7. Nervous system – definition. Types. General characteristics in its structure and organization.

ORGANIZATION OF NERVOUS SYSTEM

• The nervous system is responsible for sending and reciving signals throughout the body and is responsible for all movement.
• Nervous System → Structural division.
• Central Nervous System (CNS)
• Brain: Receives and processes sensory information, initiates responses, stores, memories generates thoughts and emotions
• Spinal cord: Conducts signals to and from the brain, controls reflex activities
• Peripheral Nervous System (PNS)
• Motor Neurons: CNS to muscles and glands → functional division
• Somatic Nervous System: Controls voluntary movements → send signals to skeletal muscles.
• Autonomic Nervous System: Controls involuntary responses
• Sympathetic Division: “Fight or Flight” → Preparing the body for intense physical activity or emergency situations.
• Effects: ↑↑ Heart rate, widening dilation of pupils, ↑↑ blood pressure
• Parasympathetic Division: “Rest or Digest” → conserving energy + facilitating recovery.
• Sensory Neurons: Sensory organs to CNS
• Nervous tissue is a specialized type of tissue composed of:
• → Nerve cells (neurons): functional units
• → Neuroglia (Glial cells): Supportive cells.