Question

Long answer question.

Describe female reproductive system of human.

Answer 1

The human female reproductive system consists of:

i. Internal genitalia:
It includes ovaries, oviducts, uterus, vagina.

a. Ovary:

It is the primary female sex organ. It is a solid, oval, or almond-shaped organ. It is 3 cm in length, 1.5 cm in breadth, and 1 cm thick. It is located in the upper lateral part of the pelvis near the kidneys. Each ovary is held in position by ligaments by attaching it to the uterus and the abdominal wall. The largest of these is the broad ligament formed by a fold of peritoneum. It holds the ovary, oviduct and the uterus to the dorsal body wall. The ovarian ligament attaches the ovary to the uterus.

Functions:
Its main function is production of egg or ovum and the female reproductive hormones.
The ovary produces five hormones viz. estrogen, progesterone, relaxin, activin and inhibin.

b. Oviduct / Fallopian tube / Uterine tube:

These are a pair of muscular ducts lying horizontally over the peritoneal cavity. The proximal part of the tube lies close to the ovary and distally it opens into the uterus. Each tube is 10 to 12 cm in length. It is internally lined by ciliated epithelium. It can be divided into three regions:

1. Infundibulum:
The proximal funnel like the part with an opening called ostium surrounded by many finger-like processes called fimbriae (of these at least one is long and connected to the ovary). The cilia and the movement of fimbriae help in transporting the ovulated egg to the ostium.

2. Ampulla:
It is the middle, long and straight part of the oviduct. Fertilization of the ovum takes place in this region.

3. Isthmus / Cornua:
The distal narrow part of the duct opening into the uterus.
Functions:
Fallopian tubes carry the released egg from the ovary to the uterus. Ampulla provides the site for fertilization of the ovum.

c. Uterus:
It is commonly also called as the womb.
It is a hollow, muscular, pear-shaped organ, located above and behind the urinary bladder. It is about 7.5 cm long, 5 cm broad and 2.5 cm thick. Internally the uterine wall can be distinguished into three layers: The outermost perimetrium, middle thick muscular myometrium, made up of thick layer of smooth muscles. Vigorous contractions of these muscles cause labour during parturition (childbirth). The innermost layer called endometrium or mucosal membrane is made up of stratified epithelium. The thickness of this layer regularly undergoes changes during the menstrual cycle. It is richly supplied with blood vessels and uterine glands. These provide nourishment to the developing foetus.
The uterus can be divided into three regions:

1. Fundus: It is the upper dome shaped part. Normally implantation of the embryo occurs in the fundus.

2. Body: It is the broad part of the uterus which gradually tapers downwards.

3. Cervix: It is the narrow neck about 2.5 cm in length. It extends into the vagina. Its passage has two openings: an internal os/ orifice towards the body, and an external os/ orifice towards the vagina.

Functions:
Uterus receives the ovum. It provides site for implantation, gestation and parturition. It forms placenta for the development of foetus.

d. Vagina:
It is a tubular, female copulatory organ, 7 to 9 cm in length.
It lies between the cervix and the vestibule.
The vaginal wall has an inner mucosal lining, the middle muscular layer and an outer adventitia layer.
The mucosal epithelium is stratified and non-keratinized and stores glycogen.
There are no glands but the cervical secretion of mucus is received in the vagina.
The opening of the vagina into the vestibule is called vaginal orifice. The vaginal orifice is partially covered by the hymen.
Functions:
The vagina acts as a passage for menstrual flow as well as a birth canal during parturition.

ii. External genitalia (Vulva):

The external genital organs of female include parts external to the vagina, collectively called vulva (covering or wrapping), or pudendum. They include the following parts:

a. Vestibule:
It is a median vertical depression of vulva enclosing the urethral and vaginal opening.

b. Labia minora:
These are another pair of thin folds inner to the labia majora with which they merge posteriorly to form the fourchette (frenulum), while towards anterior end they converge into a hood-like covering around the clitoris.

c. Clitoris:
A small conical and sensitive projection lying at the anterior end of labia minora. It has a pair of erectile tissue i.e. corpora cavernosa which is homologous to the penis.

d. Labia majora:
These are a pair of fleshy folds of skin forming the boundary of the vulva. They are homologous to the scrotum. They surround and protect the other parts of the external genitalia and enclose the urethral and vaginal openings in the vestibule.

e. Mons pubis:
It is a fleshy elevation above the labia majora. The Mons pubis and outer part of labia majora show pubic hair.

iii. Accessory glands:

a. Vestibular glands / Bartholin’s glands:
It is a pair of glands homologous to the Bulbourethral or Cowper’s glands of the male. They open into the vestibule and release a lubricating fluid.

b. Mammary glands:
These are accessory organs of the female reproductive system for production and release of milk after parturition. The development of the mammary glands occur at puberty under the influence of estrogen and progesterone. Lactotropic hormone (LTH) or prolactin helps in the development of lactiferous tubules during pregnancy. The mammary glands are a pair of rounded structures present in the subcutaneous tissue of the anterior thorax in the pectoral region (from 2nd to 6th rib). These are modified sweat glands. Each mammary gland contains fatty connective tissue and numerous lactiferous ducts. The glandular tissue of each breast is divided into 15-20 irregularly shaped mammary lobes, each with alveolar glands and lactiferous duct.
Alveolar glands secrete milk which is stored in the lumen of alveoli. The alveoli open into mammary tubules. The tubules of each lobe join to form a mammary duct.
Many mammary ducts join to form a wider mammary ampulla, which is connected to lactiferous duct. These converge towards the nipple located near the tip of the breast.
It is surrounded by a dark brown coloured and circular area of the skin called areola.