Overview of the Nervous System

1
Overview of the Nervous System

• Breakdown
• The Nervous system is divided into two parts the
  CNS (central nervous sys) and the PNS (peripheral
  nervous sys)
• These two systems consists of the brain, spinal
  cord, and neurons

2
Central Nervous System

• CNS is composed of the brain and the spinal cord
• Responsible for integrating, processing, and
  coordinating sensory data and motor commands
• You stumble the CNS integrates info about balance
  and limb position and then recovers by sending
  motor commands where needed (without conscious
  effort)
• Also contains higher functions such as
  intelligence, memory, emotion and learning

3
Peripheral Nervous System

• PNS composed of two subdivisions of neurons that
  sends stimulus to the CNS and carries motor
  commands to peripheral tissues
• Afferent division brings sensory info from
  receptors
• Efferent division carries motor commands to
  muscles and glands (they are called effectors)
• Somatic nervous sys (SNS) voluntary contraction
  of skeletal muscles
• Autonomic nervous sys (ANS) automatic movement
  and regulation of skeletal and smooth muscle due
  to stimulus (also known as a reflex)

4
Structure Of Neurons

• Cell Body (soma) contains the nucleus, most of
  the cytoplasm and cytoskeleton (cell can not
  divide due to lack of centrioles)
• Dendrites variable number of slender processes
  that extend from the cell body, typically
  receives info from other neurons and sends toward
  cell body
• Axon long process from cell body that can
  propagate an electrical impulse (action
  potential)
• Axons can be covered in segments of Myelin
  (myelin is a wrapping of insulation that
  increases the speed of the action potential along
  the axon)
• Large areas of axon wrapped in myelin are called
  Internodes
• The small gaps between internodes are called
  Nodes or nodes of Ranvier

5
Synapse Interactions

• Synapse site where one neuron communicates with
  another
• a. Presynaptic cell cell that carries the
  message
• Postsynaptic cell cell that receives message
• Neurotransmitters chemicals released into the
  synapse by the presynaptic cell which affect the
  activity of the postsynaptic cell
• Neurotransmitters are released due to the number
  of action potentials, the more action potentials,
  the more neurotransmitters that are released.
• BYGO 1-10 Pg 453