sertoli cells

Examples of sertoli cells in the following topics:

• Hormonal Regulation of the Male Reproductive System

  • The Sertoli cells themselves mediate parts of spermatogenesis through hormone production.
  • The Leydig cells are also capable of producing estradiol in addition to their main product, testosterone.
  • Follicle-stimulating hormone stimulates both the production of androgen-binding protein by Sertoli cells and the formation of the blood-testis barrier.
  • Testosterone is made in the interstitial cells of the testes.
  • Inhibin is secreted by the Sertoli cells and acts to decrease the levels of FSH.

• Male Hormones

  • FSH enters the testes, stimulating the Sertoli cells, which help to nourish the sperm cells that the testes produce, to begin facilitating spermatogenesis.
  • LH also enters the testes, stimulating the interstitial cells, called Leydig cells, to make and release testosterone into the testes and the blood.
  • The Sertoli cells produce the hormone inhibin, which is released into the blood when the sperm count is too high.
  • If the sperm count reaches 20 million/ml, the Sertoli cells cease the release of inhibin, allowing the sperm count to increase.

• Testes Ducts

  • The epithelium of the tubule consists of tall, columnar cells called Sertoli cells.
  • Between the Sertoli cells are spermatogenic cells, which differentiate through meiosis to become sperm cells.
  • The ductuli are unilaminar and composed of columnar ciliated and nonciliated (absorptive) cells.
  • The ciliated cells stir the luminal fluids, which may help ensure homogeneous absorption of water from the fluid produced by the testis.

• Spermatogenesis

  • Spermatogenesis is the process by which male primary sperm cells undergo meiosis and produce a number of cells calls spermatogonia, from which the primary spermatocytes are derived.
  • These develop into mature spermatozoa, also known as sperm cells.
  • The non-motile spermatozoa are transported to the epididymis in testicular fluid secreted by the Sertoli cells with the aid of peristaltic contraction.
  • The excess cytoplasm, known as residual bodies, is phagocytosed by surrounding Sertoli cells in the testes.
  • The mature spermatozoa are released from the protective Sertoli cells into the lumen of the seminiferous tubule in a process called spermiation.

• Testes

  • These are lined with a layer of germ cells that develop into sperm cells (also known as spermatozoa or male gametes) from puberty into old age.
  • The developing sperm travels through the seminiferous tubules to the rete testis located in the mediastinum testis, to the efferent ducts, and then to the epididymis where newly-created sperm cells mature.
  • Leydig cells located between seminiferous tubules produce and secrete testosterone and other androgens important for sexual development and puberty, including secondary sexual characteristics such as facial hair and sexual behavior.
  • The sertoli cells are the testes’ somatic cells, necessary for testis development and spermatogenesis.

• Testicular Cancer

  • Although testicular cancer can be derived from any cell type found in the testicles, more than 95% of testicular cancers are germ cell tumors .
  • Most of the remaining 5% are sex cord-gonadal stromal tumors derived from Leydig cells or Sertoli cells.
  • Most testicular germ cell tumors have too many chromosomes, and most often they are triploid to tetraploid.
  • About half of germ cell tumors of the testis are seminomas.

• Semen

  • Sertoli cells, which nurture and support developing spermatocytes, secrete a fluid into seminiferous tubules that helps transport sperm to the genital ducts.
  • The ductuli efferentes possess cuboidal cells with microvilli and lysosomal granules that modify the semen by reabsorbing some fluid.
  • Once the semen enters the ductus epididymis, the principal cells (which contain pinocytotic vessels indicating fluid reabsorption) secrete glycerophosphocholine, which most likely inhibits premature capacitation.
  • The normal environment of the vagina is a hostile one for sperm cells, as it is acidic (from the native microflora producing lactic acid), viscous, and patrolled by immune cells.

• Male Reproductive Anatomy

  • The walls of the seminiferous tubules are composed of the developing sperm cells, with the least-developed sperm at the periphery of the tubule and the fully-developed sperm in the lumen.
  • The sperm cells are mixed with "nursemaid" cells called Sertoli cells which protect the germ cells and promote their development.
  • Other cells mixed in the wall of the tubules are the interstitial cells of Leydig; these cells produce high levels of testosterone once the male reaches adolescence.
  • Sperm consist of a flagellum (as a tail), a neck that contains the cell's energy-producing mitochondria, and a head that contains the genetic material .
  • When the sperm have developed flagella, or lash-like appendages that protrude from the cell body, and are nearly mature, they leave the testicles and enter the epididymis.

• Hormonal Regulation of the Reproductive System

  • FSH also enhances the production of androgen-binding protein by the Sertoli cells of the testes by binding to FSH receptors on their basolateral membranes.
  • LH stimulates production of the sex hormones (androgens) by the Leydig cells of the testes.
  • It is also called interstitial-cell-stimulating hormone.
  • In females, FSH stimulates development of egg cells (or ova) in structures called follicles.
  • Oxytocin also stimulates the contraction of myoepithelial cells around the milk-producing mammary glands.

• Cellular Differentiation

  • Three basic categories of cells make up the mammalian body: germ cells, somatic cells, and stem cells.
  • Pluripotent stem cells undergo further specialization into multipotent progenitor cells that then give rise to functional cells.
  • Hematopoietic stem cells (adult stem cells) from the bone marrow that give rise to red blood cells, white blood cells, and platelets
  • Mesenchymal stem cells (adult stem cells) from the bone marrow that give rise to stromal cells, fat cells, and types of bone cells;
  • Epithelial stem cells (progenitor cells) that give rise to the various types of skin cells