Exam 4 study guide

• Funiculi


  Bundles of nerve fibers in the white matter of the spinal cord, responsible for transmitting sensory and motor information
• Commissures

  Connections that allow communication between the left and right sides of the spinal cord
• Filum terminale


  A fibrous extension of the pia mater that anchors the spinal cord to the coccyx
• Denticulate ligaments

  Extensions of the pia mater that secure the spinal cord to the dura mater
• Cauda equina


  A bundle of spinal nerves and spinal nerve rootlets, resembling a horse's tail, that extends from the lumbar and sacral parts of the spinal cord
• Dorsal root


  Carries sensory information to the spinal cord
• Ventral root

  Carries motor information from the spinal cord
• Central canal

  A fluid-filled channel that runs the length of the spinal cord and contains cerebrospinal fluid
• Horns of the gray matter


  Regions within the spinal cord that contain neuron cell bodies and are involved in processing information
• Tract name


  Often indicates the origin and destination of the fibers, as well as the type of information they carry
• Types of ion channels

  • Leakage channels
  • Chemical gated channels
  • Voltage gated channels
• Graded potentials

  Changes in membrane potential that are localized and diminish over distance
• Action potentials

  All-or-nothing responses that propagate without decreasing in strength
• Types of neuroglial cells

  • Astrocytes
  • Microglia
  • Oligodendrocytes
  • Schwann cells
  • Ependymal cells
  • Satellite cells
• Regions of a neuron

  • Cell body (soma)
  • Dendrites
  • Axon
  • Synaptic terminals
• There are 31 pairs of spinal nerves, distributed as 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal
• Efferent neurons


  Transmit signals from the central nervous system to effectors like muscles and glands
• Afferent neurons


  Transmit signals from sensory receptors to the central nervous system
• Adrenergic fibers

  Release norepinephrine
• Cholinergic fibers

  Release acetylcholine
• Twelve cranial nerves

  • I. Olfactory
  • II. Optic
  • III. Oculomotor
  • IV. Trochlear
  • V. Trigeminal
  • VI. Abducens
  • VII. Facial
  • VIII. Vestibulocochlear
  • IX. Glossopharyngeal
  • X. Vagus
  • XI. Accessory
  • XII. Hypoglossal
• Lobes, fissures, and sulci of the brain

  • Lobes: frontal, parietal, temporal, occipital
  • Fissures: deep grooves that separate brain regions
  • Sulci: shallow grooves on the brain surface
• Adrenergic receptors

  Respond to adrenaline/noradrenaline
• Cholinergic receptors

  Respond to acetylcholine
• CNS fiber types

  • Projection fibers (connect different regions of the CNS)
  • Commissural fibers (cross from one hemisphere to the other)
  • Association fibers (connect different parts of the same hemisphere)
• Major regions of the brain

  • Cerebrum (thought and action)
  • Cerebellum (movement coordination)
  • Brainstem (basic life functions)
• Flow of cerebrospinal fluid (CSF)

  1. Lateral ventricles

  2. Foramen of Monro

  3. Third ventricle

  4. Aqueduct of Sylvius

  5. Fourth ventricle

  6. Subarachnoid space via the arachnoid villi
• Dura mater extensions

  Falx cerebri, falx cerebelli, tentorium cerebelli
• Function of cerebrospinal fluid (CSF)

  Cushions the brain, removes waste, and provides a stable chemical environment
• Sympathetic division

  Prepares the body for action
• Parasympathetic division

  Conserves energy and maintains resting functions
• Cranial nerves in the parasympathetic division

  • III. Oculomotor
  • VII. Facial
  • IX. Glossopharyngeal
  • X. Vagus
• Dorsal root ganglia

  Contain the cell bodies of sensory neurons and are crucial for transmitting sensory information to the CNS
• Spinal nerve

  Formed by the merger of the ventral and dorsal roots, carrying both motor and sensory information
• Tract


  A bundle of nerve fibers within the CNS that shares a common origin, destination, and function
• Ascending tracts


  Carry sensory information to the brain
• Descending tracts

  Transmit motor commands from the brain to the body
• Meninges


  Three protective membranes that surround the brain and spinal cord, providing protection and support
• Blood-brain barrier


  A selective barrier that prevents certain substances in the blood from entering the brain tissue, maintaining the CNS's stable environment
• Astrocytes

  Contribute to the blood-brain barrier by forming tight junctions with endothelial cells of CNS blood vessels