[Biology Class Notes] on Stages of Gamete Development Pdf for Exam

Gamete Development

Gametes are the reproductive cells of an organism. In sexually reproducing organisms, a gamete is a haploid cell that combines with another haploid cell during fertilization. These cells have the ability to become sperm or ova.

Experiment for Stages of Gamete Development

Aim: The aim is to investigate the different stages of Gamete Development in the mammalian testis and ovary.

Tools Required for both TS of Mammalian Testis and Ovaries are Mentioned Below:

Let’s proceed with the process of conducting TS of mammalian ovary and testis.

Principle

Gamete creation takes place in the gonads of all male and female organisms, which are the testis and ovary, respectively. 

Meiotic cell division is required for gamete creation, which is referred to as gametogenesis. 

Spermatogenesis is the gametogenic development in the testis, while oogenesis is the gametogenic development in the ovary. They have distinct characteristics that can be seen in the transverse sections (T.S.) of these organs.

Procedure

1. First, wash hands properly and dry them thoroughly. 

2. With the help of lens cleaning paper and cleaning fluid, clean the slide, microscope’s eye, and objective lens.

3. Place the slide on the microscope stage.

4. Start observing under lower magnification and then proceed towards higher magnification. 

5. Write down your observations in a biology practical copy. Now draw diagrams of both TS of mammalian ovary and testis and label them. 

Transverse Section of Testis

The testis is the most vital male reproduction organ. It is responsible for producing male gametes or sperms and storing them. Also, it forms testosterone hormones that influence sex drive, fertility and increases bone mass and muscle power. 

Male humans have a pair of the testis. The process of gametogenic development in testes is known as spermatogenesis.  

TS of testis under microscope shows these components. 

Observation

1. Lower magnification will reveal a huge number of seminiferous tubules. They are somewhat round or oval. 

2. View several stages of gamete growth from the periphery to the lumen and a full tubule under increased magnification.

3. Evaluate the following types of cells:

• Germinal epithelium

• Spermatogonial cells

• Primary spermatocytes

• Secondary spermatocytes

• Spermatids

• Spermatozoa

4. The space between tubules in T.S. of the testis is filled with blood vessels and a special cell type known as Leydig’s cell or Interstitial cells. 

5. Also, you can see Sertoli cells that hold the sperms. 

6. However, the mature sperms remain inside the lumen of the Seminiferous tubule. In this stage, the sperm has ahead and tell, but the middle is still immature. 

Fill in the gap: Sertoli cells are separated by _______________ cells. 

Ans: Spermatogenic. 

Now, draw the TS of the mammalian testis diagram and label it. 

Transverse Section of Ovary

Ovaries are the primary reproductive organs of almost all female vertebrates. Their main function of them is to produce female gametes or eggs. Also, they are responsible for forming progesterone hormones. 

Most mammals, including female humans, possess two ovaries, right and left. 

The development of gametes inside ovaries is called oogenesis.

TS of mammalian ovaries will help you to study the several components of ovaries. 

Observation

1. There is a mass of tissue lined with germinal epithelium in the ovarian region.

2. You’ll find an ovum inside, which is a single cell surrounded by one to several layers of follicular cells. Furthermore, one or several layers of follicular cell guard the ovum. The number of follicular cell layers increases as the ovum matures. 

3. The number of surrounding follicular cell layers grows as the ovum matures.

4. Later in follicular development, an antrum cavity occurs.

5. The cavity and the follicle enlarges. The Graafian follicle has reached the stage where it is ready to discharge the ovum. This process is called ovulation.

6. A Corpus luteum and/or Corpus Albicans, which differ in appearance from one another and from the Graafian follicle which can be seen at the next stage.

7. They also differ from the follicular cell. Corpus Luteum forms from the ruptured follicle that contains Lutein cells and is surrounded by blood clots. 

8. Atretic follicle shows that the follicle cells are disorganised. It also carries the sign of nuclear necrosis. Moreover, it also shows the reduced size of the oocyte.    

All these stages are clearly seen in the permanent ovary slide.