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
We are living in an unprecedented age of biological discovery and the application of biological knowledge.   Programmed DNA sequencing delivered, in the year of  2001 over the 2.6

Explain Basal Metabolism Rate (BMR) - Ageing? From age 25 years, the basal metabolism decreases by about 2 percent for each decade due to the increasing proportion of body fat

How does metagenesis in cnidarians differ from the true alternation of generation shown by plants?

Anabolism and Catabolism Cellular metabolism  has two aspects 1.      Anabolism  :  This aspect includes metabolic  process  by which  complex  cellular  compounds  are

Limb Field By several marking and transplantation methods it is feasible to identify in early embryos the specific areas of groups of cells that ultimately make different org

In the typical Western diet approximately 80-140 G triglyceride and 0.5-1.5 G cholesterol are eaten daily. Following digestion, absorption and reesterification, triglyceride and c

Define the effect of dietary fibre on Nutrient Absorption? Nutrient Absorption: Inclusion of fibre has been shown to retard the absorption of some nutrients. The inclusion of v

Q. What is Moderate level of Lactase activity? Intake of milk is restricted depending on the tolerance. Fermented and cooked form of milk should be preferred as it is better to

Explain the Secretary Phase - Menstrual Cycle After ovulation, the lining of ovarian follicle is stimulated by LH to develop corpus luteum which produces progesterone. The endo

Kingdom Protista The protistans are a complex and diverse group of organisms that are placed together simply because they are all single celled eukaryotes but some form rather sp