Topic 2 - Neurons

• Nervous System


  Body's command center
• Nervous System 


  made up of brain, spinal cord, and nerves
• Nervous System 


  works by sending messages, or electric signals, between your brain and all the other parts of the body
• Central Nervous System


  within the skull and spine
• Peripheral Nervous System


  outside the skull and spine
• Somatic Nervous System 


  part of the PNS that interacts with the external environment
• Autonomic Nervous System


  autonomic system controls a variety of internal processes, including blood pressure, pupil dilation, etc...
• Sympathetic Nervous System


  stimulates, organize, and mobilize energy resources in threathening situations
• Sympathetic Nervous Sytem

  Indicative of psychological arousal
• Parasympathetic Nervous System


  Act to conserve energy
• Parasympathetic Nervous System


  Indicative of psychological relaxation
• Afferent Nerves


  carry sensory signals from the skin, skeletal muscles, joints, eyes, ears, and so on, to the CNS
• Efferent Nerves 


  carry motor signals from the CNS to the skeletal muscles
• Neuron

  Cells that are specialized for the reception, conduction, and transmission of electrochemical signals
• dendrites


  The short processes emanating from the cell body, which receive most of the synaptic contacts from other neurons.
• cell body


  The metabolic center of the neuron; also called the soma
• cell membrane


  The semipermeable membrane that encloses the neuron.
• axon


  The long, narrow process that projects from the cell body.
• axon hillock

  The cone-shaped region at the junction between the axon and the cell body.
• myelin


  the fatty insulation around many axons
• nodes of ranvier


  The gaps between sections of myelin
• buttons


  The buttonlike endings of the axon branches, which release chemicals into synapses
• synapses


  The gaps between adjacent neurons across which chemical signals are transmitted.
• endoplasmic reticulum


  A system of folded membranes in the cell body, play a role in the synthesis of proteins and fats
• ribosomes


  Internal cellular structures on which proteins are synthesized; they are located on the endoplasmic reticulum.
• cytoplasm


  The clear internal fluid of the cell
• golgi complex


  A connected system of membranes that packages molecules in vesicles
• nucleus


  The spherical DNA-containing structure of the cell body.
• mitochondria


  Sites of aerobic (oxygen-consuming) energy release.
• microtubules


  responsible for the rapid transport of material throughout neurons
• multi-polar neuron

  A neuron with more than two processes extending from its cell body
• multi-polar neuron


  defined as having three or more processes that extend out from the cell body.
• multipolar neuron


  major neuron type found in the CNS
• unipolar neuron


  one process extending from its cell body
• unipolar neuron


  The process that extends toward the CNS is the central process. Unipolar neurons are found primarily in the afferent division of the PNS.
• bipolar neuron


  a neuron with two processes extending from its cell body
• bipolar neuron


  One process is called a dendrite, and another process is called the axon.
• sensory neurons


  transmit information from sensory receptors in the skin, or the internal organs toward the CNS for processing
• motor neurons


  transmit information away from the CNS toward some type of effector
• interneurons

  located between motor and sensory pathways and are highly involved in signal integration. The vast majority of interneurons are confined within the CNS.