Axon
long, branching fiber that sends electrochemical information to other neurons
axon hillock
area where the axon joins the cell body. moniters stimulation threshold
cell body
The central part of a neuron (or other cell) that contains the nucleus and controls the cell's metabolic activities and integrates inputs
cell membrane
a thin membrane around the cytoplasm of a cell... controls passage of substances in and out of cell
dendrites
branching extensions of neuron that receives messages from neighboring neurons
myelin sheath
a layer of fatty tissue encasing a neuron's axon that speeds transmission
neurotransmitter
chemical used by a neuron to transmit an impulse across a synapse to another cell
node of ranvier
small gap between myelinated segments where axonal membrane is exposed; increase speed of impulses
synapse
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
neuron
a cell that receives signals from other neurons or sense organs, processes these signals, and sends the signals to other neurons, muscles, or organs
sensory neuron
a neuron that responds to input from sense organs
motor neuron
a neuron that sends signals to muscles to control movement
interneuron
a neuron that is connected to other neurons, (not to sense organs or muscles)
brain circuit
a set of neurons that affect one another
terminal button
a structure at the end of a branch of an axon that, when the neuron is triggered, releases chemicals into the space between neurons
resting potential
the negative charge within a neuron when it is at rest (positive outside, negative inside)
ion
an atom that has a positive or negative charge
action potential
the shifting change in a charge that moves down the axon
all-or-none law
either the potential occurs, or it doesn't; "states that if the neuron is sufficiently stimulated, it fires, sending the action potential all the way down the axon and releasing chemicals from the terminal buttons
myelin
a fatty substance that helps impulses travel down the axon more efficiently
synaptic cleft
the gap between the axon of one neuron and the membrane of another, across which communication occurs
neurotransmitter
a chemical that carries a signal from the terminal button on one neuron to the dendrite or cell body of another (excitatory or inhibitory)
neuromodulator
a chemical that alters the effect of a neurotransmitter
endogenous cannabinoids
neuromodulators released by the receiving neuron that then influence the activity of the sending neuron
receptor
a site on a dendrite or cell body where a messenger molecule attaches iteself (receives only one type of neurotransmitter or neuromodulator = lock and key)
reuptake
the process by which surplus neurotransmitter is reabsorbed back into the sending neuron so that the neuron can effectively fire again
agonist
a chemical that mimics the effect of a neurotransmitter by activation a type of receptor
selective serotonin-reuptake inhibitor (SSRI)
a chemical that blocks the reuptake of the neurotransmitter serotonin
antagonist
a chemical that interferes with the effect of a neurotransmitter (often by blocking a receptor)
glial cell
a type of cell that surrounds neurons, influences the communication among neurons, and generally helps in the "care and feeding" of neurons
peripheral nervous system (PNS)
the autonomic nervous system and the sensory-somatic nervous system
autonomic nervous system (ANS)
controls the smooth muscles in teh body, some glandular functions, and many of the body's self-regulating activitiess (digestion and circulation = "automatic")
sympathetic nervous system
readies an animal to cope with an emergency by speeding up heart, increasing breathing rate, dilating pupils, producing sweat, etc. (part of ANS)
parasympathetic nervous system
part of the ANS that is "next to" the sympathetic system and tends to counteract its effects (slow heart rate, etc.)
skeletal system
consists of nerves that are attached to striated muscles
spinal cord
the flexible rope of nerves that runs inside the backbone, or spinal column
central nervous system (CNS)
the spinal cord and the brain
reflex
an automatic response to an event
lobes
the 4 major parts of each cerebral hemisphere (occipital, temporal, parietal, and frontal)
corpus callosum
the large band of nerve fibers that connects the 2 halves of the brain (what's cut in split-brain patients)
cerebral cortex
the convoluted pinkish-gray outer layer of the brain...most mental processes take place here
sulcus
a crease in the cerebral cortex
gyrus
a bulge between sulci in the cerebral cortex
ventricle
a hollow area in the center of the brain the stores fluid
subcortical structures
parts of the brain located under the cerebral cortex and beneath the ventricles
occipital lobe
located at the back of the head.... concerned entirely with different aspects of VISION
temporal lobe
located under the temples, in front of ears, where sideburns begin to grow... visual memory and hearing
parietal lobe
located across the top part of the brain behind the ears... involved in registering spatial learning, attention, and motor control
somatosensory strip
located immediately behind the central sulcus... registers sensation on the body and is organized by body part
frontal lobe
located behind the forehead... planning, memory, search, motor control, and reasoning take place here
motor strip
primary motor cortex"... controsl fine movement and is organized by body part
split-brain patient
person whose corpus callosum has been severed for medical reasons, so that neural impulses no longer pass from 1 hemisphere to the other
forebrain
the cortex, thalamus, limbic system, and basal ganglia
thalamus
switching center".. receives inputs from sensory and motor systems and plays crucial role in attention
hypothalamus
plays central role in controlling eating and drinking and in regulating body temp, blood pressure, and heart rate
hippocampus
plays key role in allowing new information to be stored in the brain's memory banks (camp info)
amygdala
plays special role in fear and is involved in other sorts of emotions, such as anger
limbic system
a set of brain areas, including the hippocampus, amygdala, and other areas, that have long been thought of as being involved in fighting, fleeing, feeding, and sex
basal ganglia
plays a role in planning and producing movement
brain stem
set of neural structures at the base of the brain, including medulla and pons
medulla
plays central role in automatic control of breathing, swallowing, and blood circulation
reticular formation
2 part structure in brainstem "ascending" part plays key role in keeping person awake and alert "descending" part is important in producing autonomic nervous system reactions
pons
plays role in functions ranging from sleep to control of facial muscles (bridge between brainstem and cerebellum)
cerebellum
connected in part with physical coordination, estimating time, and paying attention (large structure at base of brain)... "bell" = time, clock
hindbrain
medulla, pons, cerebellum, and parts of the reticular formation
midbrain
brainstem structures that lie between forebrain and hindbrain, including parts of the reticular formation
hormone
chemical that's produced by a gland and can act as a neuromodulator
neuroendocrine system
the system, regulated by the CNS, that makes hormones that affect many bodily functions and also provides CNS with info
testosterone
the hormone that causes males to develop facial hair and other sex characteristics and to build up muscle volume
estrogen
hormone that causes breasts to develop and is involved in menstrual cycle
cortisol
hormone produced by the outer layer of the adrenal glands that helps the body cope with the extra energy demands of stress by breaking down and converting protein and fat to sugar
pituitary gland
master gland"... .regulates other glands but is itself controlled by the brain, primarily via connections from the hypothalamus
lesion
a region of impaired tissue
stroke
source of brain damage that occurs when blood fails to reach part of the brain, causing neurons in that area to die
electroencephalograph (EEG)
machine that records electical current produced by the brain
electroencephalogram
recording from the scalp of electrical activity in the brain over time, which produces a tracing of pulses at different frequencies
microelectrode
tiny probe inserted into the brain to record the electrical activity of individual neurons
neuroimaging
brain-scanning techniques that produce a picture of the structure or functioning of neurons
computer-assisted tomography (CT)
a neuroimaging technique that produces a 3-D image of brain structures using X-rays
magnetic resonance imaging (MRI)
technique that uses magnetic properties of atoms to take sharp pictures of the structures of brain
positron emission tomography (PET)
tracks blood flow to certain area... image of brain when hearing, seeing, etc. (during given activity)
functional magnetic resonance imaging (fMRI)
type of MRI that usually detects the amount of oxygen being brought to a particular place in the brain wile task is performed
transcranial magnetic stimulation (TMS)
technique where brain is stimulated from outside by putting a wire coil on a person's head and delivering a magnetic pulse... the magnetic fields are so strong that they make neurons under the coil fire
mendelian inheritance
the transmission of characteristics by individual elements of inheritance (genes), each acting seperately
DNA
molecule that contains genes
gene
a stretch of DNA that produces a specific protein
complex inheritance
the joint action of combinations of genes working together
mutation
physical change in a gene
pruning
a process whereby certain connections among neurons are eliminated
plasticity
brain's ability to be molded by experience
passive interaction
occurs when genetically shaped tendencies of parents or siblings produce an environment that's passively received by child (ex: parent reading to child)
evocative (or reactive) interaction
occurs when genetically influenced characteristics draw out behaviors from other people (es: treating "hard babies" differently)
active interaction
occurs when people choosse, partly based on genetic tendencies, to put themselves in specific situations and to avoid others (you choose)
behavioral genetics
the field in which researches attempt to determine the extent to which the differences among people are due to their genes or the environment
heritability
the degree to which variability in a characteristic is due to genetics
evolution
gene based changes in the characteristics of members of a species over successive generations
natural selection
changes in the frequency of genes in a population that arise because genes allow an organism to have more offspring that survive
adaptation
a characteristic that increases an organisms fitness for an environment
meninges
membranes that cover the brain