Question

Mr. Stevens had abdominal surgery during which he suffered a large drop in blood pressure. As a result the filtration rate of his kidney also decreased. choose THREE events that will occur in response to low blood pressure and decreased glomerular filtration in the kidneys.

- vasodilation

-glucocorticoid release by the adrenal cortex

-angiotensin II formation in the lung

-release of ADH

-release of renin by the kidney

-increased renal tubular sodium secretion

Answer 1

Ans:-Events that would occur during the low BP is:-1.) AngiotensinII formation in the lung

2.)ADH release

3.)release of Renin by kidney

Explanation:- First of there will be release of Renin is synthesized and stored in an inactive form called prorenin in the juxtaglomerular cells of the kidneys. When the arterial pressure falls, intrinsic reactions in the kidneys cause many of the prorenin molecules in the JG cells to split and release renin. Most of the renin enters the renal blood and then passes out of the kidneys to circulate throughout the entire body. However, small amounts of the renin do remain in the local fluids of the kidney and initiate several intrarenal functions. renin acts enzymatically on another plasma protein, a globulin called renin substrate (or angiotensinogen), to release a 10-amino acid peptide, angiotensin I. Angiotensin I has mild vasoconstrictor properties but not enough to cause significant changes in circulatory function. The renin persists in the blood for 30 minutes to 1 hour and continues. Angiotensin II Increases Sodium and Water Reabsorption. Angiotensin II is perhaps the body’s most powerful sodium-retaining hormone. angiotensin II formation increases in circumstances associated with low blood pressure and/or low extracellular fluid volume, such as during hemorrhage or loss of salt and water. The increased formation of angiotensin II helps to return blood pressure and extracellular volume toward normal by increasing sodium and water reabsorption from the renal tubules through three main effects: 1. Angiotensin II stimulates aldosterone secretion, which in turn increases sodium reabsorption

2. Angiotensin II directly stimulates sodium reabsorption in the proximal tubules, the loops of Henle, the distal tubules, and the collecting tubules. One of the direct effects of angiotensin II is to stimulate the sodium-potassium ATPase pump on the tubular epithelial cell basolateral membrane.Thus, angiotensin II stimulates sodium transport across both the luminal and the basolateral surfaces of the epithelial cell membrane in most renal tubular segments. These multiple actions of angiotensin II cause marked sodium and water retention by the kidneys when angiotensin II levels are increased and play a critical role in permitting the body to adapt to wide variations in sodium intake without large changes in extracellular fluid volume and blood pressure.

Release of ADH:-The permeability of the late distal tubule and cortical collecting duct to water is controlled by the concentration of ADH, which is also called vasopressin. With high levels of ADH, these tubular segments are permeable to water, but in the absence of ADH, they are virtually impermeable to water.so in the prescence of ADH there will be increse in blood pressure