1.5 Individual human development during youth: Physical
Physical Development
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.
Primary & Secondary sex characteristics
SIMILARITIES• Pubic hair• Oily skin• Voice
deepens• Acne• Increase in
height• Increase in
body odour
FEMALESPrimary sex characteristicsIncrease in size of vagina & uterusOvaries produce hormones to start the menstrual cycleSecondary sex characteristicsHips widenDevelopment of breastsDistribution of fat to hipsBody gets curvier
MALESPrimary sex characteristicsGrowth of scrotum & testesSecretion of hormones related to sperm productionGrowth of penis2ndry sex characteristicsBody & facial hairMore muscle massGreater height than femalesBroadening shoulders
Hormone Gland 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
Testosterone Testes (testicles) Responsible for the development of male sex characteristics, muscle growth, hair growth and voice changes
Oestrogen Ovaries Responsible for the development of female sex characteristics, breast development and the regulation of the menstrual cycle.
Growth Hormone (GH)
Pituitary Gland Increases the rate of growth
Thyroxine Thyroid Gland Regulates metabolism, which is required to produce the extra energy needed for the changes that occur to the body during puberty.
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
Hormone actions on the male body
GnRH is released from the brainFSH and LH are released from the pituitary gland
(brain)
LH and FSH act on the testesTestosterone is released from the testes which results in the male
characteristics developing