Answer to Question #225135 in Human Anatomy and Physiology for Moe

Question

3.2 The circulatory system is controlled in the Medulla oblongata through the accelerator
and inhibitory centres. Draw a schematic diagram to show the sequences of events
following low or high blood pressure detected at the baroreceptors.

Answer 1

Blood pressure is a complex physiological mechanism. It helps in understanding the conditions of the heart.

It can be measured as systolic and diastolic blood pressure. The pressure during contraction of the heart is the systolic blood pressure. The pressure measured during resting of the heart, in between the beats is the diastolic blood pressure.

Arterial baroreceptors help in the homeostasis of blood pressure. Any changes in the blood pressure will be sent via the carotid sinus to the medulla through the carotid sinus nerve and the glossopharyngeal nerve. This impulse originates in the aortic arch synapses with the nucleus tractus solitarius (NTS) in the medulla. Stimulation of the NTS causes inhibition of sympathetic tone that causes a vasodilatory effect which leads to decreased cardiac output and reduction in blood pressure.

A rapid decrease in blood pressure causes reduced stretching of the artery that leads to reduced action potential leading to reduced sympathetic stimulation. This causes an increase in blood pressure due to vasoconstriction leading to the increased cardiac output.

On the other hand, the stimulation of the sympathetic system occurs with the increased blood pressure, causing the increase in impulses. This causes vasodilation that leads to reduced cardiac output and reduced blood pressure.