The Baroreceptor Reflex 1. Aortic bodies 2. Carotid bodies Sensory Receptors Detect Changes in BP Specifically - Mechanoreceptors detect changes in BP Located in blood vessel walls:
Baroreceptors (aortic arch & carotid a.a.) If BP, then freq of Action Potential firing to M.O > changes to BP. If BP, then freq of Action Potential firing to M.O > changes to BP. M.O. ∆’s to ↓BP ∆’s to ↑BP ↓ ↑ BP The Baroreceptor Reflex
Modulation of the Heart by the ANS At rest, heart has Parasympathetic modulation (slows it from down to beats/min). When excited, Para dissipates and Sym takes over. When heart has Sympathetic modulation (increases to ~120 beats/min).
To SA node Parasympathetic (Vagus n.) Sympathetic (accelerator n.)
The Medulla Oblongata the ANS and the Cardiovascular System Parasympathetic Stimulation Lowers BP Sympathetic Stimulation Elevates BP
Modulation of the Heart the Endocrine System Hormones, such as E stimulate the heart rate and force of contraction (S.V.) via receptors. Atrial Natriuretic Peptide (ANP) is released from the atria when the heart is over-stretched. ANP Causes: 1) vasodilation and 2) Na + excretion