What is Spermatogonium?

Information about Spermatogonium

Germinal epithelium of the testicle. 1 basal lamina, 2 spermatogonia, 3 spermatocyte 1st order, 4 spermatocyte 2nd order, 5 spermatid, 6 mature spermatid, 7 Sertoli cell, 8 tight junction (blood testis barrier)
Histological section through testicular parenchyma of a boar. 1 Lumen of Tubulus seminiferus contortus, 2 spermatids, 3 spermatocytes, 4 spermatogonia, 5 Sertoli cell, 6 Myofibroblasts, 7 Leydig cells, 8 capillaries
subject #258 1243
MeSH Spermatogonia
A spermatogonium (plural: spermatogonia) is an intermediary male gametogonium (a kind of germ cell) in the production of spermatozoa.

There are two subtypes:

Type A(d) cells have dark nuclei and they divide to produce copies of themselves, thereby ensuring a constant supply of spermatogonia to fuel spermatogenesis.

Type A(p) cells have pale nuclei and they divide by mitosis to produce Type B cells and these Type B cells divide again to give rise to primary spermatocytes.

Each primary spermatocyte duplicates its DNA and subsequently undergoes meiosis I to produce two haploid secondary spermatocytes. Each of the two secondary spermatocytes further undergo meiosis II to produce two spermatids (haploid). (1 primary spermatocytes => 4 spermatids)

The spermatids then undergo spermiogenesis to produce spermatozoa.

Additional images


Transverse section of a tubule of the testis of a rat. X 250.

Schematic diagram of Spermatocytogenesis


Source

This article includes material from Biology Online.

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Male reproductive system
Scrotumlayers (skin, Dartos, External spermatic fascia, Cremaster, Internal spermatic fascia) • Perineal raphe • Spermatic cord
Testeslayers (Tunica vaginalis, Tunica albuginea) • Appendix • Mediastinum • Lobules • Septa • Leydig cell • Sertoli cell • Blood-testis barrier
SpermatogenesisSpermatogonium • Spermatocytogenesis • Spermatocyte • Spermatidogenesis • Spermatid • Spermiogenesis • Spermatozoon
seminal tractSeminiferous tubules (Tubuli seminiferi recti, Rete testis, Efferent ducts) • Epididymis  (Appendix) • Vas deferens • Ejaculatory duct  Seminal colliculus
urinary tractInternal urethral orifice • Urethra (Prostatic, Intermediate, Spongy) • Urethral crest • Urethral gland • External urethral orifice
PenisCorpus cavernosum • Corpus spongiosum • Navicular fossa of male urethra • Glans penis • Fundiform ligament • Suspensory ligament • Foreskin • Frenulum
accessory glandsSeminal vesicles  (Excretory duct of seminal gland) • Prostate  (Prostatic utricle, Prostatic sinus) • Bulbourethral glands
basal lamina is a layer on which epithelium sits and which is secreted by the epithelial cells. It is often confused with the basement membrane, and sometimes used inconsistently in the literature, see below.
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A spermatogonium (plural: spermatogonia) is an intermediary male gametogonium (a kind of germ cell) in the production of spermatozoa.

There are two subtypes:

Type A(d)
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A spermatocyte is a male gametocyte which is derived from a spermatogonium. Initially in spermatogenesis, a spermatogonium divides by mitosis into two so-called primary spermatocytes.
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The term spermatid refers to the haploid male gametid that results from division of secondary spermatocytes. As a result of meiosis, each spermatid contains only half of the genetic material present in the original primary spermatocyte.
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A Sertoli cell (a kind of sustentacular cell) is a 'nurse' cell of the testes which is part of a seminiferous tubule.

It is activated by follicle-stimulating hormone, and has FSH-receptor on its membranes.
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Tight junctions, or zonula occludens, are the closely associated areas of two cells whose membranes join together forming a virtual impermeable barrier to fluid. It is a type of junctional complex only present in vertebrates.
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The blood-testis barrier (abbreviated as BTB) is a physical barrier between the blood vessels and the seminiferous tubules of the animal testes.

The barrier is formed by tight connections between the Sertoli cells, which are sustentacular cells (supporting cells) of the
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S. scrofa

Binomial name
Sus scrofa
Linnaeus, 1758

The wild boar (Sus scrofa) is the wild ancestor of the domestic pig.
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Seminiferous tubules are located in the testicles, and are the specific location of meiosis, and the subsequent creation of gametes, namely spermatozoa.

The epithelium of the tubule consists of sustentacular or Sertoli cells, which are tall, columnar type cells that line
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The term spermatid refers to the haploid male gametid that results from division of secondary spermatocytes. As a result of meiosis, each spermatid contains only half of the genetic material present in the original primary spermatocyte.
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A spermatocyte is a male gametocyte which is derived from a spermatogonium. Initially in spermatogenesis, a spermatogonium divides by mitosis into two so-called primary spermatocytes.
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A Sertoli cell (a kind of sustentacular cell) is a 'nurse' cell of the testes which is part of a seminiferous tubule.

It is activated by follicle-stimulating hormone, and has FSH-receptor on its membranes.
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Myofibroblast is a cell that is in between a fibroblast cell and a smooth muscle in differentiation.

Developmental origin

There are many possible ways of myofibroblast development:
  1. Partial smooth muscle differentiation of a fibroblastic cell

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Leydig cells, also known as interstitial cells of Leydig, are found adjacent to the seminiferous tubules in the testicle. They can secrete testosterone and are often closely related to nerves. Leydig cells have round vesicular nuclei and a granular eosinophilic cytoplasm.
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capillary is used to describe any very narrow tube or channel through which a fluid can pass. See capillary action for details.


Capillaries are the smallest of a body's blood vessels, measuring 5-10 μm, which connect arterioles and venules, and are
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Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed
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A gametogonium (plural gametogonia) is a germ cell that divides into gametocytes during gametogenesis. Male gametogonia are called spermatogonia, and female gametogonia are called oogonia.
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A germ cell is part of the germline and is involved in the reproduction of organisms. Germ cells should not be confused with "germs" (pathogens).

Germ cells includes all stages of gametogenesis, i.e. gametogonia, gametocytes, gametids and gametes.
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A spermatozoon or spermatozoan (pl. spermatozoa), from the ancient Greek σπέρμα (seed) and ζῷον (living being) and more commonly known as a sperm cell
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meiosis (IPA: /maɪˈəʊsɪs/) is the process by which one diploid eukaryotic cell divides to generate four haploid cells often called gametes.
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Spermiogenesis is the final stage of spermatogenesis which sees the maturation of spermatids into mature, motile spermatozoa.

Phases

The process of spermiogenesis is traditionally divided into four stages: the Golgi phase, the cap phase, the acrosomal phase, and the
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A spermatozoon or spermatozoan (pl. spermatozoa), from the ancient Greek σπέρμα (seed) and ζῷον (living being) and more commonly known as a sperm cell
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A tubule is a very small tube or fistular structure.

In anatomy, a tubule is a minute tube lined with glandular epithelium.
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The testicle (from Latin testis, meaning "witness",[1] plural testes) or ballock is the male generative gland in animals. This article will concentrate on mammalian testicles unless otherwise noted.
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wild rats. For pet rats, see Fancy rat. For other uses, see Rat (disambiguation).

Rats
Fossil range: Early Pleistocene – Recent

Black Rat (Rattus rattus)


Scientific classification
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human male reproductive system is a series of organs located outside of the body and around the pelvic region of a male that contribute towards the reproductive process.

The male contributes to reproduction by producing spermatozoa.
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The reproductive system is the ensembles and interactions of organs and/or substances within an organism that strictly pertain to reproduction. As an example, this would include in the case of female mammals, the hormone estrogen, ova, and the uterus and the vagina, and the breasts.
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In some male mammals, the scrotum is a protuberance of skin and muscle containing the testicles. It is an extension of the abdomen, and is located between the penis and anus.
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The dartos is a layer of smooth muscular fiber outside the external spermatic fascia but below the skin.

Gender differences

  • In males it is termed tunica dartos and lies beneath the skin of the scrotum.

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The external spermatic fascia (intercrural or intercolumnar fascia) is a thin membrane, prolonged downward around the surface of the cord and testis. It is separated from the dartos tunic by loose areolar tissue.
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