Across
- 2. neurotransmitter type that includes protein molecules and shorter chains of amino acids
- 4. connection between two neurons, or any two electrically active cells, where ions flow directly through channels spanning their adjacent cell membranes
- 6. cell membrane that regulates the movement of ions so that an electrical signal can be generated
- 7. combination of graded potentials across the neuronal cell membrane caused by signals from separate presynaptic elements that add up to initiate an action potential
- 11. small gap between cells in a chemical synapse where neurotransmitter diffuses from the presynaptic element to the postsynaptic element
- 16. lipid-rich layer of insulation that surrounds an axon, formed by oligodendrocytes in the CNS and Schwann cells in the PNS; facilitates the transmission of electrical signals
- 18. neural tissue cell that is primarily responsible for generating and propagating electrical signals into, within, and out of the nervous system
- 20. organ of the central nervous system found within the vertebral cavity and connected with the periphery through spinal nerves; mediates reflex behaviors
- 22. shape of a neuron which has only one process that includes both the axon and dendrite
- 23. single process of the neuron that carries an electrical signal (action potential) away from the cell body toward a target cell
- 24. outermost layer of gray matter in the brain, where conscious perception takes place
- 25. cord-like bundle of axons located in the peripheral nervous system that transmits sensory input and response output to and from the central nervous system
- 26. chemical signal that is released from the synaptic end bulb of a neuron to cause a change in the target cell
- 27. glial cell type in the CNS that provides the myelin insulation for axons in tracts
- 28. nervous system function that causes a target tissue (muscle or gland) to produce an event as a consequence to stimuli
- 29. glial cell type in the PNS that provides support for neurons in the ganglia
- 32. in neurons, that portion of the cell that contains the nucleus; the cell body, as opposed to the cell processes (axons and dendrites)
- 34. shape of a neuron that has multiple processes—the axon and two or more dendrites
- 36. property of a channel that determines how it opens under specific conditions, such as voltage change or physical deformation
- 37. movement of an action potential along the length of an axon
- 38. glial cell type of the CNS that provides support for neurons and maintains the blood-brain barrier
- 40. second neuron in the motor command pathway that is directly connected to the skeletal muscle
- 43. type of sensory receptor capable of transducing temperature stimuli into neural action potentials
- 44. nervous system function that receives information from the environment and translates it into the electrical signals of nervous tissue
- 48. neurotransmitter system of acetylcholine, which includes its receptors and the enzyme acetylcholinesterase
- 52. graded potential in a specialized sensory cell that directly causes the release of neurotransmitter without an intervening action potential
- 53. graded potential from dendrites of a unipolar cell which generates the action potential in the initial segment of that cell’s axon
- 55. regions of the nervous system containing cell bodies of neurons with few or no myelinated axons; actually may be more pink or tan in color, but called gray in contrast to white matter
- 56. one of the various types of neural tissue cells responsible for maintenance of the tissue, and largely responsible for supporting neurons
- 58. nervous system function that combines sensory perceptions and higher cognitive functions (memories, learning, emotion, etc.) to produce a response
- 60. narrow junction across which a chemical signal passes from neuron to the next, initiating a new electrical signal in the target cell
- 62. time after the initiation of an action potential when another action potential cannot be generated
- 63. shape of a neuron with two processes extending from the neuron cell body—the axon and one dendrite
- 64. the large organ of the central nervous system composed of white and gray matter, contained within the cranium and continuous with the spinal cord
- 65. central cavity within the brain where CSF is produced and circulates
- 66. change in a cell membrane potential from rest toward zero
- 67. anatomical division of the nervous system located within the cranial and vertebral cavities, namely the brain and spinal cord
- 68. distribution of charge across the cell membrane, based on the charges of ions
- 69. glial cell type in the PNS that provides the myelin insulation for axons in nerves
- 70. end of the axon, where there are usually several branches extending toward the target cell
- 71. physiological barrier between the circulatory system and the central nervous system that establishes a privileged blood supply, restricting the flow of substances into the CNS
Down
- 1. regions of the nervous system containing mostly myelinated axons, making the tissue appear white because of the high lipid content of myelin
- 3. one of many branchlike processes that extends from the neuron cell body and functions as a contact for incoming signals (synapses) from other neurons or sensory cells
- 5. anatomical division of the nervous system that is largely outside the cranial and vertebral cavities, namely all parts except the brain and spinal cord
- 8. functional division of the nervous system that is responsible for homeostatic reflexes that coordinate control of cardiac and smooth muscle, as well as glandular tissue
- 9. in the nervous system, a localized collection of neuron cell bodies that are functionally related; a “center” of neural function
- 10. change in the membrane potential that varies in size, depending on the size of the stimulus that elicits it
- 12. circulatory medium within the CNS that is produced by ependymal cells in the choroid plexus filtering the blood
- 13. membrane voltage at which an action potential is initiated
- 14. gap between two myelinated regions of an axon, allowing for strengthening of the electrical signal as it propagates down the axon
- 15. graded potential in the postsynaptic membrane that is the result of depolarization and makes an action potential more likely to occur
- 17. enzyme that catalyzes the generation of a new molecule, which acts as the intracellular mediator of the signal that binds to the receptor
- 19. functional division of the nervous system that is concerned with conscious perception, voluntary movement, and skeletal muscle reflexes
- 21. bundle of axons in the central nervous system having the same function and point of origin
- 30. cytoplasm of an axon, which is different in composition than the cytoplasm of the neuronal cell body
- 31. first neuron in the motor command pathway with its cell body in the cerebral cortex that synapses on the lower motor neuron in the spinal cord
- 33. part of the voltage-gated Na+ channel that opens when the membrane voltage reaches threshold
- 35. in cells, an extension of a cell body; in the case of neurons, this includes the axon and dendrites
- 39. property of an axon that relates to the ability of particles to diffuse through the cytoplasm; this is inversely proportional to the fiber diameter
- 41. the difference in voltage measured across a cell membrane under steady-state conditions, typically -70 mV
- 42. connection between two neurons, or between a neuron and its target, where a neurotransmitter diffuses across a very short distance
- 45. neural tissue associated with the digestive system that is responsible for nervous control through autonomic connections
- 46. change in voltage of a cell membrane in response to a stimulus that results in transmission of an electrical signal; unique to neurons and muscle fibers
- 47. neurotransmitter receptor that acts as an ion channel gate, and opens by the binding of the neurotransmitter
- 49. glial cell type in the CNS that serves as the resident component of the immune system
- 50. an event in the external or internal environment that registers as activity in a sensory neuron
- 51. region of the central nervous system that acts as a relay for sensory pathways
- 54. return of the membrane potential to its normally negative voltage at the end of the action potential
- 57. glial cell type in the CNS responsible for producing cerebrospinal fluid
- 59. localized collection of neuron cell bodies in the peripheral nervous system
- 61. lipid-rich insulating substance surrounding the axons of many neurons, allowing for faster transmission of electrical signals