The Biological Perspective in Psychology

Brain and Nervous System Essentials

  • Nervous System: An extensive network of specialized cells that transmit information throughout the body.

  • Neuron: The basic cell of the nervous system responsible for sending and receiving messages.

    • Dendrites: Branch-like structures that receive messages from other neurons.

    • Soma: The cell body, maintaining the life of the neuron.

    • Axon: Long, tube-like structure that carries neural messages to other cells.

    • Axon Terminals: Rounded areas at the end of the axon branches, communicating with other nerve cells.

  • Glial Cells: Provide support, deliver nutrients, produce myelin (fatty insulation for axons), and clean waste.

Neural Impulse

  • Ions: Charged particles; typically negatively charged inside the neuron and positively charged outside.

  • Resting Potential: The state of a neuron when it is not firing a neural impulse.

  • Action Potential: A reversal of the electrical charge within the axon (Na^+ ions enter), constituting the neural impulse.

  • All-or-none: A neuron either fires completely or not at all.

Neurotransmission

  • Synaptic Vesicles: Sack-like structures in axon terminals containing neurotransmitters.

  • Neurotransmitter: A chemical released from synaptic vesicles that affects the next cell.

  • Synapse/Synaptic Gap: The microscopic fluid-filled space between neurons.

  • Receptor Sites: Specific holes on dendrites/cells designed to fit certain neurotransmitters.

  • Excitatory Neurotransmitter: Causes the receiving cell to fire.

  • Inhibitory Neurotransmitter: Causes the receiving cell to stop firing.

  • Agonists: Mimic or enhance neurotransmitter effects.

  • Antagonists: Block or reduce a cell's response to neurotransmitters.

  • Key Neurotransmitters: Acetylcholine (ACh), Norepinephrine (NE), Dopamine (DA), Serotonin (5-HT), GABA, Glutamate, Endorphins (diverse functions including arousal, mood, movement, sleep, pain relief).

  • Reuptake: Neurotransmitters are reabsorbed into synaptic vesicles.

  • Enzyme: Complex proteins that break down neurotransmitters in the synapse.

Central Nervous System (CNS)

  • Components: The brain and spinal cord.

  • Spinal Cord: A bundle of neurons carrying messages to and from the brain, responsible for fast reflexes.

  • Sensory Neuron (Afferent): Carries information from senses to the CNS.

  • Motor Neuron (Efferent): Carries messages from the CNS to muscles and glands.

  • Interneuron: Found in the spinal cord and brain, connects sensory and motor neurons.

  • Neuroplasticity: The ability of the brain to change structure and function in response to experience or trauma.

  • Neurogenesis: The formation of new neurons.

Peripheral Nervous System (PNS)

  • Components: All nerves and neurons outside the brain and spinal cord.

  • Somatic Nervous System: Controls voluntary muscles, carries sensory information from senses to CNS.

    • Sensory Pathway: Nerves from sensory organs to CNS.

    • Motor Pathway: Nerves from CNS to voluntary muscles.

  • Autonomic Nervous System (ANS): Controls involuntary muscles, organs, and glands.

    • Sympathetic Division: The