✅ ESPERMATOGÉNESIS ¿Como se forman los espermatozoides? | EMBRIOLOGÍA 📚

Understanding Spermatogenesis

Overview of Spermatogenesis

• Spermatogenesis is the biological process that transforms spermatogonia into spermatozoa, starting at puberty and continuing throughout a male's adult life. It occurs in the walls of the seminiferous tubules in the testes.

Temperature Regulation

• This process requires a temperature lower than 2 degrees Celsius compared to abdominal cavity temperature, which is why testes are located in the scrotal sac.

Structure of Seminiferous Tubules

• The wall of each tubule consists of a basal membrane and several layers of cells, including Sertoli cells and spermatogonia (germinal cells).

Sertoli Cells Functions

• Sertoli cells are large, tall cells extending from the basal membrane to the lumen. They protect germinal cells from the immune system, absorb testosterone and follicle-stimulating hormone (FSH), filter steroids and nutrients, produce hormones inhibiting gonadotropin release, and phagocytize degenerating spermatogonia.

Types of Spermatogonia

• There are two types of spermatogonia: Type A (basic cells that divide by mitosis to form new Type A and B cells) and Type B (more differentiated cells that grow into primary spermatocytes).

Development Stages

• Primary spermatocytes are located in the second cellular layer of the tubule. Each undergoes meiotic division to form haploid secondary spermatocytes.

Meiotic Division Process

• Secondary spermatocytes undergo a second meiotic division resulting in four haploid spermatids.

Transformation into Spermatozoa

• The next stage is spermiogenesis where these spermatids gradually transform into mature spermatozoa through five phases known as sperm metamorphosis.

Phases of Spermiogenesis

1. Golgi Phase: Formation of acrosome from Golgi apparatus; centrioles migrate for tail formation.

2. Cap Phase: Acrosome enlarges over nucleus forming a cap shape; nuclear condensation occurs.

3. Acrosomic Phase: Morphological changes occur within the cell structure.

4. Differentiation Phase: Distinct regions develop—head, neck, tail; residual cytoplasm begins detachment.

5. Spermiation/Maturation Phase: Final loss of cytoplasm which is phagocytized by Sertoli cells; mature sperm enter seminiferous tubule lumen.

Movement Towards Maturity

• After formation completion, sperm move into seminiferous tubules' lumen and are propelled towards epididymis via contractile activity rather than self-movement; they gain motility there before ejaculation.

Hormonal Regulation