Biopsychology
The specialty in psychology that studies the interaction of biology, behavior, and mental processes
Neuroscience
A relatively new interdisciplinary field that focuses on the brain and its role in psychological processes
Evolution
the gradual process of biological change that occurs in a species as it adapts to its environment
Natural selection
The driving force behind evolution, by which the environment "selects" the fittest organisms
Genotype
An organism's genetic makeup
Phenotype
An organism's observable physical characteristics
DNA
A long, complex molecule that encodes genetic characteristics. DNA is an abbreviation for deoxyribonucleic acid.
Gene
Segment of a chromosome that encodes the directions for the inherited physical and mental characteristics of an organism. Genes are the functional unites of a chromosome.
Chromosome
Tightly coiled threadlike structure along which the genes are organized, like beads on a necklace. Chromosomes consist primarily of DNA
Sex chromosomes
The X and Y chromosomes that determine our physical sex characteristics
Neuron
Cell specialized to receive and transmit information to other cells in the body - also called a nerve cell. Bundles of many neurons are called enrves
Sensory neuron
nerve cell that carries messages from sense receptors toward the central nervous system. Also called an afferent neuron.
Motor neuron
Nerve cell that carries messages away from the central nervous system toward the muscles and glands. Also called an efferent neuron.
Interneuron
A nerve cell that relays messages between nerve cells, especially in the brain and spinal cord
Dendrite
A branched fiber that extends outward from the main cel body and carries information into the neuron
Soma
The part of a cell (such as a neuron) containing the nucleus, which includes the chromosomes. Also called the cell body.
Axon
In a nerve cell, an extended fiber that conducts information from the soma to the terminal buttons. Information travels along the axon in the form of an electric charge, called the action potential.
Resting potential
The electrical charge of the axon in its inactive state, when the neuron is ready to "fire
Action potential
The nerve impulse caused by a change in the electrical charge across the cell membrane of the axon. When the neuron "fires," this charge travels down the axon and causes neurotransmitters to be released by the terminal buttons
All-or-none principle
Refers to the fact that the action potential in the axon occurs either full-blown or not at all
Synapse
the microscopic gap that serves as a communications link between neurons. Synapses also occur between neurons and the muscles or glands they serve.
Terminal buttons
Tiny bulb-like structures at the end of the axon, which contain neurotransmitters that carry the neuron's message into the synapse
Synaptic transmission
The relaying of information across the synapse by means of chemical neurotransmitters
Neurotransmitters
Chemical messengers that relay neural messages across the synapse. Many neurotransmitters are also hormones
Plasticity
The nervous system's ability to adapt or change as the result of experience. Plasticity may also help the nervous system adapt to physical damage.
Glial cells
Cells that bind the neurons together. Glial cells also provide an insulating covering (the myelin sheath) of the axon for some neurons, which facilitates the electrical impulses
Nervous system
The entire network of neurons in the body, including the central nervous system, the peripheral nervous system, and their subdivisions.
Central nervous system
The brain and the spinal cord
Reflex
A simple, unlearned response triggered by stimuli - such as the knee-jerk reflex set off by tapping the tendon just below your kneecap
Peripheral nervous system
All parts of the nervous system lying outside the central nervous system. The peripheral nervous system includes the autonomic and somatic nervous systems
Somatic nervous system
A division of the peripheral nervous system that carries sensory information to the central nervous system and also sense voluntary messages to the body's skeletal muscles
Autonomic nervous system
The portion of the peripheral nervous system that sends communications between the central nervous system and the internal organs, and glands
Sympathetic division
The part of the autonomic nervous system that sends messages to internal organs and glands that help us respond to stressful and emergency situations
Parasympathetic division
The part of the autonomic nervous system that monitors the routine operations of the internal organs and returns the body to calmer functioning after arousal by the sympathetic division
Endocrine system
The hormone system - the body's chemical messenger system, including the endocrine glands: pituitary, thyroid, parathyroid, adrenals, pancreas, ovaries, and testes
Hormone
A chemical messenger used by the endocrine system. Many hormones also serves as neurotransmitters
Pituitary gland
The "master gland" that produces hormones influencing the secretions of all other endocrine glands, as well as a hormone that influences growth. The pituitary is attached to the brain's hypothalamus, from which it takes its orders.
Agonist
Drug or other chemical that enhances or mimics the effects of neurotransmitters
Antagonist
Drug or other chemical that inhibits the effects of neurotransmitters
Neural pathway
Bundle of nerve cells that follow generally the same route and employ the same neurotransmitter
Electroencephalograph (or EEG)
A device for recording brain waves, typically by electrodes placed on the scalp. the record produced is known as an electroencephalogram.
CT scanning (or computerized tomography)
A computerized imaging technique that uses X rays passed through the brain at various angles and then combined into an image
PET scanning (or position emission tomography)
An imaging technique that relies on the detection of radioactive sugar consumed by active brain cells
MRI (or magnetic resonance imaging)
An imaging technique that relies on cells' responses in a high-intensity magnetic field
Brain stem
the most primitive of the brain's three major layers. It includes the medulla, pons, and the reticular formation
Medulla
A brain-stem structure that controls breathing and heart rate. the sensory and motor pathways connecting the brain to the body cross in the medulla
Pons
A brain-stem structure that regulates brain activity during sleep and dreaming. The name pons derives from the Latin word for "bridge
Reticular formation
A pencil-shaped structure forming the core of the brain stem. The reticular formation arouses the cortex to keep the rbain alert and attentive to new stimulation.
Thalamus
The brain's central "relay station," situated just atop the brain stem. Nearly all the messages going into or out of the brain go through the thalamus.
Cerebellum
The "little brain" attached to the brain stem. The cerebellum is responsible for coordinated movements.
Limbic system
The middle layer of the brain, involved in emotion and memory. The limbic system includes the hippocampus, amygdala, hypothalamus, and other structures.
Hippocampus
A component of the limbic system, involved in establishing long-term memories.
Amygdala
A limbic system structure involved in memory and emotion, particularly fear and aggression.
Hypothalamus
A limbic structure that serves as the brain's blood-testing laboratory, constantly monitoring the blood to determine the condition of the body.
Cerebral cortex
The tin gray-matter covering of the cerebral hemispheres, consisting of a 1/4-inch layer dense with cell bodies of neurons. The cerebral cortex carries on the major portion of our "higher" mental processing, including thinking and perceiving.
Frontal lobes
Cortical regions at the front of the brain that are especially involved in movement and in thinking
Motor cortex
A narrow vertical strip of cortex in the frontal lobes, lying just in front of the central fissure; controls voluntary movement
Parietal lobes
Cortical areas lying toward the back and top of the brain; involved in touch sensation and in perceiving spatial relationships (the relationships of objects in space).
Somatosensory cortex
A strip of parietal lobe lying just behind the central fissure. The somatosensory cortex is involved with sensations and touch
Occipital lobe
The cortical regions at the back of the brain, housing the visual cortex
Temporal lobes
Cortical lobes that process sounds, including speech. The temporal lobes are probably involved in storing long-term memories.
Association cortex
Cortical regions throughout the brain that combine information from various other parts of the brain
Cerebral dominance
The tendency of each brain hemisphere to exert control over different functions, such as language or perception of spatial relationships
Corpus callosum
The band of nerve cells that connects the two cerebral hemispheres