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)

Explain cosmid, Cosmid: The type of artificially constructed vector taken ...

Cosmid: The type of artificially constructed vector taken in use for cloning the 35-45 kb of DNA. These are plasmids carrying the phage l cos site (which permits packaging into l

the standard error to be different, Out of 67,410 randomly selected surger...

Out of 67,410 randomly selected surgeries tracked in a study in the UK, 2832 were followed by surgical site infections. a.    What is the best estimate of the probability of an

Ecology.., examples of pyramid of energy

examples of pyramid of energy

Define tips that should be followed before an event start, Define Tips that...

Define Tips that should be followed before an event Start? Before the event, following tips should be followed:   As the glycogen stores may be used up during night, a h

What is the drug permeability across the cornea, What is the drug permeabil...

What is the drug permeability across the cornea? Drug permeability across the cornea depends onto: a. Lipid and water solubility of the drug b. Molecular size, weight and

Stomata can open and close in response to changes in the co2, Stomata can o...

Stomata can open and close in response to changes in the CO 2 concentration inside the leaf. Would you expect stomata to open or close if the CO 2 concentration decreased? Explai

Cell theory, why is cosmozoic theory considered to be true?

why is cosmozoic theory considered to be true?

Brain, How brain thinks?

How brain thinks?

List the four objectives of counselling a diabetic patient, Q. List the fou...

Q. List the four objectives of counselling a diabetic patient? Objectives of Diabetes Counselling 1. Facilitating decision to start treatment and change life style 2.

Respiration.., different types of respiration system in different organisms...

different types of respiration system in different organisms

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