GET LECTURE HANDOUTS and other DOWNLOADABLE CONTENT FROM THIS VIDEO
SUPPORT US ON PATREON OR JOIN HERE ON YOUTUBE.

[ Ссылка ]


When the plasma sodium concentration is lower than normal or the renal blood flow is reduced, the juxtaglomerular cells in the kidneys convert prorenin (an intracellular protein) into renin, which is then secreted directly into the circulation. Plasma renin then cuts a short, 10 amino acid long, peptide off a plasma protein known as angiotensinogen. The short peptide is known as angiotensin I.[2] Angiotensin I is then converted, by the removal of 2 amino acids, to form an octapeptide known as angiotensin II, by the enzyme angiotensin-converting enzyme (ACE) found in the lung capillaries. Angiotensin II is a potent vaso-active peptide that causes arterioles to constrict, resulting in increased arterial blood pressure.[3] Angiotensin II also stimulates the secretion of the hormone aldosterone from the adrenal cortex.[3] Aldosterone causes the tubular epithelial cells of the kidneys to increase the reabsorption of sodium ions from the tubular fluid back into the blood, while at the same time causing them to excrete potassium ions into the tubular fluid which will become urine.


RELATED TOPICS
renin
catalysis
protein
chemical compound
organic compound
endocrine system
polymer
blood pressure
angiotensin
enzyme
Renin-angiotensin system, physiological system that regulates blood pressure
Renin is an enzyme secreted into the blood from specialized cells that encircle the arterioles at the entrance to the glomeruli of the kidneys (the renal capillary networks that are the filtration units of the kidney). The renin-secreting cells, which compose the juxtaglomerular apparatus, are sensitive to changes in blood flow and blood pressure. The primary stimulus for increased renin secretion is decreased blood flow to the kidneys, which may be caused by loss of sodium and water (as a result of diarrhea, persistent vomiting, or excessive perspiration) or by narrowing of a renal artery. Renin catalyzes the conversion of a plasma protein called angiotensinogen into a decapeptide (consisting of 10 amino acids) called angiotensin I. An enzyme in the serum called angiotensin-converting enzyme (ACE) then converts angiotensin I into an octapeptide (consisting of eight amino acids) called angiotensin II. Angiotensin II acts via receptors in the adrenal glands to stimulate the secretion of aldosterone, which stimulates salt and water reabsorption by the kidneys, and the constriction of small arteries (arterioles), which causes an increase in blood pressure. Angiotensin II further constricts blood vessels through its inhibitory actions on the reuptake into nerve terminals of the hormone norepinephrine.

Watch Again [ Ссылка ]

SUBSCRIBE [ Ссылка ]

-~-~~-~~~-~~-~-
CHECK OUT NEWEST VIDEO: "Nucleic acids - DNA and RNA structure "
[ Ссылка ]
-~-~~-~~~-~~-~-

свернуть