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| glia | cells found throughout the nervous system that provide structural support and insulation for neurons (one of two categories for cells of nervous system). They hold the nervous system together and help maintain the chemical environment of neurons |
| neurons | individual cells in the nervous system that receive, integrate, and transmit info (permit communication within the nervous system) |
| soma | cell body that contains the cell nucleus and much of the chemical machinery common to most cells |
| dendrites | parts of a neuron that are specialized to receive info |
| axon | a long thin fiber that transmits signals away from the soma to other neurons or to muscles or glands |
| myelin sheath | insulating material, derived from glial cells, that encases some axons; speeds up the transmission of signals that move along axons |
| terminal buttons | small knobs that secrete chemicals called neurotransmitters |
| synapse | junction where info is transmitted from one neuron to another |
| neural impulse | nature of a signal |
| ions | electrically charged ions |
| resting potential | neuron’s stable, negative charge when the cell is inactive |
| action potential | very brief shift in a neuron’s electrical charge that travels along an axon |
| absolute refractory period | minimum length of time after an action potential during which another action potential cannot begin |
| presynaptic neuron | neuron that sends a signal across the gap |
| postsynaptic neuron | neuron that receives the signal |
| neurotransmitters | chemicals that transmit info from one neuron to another |
| synaptic vesicles | smalls sacs that store most of the chemicals |
| receptor sites | specifically tuned to recognize and respond to some neurotransmitters but not others |
| postsynaptic potential | a voltage change at a receptor site on a post synaptic cell membrane; they vary in size and increase or decrease the probability of a neural impulse in the receiving cell in the proportion the amount of voltage change |
| excitatory PSP | positive voltage shift that increases the likelihood that the postsynaptic neuron will fire action potentials |
| inhibitory PSP | negative voltage shift that decreases the likelihood that the postsynaptic neuron will fire action potentials |
| reuptake | process in which neurotransmitters are sponged up from the synaptic cleft by the presynaptic membrane |
| acetylcholine (Ach) | the only transmitter between motor neurons and voluntary muscles; every move depends on it; appears to contribute to attention, arousal, and perhaps memory |
| agonist | chemical that mimics the action of a neurotransmitter |
| antagonist | chemical that opposes the action of a neurotransmitter |
| curare | an Ach antagonist |
| monoamines | include 3 neurotransmitters: dopamine, norepinephrine, and serotonin |
| dopamine | used by neurons that control voluntary movement |
| serotonin | used by neurons to play a role in the regulation of sleep and wakefulness |
| endorphins | entire family of internally produced chemicals that resemble opiates in structure and effects |
| peripheral nervous system | made up of all nerves that lie outside the brain and spinal chord |
| nerves | bundles of neuron fibers (axons) that are routed together in the peripheral nervous system |
| somatic nervous sys | made up of nerves that connect to voluntary skeletal muscles and sensory receptors |
| afferent nerve fibers | axons that carry info inward to the central nervous system from the periphery of the body |
| Efferent nerve fibers | axons that carry info outward from the central nervous system to the periphery of the brain |
| autonomic nervous system | made up of nerves that connect to the heart, blood vessels, smooth muscles, and glands and controls involuntary |
| sympathetic division | branch of the autonomic nervous system that mobilizes the body’s resources for energies |
| parasympathetic division | branch of autonomic nervous system that generally conserves bodily resources |
| central nervous system (CNS) | consists of the brain and the spinal chord |
| cerebrospinal fluid | nourishes the brain and provides a protective cushion for it |
| blood-brain barrier | semipermeable membrane-like mechanism that stops some chemicals from passing between the bloodstream and the brain |
| electroencephalograph (EEG) | a device that monitors the electrical activity of the brain over time by means of recording electrodes attached to the surface of the scalp |
| lesioning | involves destroying a piece of the brain |
| electrical stimulation of the brain | involves sending a weak electric current into a brain structure to stimulate it |
| CT scan | computer-enhanced X ray of the brain structure |
| PET scanning | can examine brain function, mapping actual activity of brain over time |
| MRI scan | uses magnetic fields, radio waves, and computerized enhancement to map brain structure |
| fMRI | consists of several new variations of MRI technology that monitor blood and oxygen flow in the brain to identify areas of high activity |
| hindbrain | includes the cerebellum and two structures found in the lower part of the brainstem: medulla and the pons |
| medulla | is attached to the spinal chord and has charge of largely unconscious but vital functions |
| pons | includes a bridge of fibers that connects the brainstem with the cerebellum and contain several clusters of cell bodies involved with sleep and arousal |
| cerebellum | relatively large and deeply folded structure located adjacent to the back surface of the brainstem; critical to coordination of movement and sense of equilibrium physical balance) |
| midbrain | segment of brainstem that lies between the hindbrain and forebrain concerned with certain sensory processes such as locating where things are in space |
| reticular formation | at central core of brainstem and contributes to the modulation of muscle reflexes, breathing, and pain perception |
| Forebrain | largest and most complex region of the brain, encompassing a variety of structures, including the thalamus, hypothalamus, limbic system, and cerebrum |
| thalamus | structure in the forebrain through which all sensory info (except smell) must pass to get to the cerebral cortex |
| somas | clusters of cell bodies |
| hypothalamus | structure found near the base of the forebrain that is involved in the regulation of basic biological needs and controls the automatic nervous system and is a vital link between the brain and the endocrine system and plays a major role in basic biological drives related to survival; has connections with pituitary |
| limbic system | loosely connected network of structures located roughly along the border between the cerebral cortex and deeper subcortical areas; involved in regulation of emotion, memory, and motivation |
| amygdala | may play a central role in the learning of fear responses |
| cerebrum | largest most complex part of the human brain; most complex mental activities |
| cerebral cortex | convoluted outer layer of the cerebrum |
| cerebral hemispheres | right and left halves of the cerebrum |
| corpus callosum | thick band of fibers that connects the two cerebral hemispheres |
| lobes | four divisions of each cerebral hemisphere |
| occipital lobe | at the back of the head, includes cortical area, where most visual signals are sent and visual processing begins |
| parietal lobe | forward of the occipital lobe; includes area that registers sense of touch |
| temporal lobe | below parietal lobe and contains areas devoted to auditory processing |
| frontal lobe | largest lobe in the human brain and contains principle areas that control the movement of muscles |
| Broncca’s area | plays an important role in the production of speech |
| Wernicke’s area | in the temporal lobe of the left hemisphere and has to do with comprehension of language |
| split-brain surgery | when the bundle of fibers that connects the cerebral hemispheres (corpus callosum) is cut to reduce the severity of epileptic seizures |
| perceptual asymmetry | left-right imbalances between the cerebral hemispheres in the speed of visual or auditory processing |
| endocrine system | consists of glands that secrete chemicals into the bloodstream that help control bodily functioning |
| hormones | chemical messengers in communication net are released by endocrine glands; play an important role in modulating human physiological development |
| pituitary gland | releases a great variety of hormones that fan out around the body, stimulating actions in the other endocrine glands: “master gland” of endocrine system |
| gonadotropins | affect the gonads |
| behavioral genetics | interdisciplinary field that studies the influence of genetic factors on behavioral traits |
| chromosomes | strands of DNA molecules that carry genetic info |
| zygote | single cell formed by the union of sperm and egg |
| genes | DNA segments that serve as the key functional units in hereditary transmissions |
| mutations | spontatneous, heritable change in a piece of DNA that occurs in an organism |
| homozygous condition | when two genes in a specific pair are the same |
| heterozygous condition | when two genes in a specific pair are different |
| dominant gene | gene that is expressed when paired genes are different |
| recessive gene | one that is masked when paired genes are different |
| genotype | refers to a person’s genetic makeup |
| phenotype | refers to the ways in which a person’s genotype is a manifested in observable characteristics |
| polygenic traits | characteristics that are influenced by more than one pair of genes |
| family studies | researchers assess hereditary influence by examining blood relatives to see how much they resemble one another on a specific trait |
| twin studies | researchers assess hereditary influence by comparing the resemblance of identical twins and fraternal twins with respect to a trait |
| identical twins | emerge from one zygote that splits for unknown reasons |
| fraternal twins | result when two eggs are fertilized simultaneously by different sperm cells, forming two separate zygotes |
| adoption studies | assess hereditary influence by examining the resemblance between adopted children and both their biological and their adoptive parents |
| molecular genetics | study of biochemical bases of genetic inheritance |
| genetic mapping | process of determining the location and chemical sequence of specific genes on specific chromosomes |
| fitness | reproductive success of an individual organism relative to the average reproduction success in the population |
| Natural selection | posits heritable characteristics that provide a survival or reproductive advantage are more likely than alternative characteristics to be passed on to subsequent generations and thus they come to be selected over time |
| genetic drift | consists of random fluctuations in gene frequencies over generations, as result of chance alone |
| gene flow | occurs when two gene frequencies in a population shift because some individuals leave the population and others enter it |
| adaptation | key product of evolution; an inherited characteristic that increased in a population (through natural selection) because it helped solve a problem of survival or reproduction during time it emerged |
| inclusive fitness | organism may contribute to passing on its genes by sacrificing itself to save others that share the same gene: sum of individual’s own reproduction success plus the effects the organism has on the reproductive success of related others |
| parental investment | refers to what each sex has to invest to produce and nurture offspring |
| polygyny | a mating system in which each male seeks to mate with multiple females, whereas females mate with only one male |
| Polyandry | mating system in which each female seeks to mate with multiple males, whereas each male mates with only one female |
| monogamy | a mating system in which one male and one female mate exclusively, or almost exclusively, with each other |
| critical period | limited time span in the development of an organism when it is optimal for certain capacities to emerge because the organism is especially responsive to certain experiences |
