Seminiferous tubules are located within the
testes, and are the specific location of
meiosis, and the subsequent creation of male
gametes, namely
spermatozoa.
Structure
The
epithelium
Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellul ...
of the tubule consists of a type of
sustentacular cells known as
Sertoli cells, which are tall, columnar type cells that line the tubule.
In between the Sertoli cells are
spermatogenic cells, which differentiate through
meiosis to
sperm cells. Sertoli cells function to nourish the developing sperm cells. They secrete
androgen-binding protein, a binding protein which increases the concentration of testosterone.
There are two types: convoluted and straight, convoluted toward the lateral side, and straight as the tubule comes medially to form ducts that will exit the testis.
The seminiferous tubules are formed from the testis cords that develop from the primitive
gonadal cords, formed from the
gonadal ridge.
Function
Spermatogenesis
Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis. This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubule ...
, the process for producing
spermatozoa, takes place in the seminiferous tubules. During spermatogenesis, the
DNA of spermatogenic cells in the seminiferous tubules is subject to damage from such sources as
reactive oxygen species.
The
genomic
Genomics is an interdisciplinary field of biology focusing on the structure, function, evolution, mapping, and editing of genomes. A genome is an organism's complete set of DNA, including all of its genes as well as its hierarchical, three-dim ...
integrity of spermatogenic cells is protected by
DNA repair processes.
Deficiencies in the
enzymes
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...
employed in these repair processes may lead to
infertility
Infertility is the inability of a person, animal or plant to reproduce by natural means. It is usually not the natural state of a healthy adult, except notably among certain eusocial species (mostly haplodiploid insects). It is the normal state ...
.
Additional images
File:seminiferous tubule and sperm.jpg , Seminiferous tubule (right) with sperm
Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as a flagellum, whi ...
(black, tiny, ovoid). H&E stain.
File:Gray1145.png , Longitudinal section through the left side of the scrotum and the left testis (Seminiferous tubules visible in center, but not labeled).
File:Seminiferous tubule.JPG , Seminiferous tubule (transverse section).
File:Rattestis.jpg , Photomicrograph of section through rat testis, showing seminiferous tubules.
See also
*
Leydig cells
References
External links
*
ImageDiagram
{{Authority control
Testicle
Scrotum