Puberty

PubertyAlthough 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 10-12 for females and 11-13 in males.

Males and

Females

Males Females

Puberty

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)

Pituitary Gland

Hypothalamus

Pituitary Hormones

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.

Males

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.

Effects of Testosterone

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.

Effects of Testosterone

3. Enlargement of the larynx, which causes the voice to deepen.

4. Increased growth of bone and muscle.

5. Increased sexual drive (libido).

Females

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.

Effects of Oestrogen

1. Enlargement of the uterus and vagina.

2. Growth of the ducts of the mammary glands.

3. Broadening of the pelvic girdle.

Effects of Oestrogen

4. Increased sexual drive (libido).

5. Inhibition of FSH secretion by the pituitary.

6. During pregnancy it inhibits milk secretion.

Effects of Progesterone

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.

Effects of Progesterone

4. Inhibits contraction of uterine muscles during pregnancy.

5. During pregnancy it inhibits milk secretion.