Physiology of the Nervous System

Physiology of the Nervous System

Overview

• The nervous system controls and coordinates bodily functions, responding to internal and external stimuli.
• Composed of two main parts: Central Nervous System (CNS) and Peripheral Nervous System (PNS).

Central Nervous System (CNS)

• Components: Brain and spinal cord.
• Functions:
  • Processes sensory information.
  • Integrates responses.
  • Controls higher functions: cognition, emotion, memory.

Peripheral Nervous System (PNS)

• Components: Nerves outside the CNS; divided into somatic and autonomic systems.
• Somatic Nervous System:
  • Controls voluntary movements.
  • Transmits sensory information to the CNS.
• Autonomic Nervous System:
  • Regulates involuntary functions (heart rate, digestion).
  • Divided into:
    • Sympathetic: "Fight or flight" response; increases heart rate, dilates pupils.
    • Parasympathetic: "Rest and digest" response; conserves energy, decreases heart rate.

Neurons

• Basic functional units of the nervous system.
• Structure:
  • Cell body: Contains nucleus.
  • Dendrites: Receive signals from other neurons.
  • Axon: Transmits impulses away from the cell body.
• Types:
  • Sensory neurons: Carry signals from sensory receptors to CNS.
  • Motor neurons: Transmit signals from CNS to muscles/glands.
  • Interneurons: Connect neurons within the CNS.

Action Potentials

• Electrical impulses that transmit signals along neurons.
• Triggered by depolarization of the neuron's membrane.
• Involves:
  • Resting potential: Neuron at rest (typically -70 mV).
  • Depolarization: Sodium channels open, sodium ions enter, membrane potential becomes positive.
  • Repolarization: Potassium channels open, potassium ions exit, returning to resting potential.

Synaptic Transmission

• Process of signal transmission between neurons at synapses.
• Components:
  • Presynaptic neuron: Releases neurotransmitters into the synaptic cleft.
  • Postsynaptic neuron: Contains receptors for neurotransmitters.
• Neurotransmitters: Chemical messengers (e.g., dopamine, serotonin, acetylcholine) influencing the activity of other neurons.

Neuroplasticity

• Ability of the nervous system to change and adapt in response to experience.
• Involves:
  • Formation of new synapses.
  • Strengthening or weakening of existing connections.
• Critical for learning and memory.

Key Functions

• Sensory Processing: Receives and interprets sensory information.
• Motor Control: Coordinates voluntary and involuntary muscle movements.
• Homeostasis: Regulates internal environment (temperature, hydration).
• Cognition and Emotion: Facilitates complex processes such as thinking, decision-making, and emotional responses.

Overview

• The nervous system governs the coordination and control of bodily functions, reacting to internal and external stimuli.
• It consists of two primary divisions: Central Nervous System (CNS) and Peripheral Nervous System (PNS).

Central Nervous System (CNS)

• Comprises the brain and spinal cord.
• Responsible for processing sensory data, integrating responses, and managing advanced functions like cognition, emotions, and memory.

Peripheral Nervous System (PNS)

• Includes all nerves external to the CNS; divided into somatic and autonomic subdivisions.
• Somatic Nervous System: Governs voluntary movements and conveys sensory information to the CNS.
• Autonomic Nervous System: Manages involuntary actions like heartbeat and digestion, further split into:
  • Sympathetic Division: Activates "fight or flight" responses, elevating heart rate and widening pupils.
  • Parasympathetic Division: Promotes "rest and digest" states, conserving energy and reducing heart rate.

Neurons

• Function as the fundamental units of the nervous system.
• Structure:
  • Cell Body: Houses the nucleus.
  • Dendrites: Receive input from other neurons.
  • Axon: Conducts impulses away from the cell body.
• Types:
  • Sensory Neurons: Convey signals from sensory receptors to the CNS.
  • Motor Neurons: Transfer signals from the CNS to muscles or glands.
  • Interneurons: Facilitate communication between neurons within the CNS.

Action Potentials

• Serve as electrical signals that propagate along neurons.
• Initiated through depolarization of the neuron's membrane, involving:
  • Resting Potential: The stable state of a neuron, typically around -70 mV.
  • Depolarization: Sodium channels open, allowing sodium ions to enter, resulting in a positive membrane potential.
  • Repolarization: Potassium channels open, potassium ions leave, restoring the resting potential.

Synaptic Transmission

• Refers to the mechanism of conveying signals between neurons at synapses.
• Components:
  • Presynaptic Neuron: Releases neurotransmitters into the synaptic cleft.
  • Postsynaptic Neuron: Contains receptors that bind neurotransmitters.
  • Neurotransmitters: Chemicals (e.g., dopamine, serotonin, acetylcholine) that impact neuron activity.

Neuroplasticity

• The nervous system's capacity to adapt and change in response to experiences.
• Involves the creation of new synapses and the modulation of existing connections, essential for learning and memory.

Key Functions

• Sensory Processing: Interprets and manages sensory information.
• Motor Control: Regulates both voluntary and involuntary muscle movements.
• Homeostasis: Maintains stable internal conditions (temperature, hydration).
• Cognition and Emotion: Supports complex processes, such as thinking, decision-making, and emotional regulation.

Explore the intricate functions and components of the nervous system in this quiz. Learn about the Central Nervous System (CNS) and Peripheral Nervous System (PNS), including their roles in processing sensory information and regulating bodily functions. Test your knowledge on voluntary and involuntary responses within the nervous system.