D3.1 (Reproduction in Mammals)

Reproduction

The biological process by which organisms produce offspring.

Sexual Reproduction

Reproduction involving the fusion of gametes from two parents, producing genetically varied offspring.

Asexual Reproduction

Reproduction involving one parent that produces genetically identical offspring, except for mutations.

Meiosis

Nuclear division that produces four genetically different haploid cells from one diploid cell.

Haploid

Having one complete set of chromosomes, represented as nnn.

Diploid

Having two complete sets of chromosomes, represented as 2n2n2n.

Gamete

A haploid reproductive cell, such as a sperm or egg, that can fuse during fertilisation.

Fertilisation

The fusion of male and female gamete nuclei to form a diploid zygote.

Zygote

The diploid cell formed when two gametes fuse during fertilisation.

Sperm

A small, motile male gamete produced in the testes.

Egg

A large, non-motile female gamete produced in the ovaries.

Scrotum

A pouch of skin that contains the testes and helps maintain their temperature below core body temperature.

Testis / Testes

Male reproductive organs that produce sperm and secrete testosterone.

Epididymis

A coiled tube where sperm mature and are stored.

Vas Deferens

A muscular tube that transports sperm from the epididymis to the ejaculatory duct.

Seminal Vesicle

A gland that adds fructose-rich fluid to sperm to form part of semen.

Cowper’s Gland

A gland that secretes lubricating, alkaline fluid into the urethra before ejaculation.

Prostate Gland

A gland that adds alkaline fluid to semen, helping sperm survive and move.

Urethra

A tube that carries urine and semen out of the body, although not at the same time.

Penis

The male reproductive organ that transfers semen into the vagina during sexual intercourse.

Ovary

A female reproductive organ that produces eggs and secretes oestradiol and progesterone.

Oviduct

A tube that transports an egg from an ovary to the uterus; fertilisation usually occurs here.

Uterus

A muscular organ where an embryo implants and develops during pregnancy.

Cervix

The muscular, narrow opening between the uterus and vagina.

Vagina

A muscular tube that receives the penis and sperm and forms the birth canal.

Labia

Folds of skin that protect the external openings of the female reproductive system.

Clitoris

An organ containing many sensory nerve endings that contributes to sexual arousal.

Menstrual Cycle

The recurring reproductive cycle involving the ovarian and uterine cycles and preparing the body for possible pregnancy.

Uterine Cycle

The cyclical development, maintenance and shedding of the endometrium.

Ovarian Cycle

The cyclical development of ovarian follicles and release of an egg.

Oestradiol (an Oestrogen)

An ovarian hormone that repairs and thickens the endometrium and, at high levels, stimulates the LH surge.

Progesterone

A hormone released mainly by the corpus luteum that maintains the endometrium and inhibits FSH and LH secretion.

Follicle Stimulating Hormone (FSH)

A pituitary hormone that stimulates the growth of ovarian follicles and sperm production.

Luteinising Hormone (LH)

A pituitary hormone whose surge triggers ovulation and formation of the corpus luteum.

Positive Feedback

A process in which an initial change produces effects that amplify or increase that change.

Negative Feedback

A process in which an increase in a product inhibits the processes that produced it, helping maintain stability.

Ovulation

The release of a mature egg from an ovarian follicle, triggered by a surge in LH.

Corpus Luteum

The structure formed from the ruptured follicle after ovulation that secretes progesterone.

In Vitro Fertilisation

Fertilisation outside the body in laboratory conditions, followed by transfer of an embryo to the uterus.

Superovulation

The hormone-stimulated maturation and release or collection of multiple eggs during an IVF treatment cycle.