What is aldosterone?Aldosterone is a steroid hormone produced in the outer section (cortex) of the adrenal glands, which sit above the kidneys. It plays a central role in the regulation of blood pressure mainly by acting on organs such as the kidney and the colon to increase the amount of salt (sodium) reabsorbed into the bloodstream and to increase the amount of potassium excreted in the urine. Aldosterone also causes water to be reabsorbed along with sodium; this increases blood volume and therefore blood pressure. Show
How is aldosterone controlled?Aldosterone is part of a group of linked hormones, which form the renin–angiotensin–aldosterone system. Activation of this system occurs when there is decrease in blood flow to the kidneys following loss of blood volume or a drop in blood pressure (e.g. due to a haemorrhage). Renin is an enzyme that leads to a series of chemical reactions resulting in the production of angiotensin II, which in turn stimulate aldosterone release. Aldosterone causes an increase in salt and water reabsorption into the bloodstream from the kidney thereby increasing the blood volume, restoring salt levels and blood pressure.
What happens if I have too much aldosterone?The most common cause of high aldosterone levels is excess production, frequently from a small benign adrenal tumour (primary hyperaldosteronism). The symptoms include high blood pressure, low blood levels of potassium and an abnormal increase in blood volume. What happens if I have too little aldosterone?Low aldosterone levels are found in a rare condition called Addison's disease. In Addison's disease, there is a general loss of adrenal function resulting in low blood pressure, lethargy and an increase in potassium levels in the blood (see the article on Addison's disease for further information). Last reviewed: Mar 2021
ANSWERS
Which hormone promotes the reabsorption of water from the kidneys back to the ECF by osmosis?ADH then acts primarily in the kidneys to increase water reabsorption, thus returning the osmolarity to baseline.
Which hormone promotes the reabsorption of water from the kidneys back into the ECF by osmosis quizlet?When antidiuretic hormone (ADH) levels rise, less water is reabsorbed via the kidneys, the ECF volume decreases, and urine production increases.
Which type of ECF solution will cause a cell to gain water?If a cell is placed in a hypotonic solution, there will be a net flow of water into the cell, and the cell will gain volume. If the solute concentration outside the cell is lower than inside the cell, and the solutes cannot cross the membrane, then that solution is hypotonic to the cell.
What effect does an increase in antidiuretic hormone ADH have on the volume of extracellular fluid ECF )?What effect does an increase in antidiuretic hormone (ADH) have on the volume of extracellular fluid (ECF)? ECF increases when antidiuretic hormone (ADH) is present. Decreased volume and increased concentration of the extracellular fluid (ECF) is defined as: dehydration.
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