Lecture Notes: The Nervous System

Overview

• Nervous System: Coordinates all activities of the body, enabling response and adaptation to internal and external changes.
• Consciousness: Unique to humans, allowing self-awareness and intelligence.

Major Divisions

1. Central Nervous System (CNS)
2. Peripheral Nervous System (PNS)

Central Nervous System (CNS)

Major Structures

1. Brain
   • Cerebrum: Largest section; divided into right and left hemispheres and four lobes
     • Frontal Lobe: Reasoning and thought
     • Parietal Lobe: Integrating sensory information
     • Temporal Lobe: Processing auditory information
     • Occipital Lobe: Processing visual information
   • Cerebellum: Located at the back of the head; responsible for muscle coordination, balance, posture, and muscle tone
   • Diencephalon: Located between cerebrum and midbrain; includes:
     • Thalamus: Sensory impulse relay station
     • Hypothalamus: Regulates autonomic functions (temperature, appetite, sleep, etc.) and emotions
   • Midbrain: Located below the cerebrum; controls certain eye and auditory reflexes
   • Pons: Located below the midbrain; responsible for reflex actions (chewing, tasting, saliva production)
   • Medulla Oblongata: Connects to the spinal cord; regulates vital functions (heart rate, digestion, respiration, etc.)
2. Spinal Cord
   • Link between brain and body nerves
   • Divided into four regions: cervical, thoracic, lumbar, sacral
   • Contains afferent (sensory to CNS) and efferent (motor from CNS) spinal nerves

Peripheral Nervous System (PNS)

Subdivisions

1. Somatic Nervous System
   • Carries motor and sensory information to and from the CNS
   • Connects to skin, sensory organs, skeletal muscles
   • Responsible for voluntary muscle movements and processing sensory information
   • Afferent Neurons: Conduct information to CNS
   • Efferent Neurons: Conduct information from CNS
2. Autonomic Nervous System
   • Further divided into:
     • Sympathetic Nervous System: Activates 'fight or flight' response
     • Parasympathetic Nervous System: Restores body to normal state post-threat

Recap

• Nervous System: Coordinates body activities and responses
• CNS: Brain and spinal cord
  • Brain: Cerebrum, cerebellum, diencephalon, midbrain, pons, medulla oblongata
  • Spinal Cord: Cervical, thoracic, lumbar regions; afferent and efferent nerves
• PNS: Outside brain and spinal cord
  • Somatic: Voluntary control and sensory processing
  • Autonomic: Involuntary control (sympathetic and parasympathetic systems)

Conclusion

• Nervous system is complex, essential for body coordination and response
• More detailed information available at CTEskills.com