neuroanatomy
the study of the parts and function of neurons. these cells make up our entire nervous system.
neuron
neural cell. made up of specific structures: dendrites, cell body, axon, and terminal buttons.
dendrites
rootlike parts of the cell that stretch out from the cell body. dendrites gros to make synaptic connections with other neurons.
cell body (also called the soma)
contains the nucleus and other parts of the cell needed to sustain its life.
axon
wirelike structure ending in the terminal buttons that extends from the cell body.
myelin sheath
fatty covering around the axon of some neurons that speeds neural impulses.
terminal buttons (also called end buttons, axon terminal, terminal branches of axon, and synaptic knobs)
branched ends of the axon that contains neurotransmitters.
neurotransmitters
chemicals contained in terminal buttons that enable neurons to communicate. neurotransmitters fit into receptor sites on the dendrites of neurons like a key fits into a lock.
synapse
space between terminal buttons of one neuron and the dendrites of the next neuron.
receptor sites
areas on a dendrite designed to receive a specific neurotransmitter.
threshold
level of neurotransmitters required to "fire" a neuron.
action potential
electric charge that spreads down the length of a neuron after the threshold is achieved. travels like a bullet from a gun.
all-or-none principle
neuron either fires completely or it does not fire at all. if the dendrites of a neuron receive enough neurotransmitters to push the neuron past its threshold, the neuron will fire completely every time.
neural firing
electrochemical process where electricity travels within the cell and neurotransmitters travel between cells and the synapse.
exitatory neurotransmitters
chemicals released from the terminal buttons of a neuron that excite the next neuron into firing.
inhibitory neurotransmitters
chemicals released from the terminal buttons of a neuron that inhibit the net neuron from firing.
acetylocholine
associated with motor movement. lack of this substance is associated with Alzheimer's disease.
dopamine
associated with motor movement and alertness. lack of this substance is associated with Parkinson's disease; an overabundance is associated with schizophrenia.
endorphins
neurontransmitter associated with pain control. also involved in drug addictions.
serotonin
neurotransmitter associated with mood control. lack of this drug is associated with clinical depression.
affarent neurons (or sensory neurons)
neurons that take information from the senses to the brain. they are responsible for transmitting neural impulses from the rest of the body to the brain.
efferent neurons (or motor neurons)
neurons that take information from the brain to the rest of the body. they carry information that exits the brain.
central nervous system
part of the nervous system that consists of our brain and spinal cord. all the nerves are housed within bone (the skull and vertebrae).
spinal cord
a bundle of nerves that urn through the center of the spine. transmits information from the rest of the body to the brain.
peripherial nervous system
all of the nerves in your body other than the brain and spinal cord nerves; all the nerves not encased in bone.
somatic nervous system
controls volantary muscle movements. the motor cortex of the brain sends impulses to the somatic nervous system, which controls the muscles that allow us to move.
automatic nervous system
controls heart, lungs, internal organs, glands, and so on. controls responses to stress- the fight or flight response that prepares the body to respond to a perceived threat.
sympathetic nervous system
mobilizes or body to respond to stress. carries messages to the control systems. the alert system of the human body.
parasympathetic nervous system
responsible for slowing down the body after a stress response. carries messages to the stress response system that causes the body to slow down. the "brake pedal".
accidents
early psychologists studied this as a way to investigate brain function
lesions
removal or destruction of part of the brain
EEG
device that detects brain waves
CAT scan
a sophisticated x-ray
MRI scan
uses magnetic fields to measure the density and location of brain material
PET scan
measures how much of a certain chemical (glucose, for example) parts of the brain are using. the more used, the higher the activity.
fMRI
combines elements of the MRI and PET scans
hindbrain
top part of the spinal chord holding the medulla, pons, and cerebellum.
medulla
involved in the control of our blood pressure, heart rate, and breathing.
pons
involved in the control of facial expressions.
cerebellum
coordinates some habitual muscle movements, such as tracking a target with our eyes or playing the saxophone.
midbrain
coordinates simple movements with sensory information
recticular formation
Netlike collection of cells throughout the midbrain that controls general body arousal and the ability to focus attention. If this is not working, we fall into a deep coma.
forebrain
controls what we think of as thought and reason.
thalamus
responsible for receiving the sensory signals coming up the spinal cord and sending them to the appropriate areas of the forebrain.
hypothalamus
controls several metabolic functions, including body temperature, sexual arousal (libido), hunger, thirst, and the endocrine system.
amygdala
vital to our experiences of emotion, anger and fear in particular.
hippocampus
vital to our memory system. memories are not permanently stored in this area of the brain, however. memories are processed through this area and then sent to other locations in the cerebral cortex for permanent storage.
limbic system
name for a group of brain structures including thalamus, hypothalamus, amygdala, and hippocampus.
cerebral cortex
gray wrinkled surface of the brain. a think layer of densly packed neurons covering the rest of the brain.
hemispheres
look like mirror images of one another, but they exert some differences in function. it is divided into two.
left hemisphere
gets sensory messages and controls the motor function of the right half of the body. this may be more active during spoken language, logic, and sequential tasks.
right hemisphere
gets sensory messages and controls the motor functions of the left half of the body. this may be more active during spatial and creative tasks.
brain lateralization (or hemispheric specialization)
the functions of each brain hemisphere.
corpus callosum
nerve bundle that connects the two brain hemispheres.
lobes
areas of the cerebral cortex: frontal, parietal, temporal, and occipital.
association areas
any area of the cerebral cortex that is not associated with receiving sensory information or controlling muscle movements.
frontal lobes
the prefrontal cortex that acts as the brain's central executive and is believed to be more important in foreseeing consequences, pursuing goals, and maintaining emotional control.
broca's area
responsible for controlling the muscles involved in producing speech. damage to this area might leave us unable to make the muscle movements needed for speech.
wernicke's area
interprets both written and spoken speech. damage to this area would affect our ability to understand language.
motor cortex
sends signals to our muscles, controlling our voluntary movements.
parietal lobes
contain the sensory cortex (also known as the somato-sensory cortex), which is located right behind the motor cortex in the frontal lobe.
sensory cortex
receives sensations from the bottom of the body, progressing down the cortex to the bottom, which processes signals from our face and head.
occipital lobes
interprets messages from our eyes in our visual cortex. impulses from the retinas in our eyes are sent to the visual cortex to be interpreted.
temporal lobes
process sound sensed by our ears, turning into neural impulses, and interpreting in our auditory cortices.
brain plasticity
parts of the brain can adapt themselves to perform other functions if needed.
endocrine system
system of glands that secrete hormones. affects many different biological processes in our bodies.