Functional divisions of the nervous system

Functional Divisions of the Nervous System

• The nervous system can be functionally divided into various roles, but this differs from anatomical divisions.

• Both the CNS (Central Nervous System) and PNS (Peripheral Nervous System) contribute to major functions.

• Difficulty arises in categorizing functions under anatomical divisions since structures can handle multiple functions.

  • Example: The optic nerve transmits signals for both conscious visual perception (through the cerebral cortex) and reflex actions (via the hypothalamus).

Two Functional Divisions of the Nervous System

• Basic Functions: The fundamental tasks of the nervous system consist of:

  • Sensation: Gathering information from the environment or internal states.

  • Integration: Combining sensory inputs to formulate responses.

  • Response: Actions resulting from sensory processing.

• Somatic vs Autonomic Control:

  • Somatic Nervous System (SNS): Manages voluntary actions and interactions with the environment (skeletal muscles).

  • Autonomic Nervous System (ANS): Regulates involuntary functions such as smooth and cardiac muscle actions and gland activity.

• Enteric Nervous System (ENS): A specialized division of the PNS dedicated to function in the gastrointestinal system under autonomic control.

Basic Functions of the Nervous System

• Sensation: The ability to receive external (environmental) and internal (homeostatic) stimuli.

  • Major senses include:

    • Taste, Smell, Touch, Sight, Hearing: Allow conscious perception of stimuli.

  • Additional senses involve internal signals like organ stretching and blood ion concentration changes.

• Response: Actions elicited by sensory input that can be categorized into:

  • Conscious Actions: Voluntary movements (skeletal muscles).

  • Involuntary Actions: Functions controlled by the ANS (cardiac rhythm, smooth muscle contractions, glandular activity).

Integration in the Nervous System

• After acquiring sensory information, stimuli are processed through a function called Integration.

• Integration encompasses comparing incoming stimuli with previous experiences and memories to guide the appropriate response.

  • For example: The response to a baseball's trajectory involves multiple factors beyond mere sight, including personal experience and current conditions.

Controlling Body Functions

• The nervous system is pivotal in controlling bodily functions responsively and efficiently.

Somatic Nervous System (SNS)

• Governs conscious and voluntary movements, allowing interaction with the surroundings through skeletal muscle control.

Autonomic Nervous System (ANS)

• Manages involuntary processes, maintaining vital internal balance or homeostasis through regulation of:

  • Smooth muscle.

  • Cardiac muscle.

  • Glandular activity responding to internal and external environmental changes.

Enteric Nervous System (ENS)

• Operates primarily in the digestive tract, managing smooth muscle and gland functions independently of the CNS, but interacts with it for digestive regulation.

Key Terms to Know

• Equilibrium: A balanced state where opposing forces are in harmony, resulting in stability.

• Reflexes: Automatic, involuntary responses to stimuli that occur through a simplistic neural pathway (reflex arc) without conscious thought.