Divisions of the Nervous System

• divisions of the nervous system

  the NS is divided into the central and peripheral NS

  CNS = brain, spinal cord

  PNS = further divided into somatic and autonomic NS
• somatic NS - PNS

  consists of sensory and motor neurons to carry sensory and motor info to and from the CNS: enables reflex action

  controls voluntary movements of the skeletal muscles, under conscious control. transmits info via the spinal cord to muscles/effectors to produce voluntary movement.

  has sensory and motor pathways
• autonomic NS - PNS

  acts largely involuntary. divided into the sympathetic and parasympathetic branches

  SB - activates fight or flight response due to a perceived threat, releasing adrenaline from the adrenal medulla due to activated sympathomedullary pathway. this causes direct effects.

  PSB - once you realise the threat has been removed, the parasympathetic branch will restore homeostasis through ‘rest and digest’
• fight or flight response

  hypothalamus prepares the body for action/emergency response when a threat is detected.

  adrenaline is released from the adrenal medulla in response to the activation of the sympathomedullary pathway.

  general effects: increased oxygen to brain for rapid response planning+ skeletal muscles for quick movements, increased heart rate, breathing rate, dilated pupils

  when threat has passed, parasympathetic branch activates and restores homeostasis - ‘rest and digest‘