Puberty
The time between the first onrush of hormones and full adult physical development. Puberty usually lasts three to five years. Many more years are required to achieve psychosocial maturity.
Menarche
A girls first menstrual period, signalling that she has begun ovulation. Pregnancy is biologically possible, but ovulation and menstruation are often irregular for years after menarche.
Spermarche
A boys first ejaculation of sperm. Erections can occur as early as infancy, but ejaculation signals sperm production, Spermarche may occur during sleep (in a “wet dream”) or vi direct stimulation.
Pituitary gland
A gland in the brain that responds to a signal from the hypothalamus by producing many hormones, including those that regulate growth and sexual maturation.
Adrenal glands
Two glands, located above the kidneys, that respond to the pituitary, producing hormones.
HPA (hypothalamus-pituitary-adrenal) axis
A sequence of hormone production originating in the hypothalamus and moving to the pituitary and then to the adrenal glands.
Gonads
The paired sex glands (ovaries in females, testicles in males). The gonads produce hormones and mature gametes.
HPG (hypothalamus-pituitary-gonad) axis
A sequence of hormone production originating in the hypothalamus and moving to the pituitary and then to the gonads.
Estradiol
A sex hormone, considered the chief estrogen. Females can produce much more estradiol then males do.
Testosterone
A sex hormone, the best known of the androgens (male hormone); secreted in far greater amounts be males than by females.
Circadian rhythm
A day-night cycle of biological activity that occurs approximately every 24 hours.
Secular trend
The long term upward or downward direction of a certain set of statistical measurements, as opposed to a smaller, shorter cycle variation. As an example, over the past two centuries, because of improved nutrition and medical care, children have tended to reach their adult height earlier and their adult height has increased.
Growth spurt
The relatively sudden and rapid physical growth that occurs during puberty. Each body part increases in size on a schedule: weight usually precedes height, and growth of the limbs precedes growth of the torso.
Body image
A persons idea of how their body looks.
Primary sex characteristics
The parts of the body that are directly involved in reproduction, including the vagina, uterus, ovaries, testicles, and penis.
Secondary sex characteristics
Physical traits that are not directly involved in reproduction but that indicate sexual maturity, such as a man’s beard and a woman’s breasts.
Child sexual abuse
Any erotic activity that arouses an adult and excites, shames, or confuses a child, whether or not the victim protests and whether or not contact is involved.
Sexually transmitted infection (STI)
A disease spread by sexual contact; includes HPV, gonorrhoea, genital herpes, chlamydia, and HIV.
