Myers Psychology: Biology of Mind and Genetics

Biological psychology

The scientific study of the links between biological and psychological processes.

Neuron

A nerve cell; the basic building block of the nervous system.

Dendrites

A neuron's bushy, branching extensions that receive messages and conduct impulses toward the cell body.

Axon

The neuron extension that passes messages through its branches to other neurons or to muscles or glands.

Myelin sheath

A fatty tissue layer segmentally encasing axons; enables vastly greater neural impulse speed.

Action potential

A neural impulse; a brief electrical charge that travels down an axon.

Refractory period

A brief period of inactivity after a neuron has fired.

Threshold

The level of stimulation required to trigger a neural impulse.

All-or-none response

A neuron's reaction of either firing with a full-strength response or not firing.

Synapse

The junction between the axon tip of a sending neuron and the dendrite or cell body of a receiving neuron.

Neurotransmitters

Chemical messengers that cross the synaptic gaps between neurons.

Reuptake

A neurotransmitter's reabsorption by the sending neuron.

Endorphins

Natural, opiate-like neurotransmitters linked to pain control and pleasure.

Agonist

A molecule that increases a neurotransmitter's action.

Antagonist

A molecule that inhibits or blocks a neurotransmitter's action.

Nervous system

The body's speedy, electrochemical communication network.

Central nervous system (CNS)

The brain and spinal cord.

Peripheral nervous system (PNS)

The sensory and motor neurons that connect the CNS to the rest of the body.

Nerves

Bundled axons that form neural cables connecting the CNS with muscles, glands, and sense organs.

Sensory (afferent) neurons

Neurons that carry incoming information from sensory receptors to the brain and spinal cord.

Motor (efferent) neurons

Neurons that carry outgoing information from the brain and spinal cord to muscles and glands.

Interneurons

Neurons within the brain and spinal cord that communicate internally between sensory inputs and motor outputs.

Somatic nervous system

The division of the PNS that controls the body's skeletal muscles.

Autonomic nervous system (ANS)

The part of the PNS that controls glands and internal organ muscles.

Sympathetic nervous system

The division of the ANS that arouses the body, mobilizing its energy in stressful situations.

Parasympathetic nervous system

The division of the ANS that calms the body, conserving its energy.

Reflex

A simple, automatic response to a sensory stimulus.

Endocrine system

The body's 'slow' chemical communication system; a set of glands that secrete hormones into the bloodstream.

Hormones

Chemical messengers manufactured by endocrine glands that travel through the bloodstream.

Adrenal glands

A pair of endocrine glands just above the kidneys that help arouse the body in times of stress.

Pituitary gland

The endocrine system's most influential gland, regulating growth and controlling other glands.

Lesion

Tissue destruction; a naturally or experimentally caused destruction of brain tissue.

Electroencephalogram (EEG)

An amplified recording of the waves of electrical activity sweeping across the brain's surface.

CT (computed tomography) scan

A series of X-ray photographs combined by computer into a composite representation of brain structure.

PET (positron emission tomography) scan

A visual display of brain activity that detects where a radioactive form of glucose goes during a task.

MRI (magnetic resonance imaging)

A technique using magnetic fields and radio waves to produce computer-generated images of soft brain tissue.

fMRI (functional MRI)

A technique revealing bloodflow and brain activity by comparing successive MRI scans.

Brainstem

The oldest part and central core of the brain; responsible for automatic survival functions.

Medulla

The base of the brainstem; controls heartbeat and breathing.

Thalamus

The brain's sensory control center located on top of the brainstem.

Reticular formation

A nerve network traveling through the brainstem that plays an important role in controlling arousal.

Cerebellum

The 'little brain' at the rear of the brainstem; coordinates movement output and balance.

Limbic system

Neural system associated with emotions and drives, located below the cerebral hemispheres.

Amygdala

Two lima bean-sized neural clusters in the limbic system linked to emotion.

Hypothalamus

A neural structure directing maintenance activities and governing the endocrine system via the pituitary gland.

Cerebral cortex

The intricate fabric of interconnected neural cells covering the cerebral hemispheres.

Glial cells (glia)

Cells in the nervous system that support, nourish, and protect neurons.

Frontal lobes

Portion of the cerebral cortex involved in speaking, muscle movements, and making plans and judgments.

Parietal lobes

Portion of the cerebral cortex that receives sensory input for touch and body position.

Occipital lobes

Portion of the cerebral cortex lying at the back of the head; includes visual areas.

Temporal lobes

Portion of the cerebral cortex lying roughly above the ears; includes auditory areas.

Motor cortex

An area at the rear of the frontal lobes that controls voluntary movements.

Somatosensory cortex

Area at the front of the parietal lobes that registers and processes body touch and movement.

Association areas

Areas of the cerebral cortex involved in higher mental functions like learning, remembering, and thinking.

Plasticity

The brain's ability to change by reorganizing after damage or building new pathways.

Neurogenesis

The formation of new neurons.

Corpus callosum

The large band of neural fibers connecting the two brain hemispheres.

Split brain

A condition resulting from isolating the brain's two hemispheres by cutting the corpus callosum.

Consciousness

Our awareness of ourselves and our environment.

Cognitive neuroscience

The interdisciplinary study of brain activity linked with cognition.

Dual processing

The principle that information is often simultaneously processed on separate conscious and unconscious tracks.

Behavior genetics

The study of the relative power and limits of genetic and environmental influences on behavior.

Environment

Every external influence, from prenatal nutrition to surrounding people and things.

Chromosomes

Threadlike structures made of DNA molecules that contain the genes.

DNA (deoxyribonucleic acid)

A complex molecule containing the genetic information that makes up the chromosomes.

Genes

The biochemical units of heredity that make up the chromosomes; segments of DNA.

Genome

The complete instructions for making an organism, consisting of all genetic material in its chromosomes.

Identical twins

Twins who develop from a single fertilized egg that splits in two.

Fraternal twins

Twins who develop from separate fertilized eggs, sharing a fetal environment.

Molecular genetics

The subfield of biology that studies the molecular structure and function of genes.

Heritability

The proportion of variation among individuals that can be attributed to genes.

Interaction

The interplay that occurs when the effect of one factor depends on another factor.

Epigenetics

The study of environmental influences on gene expression that occur without a DNA change.

Evolutionary psychology

The study of the evolution of behavior and the mind using principles of natural selection.

Natural selection

The principle that inherited traits contributing to reproduction and survival are passed on.

Mutation

A random error in gene replication that leads to a change.