Although the reproductive organs are present at birth, they are small and cannot function. Puberty is the change from an immature juvenile into a sexually mature adult. This usually begins between the ages of for females and in males.

Males and Females MalesFemales

1. The hypothalamus produces a hormone called gonadotropin- releasing hormone which cause a reaction in the pituitary gland. 2. This reaction induces the pituitary to secrete two different hormones: a) Follicle Stimulating Hormone (FSH) b) Luteinizing Hormone (LH)

a) Follicle Stimulating Hormone (FSH) – Stimulates sperm production in the testes and the growth of follicles in the ovaries. b) Luteinizing Hormone (LH) – causes testosterone secretion in males and stimulates ovulation and growth of the corpus luteum in females.

1. The testes respond to the rising amounts of LH and FSH by growing and beginning to produce testosterone. 2. Rising levels of testosterone causes a number of body changes.

1. Growth of the penis and reproductive tract (vas deferens, epididymis, prostate, seminal vesicles). 2. Growth of coarser and longer hair on the chest, armpits, pubic region, legs, and face.

3. Enlargement of the larynx, which causes the voice to deepen. 4. Increased growth of bone and muscle. 5. Increased sexual drive (libido).

1. The production of LH and FSH influences the ovaries to begin secreting oestrogen and progesterone. 2. The production of these 2 hormones cause various physical changes.

1. Enlargement of the uterus and vagina. 2. Growth of the ducts of the mammary glands. 3. Broadening of the pelvic girdle.

4. Increased sexual drive (libido). 5. Inhibition of FSH secretion by the pituitary. 6. During pregnancy it inhibits milk secretion.

1. Stimulates growth of the glands and blood vessels of the endometrium. 2. Stimulates growth of the secretory tissue of the mammary glands. 3. Inhibits secretion of FSH by the pituitary.

4. Inhibits contraction of uterine muscles during pregnancy. 5. During pregnancy it inhibits milk secretion.