Spermatogenesis is the process by which sperm cells are produced in the testes in males. It involves the transformation of spermatogonia into mature sperm through two stages: spermatocytogenesis where primordial germ cells develop into spermatids, and spermiogenesis where spermatids are transformed into mature sperm. In humans, it takes approximately 74 days to complete and produces around 300 million sperm cells daily. Oogenesis is the similar process that occurs in females within the ovaries to produce eggs.

1. SPERMATOGENESIS
Dr. Mohammed Mahmoud Mosaed

2. Spermatogenesis
• Maturation of Sperm Begins at Puberty
• Spermatogenesis, includes all of the events by which
spermatogonia are transformed into spermatozoa.
• It divided into 2 stages:
• Spermatocytogenesis from the PGCs to the spermatids
• Spermiogenesis from the spermatids to the mature
sperm
• At birth, germ cells in the male infant can be recognized
in the sex cords of the testis as large, pale cells
surrounded by supporting cells.
• Supporting cells (Sertoli cells), which are derived from
the surface epithelium of the testis

3. Spermatocytogenesis
• Shortly before puberty, the sex cords acquire a lumen and become the seminiferous
tubules.
• At about the same time, primordial germ cells (PGCs) give rise to spermatogonial
stem cells.
• At regular intervals, cells emerge from this stem cell population to form type A
spermatogonia, and their production marks the initiation of spermatogenesis.
• Type A cells undergo mitotic divisions to form cells.
• The last cell division produces type B spermatogonia, which then divide to form
primary spermatocytes .
• Primary spermatocytes then enter a prolonged prophase (22 days) followed by rapid
completion of meiosis I and formation of secondary spermatocytes.
• During the second meiotic division, these cells immediately begin to form haploid
spermatids.

5. SPERMATOCYTOGESIS
PRIMORDIAL
GERM CELLS
SPERMATOGONIAL
STEM CELLS
TYPE A
SPERMATOGONIA
TYPE A
SPERMATOGONIA
TYPE A
SPERMATOGONIA
TYPE B
SPERMATOGO
NIA
PRIMARY
SPERMATOCYTE
SECONDARY
SPERMATOCYT
E
SPERMATIDS

6. spermiogenesis
• The series of changes resulting in the transformation of spermatids into
spermatozoa is spermiogenesis.
• The changes include
• (1) formation of the acrosome, which covers half of the nuclear surface and
contains enzymes to assist in penetration of the egg
• (2) condensation of the nucleus;
• (3) formation of neck, middle piece, and tail; and
• (4) shedding of most of the cytoplasm as residual bodies that are
phagocytized by Sertoli cells

7. Spermiogenesis
• The series of changes resulting in the transformation of spermatids
into spermatozoa is spermiogenesis.

8. Spermatogenesis
•In humans, the time required for a spermatogonium to
develop into a mature spermatozoon is approximately 74
days, and approximately 300 million sperm cells are produced
daily.
•Spermatozoa obtain full motility in the epididymis.

9. Structure of mature sperm
• Head
• With its spheric shape, it consists of a large nucleus,
which at the same time contains an acrosome. The
nucleus contains the genetic information and 23
chromosomes. It also secretes a hyaluronidase
enzyme that destroys the hyaluronic acid of the egg
cell to enter into it.
• Neck: It contains centrioles (proximal centriole and
distal centriole).
• Middle-piece
• It is a highly important part of a sperm cells because
it gives energy to the sperm, thereby allowing it to
swim once inside the female reproductive system. It
contains spirally arranged mitochondria.
• Tail: is the end part of the sperm, which contains
the axial filaments. It helps the sperm to swim in the
female genital tract. In fact, it is the part that allows
sperm to swim fast enough.

10. SPERMATOGENESIS – Clinical Correlates
• Up to 10% of all spermatozoa have observable defects. The
head or the tail may be abnormal.
• Spermatozoa may be giants or dwarfs, and sometimes they
are joined.
• Sperm with morphologic abnormalities lack normal motility
and probably do not fertilize oocytes.
Various types of abnormal spermatozoa

11. OogenesisSpermatogenesis
Oogenesis is the process of
formation and development of the
ovum.
permatogenesis is the process of
formation and development of
spermatozoa.
Process of Formation
Oogenesis occurs in females.
Spermatogenesis occurs in males.Occurs in
The completion of oogenesis does
not occur in ovaries, major parts of
oogenesis are carried out in
ovaries while the last stage occurs
outside the ovaries in the
reproductive track of females and
is not a constant process.
The completion of all the
processes of spermatogenesis
occurs inside the testis of male,
and it is a constant process.
Place of Action
Oogenesis is a long process.Spermatogenesis is a short
process.
Time Taken
In oogenesis, condensation does
not happen.
In spermatogenisis, condensation
of material takes place.
Condensation

13. • Difference Between Spermatogenesis and Oogenesis
• Definition
• Spermatogenesis: The production of sperms from spermatogonia is called spermatogenesis.
• Oogenesis: The production of eggs from oogonia is called oogenesis.
• Location
• Spermatogenesis: Spermatogenesis occurs inside the testis in males.
• Oogenesis: Oogenesis occurs inside the ovary in females.
• Stages
• Spermatogenesis: All the stages of spermatogenesis occur inside the testis.
• Oogenesis: All the stages of oogenesis, occurs inside the ovary. Except The last stage occurs inside the oviduct.
• Releasing
• Spermatogenesis: Sperms are released from the testis.
• Oogenesis: Oocytes are released from the ovary, which matures later.
• Continuity
• Spermatogenesis: Spermatogenesis is a continuous process, occurring after the puberty till death.
• Oogenesis: Early stages of the oogenesis occurs during the fetal period. The rest of the process occurs after the
puberty. Only one ovum is produced per month until menopause.

14. • Cell Division
• Spermatogenesis: All spermatogonia are divided by meiosis, producing sperms all the times.
• Oogenesis: Some of the oogonia divide during the production of eggs, one at a time.
• Growth Phase
• Spermatogenesis: Growth phase is too short in spermatogonia.
• Oogenesis: Growth phase is prolonged in oogonia.
• Result
• Spermatogenesis: One spermatocyte produces four spermatozoa.
• Oogenesis: One oocyte produces only one ovum.
• Size
• Spermatogenesis: Sperms are smaller than spermatocyte.
• Oogenesis: Ovum is larger than the oocyte.
• Nucleus
• Spermatogenesis: The nucleus undergoes condensation in the sperm.
• Oogenesis: No nuclear condensation is found in the ovum.
• Motility
• Spermatogenesis: Spermatogenesis produces motile gametes.
• Oogenesis: Oogenesis produces non-motile gametes.