unit 2 psych

Neuron

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

- Human brains contains about 100 billion of them

- Has complex structure with as many as 10,000 physical connections with other cells

Cell Body (Soma)

The part of the neuron that contains the nucleus, which directs the manufacture of substances that the neuron needs for grown and maintenance

Dendrites

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

Axon

The part of the neuron that carries information away from the cell body toward other cells

- Some extend more than 3 feet through the body

Myelin Sheath

A layer of fatty tissue that insulates axons and speeds their impulses

- If it degenerates, multiple sclerosis results: communication to muscles slows, with eventual loss of muscle control

Glial Cells (glia)

Provide support, nutritional benefits, and other functions, and keep neurons running smoothly

- Are not specialized to process information the way neurons do

Action Potential

The brief wave of positive electrical charge that travels down the axon.

Threshold

The level of stimulation required to trigger a neural impulse.

Refractory Period

The recovery time during which another stimulus given to the neuron (no matter how strong) will not lead to a second action potential

- The neuron pumps positively charged sodium ions back outside the cell membrane and the neuron becomes negatively charged once again

All-or-None Response

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

Neurotransmitter

Chemical substances that are stored in very tiny sacs within the terminal buttons and transmit information across a synaptic gap to the next neuron

- When released by the sending neuron, they travel across the synapse and bind to receptor sites on the receiving neuron

Synapse

The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called the synaptic gap or synaptic cleft.

Reuptake

A neurotransmitter's reabsorption by the sending neuron.

Endorphins

"Morphine within"—natural, opiate-like neurotransmitters linked to pain control and to pleasure.

Agonist

A molecule that, by binding to a receptor site, stimulates a response.

Antagonist

A molecule that, by binding to a receptor site, inhibits or blocks a response.

Nervous System

The body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems

Central Nervous System (CNS)

Brain and Spinal cord.

Peripheral Nervous System (PNS)

The sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body.

Nerves

Electrical cables formed of bundles of axons.

Sensory Neurons

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

Motor Neurons

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

Interneurons

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

Somatic Nervous System

The division of the peripheral nervous system that controls the body's skeletal muscles. (Also called the skeletal nervous system.)

Autonomic Nervous System

The part of the peripheral nervous system that controls the glands and the muscles of the internal organs. Its sympathetic division arouses; its parasympathetic division calms.

Sympathetic Nervous System

The division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations.

Parasympathetic Nervous System

The division of the autonomic nervous system that calms the body, conserving its energy.

Reflex

A simple, automatic response to a sensory stimulus, such as the knee-jerk response.

Endocrine System

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

Hormones

Chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues.

Adrenal Glands

A pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress.

Pituitary Gland

The endocrine system's most influential gland. under the influence of the hypothalamus, it regulates growth and controls other endocrine glands.

Lesion

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

EEG (Electroencephalogram)

An amplified recording of the waves of electrical activity sweeping across the brain's surface. these waves are measured by electrodes placed on the scalp.

MEG (Magnetoencephalography)

A brain imaging technique that measures magnetic fields from the brain's natural electrical activity.

CT (computed tomography) Scan

Scan a series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice of the brain's structure.

PET (positron emission tomography) Scan

Scan a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task.

MRI (magnetic resonance imaging)

A technique that uses magnetic fields and radio waves to produce computer -generated images of soft tissue. The scans show brain anatomy.

fMRI (functional MRI)

A technique for revealing bloodflow and, therefore, brain activity by comparing successive MRI scans. They show brain function as well as structure.

Brainstem

The oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; responsible for automatic survival functions.

Medulla

The base of the brainstem; controls heart-beat and breathing.

Thalamus

The brain's sensory control center, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla.

Reticular Formation

A nerve network that travels through the brainstem and thalamus and plays an important role in controlling arousal.

Cerebellum

The "little brain" at the rear of the brainstem; functions include processing sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory.

Limbic System

Neural system (including the hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives.

Amygdala

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

Hypothalamus

A neural structure that directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.

Hippocampus

A neural center located in the limbic system; helps process for storage explicit (conscious) memories of facts and events.

Cerebral Cortex

The intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body's ultimate control and information-processing center.

Frontal Lobe

The portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgments.

Parietal Lobe

The portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position.

Occipital Lobe

The portion of the cerebral cortex lying at the back of the head; includes areas that receive information from the visual fields.

Temporal Lobe

The portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, each receiving information primarily from the opposite ear.

Motor Cortex

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

Somatosensory Cortex

An area at the front of the parietal lobes that registers and processes body touch and movement sensations.

Association Areas

Areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking.

Plasticity

The brain's ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience.

Neurogenesis

The formation of new neurons.

Corpus Callosum

The large band of neural fibers connecting the two brain hemispheres and carrying messages between them.

Split Brain

A condition resulting from surgery that isolates the brain's two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them.

Consciousness

Our awareness of ourselves and our environment.

Cognitive Neuroscience

The interdisciplinary study of the brain activity linked with cognition (including perception, thinking, memory, and language).

Dual Processing

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

Blindsight

A condition in which a person can respond to a visual stimulus without consciously experiencing it.

Parallel Processing

Processing many aspects of a problem simultaneously; the brain's natural mode of information processing for many functions.

Sequential Processing

Processing one aspect of a problem at a time; generally used to process new information or to solve difficult problems.

Behavior Genetics

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

Heredity

The genetic transfer of characteristics from parents to offspring.

Environment

Every external influence, from prenatal nutrition to the people and things around us.

Chromosome

Threadlike structures made of DNA molecules that contain the genes.

DNA

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

Genes

The biochemical units of heredity that make up the chromosomes; a segment of DNA capable of synthesizing a protein.

Genome

The complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes.

Identical Twins

Twins who develop from a single fertilized egg that splits in two, creating two genetically identical organisms.

Fraternal Twins

Twins who develop from separate fertilized eggs. They are genetically no closer than brothers and sisters, but they share a fetal environment.

Heritability

The proportion of variation among individuals that we can attribute to genes. It may vary, depending on the range of populations and environments studied.

Interaction

The interplay that occurs when the effect of one factor (such as environment) depends on another factor (such as heredity).

Molecular Genetics

The study of how the structure and function of genes interact with our environment to influence behavior.

Molecular Behavior Genetics

The study of how the structure and function of genes interact with our environment to influence behavior.

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 that better enable an organism to survive and reproduce in a particular environment will (in competition with other trait variations) most likely be passed on to succeeding generations.

Mutation

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

Social Script

A culturally modeled guide for how to act in various situations.

Sleep

A periodic, natural loss of consciousness — as distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation.

Circadian Rhythm

Our biological clock; regular bodily rhythms (for example, of temperature and wakefulness) that occur on a 24-hour cycle.

REM Sleep

Rapid eye movement sleep; a recurring sleep stage during which vivid dreams commonly occur. Also known as paradoxical sleep, because the muscles are relaxed (except for minor twitches) but other body systems are active.

Alpha Waves

The relatively slow brain waves of a relaxed, awake state.

NREM Sleep

Non-rapid eye movement sleep; encompasses all sleep stages except for REM sleep.

Hallucination

Physical Effects: Also called psychedelics. Similar to the neurotransmitter serotonin, which regulates moods and perceptions.Examples: LSD, Ketamine, Mescaline and MarijuanaPsychological Effects: Create loss of contact from reality, alter emotion, perception, thought and produce hallucinations: hearing/seeing things that are not real.

Hypnagogic Sensations

Bizarre experiences, such as jerking or a feeling of falling or floating weightlessly, while transitioning to sleep.

Delta Waves

The large, slow brain waves associated with the deep sleep of NREM-3.

Suprachiasmatic Nucleus (SCN)

A pair of cell clusters in the hypothalamus that controls circadian rhythm. In response to light, the SCN causes the pineal gland to adjust melatonin production, thus modifying our feelings of sleepiness.