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Physiology

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Endocrinology

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Sertoli cells are associated with (AIPG 2009)



A Spermiogenesis

B Secretion of seminal fluid

C Production of testosterones

D Production of sperm

Ans. A Spermiogenesis.Sertoli cells are associated with maturation phase of Spermiogenesis

Spermiogenesisis the final stage of spermatogenesis which sees the maturation of spermatids into mature, motile spermatozoa.

The process of spermiogenesis is traditionally divided into four stages: the Golgi phase, the cap phase, the acrosomal phase, and the maturation stage.

  1. Golgi phase

a. The spermatids, which up until now have been mostly radially symmetrical, begin to develop polarity.

b. The head forms at one end, and the Golgi apparatus creates enzymes that will become the acrosome.

c. At the other end, it develops a thickened mid-piece, where the mitochondria gather and form an axoneme.

d. Spermatid DNA also undergoes packaging, becoming highly condensed.

e. The DNA is packaged firstly with specific nuclear basic proteins, which are subsequently replaced with protamines during spermatid elongation.

f. The resultant tightly packed chromatin is transcriptionally inactive.

  1. Cap phase

The Golgi apparatus surrounds the now condensed nucleus, becoming the acrosomal cap.

  1. Acrosomal phase

a. One of the centrioles of the cell elongates to become the tail of the sperm. A temporary structure called the "manchette" assists in this elongation.

b. During this phase, the developing spermatozoa orient themselves so that their tails point towards the center of the lumen, away from the epithelium.

  1. Maturation phase

The excess cytoplasm, known as residual bodies, is phagocytosed by surrounding Sertoli cells in the testes.

Sertoli cellis a 'nurse' cell of the testes.It is activated by follicle-stimulating hormone, and has FSH-receptor on its membranes. Its main function is to nurture the developing sperm cells through the stages of spermatogenesis.

Sertoli cells also act as phagocytes, consuming the residual cytoplasm during spermiogenesis.

V. Sertoli cells secrete the following substances:

a. Anti-Müllerian Hormone (AMH) - secreted during the early stages of fetal life.

b. inhibin and activins - secreted after puberty, and work together to regulate FSH secretion

c. Androgen binding protein - facilitate spermatogenesis and sperm maturation estradiol - aromatase from Sertoli cells convert testosterone to 17 beta estradiol to direct spermatogenesis

d. glial cell line-derived neurotrophic factor (GDNF) - has been demonstrated to function in promoting undifferentiating spermatogonia, which ensures stem cell self-renewal during the perinatal period.

i. the Ets related molecule (ERM transcription factor) - needed for maintenance of the spermatogonial stem cell in the adult testis.

Endocrinology Flashcard List

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