Spermatogenesis, Sperm Production Process, Structure of Sperm. Gametogenesis

1. Topic –
Spermatogenesis
Submitted By – Ashish Verma
M.Sc. IV Semester
Department of Zoology
Paper – Gamete Biology,
Development and
Differentiation
Government Autonomous Post Graduate College Chhindwara
(M.P.) 480221

2. Content
• Introduction
• Definition
• Type A and Type B Cells
• Spermatogenesis Process
a) Formation of Spermatids
b) Spermateleosis
• Structure of Sperm
• Spermatogenesis in rodents
• Conclusion
• References

3. Introduction
• Spermatogenesis describes the production of spermatozoa
(sperm) in the seminiferous tubules of the testes
• The process begins at puberty
• Sperm are produced in the seminiferous tubules of the testes and
become mature in the epididymis.
• The entire process takes about 9 to 10 weeks.

4. Fig. Cross Section of Seminiferous
tubule

5. • The process of producing mature sperm
is called spermatogenesis
Definitio
n

6. Type A and Type B
Cells
In spermatogenesis, there are two main types
of cells involved: type A and type B cells.
1. Type A cells: These are the stem cells or
spermatogonia that are undifferentiated and
capable of self-renewal.
2. Type B cells: They are committed to
spermatogenesis and undergo meiosis to
eventually form sperm cells (spermatozoa).

7. • Spermatogenesis is completed in two steps.
a) Formation of Spermatids
:- Primordial germ cells (PGCs) → Spermatids (
Spermatid genesis)
• Spermatids form in following steps
1) Multiplication phase – PGCs divide through
mitotic division.
- The daughter cells formed by the PGCs are called
Spermatogonia.
2) Growth phase – Store food material, Size increase,
Primary Spermatocytes formed
3) Maturation phase :-
i) First Maturation Division – Primary
Spermatocytes  Second spermatocytes
ii) Second Maturation Division – Spermatids Formed
Spermatogenesis
Process

8. Fig. Process of Spermatogenesis

9. b) Spermateleosis / Spermiogenesis
In this phase, each sessile and round spermatid
converts into mobile and thread like sperm. The
process is divided into following parts :-
1) Changes in Nucleus – Nucleus of spermatid
reduces to form the head of sperm
2) Formation of acrosome – In anterior part of
sperm in front of nucleus. (Filled with
enzymes – hyaluronidase and proteases)
3) Centriole :- Both the centriole of spermatids
are arranged one after the other, behind the
nucleus.
4) Mitochondria :- This mitochondria gradually
fuse together and take the form of a
contracted body on either side of axial

10. Fig. Stages of Metamorphosis of the Spermatid into the

11. Structure of
Sperm
Fig.
A)Mature Sperm
B) Electron Microscopic View of
Fully Mature Sperm

12. • In the mouse, the entire development
process from stem cell to spermatozoon
takes 34.5 days. ( 5 weeks)
• The spermatogonial stages last 8 days,
meiosis lasts 13 days, and spermiogenesis
takes up another 13.5 days.
Morphological basis in
rodents

13. Conclusion
Spermatogenesis is a vital process in male reproductive
biology, responsible for the continuous production of
sperm cells. It involves a series of precisely
regulated steps, including mitotic divisions, meiotic
divisions, and morphological transformations,
ultimately resulting in the formation of mature
spermatozoa. Spermatogenesis is influenced by hormonal,
environmental, and genetic factors, and disruptions in
this process can lead to male infertility.
Understanding the mechanisms and regulation of
spermatogenesis is crucial for addressing reproductive
health issues and developing strategies for fertility
preservation and treatment.

14. References
• Developmental Biology - by Scott. F.
Gilbert
• Life Sciences – Fundamental and Practice –
by Usha mina and pranav Kumar

15. Thank You !