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

Test hypothesis that vertebrates evolved from echinoderms, Q. Evolutionaril...

Q. Evolutionarily protochordates may be intermediate animals between invertebrates and vertebrates. Imagine a scientist is testing the hypothesis that vertebrates evolved from echi

Explain the term bleeding, Bleeding Bleeding from injury to small blood...

Bleeding Bleeding from injury to small blood vessels pushed along the lateral wall of expanding maxillary sinus should be contained by bone wax or electrocautery rather than cr

Describe pressure controlled ventilation, Describe Pressure Controlled Vent...

Describe Pressure Controlled Ventilation (PCV) This is a pressure cycled mode (machine delivers a set pressure - the tidal volume generated depends on how compliant the lungs

What is the function of the left ventricle, Q. What is the function of the ...

Q. What is the function of the left ventricle? Where does the blood go after leaving the left ventricle? The function of the left ventricle is to pump the blood under high pres

Bats , 1. Explain how bats determine the distance (range) of their target u...

1. Explain how bats determine the distance (range) of their target using echolocation. Be sure to describe the properties of their call that make it possible (use a sketch), and ho

Explain the theory of law of minimum, Explain the theory of Law of Minimum ...

Explain the theory of Law of Minimum    This is one of the earliest hypotheses put forward by von Liebig on the relationship between the amount of plant  nutrient in the soil a

Relation of water content to functions, Relation of Water Content to Functi...

Relation of Water Content to Functions If an aquatic plant appearing turgid is removed from water and left in the open, it quickly wilts. The water content of the leaves may

Amino acid metabolism, All tissues have some capability for synthesis of th...

All tissues have some capability for synthesis of the non-essential amino acid remodeling, amino acids and conversion of non-amino acid carbon skeletons into amino acids and other

What is acute massive pulmonary embolism, what is Acute Massive Pulmonary E...

what is Acute Massive Pulmonary Embolism ? Acute Massive Pulmonary Embolism :  Before the era of open-heart surgery, Trendelenburg (1908) described technique of open p

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