Endocrine System - Hormones

• Endocrine system

  Hormonal system, manufactures and releases hormones via blood vessels, work with nervous system
• Glands


  • Cells specialised to produce and secrete hormones
• Pituitary gland


  Controlled by hypothalamus, 'master' - secretes hormones that stimulate release of other hormones
• Anterior lobe of pituitary


  • Secretes ACTH, stimulates adrenal cortex, stimulates release of cortisol when stressed
• Posterior lobe of pituitary


  • Secretes oxytocin, 'love hormone', uterus contraction in childbirth
• Pineal gland


  • Releases melatonin, important for biological rhythms (infradian = sleep-wake cycle)
• Hypothalamus


  • Stimulates and controls pituitary gland's release, connected to pituitary, controls release of hormones in the endocrine system through the pituitary gland (fight or flight response)
• Thyroid gland


  • Releases thyroxine, regulates metabolism
• Ovaries


  • Release oestrogen, regulate reproductive system (infradian = menstrual cycle, pregnancy)
• Testes


  • Release testosterone, develop male sex characteristics, promote muscle growth, puberty
• Adrenal gland medulla


  • Releases adrenaline & noradrenaline, key for 'fight or flight'
• Adrenal gland cortex


  • Releases cortisol, stimulate glucose release for body's energy while suppress immune system
• Hormones

  Chemical messengers, affect specific organs, made in large, powerful but go away quickly
• label the following

  A) thyroid

  B) hypothalamus

  C) pituitary

  D) pancreas

  E) adrenals

  
• flight or fight response

  hypothalamus prepares body for action when a stressor is detected and stimulates the sympathetic nervous system from ANS branch. adrenal medulla releases adrenaline which creates physiological arousal and changes. sympathetic nervous system increases heart and breathing rate, dilates pupils, inhibits digestion and saliva production. once threat has passed, body is returned to normal resting state by parasympathetic nervous system (antagonistic to sympathetic).
• fight or flight response - adrenaline

  (increase oxygen to skeletal muscles for physical actions and brain for rapid response, constricts blood flow which increases blood pressure)
• AO3 limitation FoF: biological reductionism


  ignores role of past experiences and learned behaviours altering response to a stressful stimulus
• AO3 limitation FoF: beta bias


  FoF response is typically a male response whereas females adopt a 'tend and befriend' response; Taylor 2000 = women more likely to protect offspring (tend) and form alliances (befriend); Lee et al = SRY gene

  studies were conducted males (andocentrism) therefore generalisation to females.
• AO3 limitation FoF: maladaptive response


  FoF response was effective for our ancestors who faced threats from predators but modern day life rarely requires an intense response. Furthermore, stressors today can repeatedly activate FoF response which can have a negative consequence - increasing blood pressure damages blood vessels and leads to heart disease. Therefore low temporal validity
• Lee et al. SRY gene


  SRY gene on the Y chromosome promotes aggression in males which may prepare them to 'fight'. This gene is absent in females - we have oxytocin and oestrogen