Nervous System - MedG

 

• Main Function:

  The nervous system detects and responds to stimuli, controls and coordinates organ functions, and maintains homeostasis (a balanced internal process).

• Divisions:

  1. Central Nervous System (CNS):

     • Composed of the brain and spinal cord.

     • The cerebrum controls voluntary actions (eating, walking).

     • The medulla oblongata controls involuntary actions (heartbeat, breathing, peristalsis).

     • The spinal cord handles reflex actions (e.g., sneezing, withdrawing hand from heat).

  2. Peripheral Nervous System (PNS):

     • Includes cranial nerves (12 pairs) and spinal nerves (31 pairs) that link the CNS to the rest of the body.

• Stimulus and Response Pathway:

  1. Stimulus: Internal (e.g., pH, glucose) or external (e.g., light, sound).

  2. Sensory receptor: Detects and converts stimulus into a nerve impulse.

  3. Brain: Interprets the impulse.

  4. Effector (muscle or gland): Produces a response or action.

• If Damaged:

  Damage to the nervous system can cause temporary, partial, or complete paralysis.

• Summary of Functions:

  1. Detect stimulus

  2. Sense information

  3. Interpret impulse

  4. Produce response