The Nervous System and Endocrine System

• What is the nervous system?

  a system of receptors and effectors that allow us to respond to stimuli and coordinate actions. Comprised of the CNS and PNS
• What does the CNS stand for?

  central nervous system
• what does the PNS stand for?

  peripheral nervous system
• What are the three main functions of the nervous system?

  1. collect, process and respond to info from the environment

  2. co-ordinate the working of different organs and cells

  3. relay messages from brain to body
• What two parts is the nervous system made up of?

  central nervous system and peripheral nervous system
• What is the CNS made up of?

  brain and spinal cord
• What is the PNS made up of?

  somatic nervous system and autonomic nervous system
• what is the autonomic nervous system split into?

  sympathetic and parasympathetic
• The CNS: brain


  • centre of awareness and physiological processes
  • cerebral cortex
  • highly developed in humans
  • two hemispheres
• The CNS: spinal cord


  • relays info from brain to body
  • connects nerves to PNS
  • connects to muscles and glands
  • allows simple reflexes without brain
• What is the function of the PNS?

  relay nerve impulses from the CNS to the body and from the body to the CNS
• What does the somatic nervous system control?


  voluntary muscle movement receives info from sensory receptors
• What does the ANS govern?

  vital functions of the body
• What is the purpose of the sympathetic nervous system?

  activate the fight or flight response, prepare for rapid action under threat
• What is the purpose of the parasympathetic nervous system?

  relaxes the body when the emergency has passed
• What are examples of the parasympathetic state?


  • decreased heart rate
  • decreased breathing rate
  • constricts pupils
  • stimulates digestion
  • stimulates saliva production
• What is the endocrine system?

  consists of glands which produce hormones that target organs for specific functions
• Adrenal gland


  • releases adrenaline
  • targets liver and heart
  • prepares for action (fight or flight)
• Ovaries-oestrogen


  • releases oestrogen
  • targets uterus
  • controls puberty and the menstrual cycle
• Ovaries- progesterone

  • releases progesterone
  • targets uterus
  • maintains womb lining
• pancreas


  • releases insulin
  • targets liver
  • controls blood sugar levels
• pituitary gland


  • releases anti-diuretic hormone (ADH)
  • targets kidney
  • control blood water level
• thyroid gland


  • releases thyroxine
  • targets liver and kidneys
  • controls metabolic rate
• testes

  • releases testosterone
  • targets male reproductive organs
  • controls puberty and sperm production
• The importance of the pituitary gland


  • known as master gland
  • produces hormones and release hormones from other glands
  • controlled by hypothalamus
  • produces hormones that stimulate other glands to release their hormones
• How do hormones work?

  1. hypothalamus signals the pituitary gland

  2. pituitary gland secretes 'stimulating hormone'

  3. target gland releases hormone

  4. level of target gland's hormone increases in blood

  5. hypothalamus stops its signal

  6. pituitary gland stops secreting hormone

  7. target gland stops releasing hormone
• What are hormones?

  Chemical substances that circulate in the bloodstream and impact target organs. Produced in large quantities and disappear quickly