Nervous system

• The central nervous system includes the brain and spinal cord.
• Facts about nerves:

  • There are around 47 miles of nerves in the human body
  • One nerve cell may be connected to 1000 nerves in the body
  • Nerve impulses can travel up to 390 feet per second
• Functions of the nervous system:

  1. Gathers information from both inside and outside the body (sensory function)

  2. Transmits information to the processing areas of the brain and spine

  3. Processes the information in the brain

  4. Sends information to the muscles, glands, and organs so they can respond appropriately (motor function)
• The nervous system:

  • Acts as the body's control center
  • Maintains balance (homeostasis)
  • Regulates and coordinates the body's responses to external and internal stimuli
• Basic cells of the nervous system:

  • Made up of dendrites, cell body, and axon
  • Structural and functional unit of the nervous system
  • Specialized for transmitting, processing, and conducting impulses or information
• Sensory Neurons:

  • Afferent
  • Carry impulses from inside and outside the body to the brain and spinal cord
• Three types of neurons:

  Interneurons:

  • Associative
  • Found within the brain and spinal cord, process incoming impulses and pass them on to motor neurons

  Motor Neurons:

  • Efferent
  • Carry impulses away from the brain and spinal cord
• Neuroglia (Glial Cell):

  • Supporting cells that form 40% of the brain’s bulk
• Schwann Cells:

  • In the PNS, produce the protective myelin sheath for insulation of axon
• Ependymal Cells:

  • Produce the cerebrospinal fluid
• Oligodendrocytes:

  • In the CNS, produce the protective myelin sheath for insulation of axon
• Astrocyte:

  • Supply nutrients to neurons
  • Help maintain their ability to transmit impulses
• Microglial Cells:

  • Help in removing debris and bacteria from the CNS
• Two

  Divisions

  of the

  Nervous

  System

  • Peripheral • Central

  A. Central Nervous System

  The CNS serves as the main processing center for the entire nervous system.

  Components:

  • Brain

  • Main parts: cerebrum,

  cerebellum, brain stem • Spinal Cord

  • serves as channel for signals between the brain and the rest of the body parts

  B. Peripheral Nervous System

  • Made up of all the nerves that carry messages to and from the central nervous system.

  • Central Nervous System and Peripheral Nervous System work together to make rapid changes in your body in response to stimuli.