Assisted Hatching:
The use of micromanipulation procedures to create an opening in the zona pellucida.

Corpus Luteum:
A structure which forms from an ovulatory follicle and which, through endocrine secretions (including progesterone), functions to prepare the uterus for pregnancy.

Cryopreservation:
The freezing and storage of living cells.

Cytoplasm:
The granular fluid which fills living cells and which contains essential cellular components including the nucleus.

Embryo:
The term used to desribe developing offspring during the period between fertilization and organ formation.

Endometriosis:
The presence of endometrial tissue (the cycling tissue which lines the uterus) at sites outside the uterus. These sites usually include the fallopian tubes, ovaries and peritoneal cavity. The condition is associated with pelvic pain, pain during menstruation and infertility.

Endometrium:
The cycling lining of the uterus. This structure receives the implanting embryo.

Estrogen:
The primary female hormone, produced mainly by developing ovarian follicles.

Fallopian Tubes:
The structures which lie between the ovaries and uterus. They normally receive the ovulated egg and provide the site for fertilization and early embryo development.

Follicle:
The structure which houses the egg and subsequently fosters its development and ultimate ovulation. At birth, there are in excess of 100,000 follicles per female ovary. This number decreases continuously throughout life.

Follicle-stimulating Hormone:
Gonadotropic hormone released from the pituitary gland and functioning to stimulate ovarian follicular growth and development. The same hormone plays an essential role in male sperm production.

Gametes:
Male and female sex cells (sperm and eggs, respectively).

Gonads:
Male (testes) and Female (ovaries) organs which produce sex cells.

Gonadotropins:
Follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Hormones produced by the pituitary gland and which stimulate gamete development in the gonads. Purified forms of these hormones are obtained from urine or genetically engineered cells.

Hormone:
A natural protein produced in one body tissue and carried via the bloodstream to initiate a response in another tissue.

Human menopausal gonadotropins (HMG):
Gonadotropin (FSH and LH) preparations obtained from urine of post-menopausal women and commonly used in the treatment of infertility.

Hypothalamus:
A major control center within the brain. Among many functions, it regulates the secretion of gonadotropins (FSH and LH) by the pituitary.

Implantation:
The attachment of the embryo to the endometrium of the maternal uterus. This process ultimately gives rise to the placenta (Respiratory and Excretory system of the developing fetus).

In vitro fertilization (IVF):
The generation of embryos outside the body by mixing eggs and sperm in tubes or dishes containing defined culture media. In the treatment of human fertility, IVF defines a multi-step process including: pituitary suppression; ovarian stimulation; egg retrieval; insemination of eggs in culture tubes or dishes containing defined media; and transfer of resulting embryos back to the uterus.

Intracytoplasmic sperm injection (ICSI):
The direct deposition of a single sperm into the cytoplasm of an egg using micromanipulation apparatus.

Laparoscopy:
Visualization of reproductive organs using a fibre optic scope inserted through a small abdominal incision.

Luteinizing Hormone (LH):
A pituitary gonadotropic hormone which plays an essential role modulating the development of sex cells (both eggs and sperm). A surge of LH causes final egg maturation and ovulation.

Oocyte:
The female sex cell ovulated at the end of each reproductive cycle.

Ovaries:
The female gonad containing the eggs (one egg per ovarian follicle). This structure also provides the chief source of estradiol and progesterone.

Pituitary Gland:
The "Master" gland which ultimately controls virtually every other endocrine gland in the body. Through gonadotropin (FSH and LH) secretion, the pituitary regulates sex cell development by testes and ovaries.

Progesterone:
A hormone which plays a central role in the establishment and maintenance of pregnancy. Initially, it is secreted by the corpus luteum (post-ovulatory follicle) to prepare the uterus for pregnancy. Later, it is secreted by the placenta to maintain pregnancy.

Recombinant Gonadotropins:
High purity FSH and LH preparations produced by genetically engineered cell lines.

Semen:
The sperm and seminal fluids ejaculated during male orgasm.

Spermatogenesis:
The process of sperm production (within the testis).

Testes:
The male gonad, functioning to produce mature sperm as well as the hormone testosterone.

Zona Pellucida:
A proteinaceous barrier surrounding eggs and embryos. This structure is normally dissolved and shed during implantation.