The document summarizes the juxtaglomerular apparatus (JGA) and tubuloglomerular feedback mechanism. The JGA is located near the glomerulus and is formed by macula densa cells, extraglomerular mesangial cells, and juxtaglomerular cells. The primary function of the JGA is secretion of hormones like renin and prostaglandins. The tubuloglomerular feedback mechanism regulates glomerular filtration rate through detection of NaCl concentration by the macula densa cells, which signals the release of adenosine to constrict or dilate the afferent arteriole accordingly.

1. JUXTA GLOMERULAR
APPRATUS
AND
TUBULOGLOMERULAR
FEEDBACK
MECHANISM
NEERAJ SHARMA
ROLL NO-49
BATCH 2017-18

2. CONTENTS
 JUXTA GLOMERULAR
APPRATUS(JGA)
 FUCTION OF JGA
 TUBULO GLOMERULAR
FEEDBACK MECHANISM
 BIBLIOGRAPHY

3. JUXTAGLOMERULAR APPRATUS
 JGA is a combination of specialized
tubular and vascular cells located near
the glomerulus of each nephron
 JGA is formed by three different
structures
1. Macula densa cells
2. Extra glomerular mesangial cells
3. Juxtaglomerular cells

4. JUXTAGLOMERULAR APPRATUS

5. MACULA DENSA
 These are specialized renal tubular epithelial
cells.
 Situated between afferent & efferent
arterioles of the same nephron.
 Macula densa plays important role in tubulo-
glomerular feedback mechanism.
 These cells are not innervated.

6. EXTRAGLOMERULAR
MESENGIAL CELLS
 These cells are also called agranular
cells,lacis cells
 These cells are situated in the triangular
region bound by afferent arteriole ,
efferent arteriole & macula densa cells
 These cells play important role in the
regulation of glomerular filtration by
their contractile property
 These cells are phagocytic in nature

7. JUXTAGLOMERULAR CELLS
 Myoepithelial cells(modified vascular
smooth muscle cells) called JG cells
 Also called granular cells because
presence of secretory granules in their
cytoplasm
 JG cells are well developed golgi
apparatus and endoplasmic reticulum
and ribosomes
 JG cells act as baroreceptors and
innervated by sympathetic nerve fibers

8. FUCTION OF JGA
 Primary function of JGA is secretion of
hormones
It also regulates blood flow and GFR
Secretion of hormone-
1. Renin
2. Prostaglandins

9.  Renin-
 It is a peptide with 340 amino acids
 Along with angiotensin , renin forms RAAS
 Plays an important role in the maintainace of
blood pressure
 Prostaglandin
 Secreted by interstitial cells of medulla
 JGA secretes cytokines like interlukin-2 and tumor
necrosis factor.

11. REGULATION OF GLOMERULAR
FLOW AND GFR
 Macula densa of JGA plays
important role in feedback
mechanism called
tubuloglomerular feedback
mechanism which regulate the
renal blood flow and glomerular
filtration rate

12. TUBULOGLOMERULAR
FEEDBACK MECHANISM
 Tubuloglomerular feedback is the
mechanism that regulate GFR through
renal tubule & macula densa
 Macula densa detects the NaCl
concentration via Na+ K+ 2Cl-
Cotransporter
 Adenosine acts on afferent arteriole via
adenosine A1 receptors

13. FACTORS AFFECTING THE
SENSTIVITY OF TGF
INCREASE
 ADENOSINE
 THROMBOXANE
 PROSTAGLANDIN
DECREASE
 ANP
 PROSTAGLANDIN
 CYCLIC AMP
 NITROUS OXIDE

14. • INCREASE IN GFR
• INCREASE IN NACL CONCENTRATION IN RENAL TUBULE
• DETECTION OF NACL BY MACULA DENSA
• ADENOSINE
• CONSTRICTION OF AFFERENT ARTERIOLE
• DECREASE IN GLOMERULAR BLOOD FLOW
• TUBULOGLOMEULAR FEEDBACK
• WHEN GFR DECRESE
• CONC. OF NACL DECRESASE IN FILTRATE
• MD SECRETES PROSTAGLADIN,BRADYKININ,RENIN
• PGE2,BRADYKININ CAUSE DILATION OF AFFERENT ARTERIOLES
• RENIN CAUSE CONSTRICTION OF EFFERENT ARTERIOLES
• INCRESE IN GLOMERULAR BLOOD FLOW AND GFR

15. BIBLIOGRAPHY
1.Guyton and Hall Textbook of Medical
Physiology E-Book (Guyton Physiology)
2.Google
3.TEXTBOOK OF PHYSIOLOGY BY AK
JAIN
4. Ganongs Review Of Medical Physiology
25th Edition