Blood pressure homeostasis: the baroreceptor reflex

unit 3 week 11 lesson 6

why is regulating map crucial

for maintaining adequate blood flow to our organs. proper map ensures that tissues receive sufficient oxygen and nutrients which is essential for their function and survival.

effects of failure to regulate map

failure of map can lead to serious health consequences. hypertension (high blood pressure) can cause damage to blood vessels leading to conditions such as heart disease and stroke. Hypotension (low pressure) can result in inadequate blood flow to organs, causing dizziness, fainting or even shock.

what is the negative feedbak system used for bp homeostasis

its called the baroreceptor reflex. its critical to maintain mean arterial pressure within a narrow range to ensure stable bp and appropriate blood flow.

what receptors are involved in the baroreceptor reflex 

stretch receptors called baroreceptor detect changes in blood pressure and send signals to the medulla oblongata of ur brainstem. this initates a negative feedback loop that adjusts HR, stroke volume and blood vessel diameter to stabilize map

what happens when the map deviates from the normal set point

the reflex quickly counteracts these changes, preventing potential damage from prolonged hypertension or hypotension, these fast changes involve activation of parasympathetic or sympathetic nervous system

negative feedback loop to regulate map

1. sensor: baroreceptor sense stretch—more blood flow is gonna stretch the vessel, low blood flow causes baroreceptor to stretch less

Theyre actually mechanoreceptors bc they sense changes in the shape of the baroreceptor or those cells which then sends info to the cardiovasular center (control centre)

3. control centre found in ur brainstem (medulla oblongata) by action potentials set point: mean arterial pressure (regulated variable) gonna send command that is either going to be through either the syn or psyn

4. psyn or sns communicates with the (effectors) heart to change cardiac output and with blood vessels to potentially change total peripheral resistance. causing the heart and the blood vessels’ activities to change or behaviour to change -causing a change in mean arterial pressure

where are baroreceptors found and what do they do in a negative feedback loop 

located in carotid sinus and the aortic arch. if it communicates with the sns, the HR goes up (sa node), sv (ventricular contractility) goes up, and the total peripheral resistance goes up. all three together increases mean arterial pressure. sns talks to adrenal glands sitting on top of our kidneys and release epinephrine. epinephrine  binds to alpha adrenergic receptors, causing vasoconstriction and also help increase total peripheral resistance

psyn doesnt talk to blood vessels at all but you do see neurons going to the sa node causing decrease in hr, tiny drop in stroke volume, drop in map, decrease syn activity (removing innervation of syn)