Answer the following question. Explain the histological structure of testis - Biology

Answer in Brief

Explain the histological structure of testis.

Describe histological structure of Testis with well labelled diagram.



Histology of Testis:

1. Externally, the testis is covered by three layers. These are:
a. Tunica vaginalis: It is the outermost incomplete peritoneal covering made up of connective tissue and epithelium.
b. Tunica albuginea: It is the middle layer formed by collagenous connective tissue.
c. Tunica vasculosa/vascularis: It is the innermost layers. It is a thin and membranous layer.

2. Each testis is divided into about 200-300 testicular lobules by fibres from tunica albuginea. Each lobule has 1 to 4 highly coiled seminiferous tubules.

3. Each seminiferous tubule is internally lined by a single layer of cuboidal germinal epithelial cells (spermatogonia) and few large pyramidal cells called Sertoli or sustentacular cells.

4. The germinal epithelial cells undergo gametogenesis to form spermatozoa.

5. Sertoli cells provide nutrition to the developing sperms.

6. Various stages of spermatogenesis can be seen in the seminiferous tubules. The innermost spermatogonial cell (2n), primary spermatocyte (2n), secondary spermatocyte (n), spermatids (n) and sperms (n).

7. Between seminiferous tubules, few groups of interstitial cells (Cells of Leydig) are present

8. After puberty, interstitial cells produce a type of androgen i.e. testosterone.

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Chapter 2: Reproduction in Lower and Higher Animals - Exercises [Page 48]


Balbharati Biology 12th Standard HSC for Maharashtra State Board
Chapter 2 Reproduction in Lower and Higher Animals
Exercises | Q 5.03 | Page 48


Which mode of reproduction gives rise to variation?

Give the importance of variation in survival of species.

Complete the following table to get the differences between asexual and sexual reproduction:

Characteristics Asexual Reproduction Sexual Reproduction
Number of parents involved ........................... ..............................
Type of cells involved Somatic cells Germ cells
Type of cell division ............................ Meiosis and mitosis

What is meant by sexual reproduction?

Name two main processes of sexual reproduction

What are chromosomes?

What is amphimixis?

Describe the process of fertilization in human beings.

Choose the most appropriate answer.

Internal fertilization occurs

Choose the most appropriate answer.

The number of nuclei present in a zygote is

Indicate whether the following statements are True (T) or False (F).

Oviparous animals give birth to young ones. ( )

Indicate whether the following statement is True (T) or False (F).
A new human individual develops from a cell called gamete. ( )

Indicate whether the following statement is True (T) or False (F).

A zygote is formed as a result of fertilization. ( )

Indicate whether the following statement is True (T) or False (F).
An embryo is made up of a single cell. ( )

Give two differences between a zygote and a foetus.

In which female reproductive organ does the embryo get embedded?

Complete the crossword puzzle using the hints given below.


1. The process of the fusion of the gametes.

6. The type of fertilization in hen.

7. The term used for bulges observed on the sides of the body of Hydra.

8. Eggs are produced here


2. Sperms are produced in these male reproductive organs.

3. Another term for the fertilized egg.

4. These animals lay eggs.

5. A type of fission in amoeba.

Which species is likely to have better chances of survival - the one reproducing asexually or the one reproducing sexually? Justify your answer.

name the organ which produces male sex cells.

What are gametes?

Give reason for the following:

The parents and off-springs of organisms reproducing sexually have the same number of chromosomes.

The correct sequence of organs in the male reproductive system for the transport of sperms is:
(a) testis → vas deferens → urethra
(b) testis → ureter → urethra
(c) testis → urethra → ureter
(d) testis → vas deferens → ureter

The offsprings formed as a result of sexual reproduction exhibit more variations because ______

Distinguish between the following pair of terms:

Sexual reproduction and asexual reproduction.

Distinguish between the following pair of terms:

Budding and Regeneration.

What is the function of uterus?

Multiple choice question. Tick (✓) the correct choice:

Butterfly in its development from larva to an adult shows

  1. multiplication
  2. metamorphosis
  3. fertilisation
  4. none of the above

Multiple choice question. Tick (✓) the correct choice:

Which of the following glands is responsible for bringing about changes during adolescence in boys and girls?

  1. pituitary
  2. adrenal
  3. thyroid
  4. testis

Differentiate between the following:

External fertilisation and Internal fertilisation.

Mention the common method of reproduction in Start fish.

Mention the changes which occur during adolescence in humans.

Adolesecence is considered a critical stage in the life of boys and girls. Explain this statement.

Describe the various stages in the life cycle of a butterfly.

Name the two types of mammalian gametes. How are these different from each other? Name the type of reproduction they are involved in. Write the advantage of this type of reproduction. 

Explain why variations are observed in the offsprings of sexually reproducing organisms?

Sketch and label the diagram showing self- and cross-pollination.

In the sexual mode of reproduction, greater diversities are generated.

Answer in one sentence.

Outline the path of sperm upto the urethra.

Answer in one sentence.

Which glands contribute fluids to the semen?

Answer in one sentence.

Name the endocrine glands involved in maintaining the sex characteristics of males.

Answer the following question.

Explain the histological structure of ovary in human.

Answer the following question.

Which is the function of male accessory glands?

Answer the following question.

Explain the following parts of male reproductive system along with labelled diagram showing these parts- Testis, vasa deferentia, epididymis, seminal vesicle, prostate gland and penis.

Long answer question.

Describe female reproductive system of human.

What is atresia with respect to ovary in human females?

Write an account of the seminal vesicle and bulbourethral gland in the male reproductive system.

Which are the components of pollination?

Animals which give birth to young ones directly are named as ______.

What are the different stages of sexual reproduction?

Which organs/glands produce eggs and sperms?

In an ovule, meiosis occurs in ______

Due to presence of which of the following chemical component, pollen grains can remain well preserved in fossil?

Testosterone is produced by ____________.

Which of the following is the male accessory gland?

Identify the INCORRECT statement.

Match column -1 with column - II and select the correct option.

  Column - I   Column - II
1. Seminal vesicles a. Membranous urethra
2. Scrotum b. Thermoregulatory
3. Tunica vaginalis c. Fibro muscular pouches
4. Cowper's gland d. Peritoneal covering

______ is the first stage of sexual reproduction.

______ fertilisation takes place in frogs and fish.

The zygote divides repeatedly into a group of cells, which develops into different tissues and organs constituting a full body. This structure is known as ______.

______ lay thousands and sometimes millions of small, soft eggs in water.

In ______ animals, the development of the embryo takes place inside the body.

Name the two ways by which fertilisation in animals takes place.

What is external fertilisation?

What are oviparous animals?

Explain the formation of the embryo.

Which is a better mode of reproduction, sexual or asexual? Why?

Explain how stability of the DNA of the species is ensured in sexually reproducing organisms.


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