The juxta-glomerular apparatus consists of three main components: the macula densa, renin secreting cells, and extraglomerular mesangial cells. It is located at the junction of the afferent arteriole and distal convoluted tubule of each nephron. The macula densa contains specialized cells that are sensitive to sodium ion concentration in the distal convoluted tubule. The renin secreting cells are modified smooth muscle cells that contain granules of the renin enzyme. The extraglomerular mesangial cells lie in the triangular region between the afferent and efferent arterioles and macula densa. The main functions of the juxt

1. Juxta-Glomerular
Apparatus
MENOFIA FACULTY OF MEDICINE EGYPT
HISTOLOGY DEPARTMENT

2. Students from class 35
Section A
Made by :

3. •SiteAnatomy
•Definition
•componentsHistology
•Functionphysiology
Outlines

7. It is a specialization of glomerular
afferent arteriole and the distal
convoluted tubule of the corresponding
nephron .
Definition

9. Components
Macula densa
Renin secreting (JG)
cells
Extraglomerular
mesangial cells

10. Macula Densa
It is an area of closely
packed ,specialized cells
lining the DCT as it
comes close to the
vascular pole.

11. L/M
• columnar
•Apical deeply stained nucleus.
E/M:
•Basal crowded mitochondria .
•Extremely thin basement
membrane.
•Sensitive to Na ions
concentration in DCT.

12. Renin secreting (Juxta-Glomerular) cells
They are modified
smooth muscle cells of
the afferent arteriole
and small numbers are
present in the efferent
arteriole

13. L/M
• Features of myoepithelial
cells:
• rounded nucleus ,
granular cytoplasm
E/M:
•Contain mature &immature
membrane bounded granules
of renin enzyme.

14. Extraglomerular mesangial cells
(Polar cushion – Polkissen cells
–lacis cells )
Lies in the
triangular region
between AA&EA at
sides & macula densa
at the base.

15. L/M
• Flat branched basophilic cell.
NB:
•They are continuous with
similar cells known as the
intra-glomerular mesangial
cells between endothelium
& basal membrane.

16. Juxta-Glomerular apparatus
Triangle
Apex : Glomerular
mesangial cells
•Sides : afferent &
Efferent arteriole
•Base : Macula Densa
•Inside : Lacis cells

18. Function
1.Secretion of
renin
2. Secretion of
erythropoietin

19. Secretion of renin

21. Kidney secretes 90%
of erythropoietin hormone

22. Thanks