nervous & endocrine system

• peripheral NS


  nerves outside CNS

  outside world = CNS = muscles
• somatic NS 


  voluntary actions
• autonomic NS


  involuntary action
• endocrine system


  instructs glands to release hormones to regulate the body's functions
• hypothalamus


  controls the pituatary gland
• pituitary gland

  'master gland'

  controls the other glands
• sensory neurone

  PNS - CNS
• relay neurone

  CNS
• motor neurone

  CNS = muscles/glands (effector)
• nodes of Ranvier

  the gaps between the myelin sheath
• inhibitory effect NTs

  increase the negative charge and making it less likely to pass on the electrical impulse
• excitatory effect NTs


  increasing the positive charge making it more likely to fire
• summation

  • neurones receive signals from many different neurones at the same time
  • it sums all the signals it receives and decides whether or not it fires
  • if the net is mostly excitatory signals it will fire (vice versa with inhibitory)
• describe the role of the sympathetic NS

  • involved in how we respond to emergencies - fight or flight
  • prepares the body for rapid action
  • e.g. releases stored energy for the body/ pupils dilate/ slows down less important bodily processes (digestion/ urination)
• describe the role of the parasympathetic NS

  • involved in returning the body into resting state once an emergency has passed
  • returns the bodily processes back to normal
  • 'rest and digest'
• describe the endocrine system

  a system in our body that instructs glands to release hormones by using blood vessels for transport

  hormones commute as chemicals
• describe the role of the endocrine system

  helps to regulate bodily functions by working closely with the nervous system

  e.g. to keep our core temperature even
• compare the endocrine system with the nervous system

  slower but widespread, powerful and long-lasting effect
• describe the role of glands

  • an organ in the body that produces and secretes hormones to regulate the body
  • the main gland or 'master gland' is the pituitary gland located in the brain = controls the release of hormones from all other endocrine glands in body
• define hormones

  a chemical that circulates the bloodstream and only affects TARGET organs
• why are hormones crucial to the body?

  timing and level of hormones released can be crucial

  too much or too little at the wrong time can result in dysfunction of the bodily system
• how are hormones released?

  • specific hormones come from specific glands
  • the hypothalamus is connected and controls the pituitary gland
  • it receives the information on the body's functioning and control's hormones releasing
• what is negative feedback in terms of hormones?

  the hypothalamus recognises the levels of hormones and can stop the pituitary gland from more, stopping the effect it has on other glands and physiological processes
• thyroid gland releases?

  thyroxine
• what is the role of thyroxine?

  aids heart and digestive functioning, metabolism, brain development, bone health and muscle control
• adrenal gland releases?

  adrenaline
• what is the role of adrenaline?

  involved in the sympathetic NS = triggers the fight or flight response by increasing heart, breathing rate and contraction of blood vessels
• testes gland releases?

  testosterone
• what is the role of testosterone?

  controls the development of male physical features - genitalia/ facial and body hair/ growth/ deeper voice

  (also involved in the development of the masculine gender)
• ovaries release?

  oestrogen & progesterone
• what is the role of oestrogen and progesterone

  they control the development of female physical features - genitalia/ breast/ menstruation

  (involved in the development of the feminine gender)
• pancreas releases?

  insulin
• what is the role of insulin?

  it maintains blood-glucose concentration - allows cells to absorb glucose from the blood

  also involved in the breakdown of fat and protein
• how does the endocrine and autonomic NS work together during stress?

  • stressor
  • hypothalamus activates the pituitary gland
  • this triggers the sympathetic branch of ANS = from parasympathetic (resting) to sympathetic (rapid action)
  • sympathetic branch sends a message to the adrenal gland
  • adrenaline is release into the blood (describe adrenaline's role)
  • once the threat/ stress is over the body returns to normal via the parasympathetic branch of ANS
• why does synaptic transmission only travel in one direction?

  • the receptors are only on the post-synaptic membrane
  • synaptic vesicles are only on the pre-synaptic membrane
  • so diffusion of neurotransmitters can only go from a high to low concentration