Nervous System Structure and Function

Nervous System Structure

• Composed of neurons and glial cells.
• Primary components:
  • Central Nervous System (CNS): Brain and spinal cord.
  • Peripheral Nervous System (PNS): Nerves and ganglia outside the CNS.

Central Vs Peripheral Nervous System

• Central Nervous System (CNS):

  • Integration center for information.
  • Responsible for processing sensory information.
  • Coordinates motor responses.
  • Protected by the skull and vertebral column.

• Peripheral Nervous System (PNS):

  • Connects CNS to limbs and organs.
  • Divided into:
    • Somatic Nervous System: Controls voluntary movements.
    • Autonomic Nervous System: Controls involuntary functions (further subdivided into sympathetic and parasympathetic).

Signal Transmission

• Involves electrical impulses known as action potentials.
• Signal propagation:
  • Initiated by the depolarization of neuron membranes.
  • Propagated via ion channels (sodium and potassium).
  • Myelin Sheath: Insulates axons, speeding up signal transmission.
• Synaptic transmission:
  • Action potential leads to neurotransmitter release across synaptic clefts.
  • Interaction with receptors on post-synaptic neurons triggers responses.

Neuron Function

• Types of Neurons:

  • Sensory Neurons: Transmit sensory information to the CNS.
  • Motor Neurons: Convey commands from the CNS to muscles and glands.
  • Interneurons: Connect sensory and motor neurons within the CNS.

• Neuron Structure:

  • Dendrites: Receive incoming signals.
  • Soma (cell body): Contains nucleus and organelles.
  • Axon: Transmits signals away from the soma to other neurons or muscles.
  • Synapse: Junction where signal transmission occurs between neurons.

Nervous System Structure

• Composed of two main cell types: neurons and glial cells.
• Divided into two main components: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).
• The CNS includes the brain and spinal cord, acting as the control center for the body.
• The PNS consists of nerves and ganglia located outside the CNS, connecting the CNS to the rest of the body.

Central Vs Peripheral Nervous System

• The CNS acts as the central processing unit for all information received from the body.
• It is responsible for interpreting sensory information and coordinating appropriate motor responses.
• The CNS is protected by the skull and vertebral column.
• The PNS acts as a communication network, connecting the CNS to the limbs and organs.
• The PNS is further subdivided into two systems: the Somatic Nervous System and the Autonomic Nervous System.
• The Somatic Nervous System controls voluntary movements of skeletal muscles.
• The Autonomic Nervous System controls involuntary bodily functions such as heart rate, breathing, and digestion.

Signal Transmission

• Neurons transmit signals via electrical impulses called action potentials.
• Action potentials are initiated by the depolarization of a neuron's membrane.
• These signals are propagated along the axon via ion channels, primarily sodium and potassium channels.
• The myelin sheath, a fatty substance that insulates axons, speeds up signal transmission.
• At the synapse, the action potential triggers the release of neurotransmitters into the synaptic cleft.
• These neurotransmitters bind to receptors on the post-synaptic neuron, initiating a response in the receiving neuron.

Neuron Function

• Neurons are specialized cells responsible for transmitting information throughout the nervous system.
• Three main types of neurons: sensory neurons, motor neurons, and interneurons.
• Sensory neurons transmit sensory information from the body to the CNS.
• Motor neurons convey commands from the CNS to muscles and glands.
• Interneurons act as connectors within the CNS, linking sensory and motor neurons.
• Each neuron has a distinct structure:
  • Dendrites: Receive incoming signals from other neurons.
  • Soma (cell body): Contains the nucleus and other organelles essential for neuronal function.
  • Axon: Transmits signals away from the soma to other neurons or target cells.
  • Synapse: The junction where signal transmission occurs between neurons.

Explore the fundamental components of the nervous system, including the roles of the Central Nervous System (CNS) and Peripheral Nervous System (PNS). This quiz covers the distinction between central and peripheral functions, as well as the basics of signal transmission within neurons. Test your knowledge on how these systems work together to facilitate body functions.