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A&P1 - Chapter 12
Neural Tissue
| Question | Answer |
|---|---|
| What are the functions of the nervous system? | to maintain body homeostasis with electrical signals, provide sensation, mental functioning, emotion response and activate muscles and glands |
| The cytoplasm that surrounds the nucleus of a neuron is called the __________? | perikaryon |
| Clusters of RER and free ribosomes in neurons are called ______________. | nissl bodies |
| Neurotransmitters ready for release are stored in synaptic ______________. | synaptic vesicles |
| The rabies virus travels to the CNS via ___________. | retrogade axoplasmic transport |
| ___________ are most numerous type of neuron in the CNS. | astrocytes |
| Most CNS neurons lack centrioles. This observation explains why... | they can't divide/reproduce |
| How does blocking retrograde axoplasmic transport in an axon affect the activity of a neuron? | the soma becomes unable to respond to changes in the distal end of the axon |
| Use Figure 12-1 (The Neuron) The structures labeled "1" are dendrites. their membranes contain numerous chemically-gated ion channels. Are both these statements true? | yes |
| Use Figure 12-1 (The Neuron) Which type of membrane channels are found at label "3"? | leak channel |
| Use Figure 12-1 (The Neuron) Identify the structure labeled "5". | synaptic terminals |
| Use Figure 12-1 (The Neuron) What is contained inside the structure labeled "5"? | calcium ions |
| Use Figure 12-1 (The Neuron) Which part(s) of the neuron can propagate an action potential? | axon |
| Use Figure 12-1 (The Neuron) On which structure do most meuron to neuron communications occur? | dendritic branches |
| Deteriorating changes in the distal segment of an axon as a result of a break between it and the some is called __________ degeneration. | wallerian |
| The largest and most numerous of the glial cells in the central nervous system are the _______________. | astrocytes |
| Functions of astrocytes include | responding to neural tissue damage, guiding neuron development, forming a 3-D framework for CNS |
| _________ account for roughly half of the volume of the nervous system. | neurolgia |
| The neuroglial cells that participate in maintaining the blood-brain barrier are the ________________. | astrocytes |
| The myelin sheath that covers many CNS axons is formed by ______________. | oligodendrocytes |
| ____________ line the brain ventricles and spinal canal. | ependymal cells |
| Small, wandering cells that surround the neurons in ganglia are ______________. | microglia |
| Glial cells that surround the neurons in ganglia are ___________. | satellite cells |
| Many medications introduced into the bloodstream cannot directly affect the neurons of the CNS because? | the endothelium of CNS cappillaries from a blood-brain barrier |
| Extensive damage to oligodendrocytes in the CNS could result in ______________. | loss of sensation and motor cotrol |
| At the normal resting potential of a typical neuron, its sodium-potassium exchange pump transports ______________. | 3 extracellular sodium ions for 2 intracellular potassium ions |
| The equilibrium potential for potassium ion occurs apporximately ________________. | 90mV |
| ___________ open or close in response to binding specific molecules. | chemically gated channels |
| A stimulus that changes a postsynaptic neuron's membrane from resting potential to -85 mV is a(n) __________ stimulus. | inhibitory |
| The following are the main steps in the generation of an action potential. | 4,3,7,1,2,6,5 |
| The all-or-none principle states.... | all stimuli great enough to bring the membrane to threshold will produce identical action potentials |
| The same __________ can have different effects depending on the properties of the ________________. | neurotransmitter, receptor |
| How would the absolute refractory period be affected if voltage-regulated sodium channels failed to inactivate? | would last indefinately |
| How would a chemical that prevents the opening voltage-regulated Na+ channels affect the function of a neuron? | neuron will only be capable of producing graded potentials |
| Puffer fish poison blocks voltage-gated sodium channels like a cork. What effect would this neurotoxin have on the function of neurons? | the axon would be unable to generate action potentials |
| Use Figure 12-2 (The Nerve Action Potential) What is occurring at the are labeled #4? | return to normal permeability |
| Use Figure 12-2 (The Nerve Action Potential) What is occurring in the are between #2 and #3? | activation of sodium channels and rapid depolariation |
| Use Figure 12-2 (The Nerve Action Potential) Which are of the graph shows when chemically gated sodium channels are open? | #2 |
| Use Figure 12-2 (The Nerve Action Potential) Which are of the graph shows when voltage gated sodium channels are open? | #2 |
| Use Figure 12-2 (The Nerve Action Potential) Which are of the graph shows when potassium channels open? | #3 |
| Use Figure 12-2 (The Nerve Action Potential) Which are of the graph occurs when there is sudden rush of sodium ions into the neuron? | #2 |
| Use Figure 12-2 (The Nerve Action Potential) Which are of the graph shows when membrane potential approaches the potassium equilibrium potential? | #4 |
| Use Figure 12-2 (The Nerve Action Potential) Which point of the graph shows when potassium ion outflow exceeds sodium ion inflow? | #3 |
| When is the neuron in the refractory period? | 0-2 msec |
| Rapid impulse conduction from "node" to "node" is called ______________. | saltatory propagation |
| What things influence the time necessary for a nerve pulse to be transmitted? | length/diameter of the axon, presence/absence of a myelin sheath and presence/absence of node of Ranvier |
| Which of the following type of nerve fiber processes the fastest speed of impulse propagation? | type A |
| Type __________ fibers have the largest diameter axons. | A |
| Sensory information from skeletal muscles travels over _____________ fibers. | Type A |
| A neuron that receives neurotransmitter from another neuron is called ______________. | the postsynaptic neuron |
| Which type of synapse is most common in the nervous system? | chemical |
| The ion that triggers the released of acetylcholine into the synaptic cleft if ____________. | calcium |
| Cholinergic synapses release the neurotransmitter _____________. | acetylcholine |
| If the chemically gated sodium channels in the postsynaptic membrane were completely blocked, ___________. | synaptic transmission would fail |
| The effect that a neurotransmitter has on the postsynaptic membrane depends on several things. List them. | the frequency of neurotransmitter release the nature of the neurotransmitter the characteristics of the receptors the quantity of neurotransmitters released |
| When cholinergic receptors are stimulated, ______________________. | sodium ions enter the postsynaptic neuron |
| What triggers the release of acetylcholine from a synaptic terminal? | diffusion of calcium ions into the synaptic terminal |
| When a second EPSP (excitatory postsynaptic potential) arrives at a single synapse before the effects of the first have disappeared, what occurs? | temporal summation |
| Summation that results from the cumulative effect of multiple synapses at multiple places on the neuron is designated ____________. | spitial summation |
| _________ nerves are nerves that connect to the brain. | central |
| _________ monitor the position of skeletal muscles and joints. | proprioceptors |
| _________ carry sensory information to the CNS. | nerves |
| _________ provide information about the external environment. | exteroreceptors |
| _________ monitor the digestive, respiratory, cardiovascular, urinary and reproductive systems. | interoceptors |
| The basic functional unit of the nervous system is the __________. | neuron |
| Products from the soma of a neuron are transported to the synaptic terminals by ___________. | anterogade axoplasmic |
| A change in the conditions in the synaptic terminal can influence the soma as a result of _____________ transport. | retrogade |
| Neuron cell bodies in the PNS are clustered together in masses called ________. | ganglia |
| The tiny gaps between adjacent Schwann cells are called __________. | nodes of Ranvier |
| Regions of the CNS with an abundance of myelinated axons constitute the __________ matter. | white |
| Regions of the CNS where neuron cell bodies dominate constitute the ___________matter. | gray |
| The separation of positive and negative charges across the membrane creates a __________ difference, or voltage. | potential |
| The sum of electrical and chemical forces acting on an ion is known as its ___________. | electrochemical gradient |
| The ________ principle state that the size and speed of the action potential are independent of the stimulus strength. | all or none |
| The period during which an excitable membrane cannot respond to further stimulation is the ________period. | absolute refractory period |
| The period during which an excitable member can respond again, but only if the stimulus is greater than the threshold stimulus, is the __________ period. | relative refractory period |
| The sensory loss and muscle weakness associated with multiple sclerosis are a consequence of ______________. | demyelination |
| At a(n) ___________ synapse, a neurotransmitter is released to stimulate the postsynaptic membrane. | chemical |
| In a(n) ___________ synapse, current flows directly between cells. | electrical |
| Compounds that alter the rate of neurotransmitter release by the presynaptic neuron or change the postsynaptic cells's response to neurotransmitters are called _____________. | neuromodulators |
| The buildup of depolarization when EPSP's arrive in rapid succession is called ______________. | temporal |
| The buildup of depolarization when EPSPs arrive at several places on the neuron is called __________ summation. | temporal |
| *SHORT ANSWER QUESTION* Rabies is caused by a virus that attacks the central nervous system. The virus is normally introduced by an animal bite that breaks the surface o the skin. Since the virus is not motile, how does it travel to the CNS? | When the skin is broken by an animal bite some cutaneous receptors are physically damaged. Through these damaged axons that the virus gains entrance to the neuron. Retrogade axplasmic transport carries the virus to the CNS, where it can reproduce/spread |
| *SHORT ANSWER QUESTION* The myelination of central and peripheral axons occur rapidly through the 1st few years of life. How can this developmental process explain the improved motor abilities of infants and toddlers? | Without full myelination, info about limb movement & body position moves slowly to the CNS & motor commands move slowly & erratically to the muscles. By the time the brain is aware of movement/position & can issue a motor command |
| *CONTINUED* the limb has already moved. When the motor command reaches the skeletal muscle, the response is no longer appropriate. As the neurons become fully myelinated, info processing speeds up, so we observe improved balance/coordination/movement. | |
| the neurilemma of axons in the peripheral nervous system is formed by _____________. | schwann cells |
Created by:
jnipper
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