Monitoring of blood pressure Flashcards
what is the equation for arterial blood pressure
cardiac output x total peripheral resistance
what are the two distinct mechanisms that both provide influence over blood pressure
→ Short-term – baroreceptor reflex (neural control)
→ Long-term – renin-angiotensin-aldosterone system (hormonal control)
Short-term control of blood pressure – neural control
Mediated by the baroreceptor reflex
→ Stretch-sensitive baroreceptors acting as the sensors (afferents)
→ Cardiovascular control center in the Medulla Oblongata acting as the integrator
→ Autonomic neurons acting as the effectors (efferents)
what is arterial blood pressure monitored by
peripheral sensors
what are arterial baroreceptors
afferent nerve fibres which relay information to brain about blood pressure-achieved because they are ideally located stretch receptors
what are cardiopulmonary baroreceptors
afferent fibres 4 types (myelinated veno arterial mechanoreceptors, non-myelinated mechanoreceptors, coronary baroreceptors and chemosensors)
how is short-term control of blood pressure achieved
principally bt the arterial baroreceptors
(carotid sinus and aortic sinus)
what is the process of baroreceptors firing
increased bp activate receptors
Impulse transmitted to glossopharyn-geal never
impulse transmitted to NTS
stimulation of NTS
Inhibition of SNS
reduction of smooth muscle
vasodilation
fall in bp
what are the fibers in the aortic arch that help deal with normal and high level blood pressure changes
A-fibres
-deal with normal range blood pressure changes
C-fibres
-deal with high level of blood pressure changes
baroceptor reflexes are shorter-term controls
seconds to minutes
longer-term control differs
→ Relies on control of blood volume
→ Think control of cardiac output by Starling’s Law of the heart
→ Involves kidneys
