Nervous System

• The nervous system is a complex network of nerves and cells that carry messages to and from the brain and spinal cord to various parts of the body.
• Purpose:

  • Coordinates all activities of the body.
  • Enables the body to respond and adapt to changes both inside and out.
• Central Nervous System (CNS) - Serves as the main processing center for the entire nervous system.
• Brain - an organ located within the cranium or skull that functions as organizer and distributor of information for the body.
• Cerebrum - the largest section that is found in the upper part of the brain that is divided into 2 major hemisphere — right & left hemisphere.
• ❋ Frontal: Reasoning and Thought
• ❋ Parietal: Integrates sensory information.
• ❋ Temporal: Processes auditory information from the ears.
• ❋ Occipital: Processing visual information from the eyes.
• Cerebellum - located below the cerebrum and above the 1st cervical of the neck. Responsible for muscle coordination, balance, posture, and muscle tone.
• Diencephalon - found between the cerebrum in the midbrain.
• Thalamus: directs sensory impulses to the Cerebrum.
• ✱ Hypothalamus: controls and regulates temperature, appetite, water balance, sleep and blood vessel constriction and dilation. Also plays in emotion such as anger, fear, pleasure, pain, and affection.
• Midbrain - located below cerebrum. Responsible for eye and auditory reflexes.
• Pons - located below the midbrain (in brainstem). Responsible for certain reflex actions such as chewing, tasting, and saliva production.
• Medulla Oblongata - located at the bottom of the brainstem. A long stem-like structure which makes up the lower part of the brainstem. Connects to the spinal cord. Also known as “The Center for Respiration”
• 1. responsible for regulating:

  • heart and blood vessel function
  • digestion 
  • respiration
  • swallowing
  • coughing
  • sneezing
  • blood pressure
• Spinal Cord - the link between the brain and the nerves in the rest of the body. Controls simple musculoskeletal reflexes without input from the brain.
• 1. Cervical 
  2. Thoracic
  3. Lumbar
  4. Afferent Spinal Nerves  

  5. Efferent Spinal Nerves
• Efferent Spinal Nerves - carries information from the brain to the body.
• Afferent Spinal Nerves - carries information from the body to the brain.
•  Peripheral Nervous System (PNS) - It connects the central nervous system to the organs and limbs.
• Somatic Nervous System - associated with the voluntary control of body movements
• ⋆ Afferent Sensory Neurons - Conducting Inward. Take information from the nerves to the CNS.
• ⋆ Efferent Motor Neurons - Conducting Outward. Take information from the CNS to the muscle fibers throughout the body.
• 1. Spinal Nerves - the nerves that carry motor and sensory signals between the spinal cord and the body.
• Cranial Nerves - the nerves fibers that carry information into and out of the brain stem.
• Autonomic Nervous System - associated with the involuntary control of body movements and has two subdivisions.
• Also responsible for nearly all voluntary muscle movements. Processes sensory information from external stimuli. (Hearing, Touching, and Sight).
• Responsible for carrying motor and sensory information. It is made up of nerves that connect to skin, sensory organs, and skeletal muscles.
• Sympathetic - “Fight or Flight” revs up the body to either defend yourself or escape the threat. It is activated when the body is in a dynamic role or stress. (e.g., increased heart rate and breathing, dilation of pupil, sweating, etc.)
• Parasympathetic - counterbalance to the sympathetic response to the danger whether real or imagined. Brings all systems of the body back to normal. It maintains body functions and restores the body to normal or relaxed mode.