Nervous system

• What are the main functions of the nervous system 


  Receives and processes sensory input

  Integrates information

  Controls muscles and glands via motor output

  Homeostasis

  Mental activity
• Cell types

  Neurons - transmit electrical stimuli through the body

  Neuroglia - support, nourish and insulate neurons
• three types of neurons

  sensory

  motor

  relay
• structures

  sensory receptors - nerve endings that detect stimuli

  nerves - bundles of axons that transmit impulses

  ganglia - collections of nerve cell bodies

  plexus - a network of nerves formed from ventral branches of spinal nerves
• nerves and nerve fibers

  individual axons surrounded by perineurium

  bundle together to make a nerve fiber

  fibers are surrounded by epineurium in their bundles to make nerves
• cranial nerves

  12 pairs

  originate directly from the brain

  sensory, motor or both
• spinal column

  grey matter in an H shape

  has a dorsal and ventral horn

  central canal where spinal chord runs

  white matter surrounding
• grey matter contains cell bodies and fibers

  white matter only contains fibers
• Types of nerve fibers

  Motor = efferent

  Sensory = afferent
• somatic

  general somatic afferent = skin to sensory neurons

  general somatic efferent = motor to skeletal muscle
• autonomic - visceral

  general visceral afferent = organ to sensory neuron

  general visceral efferent = motor neuron to smooth muscle
• afferent = peripheral to CNS

  efferent = CNS to peripheral
• sympathetic

  short preganglionic neuron

  long postganglionic neuron
• parasympathetic

  long preganglionic neuron

  short postganglionic neuron