Testes (testicles), Biology

Assignment Help:

TESTES (TESTICLES) -

  1. 2 in number (Diarchic). Pinkish in colour. Oval shaped.
  2. 4-5 cms long, 2.5 cm wide and 3 cm thick. Mesodermal.
  3. In embryonic stage attached to kidney by mesorchium membrane.
  4. In embryo at 7th month of division descend down in scrotel sac. Condition is extra abdominal, due to it 3°C less temperature is available, helpful in spermatogenesis.
  5. Both scrotel sac internally separated by septum scroti. External by a scar-like raphe.
  6. In scrotel sac fat layer is absent, involuntary muscles are dertos tunic present.
  7. Lumen of scrotel sac is vaginal coelome, in it testes present.
  8. Vaginal coelome is connected to main coelome by inguinal canal.
  9. In some cases testes do not descend down in sac, condition is cryptorchidism such animals are high flankers (sperm are not produced)
  10. Testes is attached to pre position by spermatic cord (gonadial artery, gonadial vein, nerve and connective tissue present).
  11. Testis is attached to wall of scrotel sac by elastic structure i.e. gubernaculum cordis.
  12. Unit of testis is seminiferous tubule where sperms are manufactured by spermatogenesis. All tubules form a cord of 200-400 meter. These tubules are spreaded in connective tissue.
  13. In tissue interstitial cells or cells of Leyding present. These cells secrete testastaron or androgen hormones to control secondary sexual characters.
  14. Outside each seminiferous tubule, tunica propria present. Inside it germinal epithelium or basement membrane present. Made up of cuboidal epithelium.
  15. Epithelium consists of P.G.C. and few sertoli cells.
  16. P.G.C. (Primordial germ cells) are endodermal in nature.
  17. P.G.C. are responsible for spermatogenesis.
  18. Different stages of formation of sperms can be seen as spermatogonia, primary spermatocyte, sec. spermatocyte, spermatid and sperms.
  19. Sertoli cells or nurse cells or sustentacular cells are nourishing cells i.e. provide glycogen as food to develope sperms. So sperm's head is embeded in sertoli cells.
  20. Around testes, testicular capsule present made up of 2 layers.
  21. Outer is tunica vaginalis & inner is tunica albuginea.
  22. From tunica albuginea straight vertical spetum mediastinum is originated from it septula testes are given out to form 200-300 compartments.
  23. In each compartment seminiferous tubule present.
  24. On tunica albuginea, mediastinum & septule testes, a membrane present rich in blood supply. This membrane is tunica vescularosa.
  25. Surgical removal of testes is orchidectomy & gonad is castration or gelding.

2406_testis.png 1933_testis1.png


Related Discussions:- Testes (testicles)

Placenta - human development, Placenta - Human Development We had said...

Placenta - Human Development We had said previous in the unit that in the second week of development a primitive uteroplacental circulation is established. Early in this stage

What is recombination frequency?, What is recombination frequency? The ...

What is recombination frequency? The Recombination frequency, or crossing over rate, is the percentage of recombinant gametes made by crossing over (in relation to the number o

Define the purposes of counselling, Q. Define the Purposes of Counselling? ...

Q. Define the Purposes of Counselling? 1. Supporting individuals to take charge of their own life by: Providing information; Facilitating emotional adjustments; and

Currents in estuaries, Currents in Estuaries Currents in estuaries are...

Currents in Estuaries Currents in estuaries are caused primarily by tidal action and river flow. Currents are generally confined to channels but velocities up to several knots

What do you mean by cephalopods and vertebrates, Q. How does photosensitivi...

Q. How does photosensitivity in annelids, cnidarians and worms differ from insects, cephalopods and vertebrates? In the first mentioned group of animals there are photoreceptor

Explain atrial pressure, Q. Explain Atrial Pressure? The RA pressure wa...

Q. Explain Atrial Pressure? The RA pressure wave form has three positive deflections - "a", "c", and "v" waves. The "a" wave is due to atrial systole and follows the P-wave on

Explain enfuvirtide, Explain Enfuvirtide Enfuvirtide is the first fusio...

Explain Enfuvirtide Enfuvirtide is the first fusion inhibitor approved by the FDA for treatment of HIV infection and is indicated for treatment-experienced patients with ongoin

What is coevolution, What is Coevolution ? There is considerable eviden...

What is Coevolution ? There is considerable evidence that supports an interesting theory that two individual species can affect each others evolution in reciprocal fashion. In

Endocrine glands - heart, HEAR T - The cells called cardiocytes of atr...

HEAR T - The cells called cardiocytes of atria of the heart secrete peptide hormone called atrial natriuretic factor (ANF) in response of an increased return of the deoxygen

Coelenterata – General characters and classification., Coelenterata – Gener...

Coelenterata – General characters and classification.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd