Nervous System Overview

Overview of the Nervous System

• The nervous system is a complex system that enables the body to respond to internal and external stimuli.
• It consists of two main parts: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).

Central Nervous System (CNS)

• The CNS consists of the brain and spinal cord.
• It is responsible for:
  • Integrating and processing sensory information
  • Controlling voluntary movements
  • Regulating various bodily functions, such as heart rate, blood pressure, and body temperature
• The CNS is protected by the blood-brain barrier, which separates it from the bloodstream.

Brain

• The brain is the control center of the body.
• It consists of:
  • Cerebrum: divided into two hemispheres (left and right)
  • Cerebellum: coordinates muscle movements
  • Brainstem: connects the cerebrum and cerebellum to the spinal cord
• The brain is responsible for:
  • Higher-level cognitive functions, such as thought, emotion, and memory
  • Controlling voluntary movements
  • Regulating various bodily functions

Spinal Cord

• The spinal cord is a long, thin, tube-like structure that extends from the base of the brain down to the lower back.
• It is responsible for:
  • Transmitting messages between the brain and the rest of the body
  • Controlling reflexes
  • Regulating some bodily functions, such as heart rate and blood pressure

Peripheral Nervous System (PNS)

• The PNS consists of nerves that connect the CNS to the rest of the body.
• It is responsible for:
  • Transmitting sensory information to the CNS
  • Transmitting motor signals from the CNS to muscles and glands
• The PNS is divided into:
  • Somatic Nervous System: transmits sensory information and motor signals to and from the CNS
  • Autonomic Nervous System (ANS): regulates involuntary functions, such as heart rate, blood pressure, and digestion

Autonomic Nervous System (ANS)

• The ANS is a branch of the PNS that regulates involuntary functions.
• It consists of:
  • Sympathetic Nervous System: prepares the body for "fight or flight" responses
  • Parasympathetic Nervous System: promotes relaxation and reduces stress