Physiology 3120 Lecture Notes - Reflex Syncope, Adrenal Medulla, Sweat Gland
26 Nov 2011
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Other mechanisms of cv regulation: emotional stress (i. e. joy, excitement, sorrow, anger, humiliation, embarrassment, etc. ) If people suffer from long-term stress/anger, it could damage the cv system. Stressful situations stimulates release of cortisol (induces glucose release from liver); if constantly stimulated, can lead to stress-induced hyperglycemia; can destroy endothelial cells lining vascular walls, leading to hypertension and later heart failure. To determine hr (in bpm), look at rr interval on ecg and divide 60 by that value. Stimulation of adrenal medulla, which secretes ach and further dilates muscle arterioles. Less cholinergic inhibition of heart, so hr rises. Some people receive unexpected, sudden vagal stimulation of the heart decreases hr and mean arterial pressure. Less blood goes to brain loss of consciousness and fainting. Cv response ensures (i) active muscle receive adequate blood, (ii) heat eliminated from active muscle, and (iii) blood to heart & brain isn"t compromised. Vasodilators produced metabolically, which allows increase in blood flow to active muscle.
