anatomy final

• Nervous System


  • Master controller and communicator
  • Uses rapid electrical signals which have immediate responses
  • Controls endocrine system, the 2nd communication system

  
• Functions of Nervous System


  • Provides information about internal and external environments
  • Integration of sensory (Afferent) information
  • Coordinates voluntary and involuntary motor (Efferent) information
  • Control and regulate most tissues and systems of the body

  
• Peripheral Nervous System (PNS)


  • Includes all nervous tissue outside of the CNS
  • Afferent divisions – sensory information
  • Efferent divisions – carries commands to muscles and glands
  • Somatic (muscle)
  • Visceral (ANS) (organs)

  
• Central Nervous System (CNS)


  • Consists of brain and spinal cord
  • Responsible for integrating, processing, and coordinating sensory data and motor commands

  
• Somatic Nervous System


  • Controls skeletal muscle contractions
  • May be voluntary or involuntary
  • Reflexes are involuntary somatic actions
• Autonomic Nervous System


  • Controls smooth muscle, cardiac muscle, glandular activity
  • 2 divisions: Sympathetic and Parasympathetic
• Nervous System Composition


  • 80% Cells
  • 20% extracellular matrix
  • Five types of cells in CNS
  • Three types of cells in PNS

  
• Neuron


  • Cell body = soma
  • Dendrites and soma = receptor sites
  • Axon Hillock = summing area
  • Axons = transmission
  • Axon collaterals
  • Axon terminal = terminal boutons = synaptic knobs

  
• Receptive field of a single neuron
• Neuronal Targets

  
• Chemical Synapse


  • Presynaptic membrane
  • Synaptic cleft
  • Postsynaptic membrane
  • Synaptic vesicles
  • Neurotransmitters: Excitatory (Acetylcholine, Epinephrine, Dopamine) and Inhibitory (Glycine, GABA)
• Types of Neurons


  • Anaxonic
  • Bipolar
  • Pseudo-Unipolar
  • Multipolar

  
• Neuroglia


  • Supporting cells of the nervous system
  • Create supporting framework for neurons, insulate neurons, act as phagocytes, regulate enzyme/transmitter levels, form blood-brain barrier
  • Five times more glia than neurons (100 billion)
  • Most are smaller than neurons

  
• PNS Neuroglia


  • Satellite Cells surround cell bodies
  • Schwann Cells surround axons in PNS
  • Myelination

  
• CNS Neuroglia


  • Oligodendrocytes
  • Astrocytes
  • Microglia
  • Ependymal

  
• Myelinated axons = white matter, unmyelinated = gray matter

  
• Multiple Sclerosis


  • Chronic, inflammatory, demyelinating disease that affects the oligodendrocites of the central nervous system (CNS)
  • Symptoms include: muscle weakness, balance and walking problems, fatigue, speech impairments, and many others
  • Symptoms are worse in heat