Question

The given diagram shows L.S. of testis showing various parts. Identify the parts labelled (A to G) from the list given below.
(i) caput epididymis
(ii) cauda epididymis
(iii) vas deferens
(iv) vasa efferentia
(v) corpus epididymis
(vi) seminiferous tubules
(vii) tunica vaginalis
(viii) tunica albuginea
(ix) tunica vasculosa
(x) rete testis

a) A-(ii), B-(iii), C-(iv),D-(x),E-(vii),F-(i),G-(ix)
b) A-(v),B-(iv), C-(iii),D-(vi),E-(i), F-(i), G-(vii)
c) A-(i),B-(iv), C-(x),D-(iii),E-(ii), F-(vi), G-(viii)
d) A-(i),B-(vi), C-(iv),D-(iii),E-(v), F-(x), G-(ix)

Answer 1

Hint: The above diagram shows the longitudinal section of testis comprises various parts. This is the site where production of spermatozoa (Male gamete) takes place. 

Complete answer:

Testis is covered with tough, fibrous layers of tissue called the tunica. The outermost layer is called tunica vaginalis and the innermost is called tunica albuginea.The testicle is divided into different lobules. Each lobule contains tiny U-shaped tubes called seminiferous tubules where the production of spermatozoa takes place. After formation it moves to epididymis where the spermatozoa are stored. Then it descends down to the urethra through vas deferens.

The correct option is C i.e. A-(i),B-(iv), C-(x),D-(iii),E-(ii), F-(vi), G-(viii).

Additional information: Seminiferous tubules are present within the testis where the sperm cells are produced by the process of meiosis. Apart from this, sustentacular cells also called sertoli cells are present which provide nourishment to the sperm cells. Hence sertoli cells are also called nurse cells.

Epididymis is divided into three parts i.e. caput (head/anterior), corpus and cauda(tail/posterior). It is the place where spermatozoa gets stored after production and gets matured there. 

Vas deferens transports mature spermatozoa to the urethra for ejaculation. Some hormone releasing cells are also present in the testes called Leydig cells which are responsible for the production of testosterone.

Note: Testis is homologous to the female ovary. Testis is protected in the folds of skin called scrotum which is located outside the body because the spermatozoa production needs 2-3°C lower temperature than the body temperature. In some animals, testicles descend down after birth like in rats while in some animals they are intra-abdominal (inside the body) for their whole life like in elephants.