1. Hormones — endocrine system
Definition: Chemical messengers created by the body. They transfer information to cells to coordinate functions of different parts of the body.
Function: Bridges synapses between neurons, faster transmission
Hormones: Testosterone and melatonin
Where it’s produced: In the male testes gland and ovary gland in females. There is 10 times more testosterone in adult males than adult females.
Physical effects: Development and emotion in puberty. Male - deepening voice, sperm development and muscles.
Also increase in aggression, dominance and sexual behaviour.
Archer stated in a research review that testosterone levels had low but positive correlation with aggression but higher with dominance.
Experiment: Dabbs et al.
Where it’s produced: Pineal gland in brain
Physical effects: Regulates sleep wake cycle, pubertal development and seasonal adaptation
- Melatonin is released less when there is sun
- Released more when there is no sun… which causes drowsiness
Light enters the eye, then through the optic nerve to the suprachiasmatic nucleus (SCN) to send information to the pineal gland and else where. It (SCN) modulates hormones including melatonin.
Found areas with less sunlight around the world (e.g. Scandinavia) had people with higher levels of melatonin, which cause Seasonal Affective Disorder (SAD). Symptoms include depression and lethargy.