Nervous System Flashcards
Neurons
Cell of the nervous system specialized to generate and transmit electrical signals (action potentials and graded potentials).
Dendrites
Branching neuron process that serves as a receptive, or input, region; transmits an electrical signal toward the cell body.
Axons
Neuron process process that carries action potentials away from the nerve cell body; efferent process; the conducting portion of a nerve cell.
Schwann Cells
A type of supporting cell in the PNS; forms myelin sheaths and is vital to peripheral nerve fiber regeneration. Also called a neurolemmocyte.
Myelin
Fatty insulating sheath that surrounds all but the smallest nerve fibers.
Neurilemma
The thin sheath that surrounds all but the smallest nerve fibers.
Nodes of Ranvier
A gap in the sheath of a nerve, between adjacent Schwann cells.
Synapse
Functional junction or point of close contact between two neurons or between a neuron and an effector cell.
Nissl Bodies
A large granular body found in neurons, believed to be primarily concerned with the synthesis of proteins for intercellular use.
Neuroglia
Nonexcitable cells of neural tissue that support, protect, and insulate the neurons; glial cells.
Astrocytes
A type of CNS supporting cell; assists in exchanges between blood capillaries and neurons.
Oligodendrocytes
A type of CNS supporting cell that composes myelin sheaths.
Microglia
A type of CNS supporting cell; can transform into phagocytes in areas of neural damage or inflammation.
Autonomic Nervous System
Part of the nervous system that controls the visera, such as the heart and various glands, and thus causes involuntary sub-conscious actions.
Sympathetic Nervous System
Part of the nervous system that controls the peripheral nervous system that lead to the skeletal muscles, and thus causes voluntary actions.
Central Nervous System
The complex of nerve tissue that controls the activities of the body, and comprises the brain and spinal cord.
Peripheral Nervous System
Parts of the nervous system that relays nerve impulses to and from the brain and spinal cord; and comprises cranial nerves and spinal nerves.
Sensory Neuron
An afferent nerve cell that detects and responds to external signals.
Motor Neuron
An efferent nerve cell responsible for carrying signals away from the CNS towards the muscles to cause movement.
Interneuron
Nerve cell located between motor and sensory neurons that shuttles signals through CNS pathways where integration occurs.
Resting Potential of Nerve
The imbalance of electrical charge that exists between the interior of electrically excitable neurons (nerve cells) and their surroundings.
Action Potential of Nerve
A large transient depolarization event, including polarity reversal, that is propagated along the membrane of a muscle cell or an axon of a neuron.
Excitatory Postsynaptic Potential
When a neurotransmitter can depolarize the postsynaptic membrane; triggering an action potential for the neuron.
Inhibitory Postsynaptic Potential
When a neurotransmitter binds with other receptors and increases membrane permeability to potassium ions, which hyperpolarize the postsynaptic membrane; prevents an action potential foe the neuron.
Refractory Period
A period of time during which a cell is incapable of repeating an action potential.
Acetylcholine
A neurotransmitter in the basal forebrain and the mesopontine tegmentum that plays an important role in many of your body’s functions, including muscle movement, memory and cognition, REM sleep, and attention and learning.
Acetylcolinesterase
Enzyme that degrades acetylcholine and terminates its action at the neuromuscular junction and synapses.
Dopamine
A neurotransmitter in the substantia nigra, the ventral tegmental area, and the hypothalamus that allows one to feel pleasure, satisfaction, and motivation.
Serotonin
A neurotransmitter in the raphe nuclei of the midbrain and the GI tract that functions in mood, appetite, sleep, body temperature, and blood.
Neuropeptides
A class of neurotransmitters and gut-brain peptides (examples: endorphins and enkephalins).
Epilepsy
A disorder in which nerve cell activity in the brain is disturbed, causing seizures.
Huntington Disease
Hereditary disorder leading to degeneration of the basal nuclei and the cerebral cortex.
Parkinson Disease
Neurodegenerative disorder of the basal nuclei due to an insufficient secretion of the neurotransmitter dopamine; symptoms include tremor and rigid movements.
Insomnia
A sleep disorder that results in one having trouble falling asleep, staying asleep, or getting good quality sleep.
Alzheimer Disease
Degenerative brain disease resulting in progressive loss of memory and motor control, and increasing dementia.
Convergent Nerve Impulse
An electrochemical signal transmitted from various sensory receptors to a single neuron in order to collect, process, and respond to the information.
Divergent Nerve Impulse
An electrochemical signal transmitted from one neuron to reach several neurons; example: a single neuron in the CNS may stimulate several motor neurons.
