Nervous

• Nervous System


  the body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous system
• Functions of the nervous system

  sensory input, integration, motor output, maintaining homeostasis and mental activity
• Central Nervous System


  consists of the brain and spinal cord
• Peripheral Nervous System


  consists of the nerves and ganglia outside of the brain and spinal cord
• Peripheral Nervous System


  communication link between the CNS and the various part of the body
• Afferent Division (Sensory)


  conducts action potentials from sensory receptors to the CNS
• Sensory Neurons

  nerve cells that transmit action potential's from the periphery to the CNS
• Efferent Division (Motor)


  conducts action potentials from the CNS to effector organs such as muscle and glands
• Motor Neurons


  nerve cells that transmit action potentials from the CNS toward the periphery
• Somatic Nervous System


  transmits action potentials from the CNS to theskeletal muscles
• Autonomic Nervous System


  transmits action potentials from the CNS tocardiac muscle, smooth muscle and glands
• Enteric Nervous System


  unique subdivision of the PNS in which it has both sensory and motor neurons contained wholly within the digestive tract
• Neurons


  receive stimulus, conduct action potentials and transmit signals to other neurons or effector organs
• Cell Body


  Largest part of a typical neuron; contains the nucleus and much of the cytoplasm
• Dendrites


  Highly branched extensions that receive signals from other neurons.

  
• Axon


  single long process extending from the cell body where it conducts action potentials toward and away the CNS

  
• Axon Hillock


  the cone-shaped area on the cell body from which the axon originates

  
• Collateral Axons


  axon branches
• Multipolar neurons


  have many dendrites and single axon

  
• Bipolar neurons


  one axon and one dendrite

  
• Pseudo-unipolar neurons


  single process extending from cell body

  
• Glial Cells


  supportive cells of the CNS and PNS which do not conduct action potentials, rather enhance neuron function and maintain normal conditions within nervous tissue
• Ability to Divide


  Main difference of neurons and neuroglia
• Astrocyte


  major supporting cell in the CNS, stimulate or inhibit the signaling activity of nearby neurons

  
  

  participate to form blood brain barrier
• Blood Brain Barrier


  a filtering mechanism of the capillaries that carry blood to the brain and spinal cord tissue, blocking the passage of certain substances.
• Ependymal cells


  line cavities of the brain and spinal cord, produce or circulate cerebrospinal fluid
• Microglia


  immune cells of CNS
• Oligodendrocytes


  provide an insulating material that surrounds axons
• Myelin Sheath


  specialized layers that wrap around the axon of some neurons; excellent insulator that prevents ion movement across cell membrane
• Myelinated Axons


  axons covered with myelin sheaths
• Nodes of Ranvier


  gaps in the myelin sheath
• Unmyelinated axons


  Axons that lack myelin sheaths .
• Gray Matter


  consists of group of neuron cell bodies and their dendrites where there is very little myelin
• Cortex


  gray matter on the surface of the CNS is called
• Nuclei


  clusters of gray matter located deeper within the braine
• Ganglion


  cluster of neuron in the PNS
• White Matter


  consists of bundles of parallels axons with their myelin sheaths
• Nerve Tracts


  white matter in CNS
• Nerves


  forms from the white matter in the PNS
• Schwann cells


  single cells surrounding axons that form myelin sheaths around axons or enclose unmyelinated axons in the PNS