Humans have evolved a longer childhood than other primates, which means that the development of sexual maturity is
delayed
The nervous system develops very quickly both before the baby is born and
afterwards
A human baby is born with a large brain that develops quickly into
its adult size
The reproductive organs do not develop much until puberty - this means that a human child has an extended childhood when it is dependent upon its
parents
This growth patten allows a human child to
- Learn advanced skills (tool use and language)
- Ensures that a human does not become a parent until it has learned advanced social skills (as bringing up a highly dependent child requires considerable skills)
Puberty is the stage in life when the
sex organs and secondary sex characteristics develop
Puberty occurs in males between the ages of…
12-16
(Male puberty) the hypothalamus in the brain releases a hormone called…
Gonadotrophin releasing factor (GnRF)
(Male puberty) GnRF stimulates the release of 2 different hormones from the pituitary gland called…
Follicle Stimulating Hormone (FSH) Luteinising Hormone (LH)
(Male puberty) LH is sometimes called…
Interstitial cell stimulating hormone (ICSH)
(Male puberty) FSH and LH stimulate the release of another hormone….
testosterone from the testes
(Male puberty) the changes that occur are mainly the result of
testosterone
(Male puberty) 7 changes that occur are:
- Growth of cartilage in the thorax (chest) and pectoral girdle (shoulders) = broader and more muscular
- Growth of penis and testes
- Growth of pubic hair
- Growth of axillary (underarm) and facial hair, and often chest and body hair
- Growth of the larynx, causing voice to deepen
- General body growth and development of muscles
- Increase activity of sweat gland and sebaceous glands
Female puberty occurs between the ages of:
10-15
(Female puberty) the release of GnRF by the hypothalamus triggers the release of
FSH and LH from the pituitary gland
(Female puberty) FSH and LH interact to cause the events of the
menstrual cycle
(Female puberty) The time of the first menstrual cycle in a female is called the…
Menarche
(Female puberty) a female is not usually fertile until about
2 years after the menarche
(Female puberty) the development of secondary sex characteristics in females is the result of female sex hormones, especially
oestrogen
(Female puberty) 8 changes that occur are:
- Growth of the female sex organs (ovaries, oviducts, uterus and vagina)
- Growth of breasts
- Growth of pubic hair
- Growth of axillary (underarm) hair
- Increase of cartilage in the pelvic girdle (hips) which causes the diameter of the pelvic girdle to increase
- The ‘carrying angle’ of the arms and legs changes, so they are at a slight angle
- Accumulation of fat (especially on hips, breasts and thighs)
- Increased activity of sweat glands and sebaceous
Although we know that GnRF triggers puberty, we do not know the stimulus that causes the hormone to be released. One factor that seems to stimulate its release is diet. Over the past 150 years, the age at which females begin menstruating has dramatically
decreased
