Nervous System

• Nervous System - a complex network of nerves, neurons, and other specialized cells that communicate with each other to control and coordinate the body's functions. It is the body's control center and helps to maintain homeostasis, or a stable internal environment, by responding to internal and external stimuli.
• Two main parts

  • Central nervous system (CNS): made up of the brain and spinal cord
  • Peripheral nervous system (PNS): is composed of all the nerves and ganglia outside of the CNS.

  
• Brain - is the command center of the nervous system and controls all bodily functions, including movement, sensation, emotion, and thought.
• Spinal cord - is a long, tubular structure that runs from the base of the brain to the lower back. It carries messages between the brain and the rest of the body.
• PNS

  • Somatic Nervous System: controls voluntary movements and sensations, such as walking and feeling a touch on your skin.
  • Autonomic Nervous System: controls involuntary functions, such as heart rate, breathing, and digestion.
• Somatic Nervous System:

  • Sensory System – Peripheral → CNS
  • Motor System – CNS → Peripheral
• Autonomic Nervous System

  • Parasympathetic - “rest and digest” and occur when the body is at rest (digestion, relaxation, and slowing the heart rate.)
  • Sympathetic - "fight or flight" response when the body is faced with a perceived threat or stressor. (increasing heart rate, respiration rate, and blood pressure)