Genes, Evolution, and Brain & Nervous System Architecture

Vocabulary flashcards covering topics on genetics, natural selection, neuronal physiology, neurotransmitters, nervous system divisions, and brain structures.

Psychology

The scientific study of mind and brain to explain behavior.

Forer Effect

The tendency for individuals to believe that a general personality description applies uniquely and personally to themselves.

Genes

Meaningful sections of the DNA molecule that govern cell functioning by providing instructions for making proteins.

Gene Expression

The process determining whether a gene is turned on or off, defined as the extent to which a gene is transcribed into a sequence of amino acids to form a protein.

Methylation

An epigenetic modification where a methyl group is added to DNA, changing how accessible and active a gene is without removing it, often reducing gene expression.

Genome

The complete set of DNA belonging to an organism or species.

Genotype

The specific set of genes possessed by an organism.

Phenotype

The overt, observable traits and behaviors of an organism, determined by the interaction of its genotype and environment.

Allele

A specific variant or alternative version of a gene.

Homozygote

An organism or cell that possesses identical alleles at a specific chromosomal locus.

Heterozygote

An organism or cell that possesses different alleles at a specific chromosomal locus.

Polygenetic Inheritance

The determination of a complex trait or behavior through the interaction between the environment and multiple gene pairs.

Natural Selection

The key mechanism of evolution requiring population trait variation, differential survival and reproduction, and heritability of advantageous traits to future generations.

Pseudogene

A nonfunctioning gene sequence within DNA that served a function in ancestral species.

Continental Island

An island type, such as Japan, that possesses a very large variety of native species due to historical land connectivity.

Oceanic Island

An island type, such as Hawaii, that originally lacked many basic animal types (such as land mammals and amphibians) because they could not colonize across long ocean distances.

MAOA Gene

A gene regulating monoamine oxidase enzyme levels that interacts with child maltreatment to influence susceptibility to violent behavior.

Central Nervous System (CNS)

The core division of the nervous system consisting of the brain and the spinal cord.

Peripheral Nervous System (PNS)

All nerve cells in the body outside the central nervous system, consisting of the somatic and autonomic nervous systems.

Somatic Nervous System

A component of the peripheral nervous system responsible for voluntary behavior, such as reaching for an object.

Autonomic Nervous System

A component of the peripheral nervous system responsible for controlling less voluntary bodily adjustments, such as regulating heart rate.

Sensory Receptors

Specialized neurons that translate environmental physical energy into electrical signals and relay that information to the brain.

Sensory Neurons

Afferent neurons that carry incoming sensory information into the central nervous system.

Motor Neurons

Efferent neurons that carry outgoing signals from the central nervous system to direct muscle contraction or relaxation.

Interneurons

Neurons that act as local relay stations facilitating communication between sensory neurons and motor neurons.

Dendrites

Branchlike extensions of a neuron that detect chemical signals from neighboring neurons.

Cell Body

The soma of a neuron where chemical inputs received via dendrites from thousands of other neurons are collected and integrated.

Axon

A long narrow outgrowth of a neuron down which electrical impulses travel away from the cell body toward terminal buttons.

Terminal Buttons

Knoblike structures at the end of an axon that release chemical signals into the synapse.

Synapse

The site where chemical communication occurs and signals pass from one neuron to another.

Myelin Sheath

A fatty layer composed of glial cells that insulates axons to allow faster movement of electrical impulses.

Nodes of Ranvier

Small gaps of exposed axon between myelin sheath segments where action potentials occur.

Resting Membrane Potential

The electrical charge inside an inactive neuron relative to the outside, typically $-70\text{ millivolts}$.

Polarized State

The state of a resting neuron when it contains more negative ions inside than outside, generating the electrical energy required for firing.

Sodium-Potassium Pump

A membrane mechanism that increases potassium and decreases sodium inside the neuron, helping maintain resting membrane potential.

Action Potential

The electrical impulse that travels down the axon away from the cell body to the terminal buttons, causing neurotransmitter release.

All-or-None Law

The principle stating that a neuron fires with identical potency every time, meaning it either fires completely or does not fire at all.

Absolute Refractory Period

The brief period immediately following an action potential during which ion channels are completely unable to respond again.

Relative Refractory Period

The brief period following an action potential when the neuron's membrane potential is hyperpolarized, making it harder to fire again.

Neurotransmitters

Chemical substances made in the axon or cell body and stored in vesicles that transmit signals across the synapse.

Receptors

Specialized protein molecules on the postsynaptic membrane that bind specifically with matching neurotransmitters.

Agonists

Drugs that increase or enhance neurotransmitter actions by increasing precursors, blocking reuptake, or mimicking the neurotransmitter.

Antagonists

Drugs that decrease or inhibit neurotransmitter actions by decreasing precursors, enhancing cleanup enzymes, or blocking postsynaptic receptors.

Acetylcholine

A neurotransmitter controlling motor action over muscles and playing key roles in learning, memory, sleeping, and dreaming.

Norepinephrine

A neurotransmitter responsible for regulating states of arousal, vigilance, and attention.

Serotonin

A neurotransmitter involved in regulating emotional states, impulsiveness, and dreaming.

Dopamine

A neurotransmitter primarily associated with reward, motivation, and motor control over voluntary movement.

GABA

Gamma-aminobutyric acid, the primary inhibitory neurotransmitter in the brain responsible for anxiety reduction and inhibition of action potentials.

Glutamate

The primary excitatory neurotransmitter responsible for enhancing action potentials, learning, and memory.

Endorphins

Neurotransmitters that function primarily in pain reduction and reward processing.

Sympathetic Nervous System

The division of the autonomic nervous system that prepares the body for physical action during stressful or high-energy situations.

Parasympathetic Nervous System

The division of the autonomic nervous system that calms the body and returns it to a resting state.

Phrenology

A 19th-century pseudoscience originated by Franz Joseph Gall proposing that skull bumps reflect localized brain growth and personality traits.

Broca's Area

A small region in the left frontal lobe of the cerebral cortex crucial for speech and language production.

Transcranial Magnetic Stimulation (TMS)

A noninvasive technique using strong magnetic fields to induce brief temporary disruptions in specific brain regions.

Corpus Callosum

A thick band of nerve fibers connecting the left and right cerebral hemispheres, facilitating interhemispheric communication.

Cerebellum

A brain region situated behind the brain stem that is essential for coordinated motor function and movement.