Question

Draw a labeled diagram of a section through the ovary.

Answer 1

Hint: A pair of ovaries, a duct system consisting of a pair of fallopian tubes, a uterus, cervix, and vagina make up a female reproductive system. The primary female sex organ constitutes the ovary.

Complete answer: The ovary is the primary sex organ in females. The free surface of the ovaries is covered by a germinal epithelium composed of a single layer of the cuboidal cells. This epithelium is continuous with the mesothelium lining called the peritoneum. Ovarian stroma is enclosed by the epithelium. This ovarian stroma is divided into- A the peripheral cortex and an inner medulla. Immediately below the germinal epithelium, the cortex is covered by a connective tissue called tunica albuginea. The cortex contains numerous sac- like masses known as ovarian follicles.
The medulla contains loose connective tissue, elastic fibers, numerous blood vessels, and smooth muscle fibers.

The internal structure of an ovary:
- Ovarian follicle: The ovarian follicle contains a large, centrally placed ovum, surrounded by several layers of granular cells. It is suspended in a small cavity called the antrum.
- The secondary oocyte in the tertiary follicle also forms a new membrane called zona pellucida. The ovary bulges out because of the follicle. Such a mature follicle is known as the Graafian follicle.
- Corpus Luteum: The ovum is shed from the ovary by the rupture of the follicle. The shedding of the ovum is called ovulation and occurs nearly 14 days before the onset of the next menstrual cycle. Corpus Luteum (yellow- colored body) is the remains in the Graafian Follicle after the extrusion of the developing ovum. The cytoplasm of the corpus luteum is filled with a yellow pigment called lutein. The corpus luteum grows for a few days and if the ovum is fertilized and the pregnancy results, it continues to grow.
But if the ovum is not fertilized, the corpus luteum persists only for about 14 days, and during this, it secretes progesterone and a small amount of estrogen. At the end of its functional life, the corpus luteum degenerates and is converted into a mass of the fibrous tissue called corpus Albicans (white body).

Additional Information: The ovary produces ova and secretes the female sex hormones, estrogen, and progesterone which are responsible for the development of secondary female sex characters and cause marked cyclic changes in the uterine endometrium. These are small, almond- like flattened bodies, about 2 to 4 cm in length and are connected to the pelvic wall and the uterus by ligaments. Ovaries remain attached to the lower abdominal cavity through the mesovarium and are located near the kidneys.

Note: - The granular cells that surround an ovarian follicle is also known as follicular granulosa or discus proligerus or cumulus oophorus. - Antrum is filled with fluid known as Liquor folliculi. - Follicular atresia is the process of degeneration of a large number of ovarian follicles from birth to puberty. - During ovulation, a secondary oocyte arrested at meiosis II is released which converts into an ovum when the sperm enters the secondary oocyte before fertilization.