Nervous System

• Nervous system


  Body wide system of nerve cells that collects information from the world, processes this information and then takes action by directing bodily organs and muscles via the transmission of electrochemical messages
• Divisions of the nervous system

  • Central nervous system (CNS)
  • Peripheral nervous system (PNS)
  • Autonomic nervous system (ANS)
  • Somatic nervous system (SNS)
• Central nervous system (CNS)


  Involves complex processing, includes the brain for all conscious and most unconscious processing, and the spinal cord which receives and transmits information and some reflex processing
• Peripheral nervous system (PNS)

  A body-wide network of messenger neurons, sensory afferent neurons take information to the CNS, motor efferent neurons take information away from the CNS
• Autonomic nervous system (ANS)


  The part of the PNS that controls actions of internal glands and is an involuntary system so not under conscious control
• Somatic nervous system (SNS)


  The part of the PNS that controls skeletal muscles, it's a voluntary system so under conscious control
• Parts of the ANS


  • Sympathetic system
  • Parasympathetic system
• Sympathetic system


  Part of the ANS, increases bodily activities, release of noradrenaline, activates the fight or flight response, increases heart rate, sweat, breathing rate, and dilates pupils
• Parasympathetic system


  Part of the ANS, decreases bodily activities, releases acetylcholine, activates the rest and digest response, decreases heart rate, sweat, and breathing rates, constricts pupils
• Homeostasis is maintained by a balance between the sympathetic and parasympathetic systems
• Endocrine system glands


  • Pituitary gland
  • Hypothalamus
  • Pineal gland
  • Thyroid gland
  • Adrenal glands
  • Ovaries
  • Testicles
• Pituitary gland


  Also known as the master gland, hormone A controls the release of hormones from other glands
• Hypothalamus


  Hormone CRH links the nervous system to the endocrine system
• Pineal gland


  Hormone melatonin modulates sleep pattern, keeping the body to a day-night rhythm
• Thyroid gland


  Hormone thyroxine modulates metabolism, the rate of use in the body
• Adrenal glands


  Hormone adrenaline regulates the effect of the fight or flight response
• Ovaries


  Hormone estrogen develops secondary sexual characteristics in females
• Testicles


  Hormone testosterone leads to the development of secondary sexual characteristics in males