neuron
a nerve cell; the basic building block of our nervous system
dendrites
a nueron’s bushy, branching extensions that receives messages through its branches and conduct impulses towards the cell body
axon
the neuron extension that passages messages through its branches to other neurons or to muscles or glands
myelin sheath
a fatty tissue layer segmentally encasings the axons of some neurons; enables the axons of some neuron; enables vastly greater transmission speed as neural impulses hop from one sausage like neuron to the next
action potential
a neural impulse; a brief electrical charge that travels down an axon
refractory period
a period of inactivity after the neuron has fired
threshold
the level of stimulation required to trigger an impulse
all or none response
a neuron’s reaction of either firing or not firing, regardless of the intensity of the trigger
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.
neurotransmitter
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.
reuptake
a neurotransmitter’s reabsorption by the sending neuron
endorphins
“morphine within” – natural, opiate-like neurotransmitter linked to pain control and to pleasure
agonist
a molecule that, by binding to a receptor site, stimulates a response
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
the brain and spinal cord
peripheral nervous system
the sensory and motor neurons that connect the central
nervous system (CNS) to the rest of the body.
somatic nervous system
the division of the peripheral nervous that controls the body’s skeletal system
autonomic nervous system
controls the glands and the organs. Has two systems, sympathetic and parasympathetic
sympathetic nervous system
arouses the body, half of the autonomic nervous system. Mobilizes energy in stressful situations.
parasympathetic nervous system
calms the body in stressful situations, this is done to preserve energy
endocrine system
the body’s slow chemical reaction system, set to secrete hormones into the blood stream
hormones
chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream and to tissue
pituitary glands
the endocrine system’s most influential gland. Also called the “master gland” Under the influence of the hypothalamus, the pituitary gland regulates the growth and controls the other endocrine glands
adrenal glands
a pair of glands that sit above the kidney and secrete hormones (epinephrine and norepinephrine) that help arouse in times of stress (adrenaline comes from this)
lesion
tissue destruction. A brain lesion is the destruction of brain tissue. This is done either experimentally or can happen naturally
EEG
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
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. (Also called CAT scan.)
PET scan
a visual display of brain activity that detects
where a radioactive form of glucose goes while the brain performs a given task.
MRI
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. fMRI scans show brain function as well as its structure.
brainstem
the oldest part and central part of the brain, beginning where the spinal cord swells as it enters the skull; the brain stem is responsible for automatic survival functions
medulla
the base of the brain stem, 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.
pons
coordinates movement
reticular formation
a nerve network that travels through the brainstem and thalamus and plays an important role in controlling arousal.
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 hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives.
amygdala
two lima bean sized neural clusters in the limbic system; linked to emotion
hypothalamus
a neural structure lying below (hypo) the thalamus; 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.
corpus collosum
connects the two hemispheres of the brain
cerebellum
the intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body’s ultimate control and information-processing center
dual processing
the principle that information is often simultaneously processed on separate conscious and unconscious tracks.
consciousness
our awareness of ourselves and our environments
split brain
\n a condition resulting from surgery that isolates the brain’s two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them.
left brain
handles creative thinking and problem solving
right brain
handles sense of self and and makes inferences and handles perceptual tasks
behavior genetics
the study of the relative power and limits of genetics and environmental influences on behavior
heritability
the proportion of variation among individuals that we can attribute to genes. The heritability of a trait may vary, depending on the range of populations and environments studied (IN A GROUP)
epigenetics
the study of environmental influences on gene expression that occur without a DNA change
mutations
a random error in gene replication that leads to a change