Central Nervous System: Brain and Spinal Cord

Central Nervous System: Brain and Spinal Cord

• The cerebral hemispheres have three basic regions:

  • Cerebral cortex (gray matter)
  • Cerebral white matter
  • Basal nuclei (ganglia) and cerebellum

• Ridges on the brain surface are called gyri

• Shallow grooves on the brain surface are called sulci

• Deep grooves on the brain surface are called fissures

Cerebral Cortex

• A general term for nerve fiber tracts that connect the two hemispheres is a commissure

• Commissures help process sensory information, emotional responses, consciousness, and interpret sensations. They also process voluntary movements, memories, and more.

• A general term for nerve fiber tracts that connect areas within one hemisphere is projection fibers

• The area that processes sensory information from the body (except special senses) is the primary somatic sensory area

• The area that controls voluntary skeletal muscles is the primary motor area

• A motor homunculus is a map showing the amount of cerebral tissue devoted to various motor functions.

• A sensory homunculus is a map showing the amount of cerebral tissue devoted to various sensory functions.

• These pathways connect the cerebrum to the brain stem.

• The anterior association area helps with intellectual reasoning, social behaviors.

• Broca's area is involved in motor speech.

• The pathway of neurons from the precentral gyrus to the spinal cord is called the pyramidal tract (corticospinal tract).

Other Brain Structures

• Basal nuclei help regulate voluntary movements through modifying instructions to skeletal muscles.
• The cerebellum helps regulate voluntary movements and, in general, modification of instructions.
• The corpus callosum is a large commissure connecting the left and right cerebral hemispheres.
• The posterior association area coordinates aspects of a whole situation, recognizing patterns like faces.