Bloop pressure physiology Flashcards
(15 cards)
What is Blood pressure
outward pressure exerted on the walls of a vessel by the blood
systolic/ diastolic B.P
systolic - when hearts contracted
diastolic - when the heart Is relaxed
systemic arterial B.P
pressure exerted on an artery/arteriole
hypertension
high bp - >140 mm Hg in clinic, >135 mm Hg avg
pulse pressure
systolic - diastolic (norm. 30-50mm Hg)
Mean Arterial Blood Pressure
Average pressure on arteries over 1 cardiac cycle
control of M.A.P over short term
negative feed back loop
Mean arterial B.P calculations
=2D+S/3, =D+1/3P.P, =CO x SVR
standard values of M.A.P
- 70 - 105 mm Hg, <60 mm Hg cant perfuse the brain, >105 mmHg damages blood vessels
receptors of M.A.P
= baroreceptors - stretch receptors around arteries
carotid arteries -> glossopharyngeal nerve
Aorta -> vagus nerve
effect of increase / decrease on baroreceptors
- increase - more afferent nervous signals
- decrease - less afferent nervous impulses
control centre for M.A,P + first synapse
- controlled by cardiovascular control centre
- first synapse = NTS
(nucleus tractus solitarium)
Increased M.A.P effect
Increased parasympathetic stimulation - vegal nerve stimulation (acetyl choline) - decreases HR Decreased sympathetic stimulation - decreases SVR + stroke volume
SVR
systemic vascular resistance
Decreased M.A.P
Increased Sympathetic innervation (noradrenaline) - Increases HR - Increases Stroke volume - Increases SVR by vasoconstriction Decreased parasympathetic innervation
