CNS AND PNS

• Central Nervous System Functions

  • Integration; command center
  • Interprets incoming sensory information
  • Issues outgoing instruction
• Cerebral Hemisphere surface is made of ridges (gyri) and grooves (sulci)
• Cerebral Hemisphere lobes are named for the cranial bones that lie over them
• Brain Regions

  • Cerebral Hemisphere
  • Diencephalon
  • Brain Stem
  • Cerebell
• White Matter in the cerebral hemisphere is due to the presence of myelinated fibers
• Primary Motor Area is located at the anterior to the central sulcus in the frontal lobe
• Basal Nuclei are deep pockets of gray matter in the cerebral hemisphere
• Broca's Area is located at the anterior parietal and is the motor speech area
• Cerebral Areas Involved in Special Senses include Visual (occipital), Auditory (Temporal), Olfactory (Temporal lobe), Anterior association area (frontal), Posterior association (posterior), Speech Area
• Basal nuclei regulate voluntary motor activities by modifying instructions sent to skeletal muscles by the primary motor cortex
• Epithalamus forms the roof of the third ventricle and houses the pineal body (an endocrine gland)
• Brain Stem attaches to the spinal cord
• Cerebral white matter is composed of fiber tracts deep to the grey matter
• Thalamus encloses the third ventricle and is a relay station for sensory impulses passing upward to the cerebral cortex
• Central Nervous System

  • Organs - Brain and Spinal Cord
• Cerebral Cortex is the superficial gray matter in the cerebral hemisphere
• Primary Somatosensory Area is located in the parietal lobe posterior to the central sulcus
• Wernicke's area (Temporal) is the language comprehension area
• Hypothalamus makes up the floor of the diencephalon and is an important autonomic nervous system center
• Corpus callosum connects hemispheres in the cerebral white matter
• Cerebral Hemisphere includes more than half of brain mass
• Brain Stem: Reticular Formation


  1. Diffuse mass of gray matter along the brain stem

  2. Involved in motor control of visceral organs

  3. RAS (Reticular Activating System) neural cells

  4. Plays an important role in our consciousness (awake/sleep cycles)

  5. Filter for incoming sensory information
• Branching white matter in the cerebellum is the arborvitae (tree of life)
• Brain Stem

  Attaches to the spinal cord
• Cerebrovascular accident (CVA) or stroke results in brain tissue death due to blocked blood circulation
• Transient ischemic attack (TIA) results in temporary brain ischemia with symptoms like numbness, temporary paralysis, and impaired speech
• Spinal cord has 31 pairs of spinal nerves arising from it
• Concussion is a slight brain injury resulting from physical trauma
• Meninges: Dura mater is the outermost leathery layer covering the brain
• Spinal cord provides a two-way conduction pathway to and from the brain
• Cerebellum is the second-largest brain region, posterior part of the brain
• Brain Stem: Midbrain


  1. 2 bulging fiber tracts, cerebral peduncles, convey ascending and descending impulses

  2. Bundles of nerve fibers in the CNS connecting CNS structures

  3. 4 rounded protrusions, Corpa quadrigeminal are visual and auditory reflex
• Meninges: Arachnoid Mater is the middle layer of the meninges
• Parts of the Brain Stem

  • Midbrain
  • Pons
  • Reticular Formation
• Cerebellum


  Balance and accuracy in skeletal muscle activity/body movements
• Spinal tap is a procedure to obtain fluid in the lumbar region to determine infection
• Spinal Cord extends from the foramen magnum of the skull to the first or second lumbar vertebra
• Contusion results in marked nervous tissue destruction, coma, and potential death
• Brain Stem: Pons

  The most inferior part of the brain stem that merges into the spinal cord
• Cerebrospinal fluid

  1. Similar to blood plasma in composition

  2. Formed continually by the choroid plexuses

  3. CSF forms a watery cushion to protect the brain and spinal cord

  4. Circulated in the arachnoid space, ventricles, and central canal of the spinal cord