Key Terms
- acetylcholine
- neurotransmitter released by neurons in the central nervous system and peripheral nervous system
- action potential
- self-propagating momentary change in the electrical potential of a neuron (or muscle) membrane
- Alzheimer’s disease
- neurodegenerative disorder characterized by problems with memory and thinking
- amygdala
- structure within the limbic system that processes fear
- arachnoid mater
- spiderweb-like middle layer of the meninges that cover the central nervous system
- astrocyte
- glial cell in the central nervous system that provide nutrients, extracellular buffering, and structural support for neurons; also makes up the blood-brain barrier
- attention deficit hyperactivity disorder (ADHD)
- neurodevelopmental disorder characterized by difficulty maintaining attention and controlling impulses
- autism spectrum disorder (ASD)
- neurodevelopmental disorder characterized by impaired social interaction and communication abilities
- autonomic nervous system
- part of the peripheral nervous system that controls bodily functions
- axon
- tube-like structure that propagates a signal from a neuron’s cell body to axon terminals
- axon hillock
- electrically sensitive structure on the cell body of a neuron that integrates signals from multiple neuronal connections
- axon terminal
- structure on the end of an axon that can form a synapse with another neuron
- basal ganglia
- interconnected collections of cells in the brain that are involved in movement and motivation; also known as basal nuclei
- basal nuclei
- see basal ganglia
- brainstem
- portion of the brain that connects with the spinal cord; controls basic nervous system functions like breathing, heart rate, and swallowing
- cerebellum
- brain structure involved in posture, motor coordination, and learning new motor actions
- cerebral cortex
- outermost sheet of brain tissue; involved in many higher-order functions
- cerebrospinal fluid (CSF)
- clear liquid that surrounds the brain and spinal cord and fills the ventricles and central canal; acts as a shock absorber and circulates material throughout the brain and spinal cord.
- choroid plexus
- spongy tissue within ventricles that produces cerebrospinal fluid
- cingulate gyrus
- helps regulate emotions and pain; thought to directly drive the body’s conscious response to unpleasant experiences
- corpus callosum
- thick fiber bundle that connects the cerebral hemispheres
- cranial nerve
- sensory and/or motor nerve that emanates from the brain
- dendrite
- structure that extends away from the cell body to receive messages from other neurons
- depolarization
- change in the membrane potential to a less negative value
- dura mater
- tough outermost layer that covers the central nervous system
- ependymal
- cell that lines fluid-filled ventricles of the brain and the central canal of the spinal cord; involved in production of cerebrospinal fluid
- epilepsy
- neurological disorder characterized by recurrent seizures
- excitatory postsynaptic potential (EPSP)
- depolarization of a postsynaptic membrane caused by neurotransmitter molecules released from a presynaptic cell
- frontal lobe
- part of the cerebral cortex that contains the motor cortex and areas involved in planning, attention, and language
- glia
- (also, glial cells) cells that provide support functions for neurons
- gyrus
- (plural: gyri) ridged protrusions in the cortex
- hippocampus
- brain structure in the temporal lobe involved in processing memories
- hyperpolarization
- change in the membrane potential to a more negative value
- hypothalamus
- brain structure that controls hormone release and body homeostasis
- inhibitory postsynaptic potential (IPSP)
- hyperpolarization of a postsynaptic membrane caused by neurotransmitter molecules released from a presynaptic cell
- limbic system
- connected brain areas that process emotion and motivation
- long-term depression (LTD)
- prolonged decrease in synaptic coupling between a pre- and post-synaptic cell
- long-term potentiation (LTP)
- prolonged increase in synaptic coupling between a pre- and post-synaptic cell
- major depression
- mental illness characterized by prolonged periods of sadness
- membrane potential
- difference in electrical potential between the inside and outside of a cell
- meninge
- membrane that covers and protects the central nervous system
- microglia
- glia that scavenge and degrade dead cells and protect the brain from invading microorganisms
- myelin
- fatty substance produced by glia that insulates axons
- neurodegenerative disorder
- nervous system disorder characterized by the progressive loss of neurological functioning, usually caused by neuron death
- neuron
- specialized cell that can receive and transmit electrical and chemical signals
- nodes of Ranvier
- gaps in the myelin sheath where the signal is recharged
- norepinephrine
- neurotransmitter and hormone released by activation of the sympathetic nervous system
- occipital lobe
- part of the cerebral cortex that contains visual cortex and processes visual stimuli
- oligodendrocyte
- glial cell that myelinates central nervous system neuron axons
- parasympathetic nervous system
- division of autonomic nervous system that regulates visceral functions during rest and digestion
- parietal lobe
- part of the cerebral cortex involved in processing touch and the sense of the body in space
- Parkinson’s disease
- neurodegenerative disorder that affects the control of movement
- pia mater
- thin membrane layer directly covering the brain and spinal cord
- proprioception
- sense about how parts of the body are oriented in space
- radial glia
- glia that serve as scaffolds for developing neurons as they migrate to their final destinations
- refractory period
- period after an action potential when it is more difficult or impossible for an action potential to be fired; caused by inactivation of sodium channels and activation of additional potassium channels of the membrane
- saltatory conduction
- jumping of an action potential along an axon from one node of Ranvier to the next
- satellite glia
- glial cell that provides nutrients and structural support for neurons in the peripheral nervous system
- schizophrenia
- mental disorder characterized by the inability to accurately perceive reality; patients often have difficulty thinking clearly and can suffer from delusions
- Schwann cell
- glial cell that creates myelin sheath around a peripheral nervous system neuron axon
- sensory-somatic nervous system
- system of sensory and motor nerves
- somatosensation
- sense of touch
- spinal cord
- thick fiber bundle that connects the brain with peripheral nerves; transmits sensory and motor information; contains neurons that control motor reflexes
- spinal nerve
- nerve projecting between skin or muscle and spinal cord
- sulcus
- (plural: sulci) indents or valleys in the cortex
- summation
- process of multiple presynaptic inputs creating EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential
- sympathetic nervous system
- division of autonomic nervous system activated during stressful fight or flight situations
- synapse
- junction between two neurons where neuronal signals are communicated
- synaptic cleft
- space between the presynaptic and postsynaptic membranes
- synaptic vesicle
- spherical structure that contains a neurotransmitter
- temporal lobe
- part of the cerebral cortex that processes auditory input; parts of the temporal lobe are involved in speech, memory, and emotion processing
- thalamus
- brain area that relays sensory information to the cortex
- threshold of excitation
- level of depolarization needed for an action potential to fire
- ventricle
- cavity within brain that contains cerebrospinal fluid