| A | B |
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| Acetylcholine (ACh) | Neurotransmitter that causes contraction of skeletal muscles. Helps regulate heart muscles. Involved in memory. |
| Action Potential or Impulse | The "firing" of a neuron. the inside of the axon is negative to the outside. |
| Adrenal Glands | Endocrine glands atop kidneys. Adrenal cortex (outer layer) produces the steroid cortisol, a stress hormone.Adrenal medulla (core) secretes adrenaline (epinephrine) and norepinephrine that prepare the body for "fight or flight" like the ANS. |
| Albinism | Recessive trait that produces lack of pigment and involves quivering eyes and inability to perceive depth with both eyes. |
| All-or-None Principle | Law that the neuron either generates an action potential when the stimulation reaches threshold or it doesn't fire when stimulation is below threshold. The strength of the action potential is constant whenever it occurs. |
| Amygdala | Part of limbic system in the brain. Influences emotions such as aggression, fear, and self-protective behaviors. Proccesses emotional memory. |
| Association Areas | Regions of cerebral cortex that are not primary regions for sensory processing or motor functions.Involved in higher mental functions such as thinking, planning, and communicating. |
| Autonomic Nervous System (ANS) | Subdivision of PNS that includes motor nerves that innervate smooth (involuntary) and heart muscle. Its sympathetic subdivision prepares the body for "fight or flight". Its parasympathetic subdivision causes bodily changes for maintenance or rest. |
| Axon | Long, single conducting fiber of neuron that extends from the cell body, transmits an action potential, branching and ending in tips called terminal buttons (axon terminals) that secrete in neurotransmitters.Presence of fatty myelin sheath speeds up conduction of action potential. |
| Basal Ganglia | Also called basal nuclei, links the thalamus with the motor cortex of the cerebrum and other motor areas. Regulates initiation of movements, balance, eye movements, and posture. Involved in reward and punishment learning.Some neural clusters involved in emotion. |
| Brain | Part of the CNS covered by the meninges, housed in the skull, bathed by the cerebrospinal fluid.Outer cerebral cortex has folds (convolutions) that increase surface area--folding-out peaks are gyri and folding-in valleys are sulci with deep fissures. |
| Cell Body or Cyton | Part of neuron also called soma.Contains nucleus and most of cytoplasm. Directs synthesis of such substances as neurotransmitters. |
| Central Nervous System (CNS) | The portion of the nervous system that includes the brain and the spinal cord. |
| Cerebellum | "Little brain" located behind the medulla. Coordinates motor function, integrating motion and positional information from the inner ear and muscles; prevents jerky movements.Helps maintain balance. |
| Cerebral Cortex | Largest part of the brain. Center for higher-order processes such as thinking, planning, and judgment.Receives and processes sensory information and directs movement. Geographically divided into 8 lobes: 4 on left side and 4 on right. |
| Chromosomal Mutations | Errors in fertilization result in 45 or 47 chromosomes in cells of resulting baby. Turner's syndrome--females with 45 (only 1 X), typically short with webbed neck and some cognitive deficits. Klinefelter's syndrome--males with 47 (XXY), typically passive, "breasts". |
| Chromosome | Structure in the nucleus of cells that contains genes that influence traits. Normal human body cells have 23 pairs of chromosomes.Both chromosomes of 22 pairs appear the same with genes for same traits; 23rd determines sex: XX = female, XY = male. |
| Computerized Axial Tomography (CAT or CT) | Creates a computerized image using x-rays passed through the brain to show structure and/or the extent of a lesion.Quicker and cheaper than MRI. |
| Dendrites | part of neuron. Branching tubular process that have receptor sites for receiving information. |
| Developmental Model of Brain | Hindbrain--medulla, pons, and cerebellum. Medulla--small region with parts involved in eye reflexes and movements. Forebrain--limbic system, hypothalamus, thalamus, and cerebral cortex. |
| Dopamine | Neurotransmitter that stimulates the hypothalamus to make hormones,affects alertness, attention, and movement. Lack of dopamine is associated with Parkinson's disease. Too much dopamine is associated with schizophrenia. |
| Down Syndrome | Baby typically has 47 chromosomes (3 copies of chromosome number 21). Typically person with Down syndrome is mentally retarded, has a round head, fold in eyelid, flat nose, protruding tongue, and poormuscle tone and coordination. |
| Electroencephalogram (EEG) | An amplified tracing of brain activity produced when electrodes positioned over the scalp transmit signals about the brain's electrical activity ("brain waves") to an electroencephalograph machine. Shows function. |
| Endocrine System | Ductless glands that typically secrete hormones directly into the blood.Help regulate body and behavioral processes.Slower-acting and longer-lasting chemical communication than nervous system. |
| Endorphins | Neurotransmitters similar to the opiate morphine. Relieve pain and may induce feelings of pleasure. |
| Evolutionary Model of Brain | Reptilian brain--medulla, pons, and cerebellum. Old mammalian brain--limbic system, hypothalamus, and thalamus.New mammalian brain--cerebral cortex. |
| Fraternal Twins (Dizygotic Twins) | Siblings that share about half of the same genes because they develop from 2 different zygotes (2 eggs fertilized by 2 different sperms) from the same parents.Studied to help separate the contributions of heredity and of environment to behavior. |
| Frontal Lobes | Front regions of cerebral cortex. Interpret and control emotional behaviors, make decisions, and carry out plans. Motor cortex strip in front of somato-sensory cortex initiates movements and integrates activities of skeletal muscles. Produces speech (Broca's area). |
| Functional Magnetic Resonance Imaging (fMRI) | also called Functional MRI. Shows brain activity at higher resolution than the PET scan when changes in oxygen concentration near active neurons alter magnetic qualities. Shows function. |
| GABA or Gamma-Aminobutyric Acid | Inhibitory neurotransmitter. Huntington's disease and seizures are associated with malfunctioning GABA systems. |
| Gene | Segment of a chromosome that consists of DNA that codes for peptides or proteins. The code is contained in the sequence of bases in the DNA segment, which guides synthesis of compounds such as neurotransmitters, enzyme, hormones, structural compounds, and thus, traits. |
| Genotype | Genetic makeup for a trait. Can involve 1 or more pairs of genes; if only 1 pair is involved: Homozygous--both genes are the same and are expressed. Heterozygous, hybrid--genes different; dominant is expressed, recessive hidden. |
| Glial Cells (or Glia) | Supportive cells of the nervous system. Guide growth of developing neurons, provide nutrition for and get rid of wastes of neurons. Form an insulating sheath around neurons that speeds conduction. |
| Glutamate | Neurotransmitter that stimulates cells throughout the brain, especially in the hypothalamus. Glutamate is associated with memory formation and information processing. |
| Heritability | The proportion of variation among individuals in a population that is due to genetic causes. |
| Hippocampus | Part of limbic system in the brain. Enables formation of new long-term memories. Produces new neurons throughout life. |
| Hormone | Chemical messenger of the endocrine system that travels from gland through the blood to a receptor site on a target organ. Receptor site on target organ is specific for a particular hormone. |
| Huntington's Disease | Dominant gene defect that generally shows effects in adulthood. Nervous system degenerates, characterized by tremors, jerky motions, blindness, and death. Genetic test for presence of the gene is reliable. |
| Hypothalamus | Part of brain under thalamus that controls feeding behavior, drinking behavior, body temperature, sexual behavior, threshold for rage behavior, activation of sympathetic and parasympathetic systems, and secretion of hormones of the pituitary. |
| Identical Twins (Monozygotic Twins) | Two individuals who share all of the same genes and heredity because they develop from the same zygote (fertilized egg). Studied to help separate the contributions to behavior of heredity and environment. |
| Interneuron | Nerve cell in the central nervous system (CNS) that transmits impulses between sensory and motor neurons. Neural impulses travel one way along the neuron from dendrites to axons to axon terminals, and among neurons from the receptor to the effector. |
| Lesions | Precise destruction of brain tissue that enables systematic study of loss of function resulting from surgical removal (also called ablation), cutting of neural connections, or destruction by chemical applications; loss of structure is linked to loss of function. |
| Magnetic Resonance Imaging (MRI) | Creates more detailed computerized images than CT, using a magnetic field and pulses of radio waves that cause emission of signals that depend upon the density of tissue; shows structure. More expensive and takes longer than a CAT scan. |
| Medulla Oblongata | Lower region of brain where most fibers cross, resulting in contralateral (opposite side) control.Regulates heart rhythm, blood flow, breathing rate, digestion, and vomiting. |
| Motor Neuron | Also called efferent neuron. Nerve cell in the peripheral nervous system (PNS) that transmits impulses from sensory or interneurons to an effector. Whichare muscle cells that contract or gland cells that secrete. |
| Neuron | Basic unit of structure and function of the nervous system. Neurons perform 3 major functions: receives information, processes it, and transmits it to the rest of the body. |
| Neuropsychologists | Explore the relationships between brain and nervous systems, and behavior. Also called biopsychologists, biological psychologists, behavioral geneticists, physiological psychologists, and behavioral neuroscientists. |
| Neurotransmitters | Chemical messengers released by the terminal buttons of the presynaptic neuron into the synapse. Can be excitatory--increases the probability that the postsynaptic neuron will fire, or inhibitory--decreases the probability the next neuron will fire. |
| Occipital Lobes | Back regions of the cerebral cortex. Primary regions for processing visual information. |
| Ovaries and Testes | Gonads (sex glands) in females and males respectively.Sex hormones necessary for both reproduction and development of secondary sex characteristics. |
| Pancreas | Gland near the stomach. Secretes hormones insulin and glucagon, which regulate sugar that fuels all behavioral processes. Imbalances can result in diabetes and hypoglycemia. |
| Parasympathetic Nervous System | restores pupils to normal size. |
| Parathyroids | normal functioning of neurons. |
| Parietal Lobes | Top regions of the cerebral cortex. |
| Peripheral Nervous System (PNS) | Portion of the nervous system outside the brain and spinal cord. Includes all of the sensory and motor neurons. Subdivisions of the PNS are the autonomic and somatic nervous systems. |
| Phenotype | Expression of the genes for a trait. The recessive phenotype is shown only when all genes for the trait are recessive. When neither gene dominates, the phenotype can involve expression of both genes. |
| Phenylketonuria (PKU) | Recessive trait that results in severe, irreversible brain damage unless the baby is fed a special diet low in phenylalanine. |
| Pineal Gland | Endocrine gland in brain that produces melatonin. Melatonin helps regulate circadian (daily) rhythms and is associated with seasonal affective disorder (SAD). |
| Pituitary Gland ("Master Gland") | Endocrine gland in brain that produces stimulating hormones, which promote secretion by other glands including: TSH--thyroid stimulating hormone;ACTH--adrenocorticotropic hormone that stimulates the adrenal glands; FSH--follicle-stimulating hormone that stimulates egg or sperm production. |
| Pons | Bridge between cerebral hemispheres, and both the medulla and cerebellum. Includes portion of reticular activating system (also called reticular formation) critical for arousal. |
| Positron Emission Tomography (PET) | Shows brain activity when radioactively tagged glucose rushes to active neurons and emits positrons. Show functions. |
| Psychophysics | The study of the relationship between physical energy and psychological experiences. |
| Reflex Arc | The path over which the reflex (the simplest form of behavior) travels. Typically includes sensory receptor, sensory (afferent) neuron, interneuron, motor (efferent) neuron, and an effector, which is a muscle that contracts or a gland cell that secretes. |
| Sensory Neuron | Also called afferent neuron. Nerve cell in the peripheral nervous system (PNS) that transmits impulses from receptors to the brain or spinal cord. |
| Sensory Receptors | Cell typically in sense organs that initiates action potentials, which then travel along sensory neurons to the CNS.Especially concentrated in the retina of the eye, cochlea of the ear, taste buds of the tongue, and olfactory epithelium in the nasal cavity, as well as in skin, muscles, tendons, and joints. |
| Serotonin | Neurotransmitter associated with arousal, sleep, appetite, moods, and emotions.Lack of serotonin is associated with depression. |
| Sex-Linked Trait | Trait expressed more frequently in males because it results from recessive gene located on the X chromosome that has no corresponding gene on the Y. Females would need a recessive gene on both X chromosomes to show trait. Example: color blindness, hemophilia. |
| Somatic Nervous System | Part of peripheral nervous system (PNS) that includes motor nerves that stimulate skeletal (voluntary) muscle. Enables you to move your head and neck, arms, hands, legs, and feet purposefully. |
| Spinal Cord | Part of central nervous system (CNS). Extends below the medulla of the brain through the bony spinal column to the base of your back. |
| Sympathetic Nervous System | Part of autonomic nervous system whose stimulation results in responses that help your body deal with stressful events. Speeds heart rate, raises blood pressure, quickens breathing, releases glucose, and dilates pupils. |
| Synapse | Region of communication between transmitting (presynaptic) neuron and receiving (postsynaptic) neuron, muscle, or gland. |
| Tay-Sachs Syndrome | Recessive trait that produces progressive loss of nervous function and death in a baby. |
| Temporal Lobes | Lateral (side) regions of cerebral cortex.Primary area for hearing, understanding language (Wernicke's area), and understanding music or tonality. Primary regions for processing smell (olfaction) information contralaterally. |
| Thalamus | "Relay station" of brain transmits messages from sensory pathways (from sense organs) for vision, hearing, taste, and skin senses to and from appropriate areas of the cerebral cortex and regions of the medulla and cerebellum. Does NOT carry information about smell. |
| Thyroid Gland | Endocrine gland in neck. Secretes thyroxine, which stimulates and maintains metabolic activities. Is stimulated by TSH from pituitary gland. |
