PHSI 208 Lecture Notes - Lecture 23: Adrenal Medulla, Preganglionic Nerve Fibers, Blood Pressure
Document Summary
Blood pressure is defined as the force exerted by blood against a vessel wall. Two basic categories of cardiovascular function control: autonomic neural control. Higher centers such as the cortex: responsible for alternating cardiovascular function during emotional stress. Hypothalamus: plays an integrative role by modulating neuronal activity, i. e. ) as the principle locus of integration of the entire autonomic system. Direct stimulation of myocytes in ventricles (increase force of contraction via b1-receptor) Increases hr (both automaticity and conduction velocity) mediated by b1-receptor. Vasoconstriction in resistance vessels and veins (a- receptor) Both the b-receptors and a-receptors are adrenergic receptors (adrenoceptors) Cardiovascular changes induced by parasympathetic innervation: vagal stimulation causes the release of acetycholine (ach) from the postganglionic fibers which produces a negative. Inotropy (contractility: the negative inotropic effects by sympathetic is more evident in the atria that in ventricles. Primary sensors for the detection of cardiovascular changes. Pressure sensors that regulate the arterial blood pressure through negative feedback.
