BSC 2085 Anatomy and Physiology 1 - Chapter 12: Central Nervous System Overview

Central Nervous System Components

• Consists of the brain and spinal cord.
• Cephalization: movement of nervous materials to the anterior end (head in humans).
• Highest degree of cephalization in humans correlates with intelligence.

Neural Tube

• Where the brain and spinal cord begin.
• Importance of folic acid during pregnancy to prevent neural tube defects.

Brain Development

• Cerebral Hemispheres:

  • Telencephalon becomes two cerebral hemispheres (left and right).
  • Control is contralateral (right hemisphere controls left body and vice versa).
  • Cerebrum is the largest brain part.

• Diencephalon:

  • Becomes epithalamus, thalamus, hypothalamus, and retina.
  • Functions:
    • Epithalamus: contains the pineal gland, secretes melatonin.
    • Thalamus: gateway to the cerebral cortex.
    • Hypothalamus: regulates many bodily functions, known as 'the boss.'

• Brainstem:

  • Composed of midbrain, pons, medulla oblongata.
  • Pons: connects spinal cord to brain.
  • Medulla Oblongata: multiple functions, connects to spinal cord.

• Ventricles:

  • Cavities in the brain filled with CSF (e.g., lateral, third, fourth ventricles).

Brain Matter

• Gray Matter: non-myelinated, slower conduction.
• White Matter: myelinated fibers, faster conduction.
• Patterns in brain vs. spinal cord differ.

Cerebral Cortex

• Functional Areas:

  • Motor Areas: premotor, primary motor, Broca's area (speech).
  • Sensory Areas: somatosensory, visual, auditory, olfactory, gustatory, vestibular.
  • Association Areas: understanding and processing of sensory inputs.

• Contralateral Control:

  • Right hemisphere controls left side of body and vice versa.

• Lateralization:

  • Specific functions are divided between hemispheres.

Sensory and Motor Functions

• Primary areas for somatosensory sensations, visual processing, auditory, and balance.
• Somatosensory association: understanding tactile sensations.

Multimodal Association Areas

• Anterior, posterior, and limbic association areas.
• Anterior (prefrontal cortex): intellect, personality, social interaction.
• Limbic: emotions, memory.

Brain Imaging

• Visualizing activity in the cerebral cortex during different tasks.

Disorders and Injuries

• Stroke effects depending on location (e.g., Broca's area leading to speech loss).
• Damage in specific areas leads to loss of function related to that area.

Basal Nuclei

• Gray matter involved in movement regulation.
• Disorders such as Parkinson's and Huntington's disease affect basal nuclei.

Thalamus and Hypothalamus

• Thalamus: relay station for sensory information.
• Hypothalamus: regulates autonomic functions, homeostasis, endocrine activity.

Cerebellum

• Involved in motor control and balance.
• Ipsilateral control (same side control).

Key Terms

• Gyri and Sulci: ridges and grooves on the cerebral cortex.
• Pyramidal Tracts: major motor pathways.
• Homunculus: represents motor and sensory cortical organization.