Lecture Notes: The Nervous System

Overview of the Nervous System

• Components: The nervous system is divided into two main parts:
  • Central Nervous System (CNS): Includes the brain and spinal cord.
  • Peripheral Nervous System (PNS): Comprises nerves connecting the spinal cord to muscles and sensory receptors.
• Neurons: Both parts contain billions of neurons.

Central Nervous System (CNS)

• Brain: Central organ that processes information.
• Spinal Cord: A fibrous, rope-like structure running through the spinal column, crucial for transmitting signals.

Peripheral Nervous System (PNS)

• Functionality:
  • Manages reflexes to prevent injury.
  • Controls the fight-or-flight response to stress or danger.
• Structure: Consists of thousands of nerves.

Neuron Anatomy

• Peripheral Nerve: Made of nerve bundles (fascicles) containing hundreds of nerve fibers.
• Neuron Components:
  • Dendrites: Tree-like structures receiving signals from other neurons or sensory cells.
  • Cell Body: Contains the neuron's DNA; acts as the headquarters.
  • Axon: Transmits signals from the cell body to other neurons.
• Insulation: Many neurons are insulated to protect and speed up signal transmission.

Functionality of Neurons

• Motor Neurons: Responsible for voluntary muscle control.
• Signal Transmission:
  • Electrical signals convert to chemical signals to travel between neurons.
  • Synapse: A small gap about a millionth of an inch wide.
  • Neurotransmitters: Chemicals that enable neuron communication across the synapse.

Importance of the Nervous System

• Acts as the body's master communicator by facilitating neuron interactions through neurotransmitters.