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The vasodilatory actions of nitric oxide play a key role in renal control of extracellular fluid homeostasis and is essential for the regulation of blood flow and blood pressure. [51] NO also plays a role in erection of the penis and clitoris. [52] Nitric oxide also acts on cardiac muscle to decrease contractility and heart rate. NO contributes ...
In the rest of the body, norepinephrine increases heart rate and blood pressure, triggers the release of glucose from energy stores, increases blood flow to skeletal muscle, reduces blood flow to the gastrointestinal system, and inhibits voiding of the bladder and gastrointestinal motility.
Vasculogenesis, in contrast, is when endothelial precursor cells (angioblasts) migrate and differentiate in response to local cues (such as growth factors and extracellular matrices) to form new blood vessels. These vascular trees are then pruned and extended through angiogenesis.
When renal blood flow is reduced, juxtaglomerular cells in the kidneys convert the precursor prorenin (already present in the blood) into renin and secrete it directly into the circulation. Plasma renin then carries out the conversion of angiotensinogen , released by the liver , to a decapeptide called angiotensin I , which has no biological ...
The megakaryoblast is a platelet precursor that undergoes endomitosis to form megakaryocytes that have 8 to 64 nuclei. Megakaryocytes shed platelets into the bloodstream. β1-tubulin microtubules, which are found in megakaryocytes, facilitate this process of shedding platelets into the bloodstream. [5]
The angiogenesis process forms new blood vessels form blood vessels that have already been through vasculogenesis. [9] The former requires differentiation of endothelial cells from hemangioblasts and then the further organization into a primary capillary network. The latter occurs when new vessels are built from preexisting blood vessels. [8]
Angiotensin is a peptide hormone that causes vasoconstriction and an increase in blood pressure. It is part of the renin–angiotensin system, which regulates blood pressure. Angiotensin also stimulates the release of aldosterone from the adrenal cortex to promote sodium retention by the kidneys.
Prorenin (/ p r ə ˈ r iː n ɪ n / [1]) is a protein that constitutes a precursor for renin, [2] the hormone that activates the renin–angiotensin system, which serves to raise blood pressure. Prorenin is converted into renin by the juxtaglomerular cells , which are specialised smooth muscle cells present mainly in the afferent, but also the ...