the nervous system and endocrine system

• what is the nervous system?

  consists of the CNS and PNS and communicates using electrical signals.
• whats the central nervous system?

  consists of the brain and spinal cord and is the origin of all complex commands and decisions.
• what is the peripheral nervous system?

  sends info to the CNS from the outside world and transmits messages from the CNS to muscles and glands in the body
• what is the somatic nervous system?

  transmits info from receptor cells in the sense organs to CNS. receives info from the CNS that directs muscles to act.
• what is the autonomic nervous system?

  transmits info to and from internal bodily organs. system operates involuntarily and has 2 main divisions- sympathetic and parasympathetic nervous system.
• what are the 2 main functions of the nervous system?

  to collect, process and respond to info in the environment.

  to coordinate the working of different organs and cells in the body.
• what is the endocrine system?

  one of the body's major information systems that instructs the glands to release hormones directly into the bloodstream. these hormones are carried towards target organs in the body and communicates via chemicals.
• what is the fight or flight response?

  the way an animal responds when stressed. the body becomes physiologically aroused in readiness to fight an aggressor or flee.
• how does the fight or flight response work?

  1. stressor perceived and hypothalamus activates the pituitary gland.
  2. this triggers activity in the sympathetic branch of the autonomic nervous system.
  3. ANS changes from its parasympathetic state to sympathetic state.
  4. adrenaline released from adrenal gland into bloodstream and adrenaline triggers physiological changes in the body which creates a physiological arousal for fight or flight response.
  5. once threat passed parasympathetic nervous system returns body to normal state
• biological changes associated with sympathetic state

  -increased heart rate

  -increased breathing rate

  -dilated pupils

  -digestion inhibited

  -saliva production inhibited

  -rectum contracted
• biological changes associated with parasympathetic state

  -decreased heart rate

  -decreased breathing rate

  -pupils constricted

  -digestion stimulated

  -saliva production stimulated

  -rectum relaxes