Question

Describe the histological structure of human ovary. Add a note on the structure of sperm.

Accepted Answer

The histology of the human ovary can be described as follows:

The ovary can be characterised as a compact structure that consists of the inner medulla and outer cortex area. The inner area contains connective tissue called the stroma. The germinal epithelium line the outer area of the ovary. Oogonia arise from the endoderm of the yolk sac and migrate to ovaries during embryonic development.

Tunica albuginea is a whitish capsule and made up of dense irregular connective tissue. It is located immediately inside the germinal epithelium. Each follicle contains a large ovum surrounded by many layers of follicle cells. These cells secrete estrogen.

In the beginning, a single layer of follicular cells surround each oocyte, and the entire structure is called a primordial follicle. As the follicle grows, it forms a clean glycoprotein layer called the zona pellucida. It is located between the primary oocyte and granulosa cells. The innermost layer of these cells becomes firmly attached to zona pellucida to form corona radiata.

The outermost granulosa cells based on a basement membrane. These cells encircle the basement membrane in a region called theca folliculi.

As the primary follicle continued to grow, the theca folliculi differentiates into theca internal and external. The granulosa cells begin to secrete a follicular fluid that fills a cavity called the antrum. It is located in the centre of the follicle and called a secondary follicle.

The degeneration of the Corpus luteum forms corpus Albicans. The Corpus luteum is formed in the antrum or follicular cavity of an empty Graafian follicle after the release of its ovum. It acts as a temporary endocrine gland and secretes progesterone. This hormone helps in the maintenance of the pregnancy in the body of a female.

The sperms are considered as the male gametes in the body that helps in the reproduction process. It can be characterised as an elongated, haploid and motile structure. It remains viable for 72 hours and can fertilize the ovum in the first 12 to 14 hours. It consists of head, neck, middle piece and tail.

Head: This structure is a v-shaped, flat and oval area having a large nucleus and an acrosome. The acrosome is the cup-like structure of the head, and it secretes a hydrolytic enzyme called hyaluronidase. It facilitates the penetration of the egg during fertilization.

Neck: It is a very short region having two centrioles. The proximal centriole helps in the first cleavage of zygote. The distal centriole gives rise to the axial filament of the sperm.

Middle piece: This structure serves as a powerhouse for the sperm. It contains many mitochondria that provide energy. This helps in the movement of the sperm in the female genital tract.

Tail: The tail can be characterised as a long, slender and tapering structure formed by cytoplasm. The axial filament is a thread-like structure that arises from the distal centriole and transverse the middle piece and tail.

Column–I		Column–II
a.	Mons pubis	(i)	Embryo formation
b.	Antrum	(ii)	Sperm
c.	Trophectoderm	(iii)	Female external genitalia
d.	Nebenkern	(iv)	Graafian follicle

Describe the histological structure of human ovary. Add a note on the structure of sperm.

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