Chapter 12 review
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96 terms
Terms | Definitions |
|---|---|
 CNS | Brain and spinal cord |
| PNS | Neural tissue outside CNS |
| Afferent and Efferent | Divisions of the PNS |
| affferent division | carries sensory information from receptors to CNS |
| efferent division | brings motor commands from CNS to effectors to either enhance or oppose the stimulus |
| SNS and ANS | Efferent division includes: |
| SNS | controls skeletal muscle contractions; conscious and involuntary (reflex) |
| ANS | visceral motor system, automatic regulation of smooth muscle, cardiac, muscle, glandular secretions |
| Sympathetic and Parasympathetic | Autonomic Nervous System is divided into the ___________________ divisions |
| sympathetic | division of ANS that speeds up heart |
| parasympathetic | division of ANS that slows down heart |
| neuron | basic functional unit |
| neuroglia | supporting cells |
| separate and protect, support, regulate composition of interstitial fluid | functions of neuroglia |
| perikaryon | cytoplasm around nucleus |
| synapse | site of intercellular communication. Neurotransmitters released here. |
| sensory neurons | neurons in afferent PNS |
| interoceptors, exteroceptors, and proprioceptors | three types of receptors in afferent PNS |
| motor neurons | neurons in efferent PNS |
| sensory neurons, motor neurons, interneurons | PNS neuron types |
| ganglia | sensory neurons in afferent PNS have cell bodies in ________________ |
| exteroceptors | info from external environment (temp., senses, touch, pressure) |
| interoceptors | info from internal systems and pain |
| proprioceptors | position and movement |
| efferent fibers | axons traveling away from CNS are called |
| SNS and ANS | two divisions of efferent system |
| somatic motor neurons | innervate skeletal muscles |
| visceral motor neurons | innervate smooth muscle, cardiac muscle, and glands |
| interneurons | association neurons, located entirely in CNS, distribute sensory info and coordinate motor activity, involved with higher functions, memory, planning, learning |
| ependymal cells, astrocytes, oligodendrocytes, and microglia | four types of neuroglia in CNS |
| ependymal cells | many functions including monitoring CSF |
| astrocytes | maintain blood-brain barrier |
| oligodendrocytes | myelination of CNS axons |
| white matter | myelinated axons form |
| gray matter | unmyelinated axons form |
| microglia | phagocytic cells in CNS |
| satellite cells and Schwann cells | neuroglia of PNS |
| ganglia | clusters of cell bodies in PNS |
| amphicytes | satellite cells |
| satellite cells | surround neuron cell bodies in ganglia, regulate environment |
| Schwann cells | form sheath around peripheral axons (neurilemma) |
| neurilemmocytes | Schwann cell |
| demyelination | progressive destruction of myelin sheaths in both CNS and PNS |
| heavy-metal poisoning, diphtheria, MS, and Guillain-Barre' syndrome | demyelination occurs in these diseases |
| transmembrane potential | potential difference across a cell membrane is called |
| resting potential | transmembrane potential of a resting cell |
| -10mv to -100mv | each type of cell has a different resting potential from |
| -70mv | resting potential of neuron |
| -85mv | resting potential of skeletal muscle cells |
| -90mv | resting potential of cardiac muscle cell |
| chemical gradient | concentration gradient, net movement of materials from high concentration to low concentration |
| concentration gradient | difference between high and low concentrations, chemical gradient |
| electrical gradient | potential difference that arises when + and - ion are held apart |
| graded potential | stimulus produces temporary, localized change in resting potential |
| action potential | electrical impulse that is propagated across the surface of the membrane does not diminish as it moves away from its source; travels along axon to one or more synapses |
| synaptic activity | produces graded potentials in cell membrane of postsynaptic cell; involves release of neurotransmitters (ACh), that bind to receptors on postsynaptic cell membrane |
| electrochemical gradient | net result of chemical and electrical forces |
| Na | high outside cell; low inside |
| K | high inside cell; low outside |
| 1 3 2 | for every ___ ATP molecule; ___ Na moved out of cell, ___ K moved into cell |
| -70mv | Sodium potassium exchange pump stabilizes resting potential at |
| passive (leak) and active (gated) | membranes contain two kinds of channels |
| passive (leak) | channels that are always open |
| active (gated) | channels that open and close in response to stimuli |
| depolarization | any shift from resting potential toward 0. |
| repolarization | process of restoring normal resting potential after depolarization; ion movement through membrane channels (sodium-potassium pump) |
| opening of voltage-regulate Na+ channels | First step of action potential is to have |
| all-or-none principle | a stimulus either triggers an action potential or does not produce one at all |
| axon hillock | action potential develops there |
| saltatory propagation | action potential jumps from node to node (faster). |
| cholinergic synapse | a synapse that release ACh; neuromuscular junctions |
| 1. an action potential arrives and depolarizes synaptic knob, 2.extracellular Ca2+ enters synaptic cleft triggering exocytosis of ACh, 3. ACh binds to receptors and depolarizes the postsynaptic membrane, 4. ACh is removed by AChE | events in the functioning of a cholinergic synapse |
| NE, Dopamine, Serotonin, GABA | other Neurotransmitters |
| NE | sympathetic/parasympathetic responses |
| dopamine | role in control of movements; problem with neurons that produce it leads to Parkinson's disease |
| serotonin | can cause severe chronic depression, SSRI |
| Prozac, Paxil, Zoloft | Examples of SSRI |
| GABA | appears to reduce anxiety |
| botulinus toxin | blocks release of ACh; Botox paralyzes small facial muscles that cause wrinkles |
| Black widow spider venom | causes massive release of ACh, produces muscular cramps, spasms |
| Anticholinesterase drugs | block breakdown of ACh; nerve gas, malathion |
| Atropine, d-turbocurarine | prevent ACh from binding to postsynaptic receptors |
| curare | plant extract used by S. Am. natives to paralyze prey; induces paralysis by preventing stimulation of neuromuscular junction by ACh. |
| nicotine | binds to receptor sites and stimulates postsynaptic membrane; no enzymes exist that remove these compounds, and their effects are prolonged |
| seafood toxins | block sodium ion channels; produce abnormal sensations and interfere with muscle control or death |
| caffeine, theobromine, theophylline | drugs that facilitate lowered threshold |
| coffee, cola, cocoa, tea | lower threshold at initial segment, so a smaller that usual depolarization will cause an action potential and increase amount of ACh released; excitable, more alert |
| Seafood toxins | block membrane channels |
| lipid-soluble anesthetics | depress membrane sensitivity |
| caffeine, theobromine | depolarize axon hillock |
| arsenic, lead | demyelinate axons |
| botulinus toxins | block neurotransmitter release |
| spider venom | increase neurotransmitter release |
| anticholinesterase drugs | block neurotransmitter inactivation |
| nicotine | stimulate receptors |
| atropine | prevent neurotransmitter binding |
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