05-03-2013, 10:40 AM
Structures of Sertoli Cells
Structures of Sertoli.ppt (Size: 77 KB / Downloads: 28)
INTRODUCTION
Each testis is covered with a layer of connective tissue known as tunica albuginea.testes are formed of coiled seminiferous tubules and the interstitial cells or leydig’s cells leying between them.
Seminiferous tubules are long coiled tubules lined with a layer of germinal epithelium.its calls give rise to spermatogonia from which sperms are produced .
The long sertoli cells are present amongst the calls of germinal epithelium in seminiferous tubules .these cells provide nourishment to the developing sperms.
sertoli cells
A sertoli cell is a ‘nurse’ cell of the testes that is part of a seminiferous tubule . It is activated by follicle-stimulating hormone and has FSH-receptor on its membranes.it is specifically located in convoluted seminiferous tubules.
structures of sertoli cells
The cells of sertoli are relatively long,slender elements placed perpendicularly to the basement membrane.
It is said that sertoli cells may round up and from phagocytes which become free from the basement membrane and move ameba-like in the lumen of the seminiferous tubule ,phagocytizing degenerating sperm cells.
leydig cells
Leydig cells also known as interstitial cells of leydig,are found adjacent to the seminiferous tubules in the testise they produce testosterone in the presence of luteinizing hormone leydig cells polyhedral in shape.
It consists of a layer of connective tissue applied to the basement membrane of the seminiferous tubule and of many other structures. Such as small blood and lymph vessels connective tissue fibres, connective tissue cells mast cells ,fixed macrophages etc.
Structures of leydig cells
The mammalian leydig cells is polyhedral epithelioid cell with a single eccentrically located ovoid nucleus.
The nucleus contain one to three prominent nucleoli and large amounts of dark-staining peripheral heterochromatin.
The acidophilic cytoplasm usually contains numerous membrane-bound lipid droplets and large amounts of smooth endoplasmic reticulum.
Besides the obvious abundance of ser with scattered patches of rough endoplasmic reticulum.several mitochondrial are also prominent within the cytoplasm.
frequently lipofusin pigment and rod shaped crystal-like structures 3 to 20 micrometrer in diameter are found .
Development of leydig cells
adult type leydig cells differentiate in the post-natal testis and are quiescent until puberty .they are preceded in the testis by a population of ‘fetal’-type cells from the 8th to 20th week of gestation .which produce enough testosterone for masculinisation of a male fetus.
functions of sertoli cells
Because is main function is to nourish the developing sperm cells through the stages of spermatogenesis ,the sertoli cell has also been called the ‘‘mother’’ or ‘’nurse’’ cell .
Sertoli cells also act as phagocytes consuming the residual cytoplasm during spermatogenesis.
Translocation of germ cells from the base to the lumen of the seminiferous tubules occurs by conformational changes in the lateral margins of the sertoli cells.