The overall effect of angiotensin II
Angiotensin is a peptide hormone that causes vasoconstriction and a subsequent increase in blood pressure. It is part of the renin-angiotensin system, which is a major target for drugs that lower blood pressure. Angiotensin also stimulates the release of aldosterone, another hormone, fro…
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As it passes in the bloodstream through the lungs and kidneys, it is further metabolised to produce angiotensin II by the action of angiotensin-converting enzyme. The overall effect of angiotensin II is to increase blood pressure, body water and sodium content. Angiotensin II has effects on:
As it passes in the bloodstream through the lungs and kidneys, it is further metabolised to produce angiotensin II by the action of angiotensin-converting enzyme. The overall effect of angiotensin II is to increase blood pressure, body water and sodium content.
The liver creates and releases a protein called angiotensinogen. This is then broken up by renin, an enzyme produced in the kidney, to form angiotensin I. This form of the hormone is not known to have any particular biological function in itself but, is an important precursor for angiotensin II.
The renin–angiotensin system is also activated by other hormones, including corticosteroids , oestrogen and thyroid hormones. On the other hand, natriuretic peptides (produced in the heart and central nervous system) can impede the renin–angiotensin system in order to increase sodium loss in the urine. What happens if I have too much angiotensin?
The overall effect of angiotensin II is to increase blood pressure, body water and sodium content. Angiotensin II has effects on: Blood vessels – it increases blood pressure by causing constriction (narrowing) of the blood vessels. Nerves: it increases the sensation of thirst, the desire for salt, encourages the release ...
Control of plasma sodium and potassium concentrations, and the regulation of blood volume and pressure, are all hormonal mechanisms that are impaired by low angiotensin levels. Absence of angiotensin can be associated with retention of potassium, loss of sodium, decreased fluid retention (increased urine output) and low blood pressure.
The overall effect of angiotensin II is to increase blood pressure, body water and sodium content. Angiotensin II has effects on: 1 Blood vessels – it increases blood pressure by causing constriction (narrowing) of the blood vessels 2 Nerves: it increases the sensation of thirst, the desire for salt, encourages the release of other hormones that are involved in fluid retention. 3 Adrenal glands: it stimulates production of the hormone aldosterone, resulting in the body retaining sodium and losing potassium from the kidneys 4 The kidneys: it increases sodium retention and alters the way the kidneys filter blood. This increases water reabsorption in the kidney to increase blood volume and blood pressure.
An increase in renin production occurs if there is a decrease in sodium levels and a decrease in blood pressure, which is sensed by the kidneys. In addition, low blood pressure can stimulate the sympathetic nervous system to increase renin production, which results in increased conversion of angiotensinogen to angiotensin I, and so the cycle continues.
What is angiotensin? The liver creates and releases a protein called angiotensinogen. This is then broken up by renin, an enzyme produced in the kidney, to form angiotensin I. This form of the hormone is not known to have any particular biological function in itself but, is an important precursor for angiotensin II.
The renin–angiotensin system is also activated by other hormones, including corticosteroids , oestrogen and thyroid hormones. On the other hand, natriuretic peptides (produced in the heart and central nervous system) can impede the renin–angiotensin system in order to increase sodium loss in the urine.
Too much angioten sin II is a common problem resulting in excess fluid being retained by the body and, ultimately, raised blood pressure. This often occurs in heart failure where angiotensin is also thought to contribute to growth in the size of the heart. To combat these adverse effects, drugs such as angiotensin-converting enzyme inhibitors and angiotensin receptor blockers are used in the clinic, although these do have side effects and can lead to excessive retention of potassium (hyperkalaemia).