Juxtaglomerular apparatus, Biology

Juxtaglomerular Apparatus

The autoregulation of renal blood flow involves a neuroendocrine mechanism related to the juxtaglomerular apparatus in the kidney.

1896_Juxtaglomerular apparatus.png

 Figure: Structure of the juxtaglomerular apparatus in mammals

When the afferent arterial blood pressure is low, the stretch sensitive receptors of the arterioles initiate nerve impulses which induce the secretion of a proteolytic enzyme called renin by the juxtaglomerular cells into the blood. This enzyme causes the release of a decapeptide called angiotensin-I from a large globular plasma protein known as angiotensinogen. Another proteolytic enzyme from the plasma, the converting enzyme, removes two amino acids from angiotensin-I to form an octapeptide called angiotensin-II. Angiotensin-II is about 200 times more powerful than norepinephrine in its lasopressor activity. It increases the blood pressure by two mechanisms. Firstly, it acts on the smooth muscle of the arterioles and causes strong vasoconstriction. Secondly, it stimulates the secretion of aldosterone by the adrenal cortex. Aldosterone enhances the uptake of Na+ by the kidney tubules and hence causes a rise in the plasma Na+ level. This results in an increase in the extracellular fluid volume and consequently an elevation in blood pressure. Angiotensin-II is degraded by an enzyme called Angiotensinase, present in plasma.

Posted Date: 1/16/2013 2:10:36 AM | Location : United States







Related Discussions:- Juxtaglomerular apparatus, Assignment Help, Ask Question on Juxtaglomerular apparatus, Get Answer, Expert's Help, Juxtaglomerular apparatus Discussions

Write discussion on Juxtaglomerular apparatus
Your posts are moderated
Related Questions
What was the Oral Status of the Patient It is imperative that the patient carry out a strict oral hygiene regimen as dental plaque is one of the main factors that leads to impl

Chief Complaint and Patient's Expectations It is extremely vital to know what the patient really wants. 1. The chief complaint should be recorded in patient's own words as f

Q. How does facilitated diffusion present resemblance with enzymatic chemical reactions? One of the main examples of facilitated transport is the entry of glucose from the bloo

Explain Alternate Photosynthetic Pathways? An alternate photosynthetic pathway is the C4 pathway, where plants incorporate carbon into four-carbon compounds instead of 3PG. Thi

HACCP Control Measure HACCP Control Measure :  Any action or activity that can be used to prevent, eliminate or reduce a significant hazard.

Direct demonstration of the causative agent by electron microscopy (EM): Where facilities for electron microscopy are available and a viral disease is suspected, presence o

Explain the Clinical manifestations for Obesity? You must have observed that your overweight friends and colleagues seem to have less energy which makes them an easy prey for f

Explain Phylum Cnidaria - Coelenterates? Members of the Phylum Cnidaria and one other group-Phylum Ctenophora (the comb jellies)-are the only two animal phyla that have radiall

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

VITAMIN - K Also known as naptho quionone / anti haemorrhagic vitamin / coagulation vitamin / menadone . It requires for formation of blood clotting factor prothrombin.