The Nervous System - Part 2 CNS

The Nervous System - Part 2 CNS

• The nervous system, specifically the central nervous system (CNS), is a complex network of nerves and structures.
• The CNS consists of the brain and spinal cord.
• An outline of the topics to be covered includes:
  • Anatomy of the spinal cord
  • Structure of a spinal nerve
  • Spinal nerves, plexuses, and their functions
  • Reflexes
  • Cerebrospinal fluid (CSF) and blood-brain barrier (BBB)
  • Brain subdivisions and their functions
  • Lobes of the cerebrum and their functions
  • 12 cranial nerves and their functions
• Protective structures and spinal meninges:
  • Spinal cord runs from the foramen magnum to vertebrae L1 and L2.
  • The spinal cord is suspended within the vertebral canal.
  • Vertebrae, adipose tissue and spinal meninges protect the spinal cord.
    • Spinal meninges include dura mater (outer layer), arachnoid mater (middle layer), and pia mater (inner layer).
    • Arachnoid mater resembles a spider's web and is located between the dura and pia mater.
    • The subarachnoid space is located between the arachnoid and pia mater, filled with cerebrospinal fluid (CSF).
    • Dura mater is the tough outer layer of the spinal meninges.
  • Cerebrospinal fluid (CSF)
• Functions of the spinal cord:
  • Sensory and motor information
  • Motor output.
  • Spinal reflexes (Processing sensory input and conveying motor output.)
• Spinal cord gross anatomy:
  • The spinal cord is divided into right and left halves.
  • White matter surrounds a centrally located H-shaped gray matter.
  • The central canal contains cerebrospinal fluid (CSF).
• Spinal nerves:
  • Spinal nerves serve as a path of communication between the spinal cord and specific regions of the body.
  • Two bundles of axons, called roots, connect each spinal nerve to a segment of the cord.
  • Dorsal roots contain sensory axons that conduct impulses from sensory receptors to the CNS.
  • Dorsal root ganglion contains cell bodies of sensory neurons.
  • Ventral roots contain axons of motor neurons that conduct impulses from the CNS to muscles and glands.
  • Each spinal nerve is a mixed nerve, containing both sensory and motor fibers.
• Spinal nerves and spinal nerves plexuses:
  • 31 pairs of spinal nerves.
  • Spinal nerves are named according to the region and level of the vertebral column from which they emerge.
  • Spinal nerves pass through intervertebral foramina, and branch.
  • Some spinal nerves form networks called plexuses,.
• Spinal cord - gross anatomy (additional information)
  • The spinal cord extends from the medulla oblongata to the upper boundary of L2.
  • The cauda equina is a collection of spinal nerves that angle down the vertebral canal.
  • Specific enlargements of the spinal cord (cervical and lumbar) innervate different parts of the body.