1. Definition of Spermatogenesis
Spermatogenesis is the process of biological in which the mature of gametes produce of the human
It occurs in the Male testis
Approximately 200–300 million sperms are produced daily in adult males.
Initially formed sperms are immature and later undergo maturation.
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2. Site of Spermatogenesis
Spermatogenesis takes place in the seminiferous tubules of the testes.
Each seminiferous tubule consists of:
An outer wall
A central lumen
The Wall of the seminiferous tubules aur main part of the produce human sperm
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3. Seminiferous Tubule Wall
The wall contains different types of cells, including:
Primary germ cells
Sertoli cells
Primary germ cells undergo several stages of division to form immature sperms called spermatids.
Sertoli cells provide nutrition and support to developing sperms.
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4. Phases of Spermatogenesis
Spermatogenesis is divided into two main phases:
A. Spermatocytogenesis
In this phase, one germ cell divides to form four spermatids.
These spermatids are immature sperm cells.
B. Spermiogenesis
In this phase no cell division.
Spermatids undergo maturation and differentiation to become mature sperms.
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5. Cell Divisions During Spermatocytogenesis
Step 1: Spermatogonia
The process begins with Type A spermatogonia, present in the basal layer.
Type A spermatogonia divide to:
Maintain their own population
Form Type B spermatogonia
Step 2: Primary Spermatocytes
Type B spermatogonia divide by mitosis to form primary spermatocytes.
These cells are diploid (2n).
Step 3: Secondary Spermatocytes
Primary spermatocytes undergo Meiosis I.
They form secondary spermatocytes, which are haploid (n).
Step 4: Spermatids
Secondary spermatocytes undergo Meiosis II.
This produces four haploid spermatids.
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6. Position of Cells in Seminiferous Tubules
Spermatogonia are located near the basement membrane.
Developing cells move towards the lumen as they mature.
Spermatids are found closer to the center of the tubule.
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7. Spermiogenesis (Maturation of Spermatids)
Spermiogenesis converts spermatids into mature sperms through four phases:
1. Golgi Phase
Golgi apparatus forms enzymes that help in the formation of the acrosome.
2. Acrosome Phase
The acrosome spreads over the nucleus forming an acrosomal cap.
3. Tail Phase
The centriole forms the tail (flagellum) of the sperm.
4. Maturation Phase
Excess cytoplasm is removed.
The spermatid becomes a streamlined mature sperm.
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8. Spermiation
Mature sperms are released into the lumen of seminiferous tubules.
This release process is called spermiation.
At this stage, sperms are non-motile.
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9. Role of Epididymis
Sperms move from seminiferous tubules to the epididymis.
They stay there for a few days.
In the epididymis, sperms gain motility and become capable of fertilization.
Note :
Azoospermia tha condition in which male have no semen or sperm cell, Oligospermia tha condition of the sperm of the cell present but some sperm cell
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