Question

Under hypertension stimulus, describe the interaction between the nervous system and the urinary system to main blood pressure homeostasis?

Answer 1

The kidney is innervated by the sympathetic nerves. It plays a major role in blood pressure regularion. Sympathetic nerves send signals that brings changes in urinary sodium and water excretion by regulating the renal tubular water and sodium reabsorption throughout the nephron, changes in the renal blood flow and the glomerular filtration rate by regulating the constriction of renal vasculature, and changes in the activity of the renin-angiotensin system by regulating the renin release from juxtaglomerular cells. Renal sensory afferent fibres also project to the autonomic central nuclei that regulate blood pressure. During hypertension there is increased Renal Sympathetic Nervous System Activity (RSNA). It contributes to further increase in blood pressure by (a) increase in tubular reabsorption of renal sodium and water, (b) reduction of renal blood flow and Glomerular filtration rate (GFR) and (c) release of renin to activate the renin- Angiotensin- aldosterone cascade. Sustained blood pressure leads to end organ damage of the kidneys and hence resulting in renal hypertension.