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Unformatted text preview: constriction. CV “Reflexes”
Cardiovascular reflexes are produced by afferent signaling of:
Baroreceptors Chemoreceptors Proprioceptors NOTE: Baroreceptors and chemoreceptors are by far the most important receptors in cardiovascular regulation. Baroreceptors
High pressure baroreceptors are located in the carotid sinus and aortic arch, and enter the CV center via cranial nerves IX and X, respectively Low pressure baroreceptors are located in the walls of the right atrium and vena cavae, and enter the CV center via cranial nerve X Short-term Mechanisms: Baroreceptor -initiated Reflex Chemoreceptors
Chemoreceptors are also located in the carotid sinus and in the walls of the ascending aorta Carotid sinus receptors reach the medulla via cranial nerve IX, and aortic chemoreceptors via cranial nerve X They respond to increased hydrogen ion content, increased CO2, and most strongly to hypoxia They activate the SNS, leading to increased HR, SV, and vasoconstriction Hormonal Control of Blood Pressure-catecholamines
Catecholamines (NE and EPI) circulate, and bind directly to cardiac muscle fibers and to blood vessel smooth muscle cells The effect is an increase in HR and SV, and constriction of veins and arterioles NOTE: arteries supplying the brain and heart have little smooth muscle and are not subject to vasoconstriction...
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- Spring '08