The Female Reproductive System

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Gilbert McKinney
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1 The Female Reproductive System STD X The female reproductive system consists of a pair of ovaries, a pair of oviducts, uterus, a vagina and the outermost part - the vulva. 1

1. Ovaries The ovaries are a pair of glands resembling unshelled almonds in shape and size. They are positioned in the upper pelvic cavity, one on each side of the uterus.

2 1. Ovaries The ovaries are a pair of glands resembling unshelled almonds in shape and size. They are positioned in the upper pelvic cavity, one on each side of the uterus. They are held in position by a series of ligaments and attached to the broad ligament of the uterus. The peripheral part of the ovary produces ova or the egg towards inner side and generally one egg matures in each ovary in every alternate month. The process of producing a mature ova is called oogenesis. A maturing egg is present in a follicle. When the follicle enlarges and fills with fluid, it is called graafian follicle. When the Graafian follicle is ripe, it projects from the surface of the ovary, bursts and releases the ovum into the oviduct. The release of the mature ovum by the rupture of the Graafian follicle is called ovulation. The remnant of the ruptured graafian follicle persists and converts into a yellow mass of endocrine tissue called the corpus luteum. The corpus luteum secretes oestrogen, progesterone and relaxin. Oestrogen stimulates the development of the sex organs and the secondary sex characteristics. Progesterone prepares the uterus for receiving the embryo, and Relaxin helps to dilate the uterine cervix towards the end of pregnancy. 2

3 2 Oviduct Extending laterally on each side of the uterus is the fallopian tube or the oviduct. Each oviduct is about cm long muscular tube and its open distal end is funnel shaped and is called infundibulum or oviducal funnel. The oviducal funnel is fringed by fingerlike projections called fimbriae. It picks up and transports the released ovum from the ovary to the uterus and also provides the appropriate environment for its fertilisation. Internally, the walls of the oviducts are made up of unstriped muscle fibre which show peristaltic movements to push the ovum into the uterus. 3. Uterus The uterus is a pear shaped, hollow, muscular organ situated between the urinary bladder and the rectum. It consists of a upper dome shaped fundus, the tapering central portion of the uterus body and the lower narrow portion opening into the vagina called the cervix. The interior of the body of the uterus is called the uterine cavity. The uterus has a thick, highly vascular wall composed of three layers outer perimetrium, middle smooth muscle layer called myometrium and inner mucous membrane known as endometrium. The endometrium is rich in tubular glands. 4. Vagina The uterus plays multiple roles : a) It receives the ovum from the fallopian tubes. b) It forms placenta for the development of the foetus. c) Protects and nourishes the growing embryo. d) It expels the young one at birth. It is a large, median, elastic, muscular tube about 10cm long. It extends from the lower end of the uterus to the outside. The vagina is adapted for (i) receiving the penis during coitus (intercourse) (ii) allowing menstrual flow. (iii) serving as the birth canal during parturition. The opening of the vagina in young females is partially closed by a thin membrane called hymen. It is frequently ruptured in childhood due to strenuous exercise. 3

4 5. Vulva The external genitilia of the female is collective called vulva. It consists of two outer longitudinal folds of skin, the labia majora, covering two inner, more delicate folds the labia minora. In the uppermost angle of the vulva, is located a small cylindrical mass of erectile tissue called the clitoris. It is richly supplied with nerves. The cleft between the labia minora is called the vestibule. Within the vestibule are the hymen, vaginal orifice (opening ),urethral orifice and the openings of several other ducts. Puberty Puberty is the period during which immature reproductive system of boys and girls mature and capable of reproducing. For example: In boys, the enlargement of the testis and in girls, the enlargement of the breasts. Menarche and Menopause Menarche is the onset of menstruation in young females. Menopause is the permanent stoppage of menstruation at about the age of 45 years. The Menstrual Cycle The reproductive period in human females is from about the age of 13 years to years. This period is marked by a characteristic event repeated almost every month (28 days, with minor variation) in the form of a menstrual flow. The menstrual flow may be temporarily stopped by pregnancy. The period of a menstrual flow is counted from the day of the onset of the flow to the next onset after 28 days. This period is divided into four main phases : Menstrual Phase: 3 to 5 days during which the endometrium &unfertilized ovum are discharged out of the uterus causing bleeding. Follicular Phase: Conversion of Primary Follicle to Graafian Follicle & secretion of Oestrogen for thickening of endometrium as a preparation for receiving the blastocyst (few celled fertilised ovum) for implantation. 4

5 Ovulatory Phase: Ovulation leading to the release of a mature ovum on the14th day of menstral cycle. Luteal Phase: Conversion of ruptured Graafian follicle to Corpus luteum for secretion of hormone Progesterone. *************************** 5

Female Reproductive System

Female Reproductive System (Part A-1) Module 10 -Chapter 12 Overview Female reproductive organs Ovaries Fallopian tubes Uterus and vagina Mammary glands Menstrual cycle Pregnancy Labor and childbirth Menopause