Biological Basis of Human Behavior - Neurons and Nervous System

Jun 10, 2024

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Biological Basis of Human Behavior - Neurons and Nervous System

Unit 4: Overview

  • Main Topic: Biological basis of human behavior
  • Focus: Nervous system and its role in our actions and behavior

Key Concepts

How the Nervous System Works

  • Response to Stimuli: Example: When a cellphone rings
    • You get alert, contemplate, decide to attend the call, etc.
  • Nervous System: Manages this response using neurons
  • Neurons: Basic building blocks of the nervous system
    • Specialize in communication and information processing
  • Communication: Similar to postmen delivering messages throughout the body

Structure of Neurons

  • Components:
    • Cell Body: Contains nucleus with DNA/RNA
    • Dendrites: Receive information from other neurons
    • Axon: Carries information away from the cell body
    • Axon Terminals: Transmit signal to other neurons
    • Myelin Sheath: Protective layer that speeds up signal transmission
  • Function: Action potentials allow neurons to transmit signals quickly

Types of Cells in Nervous System

  • Neurons: Involved in communication
  • Glial Cells: Support neurons, provide nutrients, remove pathogens and dead neurons

Signal Transmission

  • Electrical Signals: Travel within neurons
  • Chemical Signals: Transmitted between neurons at synapses
    • Synaptic Vesicles: Contain neurotransmitters
    • Neurotransmitters: Chemicals released into the synaptic cleft
    • Receptors: On the postsynaptic neuron receive the neurotransmitter

Phases of Neuronal Activity

  1. Resting Phase: -70mV inside the neuron, channels are closed
  2. Graded Potential: Slight change in membrane potential
  3. Action Potential: Significant change, depolarization occurs, reaches +40mV
  4. Repolarization: Potassium channels open, potassium flows out
  5. Hyperpolarization: Membrane potential becomes more negative than the resting potential
  6. Refractory Period: Neuron canтАЩt fire another action potential immediately after one

Important Concepts

  • Membrane Potential: Difference in electrical charge between inside and outside of neuron
    • Resting potential: -70mV
    • Threshold: -55mV
  • Depolarization: Influx of sodium ions
  • Repolarization: Efflux of potassium ions
  • Refractory Period: Time period after action potential when neuron is less responsive

Synaptic Transmission

  • Electric Impulse: Travels down the axon
  • Neurotransmitter Release: Converts electric impulse into chemical signal
  • Receptor Binding: Post-synaptic neuron receives chemical signal and converts it back to an electrical impulse

Potassium and Sodium Channels

  • Sodium Channels: Allow influx of sodium, cause depolarization
  • Potassium Channels: Allow efflux of potassium, cause repolarization

Important Terms

  • Neuron: Nerve cell specialized for communication
  • Synapse: Junction between two neurons
  • Neurotransmitter: Chemical messenger
  • Action Potential: Electrical signal traveling down the axon

Biological Processes

  • Neurons and Glial Cells: Work together for efficient nervous system function
    • Glial cells: Support and protect neurons
    • Neurons: Communicate through electric and chemical signals

Conclusion

  • This lecture covered the basic biological mechanisms underlying human behavior focusing on neurons and the nervous system, providing insight into how neurons communicate and process information.