1. 1.5 Individual human development during youth: Physical Physical Development

2. Primary and Secondary Sex Characteristics Primary sex characteristics are those change that are directly involved in REPRODUCTION – these will involve enlargement of sex organs eg: penis and vagina Secondary sex characteristics are not directly required for reproduction. So they will involve all the other changes that occur during puberty eg: widening of shoulders, pubic hair, oily skin, breast development.

3. Primary & Secondary sex characteristics SIMILARITIES Pubic hair Oily skin Voice deepens Acne Increase in height Increase in body odour FEMALES Primary sex characteristics Increase in size of vagina & uterus Ovaries produce hormones to start the menstrual cycle Secondary sex characteristics Hips widen Development of breasts Distribution of fat to hips Body gets curvier MALES Primary sex characteristics Growth of scrotum & testes Secretion of hormones related to sperm production Growth of penis 2ndry sex characteristics Body & facial hair More muscle mass Greater height than females Broadening shoulders

4. HormoneGland that secretes it / them Role it plays in physical development during puberty Follicle Stimulating Hormone (FSH) & Lutenising Hormone (LH) Pituitary gland (in brain) Act on the testes and ovaries to release testosterone or oestrogen TestosteroneTestes (testicles)Responsible for the development of male sex characteristics, muscle growth, hair growth and voice changes

5. OestrogenOvariesResponsible for the development of female sex characteristics, breast development and the regulation of the menstrual cycle. Growth Hormone (GH) Pituitary GlandIncreases the rate of growth ThyroxineThyroid GlandRegulates metabolism, which is required to produce the extra energy needed for the changes that occur to the body during puberty.

6. Hormone actions on the female body For females: For males: GnRH is released from the brain FSH and LH are released from the pituitary gland (brain) LH and FSH act on the ovaries Oestrogen is released from the ovaries which results in female characteristics developing

7. Hormone actions on the male body GnRH is released from the brain FSH and LH are released from the pituitary gland (brain) LH and FSH act on the testes Testosterone is released from the testes which results in the male characteristics developing