Juxta-Glomerular Apparatus
MENOFIA FACULTY OF MEDICINE EGYPT HISTOLOGY DEPARTMENT
Students from class 35 Section A
Made by :
• SiteAnatomy
• Definition• componentsHistology
• Functionphysiology
Outlines
Anatomy
Histology
It is a specialization of glomerular afferent arteriole and the distal convoluted tubule of the corresponding nephron .
Definition
Components
Macula densa
Renin secreting (JG) cells
Extraglomerular mesangial cells
Macula Densa
It is an area of closely packed ,specialized
cells lining the DCT as it comes close to the
vascular pole.
L/M• columnar• Apical deeply stained
nucleus.
E/M:• Basal crowded mitochondria .• Extremely thin basement
membrane.• Sensitive to Na ions
concentration in DCT.
Renin secreting (Juxta-Glomerular) cells
They are modified smooth muscle cells
of the afferent arteriole and small
numbers are present in the efferent
arteriole
L/M• Features of myoepithelial cells:
rounded nucleus , granular cytoplasmE/M:
• Contain mature &immature membrane bounded granules of renin enzyme.
Extraglomerular mesangial cells(Polar cushion – Polkissen cells –lacis cells )
Lies in the triangular region between
AA&EA at sides & macula densa at the
base.
L/M• Flat branched basophilic
cell.
NB:• They are continuous with
similar cells known as the intra-glomerular mesangial cells between endothelium & basal membrane.
Juxta-Glomerular apparatus
TriangleApex : Glomerular mesangial cellsSides : afferent & Efferent arterioleBase : Macula DensaInside : Lacis cells
Physiology
Function 1.Secretion
of renin
2. Secretion of
erythropoietin
Secretion of renin
Kidney secretes 90% of erythropoietin hormone
Thanks