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Puberty. Puberty. 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 10-12 for females and 11-13 in males. Puberty.
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Puberty • 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 10-12 for females and 11-13 in males.
Puberty • The hypothalamus produces a hormone called gonadotropin-releasing hormone which cause a reaction in the pituitary gland. • This reaction induces the pituitary to secrete two different hormones: • Follicle Stimulating Hormone (FSH) • Luteinizing Hormone (LH)
Hypothalamus Pituitary Gland
Pituitary Hormones • Follicle Stimulating Hormone (FSH) – Stimulates sperm production in the testes and the growth of follicles in the ovaries. • Luteinizing Hormone (LH) – causes testosterone secretion in males and stimulates ovulation and growth of the corpus luteumin females.
Males • The testes respond to the rising amounts of LH and FSH by growing and beginning to produce testosterone. • Rising levels of testosterone causes a number of body changes.
Effects of Testosterone • Growth of the penis and reproductive tract (vas deferens, epididymis, prostate, seminal vesicles). • Growth of coarser and longer hair on the chest, armpits, pubic region, legs, and face.
Effects of Testosterone • Enlargement of the larynx, which causes the voice to deepen. • Increased growth of bone and muscle. • Increased sexual drive (libido).
Females • The production of LH and FSH influences the ovaries to begin secreting oestrogen and progesterone. • The production of these 2 hormones cause various physical changes.
Effects of Oestrogen • Enlargement of the uterus and vagina. • Growth of the ducts of the mammary glands. • Broadening of the pelvic girdle.
Effects of Oestrogen • Increased sexual drive (libido). • Inhibition of FSH secretion by the pituitary. • During pregnancy it inhibits milk secretion.
Effects of Progesterone • Stimulates growth of the glands and blood vessels of the endometrium. • Stimulates growth of the secretory tissue of the mammary glands. • Inhibits secretion of FSH by the pituitary.
Effects of Progesterone • Inhibits contraction of uterine muscles during pregnancy. • During pregnancy it inhibits milk secretion.