3120%20Cardio%209%20Jan%202012%20for%20WebCT

Bp inc ap increased firing increased afferent traffic

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Unformatted text preview: tance CO = HR X SV Think of a tap and hose (A) Response to High BP Carotid and Aortic Baroreceptors ! Stimulation by Stretch (! B.P.) ! inc AP Increased firing ! Increased afferent traffic to solitary tract nucleus ! ! Activation of vagal center Activation of the inhibitory always excitatory ! interneurons to vasomotor center ! ! ! Vagal traffic to heart " Sympathetic outflow to ! ! ! Ach. Release Heart Blood vessels ! ! contractile force ! " Heart rate " H.R. & C.F. " Constriction (dilate) ! ! ! " Cardiac Output " Cardiac Output " Resistance ! ! ! " B.P. " B.P. " B.P. wake up in the morning, feel light headed (B) Response to fall in BP Carotid and Aortic Baroreceptors ! Little or no stretch (Low B.P.) ! Less firing by mechanoreceptors ! decreased afferent traffic to solitary tract nucleus ! ! Reduced activity in vagal center Reduced activity of the inhibitory ! neurons to vasomotor center double -ve ! ! " Vagal traffic to heart # Sympathetic outflow to ! ! ! Less inhibition of heart rate Heart Blood vessels ! ! ! ! # H.R. & C.F. # Constriction ! ! ! ! # Cardiac Output # TPR ! ! ! # B.P. # B.P. # B.P. Phys 312 - Lecture Outline Baroreceptor Reflex (A) Response to high BP ! (B) Response to a fall in BP ! CV regulation during emotional stress CV regulation during exercise CV regulation during emotional stress 1.  # activity of chol fibers to muscle arterioles sympathetic ! dilatation 2.  # activity of chol fibers to the sweat glands ! sweating 3. # activity of the preganglionic symp post ganglion fibers to the adrenal medulla ! secretion of epinephrine reinforces the dilatation of the muscle arterioles ! # HR and SV pre-ganglion...
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