What are Hormones? (HL IB Psychology)

Hormones & Their Effect on Behaviour – What are hormones?

What is a hormone?

• A hormone is a chemical that is secreted by the endocrine glands into the blood stream which then distributes it around the body

• The major endocrine gland is the pituitary gland which regulates the secretion of all hormones

• Hormones act slowly (unlike neurotransmitters which act fast) and may take years to fully have an effect: e.g. puberty involves the slow release of testosterone (males) oestrogen (females)

  • Testosterone and oestrogen are, respectively, the male and female sex hormones which control primary and secondary sexual characteristics 

  • Testosterone and oestrogen also regulate key milestones such as puberty, sperm production (testosterone), the menstrual cycle and menopause (oestrogen)

• The major gland which regulates hormones is the pituitary gland, located at the base of the hypothalamus

• Hormones will have different effects on the body and on behaviour, depending on the nature of the hormone itself: e.g. cortisol is known as the stress hormone as it is secreted during times of stress/anxiety; melatonin regulates the sleep-wake cycle

Hormones list

Secreted by the pituitary gland:

• Adrenocorticotropic Hormone (ACTH)

• Follicle-stimulating hormone

• Growth hormone

• Luteinising hormone

• Oxytocin

• Prolactin

• Thyroid-stimulating hormone

• Vasopressin

Secreted by other glands under the control of the pituitary gland:

• Melatonin

• Thyroxine

• Calcitonin

• Parathryoid

• Cortisol

• Aldosterone

• Adrenaline and noradrenaline

• Insulin

• Glucagon

• Oestrogen

• Testosterone

• Progesterone

• Thymosin