises and filtration through kidneys is faster
long term bp control indirectly
renin- angiotensin-aldosterone mechanism
if the bp drops, kidney cells release renin
what does renin do?
splits angiotensin and converts it to angiotensin I, which is converted into angiotensin II via angiotensin converting enzyme (ACE)
angiotensin II
4 ways to stabilize
aldosterone secretion, ADH release, activates hypothalamic thirst center (drink more), also increases TPR as it is potent as a vasoconstrictor
hypertension
chromic elevation in BP, need to change lifestyle as its the silent killer (130/80)
what are the risks of hypertension?
risk of heart failure, respiratory failure, vascular disease, CVA
higher resistance of hypertension
work harder and myocardium enlarges, strains, weakens walls, also atherosclerosis
primary hypertension
90% (essential),
cause of primary hypertension
genes, diet, obese, over 40, DM, stress, smoking,
how do you control hypertension
meds ACE inhibitors, diuretics, beta blockers, calcium channel blockers
secondary causes of hypertension
renal artery stenosis, kidney disease, hyperthyroid, cushings,
hypotension
low bp (<90/60) usually long life
orthostatic hypotension
temporary drop in BP causing dizziness, with sudden rise
why are old people at risk for hypotension
SNS does not respond a quickly to postural changes
what happens with hypotension
blood temporarily pools in lower limbs, BP drops and less blood travels to the brain- must change position slowly
chromic hypotension
serious underlying condition- addison’s disease, hyperthyroid, severe malnutrition
