The Reproductive Process

Masih tetap bersumber dari sini, one of my favorite website ... semoga bermanfaat:

The Reproductive Process

The Female Reprodutive Process

Normal anatomy and regular menstrual cycles are key factors in establishing fertility in the female. The female reproductive system is entirely internal.

The vagina is the passage between the outside (vulva) and the inside (cervix, or opening to the uterus). The uterus is a muscular organ about the size and shape of a pear. This is where a fertilized egg attaches and develops. The uterus is lined with a rich nourishing membrane called the endometrium. The fallopian tubes extend from the top of the uterus and reach backwards and downwards towards the ovaries, which are the two small sacs that contain the woman’s eggs (a girl is born with about 400,000 eggs and will experience about 400 ovulations in her life time).

In addition to producing a mature egg each menstrual cycle, the ovaries produce the female hormones oestrogen and progesterone. Each month, only a single egg, or ovum, matures inside a follicle within an ovary. At midcycle, the egg is released from the follicle in a process called ovulation and picked up by the fallopian tubes. The outer-most ends of the tubes are flared and have fringed fingers called fimbria, which draw the egg into the tube after ovulation. It is at this end of the fallopian tube, near the ovary, that the egg awaits fertilization. The egg then travels down one of the fallopian tubes towards the uterus.

The Menstrual cycle refers to the maturation and release of and egg, and to the preparation of the uterus to receive and nurture an embryo. A typical cycle takes approximately 28 to 32 days and is divided into three phases:

1. Follicular – Day 1 to about Day 13; on the first day of the cycle, when menstruation begin, the uterus shed its lining from the previous cycle,. The pituitary gland, located at the base of the brain, release two hormones, follicle-stimulating hormone (FSH) and letuinising hormone (LH), which stimulate the ovary and cause follicular growth. The developing follicle secretes the hormone oestrogen, and this changes the cervical mucus about the time of ovulation to receive and nourish sperm.
2. Ovulatory – around Day 14; depending on the length of the cycle This phase begins when the level of LH surges, causing the follicle to rupture and the egg to be released from the ovary. The fimbriae of the fallopian tube sweep over the ovary and wave the egg into the fallopian tube
3. Luteal – Day 15 to about Day 28; The luteal phase begins after ovulation. The follicle that produced the egg becomes a functioning gland called the corpus luteum, which produces oestrogen and progesterone, the two hormones necessary for maturing and nourishing the endometrium so that a fertilized egg may implant and develop.

If the egg meets with sperm in the fallopian tube, conception may occur. The fertilized egg travels through the tube towards the uterus with the help of tiny hair like projections called cilia, which sweep the egg along. Once inside the uterus, the embryo implants into the lining about 6 days after ovulation, and begins to produce a hormone called human chorionic gonadotrophin (hCG) telling the body that it is pregnant. The corpus luteum can sense the pregnancy and will continue to produce progesterone, thus preserving the uterine lining and pregnancy.

If fertilization does not occur, the ovum passes through the uterus, and the corpus luteum will cease to function on about Day 26. the uterine lining will then break down and be shed several days later, and the next menstrual period begins.

The Male Reproductive Process

The reproductive system of a men is both internal and external. Sperm are produced in the testes and pass into the coiled channels of the epididymis for storage and nourishment. The mature sperm then move into the vas deferens, a tube that connects the epididymis with the seminal vesicles, the two pouch-like glands behind the bladder that join each vas deferens and empty into the urethra. The seminal vesicles contribute about 90% of the fluid to the ejaculate.

Following ejaculation, semen forms a gel, which becomes liquid within 5 to 30 minutes. Sperm can like 48 to 72 hours within the female reproductive tract for fertilizing an egg. This is why sexual intercourse around the time of ovulation is often adequate for conception.

Several factors determine whether a man’s sperm can fertilise an egg:

1. Volume of semen (usually 1.5 to 5 ml)
2. Sperm count or density (usually higher than 20 million per ml)
3. Sperm morphology (shape, usually more than 60% appear normal)
4. Sperm motility (movement, usually more than 50% move rapidly forward)

Although sperm count is critical, sperm motility appears more important in determining the fertilizing capability of sperm. Despite a low sperm count, many men with high quality (viable and highly motile) sperm may still be fertile.

The production of sperm is regulated by three hormones:

1. FSH (follicle stimulating hormone)
2. LH (luteinising hormone)
3. Testosterone

FSH and LH are the same hormones necessary for regulating the female’s reproductive functions. In the male, however, these hormones have different responsibilities, FSH is responsible for stimulating sperm production in the testicles, and LH stimulates the production of testosterone, the hormone associated with the male sex drive and sperm production.

Source: www.morulaivf.com