Nerve Cell Flashcards

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Judith Craig
9 years ago
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1 1. What does the word innervates mean? Refers to a nerve supplying a muscle or organ. For example, The phrenic nerve innervates the diaphragm muscle parts of the Nervous System 1. Central Nervous System (CNS): brain and spinal cord. 2. Peripheral Nervous System (PNS): nerves of the body 3. Autonomic Nervous System (ANS): has parts of the CNS and PNS. 3. What are the two parts of the CNS? Brain and Spinal cord 4. What does the Autonomic Nervous System control and what are its 2 divisions? Controls autonomic function (blood pressure, digestion, etc). a. Sympathetic division b. Parasympathetic division 5. What kinds of neurons enter the CNS? Sensory (afferent) signals picked up by sensor receptors. They are carried by nerve fibers of PNS to the CNS 6. What kind of neurons leave the CNS? Motor (efferent) signals are carried away from the CNS. They innervate muscles and glands 7. What sheath covers the axon (not referring Endoneurium to myelin)? 8. What sheath covers a fascicle (bundle of Perineurium neurons) 9. What sheath covers a bunch of fascicles? Epineurium 10. What is the neurolemma? Outermost covering of a neuron (plasma membrane 11. What is movement of nutrients, wastes, and Axoplasmic transport organelles between the cell body and axon terminals 12. What three things do all neurons do? 1. Receive a signal. Can be any type of stimulus (change in environment, signal from another neuron, etc). 2. Transmit a signal to another location. E.g. finger touching something signal to spinal cord or brain. 3. Stimulate another cell a. Another neuron transmit signal b. Muscle contraction c. Gland secretion 13. What three characteristics do all neurons share? 1. Longevity can live and function for a lifetime 2. Do not divide fetal neurons lose their ability to undergo mitosis (the y lose their centrioles); neural stem cells are an exception 3. High metabolic rate require abundant oxygen and glucose 1

Brain and Spinal cord 4. What does the Autonomic Nervous System control and what are its 2 divisions? Controls autonomic function (blood pressure, digestion, etc). a. Sympathetic division b.

2 14. Picture of Sensory vs Motor Neurons axon 15. Photo of NEURON anatomy 16. What receives the signal and carries the nerve conduction toward the cell body? 17. Where are the nucleus, ribosomes, and most organelles located? 18. What has the function of transmitting signals from the cell body to the area with neurotransmitters? 19. What part of a neuron stimulates another cell? 20. Describe the correct path an impulse takes across a synapse. DENDRITES The CELL BODY AXON SYNAPTIC KNOBS Axon of presynaptic neuron SYNAPTIC CLEFT dendrite of post synaptic neuron 2

Where are the nucleus, ribosomes, and most organelles located? 18.

3 21. What are synaptic knobs filled with? The synaptic knob has vesicles filled with a neurotransmitter that carries the signal. 22. What are 4 types of glia cells? Oligodendrocyte Schwann Cell Astrocyte Microglia 23. What is the function of glia cells? They support the neurons 24. Do glia cells carry nerve impulses? No. The impulses jump over the oligodendrocytes and Schwann cells, and astrocytes and microglia are not involved in nerve impuses at all. 25. Do glia cells process information in the No, the interneurons do that. nervous system? 26. What are the supporting cells of the nervous GLIA system? 27. Where do most tumors originate from? Most tumors of the brain originate from glial cells. 28. What is Wallerian Degeneration? process that results when a nerve fiber is cut or crushed, in which the part of the axon separated from the neuron's cell body degenerates distal to the injury. 3

The impulses jump over the oligodendrocytes and Schwann cells, and astrocytes and microglia are not involved in nerve impuses at all. 25.

4 29. What are the types of synapses? axosomatic neuroeffector synapses axodendritic axoaxonic 30. Photo of two of the 4 types of glial cells Oligodendrocytes Schwann Cell 31. Which cells provide the myelin sheath for OLIGODENDROCYTES neurons in the CNS? 32. Which cells provide the myelin sheath for SCHWANN CELLS neurons in the PNS? 33. What is the function of MYELIN to speed up the rate of nerve impulse conduction. SHEATHS 34. What are the BARE regions of axonal NODES OF RANVIER membranes found only in myelinated axons called? 35. What conducts impulses faster myelinated Myelinated or unmyelinated axon? 36. Where are unmyelinated axons found? Neuron cell bodies, dendrites, and unmyelinated axons in the PNS and CNS. 37. Are unmyelinated axons thinner or thicker Unmyelinated axons are thinner. than myelinated? 38. What is myelin made of? Mostly lipid 39. What is an autoimmune disease where the MULTIPLE SCLEROSIS oligodendrocytes (the myelin sheaths) are destroyed, interfering with the neuron functions in the CNS and brain? 40. What is the most common neurological MULTIPLE SCLEROSIS disease of young adults? 41. What are the two differences between Schwann cells are in PNS and each cell only forms one SCHWANN CELLS and myelin sheath. OLIGODENDRICYTES? Oligodendricytes are in CNS and each cell can form more than one myelin sheaths. 4

What is the function of MYELIN to speed up the rate of nerve impulse conduction. SHEATHS 34. What are the BARE regions of axonal NODES OF RANVIER membranes found only in myelinated axons called? 35.

5 42. What are the 3 functions of an ASTROCYTE? a. Physically supports the neurons b. Transmits materials from capillaries to neurons c. Forms blood-brain barrier (BBB), which keeps out harmful substances and many medicines The only function of the blood-brain barrier is to help 43. What is the only function of the blood-brain barrier BBB? protect the central nervous system. 44. They are macrophages Define MICROGLIA and their function They pick up bacteria and debris 41. What are ependymal cells? Cells that line the ventricles of the brain and produce cerebral spinal fluid (CSF) 42. What is the portion of the CNS that is GREY MATTER unmyelinated (cell bodies of neurons, glia, and dendrites)? 45. What is the portion of the CNS with myelin WHITE MATTER 46. What is a collection of axons in the PNS? NERVE; No cell bodies, dendrites, or synapses; just axons. 47. What is a collection of axons in the CNS TRACT 48. Where is most information processed? SYNAPSES in the CNS 49. What is a collection of cell bodies in the Ganglion PNS? 50. What is a network of nerves called? NERVE PLEXUS 51. What are the neurons that leave the CNS to MOTOR NEURONS effect a muscle or gland? 52. What neurons go from body to CNS, SENSORY NEURON carrying sensory information? 53. What is a small neuron found only in the INTERNEURON CNS? 54. What is the function of interneuron? it connects two other neurons in the spinal cord 55. What makes the CNS complex? The large number of interneurons in the CNS 56. Where are the cell bodies of motor neurons In gray matter and interneurons located? 57. Gray matter in the CNS contains what Neuroglia, neuron cell bodies, dendrites. Everything structures? except myelinated neurons 58. For a substance to diffuse across a a) The membrane must be permeable to the substance semipermiable membrane, what two b) The substance must have a concentration gradient conditions must be met? 59. At resting membrane potential, is the inside of the cell membrane positive or negative? What about the outside of the cell membrane? 60. What makes the inside of a cell membrane negatively charged? Inside is negative, outside is positive Proteins inside the cell make it negative 5

What is the only function of the blood-brain barrier BBB? protect the central nervous system. 44. They are macrophages Define MICROGLIA and their function They pick up bacteria and debris 41.

6 61. What changes the overall charge on the inside and outside of the cell membrane? 62. When a cell is at resting membrane potential and is then stimulated by a neuron, what is the first thing that happens to start the change in the overall charge on the inside of the cell? 63. Does potassium leave the cell because of neuron stimulation? 64. Why does sidedness exist (inside of cell negative, outside positive)? 65. Why does potassium constantly want to leave a cell? 66. Why does potassium want to get back into a cell? 67. What is the resting membrane potential of a cell? Why does potassium constantly want to leave a cell? The charges change when sodium channels open during neuron stimulation Sodium channels open and sodium enters the cell. No, it can leave anytime because its channel is leaky. a) The cell membrane has different permeabilities to each ion b) Pumps exist which force particular ions into or out of the cell c) Channels made out of protein selectively allow particular ions into or out of the cell. It wants to leave to diffuse down its concentration gradient It wants to get back into a cell because it is attracted to the negative charges on the protein inside the cell The resting membrane potential is how negative or positive the charge of the cell membrane is when it is not being stimulated by a neuron. The resting membrane potential is Minus 70-minus 90 mv 68. When does Depolarization occur? Depolarization: Enough sodium ions flow into the cell to make the membrane potential become positive 69. When does Repolarization occur? Repolarization: Enough sodium ions flow out of the cell to make the membrane potential become negative 70. What is an action potential? Action Potential = depolarization + repolarization 71. What is the correct sequence of events at a synapse? 72. What are the three structural classifications of neurons? 73. What are the structural classification of neurons based on? 74. What happens if a neuron s supply of neurotransmitters is exhausted? The nerve impulse arrives at the synaptic knob of the presynaptic cell, then the neurotransmitter is released. The NT binds to receptors on the postsynaptic cell, generating an action potential in the postsynaptic cell axon. Then the NT is removed from the receptors of the postsynaptic cell, either by an enzyme, or they are taken back up into the presynaptic terminal knob and recycled. 1. Unipolar 2. Bipolar 3. Multipolar the number of processes that project from the cell body. It might be temporarily unable to transmit an impulse to another cell 6

Does potassium leave the cell because of neuron stimulation? 64. Why does sidedness exist (inside of cell negative, outside positive)? 65. Why does potassium constantly want to leave a cell? 66.

Nerves and Nerve Impulse

Nerves and Nerve Impulse Terms Absolute refractory period: Period following stimulation during which no additional action potential can be evoked. Acetylcholine: Chemical transmitter substance released