Studied by 301 PeopleTags & Description
neuron
a nerve cell; the basic building block of the nervous system
cell body (soma)
the part of a neuron that contains the nucleus; the cell's life-support center
dendrites
a neuron's often busy, branching extensions that receive and integrate messages conducting impulses toward the cell body (soma)
axon
the neuron extension that passes messages through its branches to other neurons or to muscles or glands
myelin sheath
a fatty tissue layer segmentally encasing the axons of some neurons, enables vastly greater transmission speed as neural impulses hop from one node to the next
glial cells (glia)
cells in the nervous system that support, nourish, and protect neurons; they also play a role in learning, thinking, and memory
action potential
a neural impulse; a brief electrical charge that travels down an axon
threshold
the level of stimulation required to trigger a neural impulse
refractory period
in neural processing, a brief resting pause that occurs after a neuron has fired; subsequent action potentials cannot occur until the axon returns to its resting state
all-or-none response
a neuron's reaction of either firing (with a full-strength response) or not firing
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
neurotransmitters
chemical messengers that cross the synaptic gaps between neurons; when released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse
endorphins
"morphine within"; natural, opiate-like neurotransmitters linked to pain control and to pleasure
agonist
a molecule that increases a neurotransmitter's action
antagonist
a molecule that inhibits or blocks a neurotransmitter's action
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)
the brain and spinal cord
peripheral nervous system (PNS)
the sensory and motor neurons that connect the central nervous system to the rest of the body
nerves
bundled axons that form neural cables connecting the central nervous system with muscles, glands, and sense organs
sensory (afferent) neurons
neurons that carry incoming information from the body's tissues and sensory receptors to the brain and spinal cord
motor (efferent) 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; they communicate internally and process information 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 (such as the heart). 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
actetylcholine (ACh)
enables muscle action, learning, and memory; associated with Alzheimer's disease
dopamine
influences movement, learning, attention, and emotion; too much is associated with Schizophrenia; too little is associated with Parkinson's disease
serotonin
affects mood, hunger, sleep, and arousal; too little associated with depression
norepinephrine
helps control alertness and arousal; too little linked with depression
GABA
a major inhibitory neurotransmitter
glutamate
A major excitatory neurotransmitter; involved in memory; too much can lead to migraines
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
CT scan (CAT 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
MRI (magnetic resonance imaging)
a technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. MRI scans show brain anatomy
fMRI (functional MRI)
a technique for revealing bloodflow and, therefore, brain activity by comparing successive MRI scans. 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; the brainstem is responsible for automatic survival functions
medulla
the base of the brainstem; controls heartbeat 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 into the thalamus and plays an important role in controlling arousal and attention
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 amygdala, hypothalamus, and hippocampus) located below the cerebral hemispheres; associated with emotions and drives
amygdala
two neural clusters in the limbic system linked to emotion
hypothalamus
it 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
located in the limbic system, helps process for storage explicit (conscious) memories of facts and events