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NCS Chapter 12
Nervous system cells notes
| Question | Answer |
|---|---|
| Dendrites | Nerve fibers, carry impulses toward cell body |
| Axon | nerve fibers, carry impulse away from the cell body |
| Nissl bodies | provides protein molecules needed for the transmission of the nerve signal |
| Nodes of Ranvier | gaps in myelin sheath, increase speed of nerve impulse |
| Telodendria | distal, branching tips of axon |
| (three types of neuron) | Multipolar neuron, bipolar neuron, unipolar neuron |
| Multipolar neuron | found in brain and spinal cord; many dendrites, |
| bipolar neuron | |
| unipolar neuron | always a sensory neuron |
| glia | supports neurons, don not conduct info |
| name the five types of glia | astrocytes,microglia,ependymal cells, oligodendrocytes,and schwann cell |
| astrocytes | "feeds" the neuron, helps form blood-brain barrier; largest & most numerous |
| microglia | phagocytosis ability |
| ependymal cells | line fluid filled cavities in brain |
| Oligodendtocytes | produces myelin sheath around nerve fibers in CNS |
| schwann cell | produces fatty myelin sheath around nerve |
| Neurilemma sheath | essentail to regeneration of injured nerve fibers; regeneration will only occur if neurilemma & cell bodies are intact |
| White matter | myleinated nerve fibers |
| grey matter | made up of cell bodies & unmyleinated fibers in CNS; ganglia & unmyleinated fibers in the PNS |
| Endoneurium | surrounds each nerve fiber |
| Fasicles | bundles of nerve fibers w/ their endoneurium |
| Perineurium | surrounds fasicles |
| Epineurium | surrounds complete nerve |
| Central Nervous system | brain and spinal cord |
| peripheral nervous system | nerves arising from brain and spinal cord |
| afferent division (aka sensory division_ | incoming sensory pathways-sense organs to cns |
| interneuron | connects afferent and efferent nerves, lies entirely within the CNS |
| Effenent Division aka Motor Division | outgoing motor pathways-CNS to muscles or glands |
| Somatic Nervous System | Voluntary; carries info to skeletal muscles |
| Autonomic Nervous system | involuntary; carries info to smooth muscles, glands & cardiac muscle |
| sympathetic | prepares body for "flight or fight" |
| parasympathetic | coordinates body's normal resting activities ex. digestion |
| A wave of electrical fluctuation | that travels along a plasma membrance |
| membrane potential | difference in electrical charge across a plasma membrane of a neuron |
| polarized | term referring to a neuron that has membrane potential |
| Resting membrane potential | when a nerve is not conducting an impulse; -70mV |
| Voltage Gated Channels | open in response to voltage fluctuation; ex. Sodium-Potassium Pump |
| Action Potential | membrane potential of an active neuron, aka nerve impulse, all-or-none response |
| stimuli | causes Na+ to come into cell |
| Influx causes | adjacent gates to open, creating a nerve impulse |
| Depolarization occurs | q |
| Repolarization | after impulse, membrane moves back to resting membrane potential;must occur before a new imulse is detected |
| Relative Refractory Period | milliseconds after impulse, membrane is re-polarizing, will only respond to a very strong stimulus |
| Anesthesia | work by inhibiting the opening of the sodium channels, thus inhibiting the impulse |
| ------ sodium ions are pumped out of the neuron for ever ------ potassium ions pumped into the neuron | three and two |
| Saltatory conduction- | type of impulse conduction where impulse "jumps" from Node of Ranvier to Node of Ranvier |
| The larger the diameter of a nerve | the faster the impulse |
| Synapse | place where signals are transmitted from one neuron(presynaptic neuron) to another neuron (postsynaptic neuron) |
| two types of synaptic transmission | electrical and chemical |
| chemical synaptic transmission | uses a chemical (Neuron transmitter) |
| Chemical synapse consists of 3 structures | Synaptic Knob, synaptic cleft, and plasma membrane |
| synaptic knob | tiny bulge at end of presynaptic neuron's axon-contains neurotransmitter |
| synaptic cleft | space between pre and postsynaptic neuron |
| Plasma membrane of a postsynaptic neuron | contains protein receptors for neurotransmitters |
| Neurotransmitters released and bind to receptors on the | postsynaptic cell |
| Neurotransmitters are classified by | function and by chemical structure |
| Neurotransmitters have 4 main chemical classes | acetylcholine, amines, amino acids, "other" small molecules |
| Where are amines found | in the brain |
| Amines can be | seratonin and histamine |
| Catecholamine | Dopamine (cociane blocks the uptake of dopamine) Epinenphrine & Norepinephrine |
| Disorder of the Nervous system involve | gila rather than neurons |
| Multiple Sclerosis | disorder of oligodendrocytes; myelin destruction and loss due to autoimmunity and/or viral infections |
| Glioma | most common type of brain tumor, usually benign, but still life threatening |
| Glioblastoma multifome | highly malignant form of an astrocytic tumor, spreads in white matter of the brain |
| Multiple neurofibromatosis | numerous fibrous neuromas throughout the body, serve disfigurement |
| Has the ability of phagocytosis | microglia |
| helps to form the blood-brain barrier | astrocyte |
| produces fatty myelin sheath in PNS | Schwann cell |
| largest and most numerous of the neuroglial cells | astrocyte |
| produces myelin sheath in Cns | oligodendrocyte |
| type of neuroglia that forms the neurilemma | schwann cell |
| star-cell | astrocyte |
| disorder of this cell associated with multiple sclerosis | oligodendrocyte |
| Which of the following are classified as nerve fibers? | axon and dendrites |
| which of the following conduct impulses towards the cell body? | dendrites |
| A neuron with one axon and several dendrites is a: | multipolar neuron |
| Which type of neuron lies entirely within the CNS? | interneuron |
| Which sequence best represents the course of an impulse over a reflex arc? | receptor, sensory neuron, interneuron, motor neuron, effector |
| A complete nerve, consisting of numerous fascicles and their blood supply, is held together by a fibrous coat called the | epineurium |
| Small, distinct regions of gray matter within the CNS are usually called: | nuclei |
| Nerve that contain mostly efferent fibers are called | motor nerves |
| gray matter in the CNS consists of | axons |
| Most nerves in the human nervous system are | mixed nerves |
| (T or F)Neurons have a vast ability to repair themselves | False |
| (T or F)Regeneration of nerve fibers will occur if the cell body is intact and the fibers have a neurilemma | True |
| (T or F) There are no differences between the CNs and PNS concerning the repair of damaged fibers | False |
Created by:
ajc93