Juxtaglomerular apparatus, Biology

Assignment Help:

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.


Related Discussions:- Juxtaglomerular apparatus

What is self-catalytic rnas, Q. What is self-catalytic RNAs? Ribozymes...

Q. What is self-catalytic RNAs? Ribozymes - Term 'ribozyme' was initially suggested by Thomas R. Cech, Nobel Prize winning biochemist, who discovered this class of RNA molecul

Two major causes of severe protein energy malnutrition, Explain Two major c...

Explain Two major causes of severe Protein Energy Malnutrition? Two major causes of severe PEM are diluted milk formulae and infections, especially diarrhoea in poor communiti

In how many parts hydrocolloids be classified, In how many parts Classifica...

In how many parts Classification of Hydrocolloids Hydrocolloids, based on their solubility, thickening and gelling properties in water, are categorized into two main classes.

Sample outline of child history questionnaire, Sample Outline of Child Hist...

Sample Outline of Child History Questionnaire Basic identifying data: Child's name Date of birth Date of evaluation Person referring for evaluation Per

Define complete and simple circulation, Q. Why is the fish circulation clas...

Q. Why is the fish circulation classified as a complete and simple circulation? Simple circulation is that in which the blood circulates only in one circuit as opposed to the d

Mechanical valves, Mechanical Valves They are made of a combination o...

Mechanical Valves They are made of a combination of metal alloys, pyrolite carbon and dacron. Types of Mechanical Valves Caged-ball Valve (Star-Edwards) A me

State the term - functional neuroanatomy, State the term - Functional neuro...

State the term - Functional neuroanatomy Functional neuroanatomy focuses on the study of anatomy using psychological measures. One application of this kind of research is to he

Explain about the food science and technology, Explain about the Food Scien...

Explain about the Food Science and Technology? Food Science and Technology are so inextricably linked that usually these are treated as one field of study. While Food Science d

Lactose intolerance - modification of carbohydrate intake, Define Lactose i...

Define Lactose intolerance - Modification of carbohydrate intake? This has been covered under the section on digestion and absorption earlier. We learnt that in case of lactose

Is hemoglobin and myoglobin are heterotetramers, Which of the following sta...

Which of the following statements about hemoglobin and myoglobin structure are true? Select the five true statements. 1. By itself, heme is not a good oxygen carrier. It must be

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd