Testis by Dr Pandian M

This PPT for all Medicos and Non medical Students for better understanding of Testis and their role education purpose only

2. SYNOPSIS
Introduction to testis
Embryonic development of testis
Anatomy
Scrotum layers
Tunica vaginalis
Tunica albuginea
Tunica vasculosa
Seminiferous tubules
Spermatogenic cell
Sertoli cell
Leydig cells
Rete testis
Efferent ductules
Testicular arteris
Summary
References.

3. TESTIS
Male gonad.
Mixed exocrine and
endocrine gland because
they produce spermand
Secreting male sex
hormones.
They are contained within
the scrotal sac, which is
located directly behind the
penis and in front of the
anus.

4. EMBRYONICDEVELOPMENT OF TESTES
During mammalian development, the gonads are at
first capable of becoming either ovariesor testes.
week 4,the gonadal rudiments are present within the
intermediate mesoderm adjacent to the developing
kidneys.
week 6, sex cords develop within the forming testes.

5. Inmales,thesex-specificgeneSRYthatisfoundon
theY-chromosomeinitiatessexdeterminationby
downstreamregulationofsex-determiningfactors,
(suchasGATA4,SOX9andAMH),whichleadsto
developmentofthemalephenotype.
firsttrimestergestation-Testosteroneanditspotent
derivative,dihydrotestosterone,playkeyrolesinthe
formationofmalegenitaliainthefetusbutdonotplay
aroleintheactualformationofthetestes.

6. seventhmonthofgestation-thetestesareformedin
theabdominalcavityanddescendintothescrotum,its
stimulatedbyandrogens.
Theproductionoftestosteronebythefetaltestesis
stimulatedbyhumanchorionicgonadotropin,a
hormonesecretedbytheplacenta.

7. Anatomy:
Paired, oval gland in the scrotum.
Length = 4-5cm
Diameter = 2.5cm
Mass = 10-15gm(single)
Temperature = 35°c

8. STRUCTURE

9. SCROTUM LAYERS
The scrotum consists of
loose skin and
subcutaneous layers and
supports the testis.
Tunica vaginalis
Tunica albuginea
Tunica vasculosa

10. Tunica vaginalis
Outer thin ,serous sac .
Derived from peritoneum.
Forms during the descent of the testis.
Partially covers the testes.

11. Tunica albuginea
Internal to the tunica vaginalis.
Tough, White fibrous capsule composed of dense irregular
connective tissue called tunica albuginea.
It extents inward
Form septa
Divide testis into serious of internal compartments called
lobules.
Each 200-300 lobules contain 1-3 tightly coiled tubules
called seminiferous tubules(semin-seed,fer-carry).

12. Tunica vasculosa
Testicular artery descends to the inferior pole just deep
to tunica albuginea.

13. Seminiferous tubules
Each lobules of the testis contain one or
three tightly coiled seminiferous
tubules.
Uncoiled-70cm in length.
Functional unit of testis . Because the
spermatogenesis occurs here.
Within the Seminiferous tubules :
Spermatogenic cell:
Here, germ cells develop into
spermatogonia, spermatocytes,
spermatidsand spermatozoonthrough
the process of spermatogenesis.

14. Sertoli cell
Sertoli cell(a kind of sustentacular cell)
is a 'nurse' cell of the testes that is part of a
seminiferous tubule.
It is activated by follicle-stimulating
hormone and has FSH-receptoron its
membranes.
Extend from the basement membrane to
the lumen of the tubule.
Internal to the basement membrane and
spermatogonia, tight junction joins
neighboring sertoli cells to one another.
These junction form obstruction known as
blood-testes barrier.

15. EXOCRINE FUNCTIONS:
Mechanical support.
Nourishment.
Phagocytosisof cytoplasmicfragments.
Release of spermatozoa.
Blood testis barrier.
ENDOCRINE FUNCTIONS:
anti-Müllerianhormone (AMH)
inhibinand activin.
androgen binding protein.
Estradiol.
Transferrin.

16. Between tubules (interstitial cells):
Leydig cells :
cells localized between
seminiferous tubules .
produce and secrete
testosterone and other
androgens
sexual development and
puberty,
secondary sexual
characteristics.
supporting spermatogenesis.
Testosterone also controls
testicular volume.

17. Retetestis:
Oncethespermproduced,theymovethroughthe
Seminiferoustubulesandentertheretetestesfor
furthermaturation.
Ciliaarelocatedonsomecellsoftheretetestis
persumablyformovingthesperm.

18. Efferentductules:
spermTransportedoutofthetestisintoepididymis
throughtheseriesofefferentductules.
Testiculararteris:
Arisesfromtheabdominalaortabelowtheoriginof
renalarteris.
Testisreceivebloodthroughthetesticulararteris.

19. Summary
It’s a male gonad, paired oval gland in the scrotum.
seventh month of gestation-the testes are formed in
the abdominal cavity and descend into the scrotum,its
stimulated by androgens.
Scrotum layer
Seminiferous tubules.
Rete testis
Efferent ductules
Testicular arteris
Function-spermatogenesis and steroidogenesis.