Endocrine system

• The endocrine system is a network of cell clusters called glands
• Glands in the brain receive electrical signals from neurons and communicate with other cells by releasing hormones into the blood stream
• Two important endocrine glands:

  Pituitary gland

  Adrenal gland
• The adrenal gland sits above our kidneys
• The adrenal gland releases hormones in response to stress
• The adrenal gland is divided into two parts:

  Outer part - adrenal cortex - cortisol

  Inner part - adrenal medulla - adrenaline
• The adrenal cortex produces cortisol
• The adrenal medulla produces adrenaline
• The pituitary gland is at the bottom of the brain
• The pituitary gland controls the release of hormones from all other glands in the body
• Fight or flight response - body's response to stress
• Fight or flight response reactions:

  Pupil dilation

  Decreased salivation

  Increased breathing rate

  Increased heart rate

  Increased muscle tension

  Increased sweat

  Decreased food digestion
• The fight or flight response is involved with the sympathetic nervous system
• The sympathetic nervous system prepares the body for action
• The hypothalamus sits above the pituitary gland
• The hypothalamus links the nervous system to the endocrine system
• The hypothalamus controls the release of hormones in the endocrine system through the pituitary gland
• Neurones in the hypothalamus send electrical signals to the autonomic nervous system
• Fight or flight process:

  The hypothalamus gets a signal of threat from the CNS and PNS

  The hypothalamus sends electrical signals to the sympathetic nervous system, which activates the adrenal medulla

  The adrenal medulla releases adrenaline into the bloodstream

  Adrenaline binds to target cells, causing them to produce bodily reactions
• Two forms of fight or flight that the hypothalamus initiates:

  Fast response - releases adrenaline - kicks in immediately in response to stress

  Slow response - releases cortisol - releases more slowly for stressful situations lasting longer
• When stress is removed, the hypothalamus activates the parasympathetic nervous system
• The parasympathetic nervous system decreases bodily activity - rest and digest response
• The parasympathetic nervous system decreases bodily activity - rest and digest response
• Limitations of fight or flight response:

  Research lacks population validity and generalisability because most of the research was just on male participants

  Research assumes that people always respond to stress by fighting or fleeing - ignores individual differences, some people freeze
• Fight or flight AO3. FoF response was an excellent way to deal with the types of danger and stress we experienced long ago as cave people, however in modern day it is an overactive response in non life threatening situations