The Nervous System Vocabulary BINGO
1. Neurons – nerve cells that are specialized to react to physical and chemical
changes in their surroundings
2. Dendrite – part of a neuron that receives electrochemical messages
3. Axon – usually only one per cell; sends information away from the cell body
4. Nerve impulse – the electrochemical process of depolarization and repolarization
along a nerve fiber; how neurons transmit information
5. Nerves – bundles of axons; a cordlike bundle (or group of bundles) of nerve fibers
within layers of connective tissue
6. Neuroglial cells – the supporting cells of nervous tissue; includes astrocytes,
microglial cells, ependymal cells, & oligodendrocytes
7. Effectors – lie outside the nervous system and include muscles that contract and
glands that secrete
8. Myelin sheath – fatty covering around axons
9. Nissl bodies – membranous sacs scattered throughout a neuron’s cytoplasm;
function in protein synthesis
10. Neurofibrils – a network of fine threads which extend into the axons
11. Nodes of Ranvier – narrow gaps in the myelin sheath between Schwann cells
12. Ganglia – specialized masses of nervous tissue made of unipolar neuron cell
bodies; found outside the brain and spinal cord
13. Threshold potential – the point to which a membrane must be depolarized in order
to initiate an action potential
14. Action potential – the rapid sequence of depolarization and repolarization, which
takes about one-thousandth of a second
15. Saltatory conduction – when a nerve impulse jumps from node to node on
myelinated axons (much faster than on unmyelinated axons)
16. Refractory period – the very short resting period following a nerve impulse; this
limits the frequency of impulses in a neuron
17. Nerve pathways – the route that nerve impulses travel
18. Synapse – the junction between any two communicating neurons
19. Presynaptic neuron – Sender; the neuron carrying the impulse into the synapse
20. Postsynaptic neuron – Receiver; the neuron that receives the input at the synapse
21. Neurotransmitter – the chemical that an axon end secretes on an effector (muscle
or gland) or another neuron
22. Synaptic knobs – the distal ends of axons; contain many membranous sacs
(synaptic vesicles) which release neurotransmitters
23. Reflex – automatic, subconscious response to changes (stimuli) within or outside
the body; helps to maintain homeostasis
24. Meninges – membranes located between the bone and soft tissues of the nervous
system; help to protect the brain and spinal cord; consists of 3 layers: dura mater,
arachnoid layer, and the pia mater
25. Ascending tracts – tracts that carry sensory information to the brain
26. Descending tracts – tracts that conduct motor impulses from the brain to muscles
and glands
27. Ventricles – a series of interconnected cavities within the brain that contain
cerebrospinal fluid
28. Convolutions– (gyri); the ridges on the surface of the cerebrum; separated by grooves
29. Choroid plexuses – tiny, reddish, cauliflower-like masses of specialized
capillaries in the pia mater that secrete cerebrospinal fluid
30. Cauda equina – (horse’s tail); formed by the extension of the lumbar, sacral, and
coccygeal nerves beyond the end of the spinal cord
31. Plexus – a network of interlaced nerves
32. Addiction – a physical or psychological dependence in which a user is
preoccupied with locating and taking a drug
33. Drug abuse – the chronic self-administration of a drug in doses high enough to
cause addiction