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Your body can be divided up into a number of compartments, the first two being the intracellular and extracellular compartments. The two compartments contain fluid referred to as intracellular fluid (ICF) and extracellular fluid (ECF). By convention, blood is considered part of the extracellular compartment, so it contributes to ECF. One of the major determinants of blood pressure is the volume of blood in the blood vessels. All other things being equal, if you raise blood volume, you raise blood pressure; conversely, if you lower blood volume, you lower blood pressure.
Since the blood is in the extracellular compartment, the blood volume is a component of the extracellular fluid. Therefore if you raise ECF, you raise blood volume; as we saw above, raising blood volume raises blood pressure. How aldosterone contributes to blood pressure is via the regulation of ECF volume.
Sodium (Na) is the major cation in the ECF. Sodium is very important for the nervous system and other parts of the body; consequently, the body works very hard to keep the blood concentration of sodium within narrow limits. If suddenly the amount of sodium in the blood were increased, your brain would trigger the sensation of thirst; you would drink water and increase the ECF volume to dilute the sodium and bring it back within the normal range. So by adding extra sodium to the blood, you increase ECF volume. And what happens to blood pressure? It increases, because ECF is a major determinant of blood pressure.
What does this have to do with aldosterone?
Aldosterone is a steroid hormone that's synthesized by the adrenal gland. It acts on the kidneys to increase sodium reabsorption. Having more aldosterone around means that more sodium ultimately winds up in the blood, activating thirst mechanisms that cause you to drink water, which increases ECF volume and therefore increases blood pressure.
You might be interested to know that the body really does use aldosterone to regulate blood pressure. When blood pressure drops, the kidneys sense a subtle change in blood flow and start secreting an enzyme called renin. Renin works through a pathway called the renin-angiotensin-aldosterone system (RAAS; see link at left) to ultimately increase aldosterone secretion in order to return blood pressure to normal.
What else can I help you with?
What is the primary stimulus for the secretion of aldosterone?
The primary stimulus for the secretion of aldosterone is low blood pressure or low blood volume, which are detected by special cells in the kidneys. The renin-angiotensin-aldosterone system is then activated to increase aldosterone secretion from the adrenal glands, leading to increased reabsorption of sodium and water by the kidneys to help restore blood pressure and volume.
Low blood pressure stimulates the secretion of the mineralcorticoid?
aldosterone
What would a rise in angiotensin II levels would result in?
A rise in angiotensin II levels can lead to vasoconstriction, increased blood pressure, and stimulation of the release of aldosterone from the adrenal glands, which increases sodium and water reabsorption in the kidneys. Ultimately, this can contribute to hypertension and increased fluid retention in the body.
What is the name of the hormone that promotes sodium retention and potassium secretion?
Aldosterone is the hormone responsible for promoting sodium retention and potassium secretion in the kidneys. It helps regulate blood pressure and electrolyte balance in the body.
When the concentration of sodium in the blood increases what happens to aldosterone and renin secretion and what then results?
High Blood Pressure
The function of angiotensin II is to?
1. constrict arterioles thus increase blood pressure, 2. stimulate ADH secretion from the anterior pituitary which increases water retention by the kidneys and also increases blood pressure, and 3. stimulate aldosterone secretion from the adrenal cortex which increases sodium retention in the kidneys leading to more water retention by the kidneys and helping to increase blood pressure too.
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 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.
What hormones increase blood volume and blood pressure and how?
aldosterone ADH
How to increase aldosterone?
Aldosterone is primarily regulated by the renin-angiotensin-aldosterone system. To increase aldosterone levels, factors that can stimulate its production include low blood pressure, low blood volume, high potassium levels, and high Angiotensin II levels. These conditions can trigger the release of aldosterone from the adrenal glands.
Why is oedema a symptom of kwashiorkor?
decrease protein intake ------> hypoalbuminemia ------>decreases oncotic pressure ---> increase capillary permeability ----> 1. decrease bl.volume and RBF leads to secretion of renin that stimulate aldosterone secretion and Na and water retention. 2. hemoconcenetration stimulate ADH production results in water retention.
What is an antagonistic hormone to actions of aldosterone?
The hormone that antagonizes the actions of aldosterone is atrial natriuretic peptide (ANP). ANP inhibits aldosterone secretion and activity, promoting salt and water loss by the kidneys, which helps to reduce blood pressure and blood volume.
