1. Growth and Development 1 PUBERTY Viv Rolfe

2. Discuss the age of onset of puberty in males and females Development of secondary sexual characteristics at puberty Identify the roles of hormones in puberty Lecture Content

3. What is Puberty? Period of growth and sexual maturity marking the transition from child to adult. Maturation of the secondary sexual characteristics.

4. How old are girls and boys when this typically happens?

5. Girls Stop Child Adolescence Adult Early Late Age1011121314151617181920 Period of Puberty

6. GirlsBoys Stop Child Adolescence Adult Early Late Age1011121314151617181920 Period of Puberty

7. Physiological Changes Voice breaks Body hair Wet dreams Behavioural changes Spots Sweat Sperm production Skeletal growth and muscle Testicles dropping? Growth – skeletal, muscle, fat Menstrual cycle – periods Breast development Body hair Sweat and spots Voice deepening Mood swings

8. Development of Secondary Sexual Characteristics (Tanner’s Stages, 1978) Stage IPre-adolescent Stage IIFirst signs of puberty Stage IIIIntermediate stage Stage IVIntermediate stage Stage VAdult characteristics

9. Girls Pubertal Changes Breast Stage 2 Pubic hair Stage 2 Pubic hair Stage 5 Breast Stage 4 Menarche AGE 8 9 10 11 12 13 14 15 16 17

10. Boys Pubertal Changes AGE 8 9 10 11 12 13 14 15 16 17 Genital Stage 2 Genital Stage 4 Pubic hair Stage 2 Pubic hair Stage 5

11. Rate of change of Height gain Sources: Malina, 1990, Tanner, 1990, Lindsay et al, 1994, Baumgartner et al, 1986 (cited in Bee, 2000)

12. Puberty is happening at a much earlier age these days. Why???

13. What Hormones Trigger Puberty in Girls?

14. SIMPSON, H. Source: Aha! Jokes, http://www.AhaJokes.com/ © www.nlm.nih.gov (National Library of Medicine) Hypothalamus Pituitary Pituitary Gland

15. GONADOTROPHIN RELEASING HORMONE GnRH FOLLICLE STIMULATING HORMONE LUTEINISING HORMONE

16. OVARIES RELEASE PROGESTERONE OESTROGEN INITIATES PUBERTY PREPARES BODY FOR PREGNANCY FSH LH

17. 0 10 20 30 40 50 60 70 80 91011121314 Age (years) Oestragen levels (pg/1ml) Boys Girls Changes in Oestragen levels

18.  Estrogens  Produced by Graafian follicles or the placenta  Stimulates the development of secondary female characteristics  Matures female reproductive organs  Helps prepare the uterus to receive a fertilized egg and maintain pregnancy. Hormones of the Ovaries

19.  Progesterone  Produced by the corpus luteum  Acts with estrogen to bring about the menstrual cycle  Helps in the implantation of an embryo in the uterus. Hormones of the Ovaries

20. What Hormones Trigger Puberty in Boys?

21. GONADOTROPHIN FOLLICLE STIMULATING HORMONE LUTEINISING HORMONE

22. FSH LH TESTES RELEASE TESTOSTERONE INITIATES PUBERTY

23. 0 50 100 150 200 250 300 350 400 91011121314 Age (years) Testosterone levels (ng/1ml) Changes in testosterone levels

24.  Interstitial cells of testes are hormone- producing  Produce several androgens  Testosterone is the most important androgen  Responsible for adult male secondary sex characteristics  Promotes growth and maturation of male reproductive system  Required for sperm cell production Hormones of the Testes

25. These hormones surge round the body completely changing it. How long puberty takes varies between individuals.