Module 5: Biological Foundations

Comprehensive vocabulary flashcards covering Module 5: Biological Foundations, including neuron anatomy, action potentials, synaptic transmission, nervous system divisions, brain structures, imaging techniques, and behavioral genetics.

Dendrites

Branch-like extensions of a neuron that receive signals from other neurons.

Soma (Cell Body)

The central part of a neuron that contains the nucleus and integrates incoming signals.

Axon

A long fiber that carries the electrical signal away from the cell body toward the terminal.

Schwann Cells

Cells that form the myelin sheath, which insulates the axon and speeds up signal transmission.

Terminal / Terminal Buttons

The end of the axon that releases neurotransmitters into the synapse.

Synapse

The small gap or junction located between one neuron's terminal and the next neuron's dendrite.

Resting Potential

The neuron's resting electrical charge of approximately $-70\,\text{mV}$ (with the inside being more negative than the outside), maintained by ion balance across the membrane.

Ion Channels

Gates embedded in the neuronal membrane that open and close to allow charged particles, primarily sodium ($\text{Na}^+$) and potassium ($\text{K}^+$), to move in and out.

Threshold

The minimum level of depolarization a neuron must reach for an action potential to fire in an all-or-none fashion.

Action Potential

A brief electrical spike traveling down the axon in one direction, generated when $\text{Na}^+$ rushes in (depolarization) and $\text{K}^+$ rushes out (repolarization).

Nodes of Ranvier

Gaps in the myelin sheath between which an electrical spike jumps to travel faster down the length of the axon.

Vesicles

Small sacs in the terminal buttons that store neurotransmitters and release their contents into the synapse when triggered by an action potential.

Neurotransmitters

Chemical messengers that cross the synaptic gap and bind to specific receptors on the postsynaptic neuron's dendrites.

Excitatory Signals

Chemical signals that push the postsynaptic neuron closer to threshold, making it more likely to fire.

Inhibitory Signals

Chemical signals that push the postsynaptic neuron further away from threshold, making it less likely to fire.

Reuptake

The process by which the presynaptic neuron reabsorbs leftover neurotransmitters from the synapse, clearing the gap and terminating the signal.

Divisions of the Nervous System

The hierarchical organization of neural structures, separating into the central nervous system (brain and spinal cord) and the peripheral nervous system (which divides into autonomic and somatic branches).

Central Nervous System (CNS)

The body's primary command center, consisting of the brain and the spinal cord.

Peripheral Nervous System (PNS)

All the nerves located outside the central nervous system that connect the CNS to the remainder of the body.

Afferent (Sensory) Division

The subdivision of nerves that carries sensory information into the central nervous system.

Efferent Division

The subdivision of nerves that carries motor commands outward from the central nervous system to the body.

Somatic Nervous System

A branch of the peripheral nervous system that controls voluntary skeletal muscle movements.

Autonomic Nervous System

A branch of the peripheral nervous system that regulates involuntary bodily functions, including heart rate, digestion, and glands.

Sympathetic Nervous System

The division of the autonomic nervous system responsible for the 'fight or flight' response that mobilizes the body for action.

Parasympathetic Nervous System

The division of the autonomic nervous system responsible for 'rest and digest' functions that calm the body down.

Reflex Arc

A neural connection where a sensory neuron connects directly to a motor neuron (frequently via the spinal cord), generating an automatic response that bypasses the brain to prevent harm.

Localization of Function

The concept that specific mental abilities and behaviors are governed by specialized brain regions rather than by the entire brain uniformly.

Phineas Gage (1848)

A famous historical case used as early evidence that localized damage to the frontal lobe alters specific functions such as personality and impulse control.

Brain Stem

A hindbrain structure responsible for controlling basic survival functions.

Cerebellum

A hindbrain structure primarily responsible for regulating balance and motor coordination.

Thalamus

A structure within the midbrain and limbic system that serves as the brain's sensory relay station.

Hypothalamus

A midbrain/limbic structure that regulates internal states including hunger, thirst, and body temperature.

Amygdala

A limbic system structure primarily involved in emotion processing, especially fear.

Hippocampus

A structure within the midbrain and limbic system that plays a critical role in memory formation.

Corpus Callosum

A forebrain bridge of nerve fibers connecting the left and right cerebral hemispheres.

Somatosensory Cortex

A forebrain region dedicated to processing touch and body sensations.

Frontal Lobes

Cortical lobes responsible for high-level decision-making, personality expression, and voluntary movement.

Parietal Lobes

Cortical lobes involved in processing touch sensations and managing spatial awareness.

Temporal Lobes

Cortical lobes involved in hearing, language processing, and memory.

Occipital Lobes

Cortical lobes situated at the back of the brain responsible for visual processing.

fMRI (Functional Magnetic Resonance Imaging)

A neuroimaging technique that detects changes in blood oxygen levels to map brain activity and function in near real time during specific tasks.

Behavioral Genetics

The study of the relative influence of genetic heredity versus environmental factors on thoughts, traits, and behavior.

Identical (Monozygotic) Twins

Twins who share $\sim 100\%$ of their genetic material, studied to estimate the heritability of psychological traits.

Non-Identical (Dizygotic) Twins

Fraternal twins who share $\sim 50\%$ of their genes (like ordinary siblings), used as a comparison group in twin studies.

Adoption Studies

Research investigations comparing adopted children to both their biological and adoptive families to separate genetic influences from shared environmental influences.

Gene-Environment Interaction

The interdependent relationship between nature and nurture that accounts for the expression of most psychological traits.