2-Spermatogenesis_sperm_semen.pdf bsc nursing

Brief details about spermatogenesis

1. Spermatogenesis, Sperm &
Semen
Dr. Ashok Sahai
Former Professor and Head, Department of Anatomy,
King George’s Medical University, UP, Lucknow, India
Email: [email protected]
Mob: [phone]

2. Male pelvis with testis

3. Testis in LS and Histology

4. Seminiferous tubules in TS

5. Sertoli cell and germ cells
Spermatogenesis:
Is defined as the cellular
events in testis which lead to
the formation of male
gametes--SPERMS.
Occurs in the testis which is a
part of male reproductive
organs.

6. Sperms in Light microscopy

7. Spermatogenesis
Some general considerations:
Spermatogenesis requires lower than normal body temperature as
compared to the Oogenesis. ---one of the reasons for testis to
descend and become extra-addominal.
The stem cells appear as early as 4
th
to 5
th
weeks of IUL in
undifferentiated gonads. and multiply to form spermatogonia.
The process ceases in IUL itself, again starts around puberty. The
child is born with spermatogonia in testis
In the seminiferous tubule, at any given level, the spermatogenic
cells are at different stages of differentiation.

8. Spermatogenesis
In each seminiferous tubule, at any given time, the epithelium is at
different stages of spermatogenesis. This cycle, the spermatogenic
cycle,is completed in 22.5 to 23 days.
One cycle is not sufficient for completion of spermatogenesis.
Instead, it takes 2.5 to 3 cycles; means 72to 75days for the
spermatogonia to form sperm.s
While Oogenesis occurs in structural isolation, all the cells in
spermatogenesis are interconnected and form a syncytium.

9. Spermatogenesis at a glance
Stages
Primordial Germ Cells
Spermatogonia
Primary Spermatocyte
Secondary Spermatocyte
Spermatid
Sperm

10. Spermatogenesis
The number of chromosome is Diploid(44 XY) in
Spermatogonia
Primary spermatocyte
The number becomes Haploid(22Y or 22X) in
Secondary Spermatocyte
Spermatid
Sperm

11. Spermatogenesis

12. Spermatogenesis

13. Spermatogenesis
Spermatogonia (Spg) (2N)
4 to 7 generations are
formed by mitosis.
Adjacent spermatogonia
form syncytium.
Spermatogonia–A (Spg-A)
are initially formed.

14. Spermatogenesis
Spg-A are of Two types
Dark type-A
Light type-A
Dark type-Aare less mature
and further divide to form
Type-A (Dark) & Type –A
(Light) by mitosis.
Light type –Aare more
mature and ready to divide
to form Spg-Type-B.

15. Spermatogenesis
Spermatogonia type-B(2N)
divide to form two Primary
Spermatocytes.
Primary Spermatocyte(2N)
take about 20 to 22 days to form two
Secondary Spermatocytes(N).
Reason-stores nutrients to undergo 1
st
meiotic division which is a reduction
division since the reduction division
requires a lot of energy.

16. Spermiogenesis
Picture of
transformation
Secondary Spermatocyte(N)
undergoes 2
nd
meiotic
division to form 2
Spermatids (N).
Spermatidtransforms into a
Sperm (N) –process is
known as Spermiogenesis or
Spermateliosis.
One spermatid one Sperm

17. Diagrammatic representation
of spermiogenesis
Spermatid Sperm
Nucleus Head
Golgi
Apparatus Acrosomal Cap
Mitochondria Body
Centriole-
Proximal Basal Body
Centriole-
Distal Annulus
Cytoplasm Cytoplasm
MicrofilamentsTail

18. Sperms
in LM and in computer animation

19. Sperm -parts
Parts of SPERM
Head
Neck
Body
Tail –principal piece
-end piece
Head:
Acrosomal cap
Nucleus
Cytoplasm

20. Sperm -parts
Neck:
Constriction distal to the head.
Also called the connecting
piece.
Has Basal Body.
Body (Mid piece): swollen part
behind the neck. Consists of
Cell membrane
Cytoplasm
Mitochondrial sheath
Axial or axinome filament.
Annulus:
Distal to the mid piece .
Also called Jenseng’s ring.
Tail or principal piece:
Two parts.
Proximal: Principal piece.
Distal:End piece.

21. Sperm –two types
Androsperm 50% of total no.
Chromosomes -22 Y
Smaller in size
Shorter life span
Faster to swim
Less resistant to vaginal pH
Alkaline medium –activity
and life increases.
Responsible for male child
Gynosperm 50% of total no.
Chromosomes -22 X
Bigger in size
Longer life span
Slow to swim
More resistant to vaginal pH
Alkaline medium –activity
and life increases.
Responsible for female child

22. Sperm
Newly formed Sperms
Non motile
Immature
Can not fertilize
To be able to fertilize the Sperm
should acquire
Motility
Maturity
Capacitation
Undergo Acrosome reaction
Sperms attain
Maturity–from epididymis to
ampulla of Vas.
Motility–ampulla of Vas to
vagina.
Capacitation –in uterus and
uterine.
Acrosomal reaction -tube.in
uterine tube and corona
radiata.

23. Sperm abnormalities
Chromosomal:
No. and shape of chromosomes.
Morphology:up to 20 -25%
abnormal are acceptable.
Amount:
less than 60 million per
ejaculate is abnormal
(oligospermia).
No sperms –azospermia.
Motility: Should be progressive .
Loop or ring motility is
abnormal. 75% should be
motile. 40% after 2 hours.
:

24. Sperm transport in male
Reproductive tract

25. Semen in Petri dish and in LM

26. Semen –Male ejaculate
Highly viscous –dull white colour.
pH 7.2 to 7.6.
2 to 6 ml at one time.
Composition
 -sperms 10%
 -fluid 90%
Sperms –100 million / ml
or 350 million per ejaculate.
Out of 10% sperms
-5% androsperms
-5% gynosperms
Out of 90% Fluid
-60% seminal fluid
-30% prostatic secretions
-10% bulbo urethral gland
secretions
Shape: 75 –80% are normal
Motility: 75% are motile. More
than 40% should be motile after
2 hours.
Movement:
0.5 mm per min in Vagina
2-3 mm / min. in uterus