nervous system

• CNS

  brain and spinal cord
• nissl bodies

  clusters of rER and free ribosomes
• dendrites

  receive input from other neurons
• cell body 


  performs all the cellular functions
• axon

  carries electrical signals to terminals
• axon terminator

  releases neurotransmitters to other neurons or organs
• sensory (afferent) 


  detect changes in the external and internal environment
• motor (efferent)


  controlling of muscles and glands
• interneurons

  processing of information coming into CNS and initiating actions through motor responses
• neuroglia in CNS

  astrocytes, oligodendrocytes, microglia, ependymal cells
• astrocytes

  help maintain appropriate chemical environment for neuron function
• microglia

  immune cells in CNS destroying foreign organisms and damaged nervous tissue
• ependymal cells

  produce CSF and aid in the movement of fluid through brains ventricles
• neuroglia in PNS

  schwann and satellite
• white matter in CNS

  myelinated axons with long axonal projections
• grey matter in CNS

  neuron cell bodies, dendrites, unmyelinated axons, neuroglia
• neurons communicate by the generation of axon potentials and the release of neurotransmitters
• neurons are seperated by the synaptic cleft
• cerebrum

  largest part of brain, processing information, contains cerebral cortex
• cerebral lobes

  frontal, temporal, parietal, occipital
• diencephalon

  sits below cerebrum and has thalamus and hypothalamus
• brainstem

  midbrain, pons, medulla
• cerebellum


  sits posterior to brain stem
• the skull is formed by the interlocking cranial bones
• the spinal cord is enclosed within the vertebral column
• cranial meninges surround the brain
• spinal meninges surround and protect spinal cord
• dura matter

  most superficial, DICT, adheres to interior surface of cranial bones
• arachnoid matter

  below dura, avascular
• subdural space is between the dura and arachnoid, and is filled with interstitial fluid
• pia matter


  innermost, adheres to surface of brain and spinal cord
• between the arachnoid matter and pia matter is the subarachnoid space, filled with cerebrospinal fluid
• blood brain barrier is formed by tight cell junctions between endothelial cells of the capillaries that line the brain
• CSF circulates continuously through cavities in brain, spinal cord, and subarachnoid space
• CSF functions

  mechanical protection, chemical protection, circulation
• CSF is formed in chloride plexis
• spinal cord ends before vertebral column does
• dorsal root

  sensory message into spinal cord
• ascending sensory tracts

  sensory information up to brain
• descending motor tract

  motor information from brain to lower motor neurons