Blood pressure short term regulation Flashcards
where are the baroreceptors?
carotide sinus and aortic arch
when do chemoreceptors become involved in BP regulation?
at very low MAP (low flow)
What is the main change in BP over our lifetimes attributed to?
Body size - bigger body = bigger BP
what is the primary purpose of the circulation?
to provide adequate blood flow to the organs
What does activation of the PNS do to the heart?
reduces HR, increases AV conduction time
What is involved in the short term BP regulation?
predominantly neural, the baroreflex
What does the PNS act on in the cardiovascular system for BP control?
SA node
What does activation of the SNS do to the heart?
increase HR, decreases AV conduction time, increases cardiac contractility, increases TPR, increases venous tone
where are the chemoreceptors?
carotid and aortic bodies sit on the outside of arteries
diurnal variation in BP
lower at night (20mmHg) less variability at night due to less sympathetic activity maintained by renin-angiotensin system at night
what is the general change in BP during ageing?
Systolic BP rises over age Diastolic BP rises until 60 years of age and then slowly goes down (reduced compliance of arteries due to hardening)
What does the SNS act on in the cardiovascular system for BP control?
SA node, ventricles, arterioles, veins
explain the anatomy of the carotid sinus
thin-walled, highly innervated, on the internal carotid artery
What do chemoreceptors respond to?
low oxygen, high CO2, low pH
Where abouts in the brainstem is the cardiovascular control centre?
medulla
