Question

1. Explain the short term control of blood pressure in a resting individual and also during exercise. What are the main differences in blood pressure control in these two different situations?

Use diagrams

Answer 1

Short term regulation of blood pressure is mainly by baroreceptors-Autonomic nervous system.

When BP is low ---------Decreased Mean Arterial Pressure-------Decreased stretching of walls of Baroreceptors ---------Decreased firing of Baroreceptors---------Decreased firing of action potentials from Baroreceptors to Nucleus tractus Solitarius -----------Decreased inhibition of Sympathetic system and inhibition of Parasympathetic system --------Result is activation of sympathetic and activation of adrenals-------leads to increased cardiac contractility and heart rate & Vasoconstriction of blood vessels------INCREASE IN BP

When BP is HIGH ---------Increased Mean Arterial Pressure-------Increased stretching of walls of Baroreceptors ---------Increased firing of Baroreceptors---------Increased firing of action potentials from Baroreceptors to Nucleus tractus Solitarius -----------Increased inhibition of Sympathetic system -------- activation of sympathetic -------leads to iecreased cardiac contractility and heart rate & Vasodilation of blood vessels------DECREASE IN BP

In exercise, Sympathetic system is activated leading to increased heart rate,cardiac contractility and vasoconstriction of blood vessels. In addition to this local tissue factors also play an important role -local increased oxygen demand by exercising muscles, Increased anaerobic glycolysis, increased lactic acid production, increased temperature and local hypoxia - all play an role in increase in bp