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When blood volume is low, sodium reabsorption in the kidneys is stimulated. The increased sodium increases osmotic pressure, causing water to be reabsorbed with the sodium. The reabsorbed water is added to the plasma, thus increasing blood volume.

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8y ago
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8y ago

a greater reabsorption means, less water leaves the body

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Q: How does the reabsorption of sodium and water from the renal tubules increase blood volume?
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The main region of aldosterone action is the?

The main region of aldosterone action is the distal convoluted tubule (DCT) and collecting duct of the kidneys. It functions to increase sodium reabsorption as well as enhance potassium excretion. The net effect of this is an increase in blood volume (via increased reabsorption of water), and thus an increase in blood pressure.


What is the meaning of vasopressin?

vasopressin is an antidiuretic hormone responsible for increased permeability of the distal tubules of the kidney, increasing water reabsorption and reducing urine volume.


What does aldostrone cause?

Aldosterone is a hormone that increases the reabsorption of sodium ions and water and the release (secretion) of potassium ions in the distal convoluted tubules of the kidneys. This increases blood volume and, therefore, increases blood pressure. Drugs that interfere with the secretion or action of aldosterone are in use as antihypertensives.


How does angiotension 2 affect kidney?

Angiotensin II affects the kidney in various ways: 1) it stimulates the secretion of aldosterone from the adrenal cortex which causes the tubules of the kidneys to increase reabsorption of sodium(Na) and water into the blood increasing the volume of fluid in the body. This can be very useful in cases of hypovolemia(low blood volume). 2) it acts as a vasoconstrictor, thereby increasing test and blood pressure. 3) it stimulates the secretion of anti-diuretic hormone, also called vasopressin which stimulates the reabsorption of water in the kidneys and also acts as a vasoconstrictor. 4)it increases renal hypertrophy in renal tubule cell leading to an increase in Na intake.


What are the three steps of urine formation and in what part of the nephron does each occur?

Urine formation and the adjustment of blood composition involve three major processes: glomerular filtration by the glomeruli, and tubular reabsorption and tubular secretion in the renal tubules. In addition, the collecting ducts work in concert with the nephrons to concentrate or dilute the urine..Functions of the nephrons include filtration, tubular reabsorption, and tubular secretion. Via these functional processes, the kidneys regulate the volume, composition, and pH of the blood, and eliminate nitrogenous metabolic wastes.


How does caffeine increase sodium loss?

Caffeine is a diuretic. It dilates smooth muscle vessels and increases the volume of fluid loss via urine. Along with water loss there will be loss of salts including Na+. I don't think that caffeine has a direct effect on sodium channels (preventing the reabsorption in the distal tubule) so I am assuming that the sodium loss is due to increased fluid loss.


How would a diuretic affect water reabsorption into the blood?

A diuretic is a substance that tends to cause diuresis (increased urine flow) by hindering the amount of water reabsorbed back into the blood. the mechanism of how this occurs depends on the type of diuretic. for example some diuretics impede the body's ability to reabsorb Na at the ascending loop of Henle thus not increasing the osmolarity of the extracellular fluid which would in turn cause water reabsorption, so the water remains in the lumen of the nephron and is excreted causing increased urine volume. other diuretics may act on the proximal and distal convoluted tubules causing water retension due to decreased Nacl reabsorption or Na reabsorption or even potassium. Due to the fact that a diuretic will cause water to lost in the urine, this will cause an increase in osmolarity above the setpoint of 300mOsm/L, therefore more ADH (anti-diuretic hormone) is released into the bloodstream. When ADH reaches the kidney, its main targets are the distal tubules and the collecting ducts. The ADH brings about changes that make the epithelium more permeable to water. the resulting increase in water reabsorption concentrates the urine, reducing urine volume and lowers blood osmolarity back to set point.


What hormone promotes the reabsorbtion of sodium and potassium ions by the kidney?

When the macula densa in the distal tubules of the kidney sense a decrease in fluid volume, the renin-aldosterone system is activated. Aldosterone is the hormone responsible for sodium retention, causing water to be conserved.


What is the purpose of aldosterone?

The major target of aldosterone is the distal tubule of the kidney, where it stimulates exchange of sodium and potassium. Three primary physiologic effects of aldosterone result:Increased resorption of sodium: sodium loss in urine is decreased under aldosterone stimulation.Increased resorption of water, with consequent expansion of extracellular fluid volume. This is an osmotic effect directly related to increased resorption of sodium.Increased renal excretion of potassium.Knowing these effects should quickly suggest the cellular mechanism of action this hormone. Aldosterone stimulates transcription of the gene encoding the sodium-potassium ATPase, leading to increased numbers of "sodium pumps" in the basolateral membranes of tubular epithelial cells. Aldosterone also stimulates expression of a sodium channel which facilitates uptake of sodium from the tubular lumen.


what hormone promotes sodium ion by the kidney in order to increase blood pressure and blood volume?

Aldesterone


In the kidneys the largest volume of water reabsorption occurs in the?

proximal convoluted tubule


Explain how antidiuretic hormone can help regulate hypotension Be specific?

it can help by increasing reabsorption of water by the kidney. With the reabsorption, blood plasma volume increases, thus raising blood pressure