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)

Define cellulose, Cellulose Cellulose is found in plants as microfibr...

Cellulose Cellulose is found in plants as microfibrils (2-20 nm diameter and 100-40,000 nm long). These form the structurally strong framework in the cell walls. Cellulose is

Design a controlled experiment, Design a controlled experiment to test the ...

Design a controlled experiment to test the hypothesis that acid precipitate inhibits the growth of elodea, a common freshwater plant.

What do you understand by flagella, What do you understand by Flagella. ...

What do you understand by Flagella. A cellular hairlike locomotory structure which comprise an extension of the plasma membrane surrounding a 9+2 organization of microtubules.

Types of aortic stenosis-aortic stenosis-valve disease, Types of Aortic Ste...

Types of Aortic Stenosis:  Obstruction to left ventricular outflow is commonly at the valvar level. Less commonly it is at the sub valvar or supra valvar level. Sub valvar ob

Give some examples of secretory cells?, Endocrine and exocrine pancreatic c...

Endocrine and exocrine pancreatic cells, thyroid and parathyroid endocrine cells, adenohypophysis, adrenal and pineal endocrine cells, the lot of types of gastric exocrine and endo

Explain how a human eye is working for the body, Explain how a human eye is...

Explain how a human eye is working for the body. Every tissue in the body requires basic components which are either derived from the body itself or we acquire them from extern

Water demands vary among communities, a)  Water demands vary among communit...

a)  Water demands vary among communities. Discuss some of the factors affecting water uses.  b)  A coastal town has a resident population of 8000 people during the winter months

Economic importance of wild life, ECONOMI C IMPORTANCE OF WILD LIFE  - ...

ECONOMI C IMPORTANCE OF WILD LIFE  - (i) Plants - Produce food. Provide Timber, paper, gums, drugs, pigments, fibres, rubber, oils, condiments & fuel. Release O

Reproduction and life cycles – protozoan, Reproduction and Life Cycles – Pr...

Reproduction and Life Cycles – Protozoan Asexual reproduction occurs in all protozoan through fission, budding and cyst formation. In this method the organism reproduces to fo

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