MED SURG NERVOUS SYSTEM

MED SURG NERVOUS SYSTEM Med surg Nervous System Nerve impulses are sent to slow the heart's rate of contraction. The nerve fibers sending these signals will most likely belong to which division of the nervous system? -Parasympathetic division An inhibitory postsynaptic potential (IPSP) is associated with . -hyperpolarization Schwann cells are functionally similar to oligodendrocytes If a motor neuron in the body were stimulated by an electrode placed about midpoint along the length of the axon . the impulse would spread bidirectionally The effect of acetylcholine can be stimulating or inhibiting. Which gives the best explanation for why this is so? Different post synaptic cells will have different receptors Which is not a function of the autonomic nervous system? innervation of skeletal muscle When a neurotransmitter like acetylcholine is acting in an excitatory manner which is likely a result of the acetylcholine acting on the post synaptic cell? Chemically gated sodium channels will open Which is not a characteristic of neurons? They are mitotic Which neurotransmitter inhibits pain and is mimicked by morphine, heroin, and methadone? endorphin Which describes the nervous system integrative function? analyzes sensory information, stores information, makes decisions Cranial nerve 2, the optic nerve sends nerve impulses to the brain carrying information about the things we see. These nerve fibers most likely belong to which division of the nervous system? sensory (afferent) division These cells in the CNS have cilia that move in order to circulate cerebrospinal fluid . ependymal cells Which is not a chemical class of neurotransmitters? nucleic acid During the relative refractory period of an action potential, a larger than normal stimulus is needed to cause another action potential. This is due to the fact that . the voltage gated potassium ion channels remain open long enough to hyper-polarize the axon membrane Which will occur when an excitatory post synaptic (EPSP) is being generated on the dendritic membrane? A single single type of channel will open, permitting simultaneous flow of sodium and potassium Which is not true of graded potentials? The increase amplitude as they move away from the stimulus point Which ion channel opens in response to a change in membrane potential and participates in the generation and conduction of action potentials? voltage-gated channel Nerve impulses leading to the brain carry information about cool temperatures on the skin. The nerve fibers sending these signals will most likely belong to which division of the nervous system? sensory (afferent) division Meningitis can be caused by infection of the central nervous system by bacteria. Which cells would be most responsible for removing the infection? microglia Which is not a function of the astrocytes? provide the defense for the CNS Like all cells, the neurons' internal organization dictates its function. Neurons have relatively many mitochondria, an extensive network of rough endoplasmic reticulum and many clusters of ribosomes. These cellular features indicate all of the following EXCEPT . neurons have stable, relatively unchanging internal environment Bacteria in the blood can be prevented entry to the fluids surrounding the brain. Which cells are most responsible for preventing bacteria from entering the fluids of the brain? astrocytes The term central nervous system refers to the brain and spinal cord The concentration of ions in the chemical environment surrounding the neurons must be tightly regulated for neurons to function properly. Which of the following cells is most responsible for this? astrocytes If a post synaptic neuron is stimulated to threshold by spatial summation this implies that . the post synaptic cells has many synapses with many presynaptic neurons Immediately after an action potential has peaked, which channel will open Voltage gated potassium channels Nerve impulses leading to the skeletal muscle carry information to direct movement. The nerve fibers sending these signals will most likely belong to which division of the nervous system? Somatic nervous system A neuron that has as its primary function the job of connecting other neurons is called a(n) . interneuron The interior surface of a neuron's plasma membrane at resting membrane potential will have a negative charge and contains less sodium than outside of the cell Which correctly describes a graded potential? It can have amplitudes of various sizes The concentration neurotransmitters in the fluid of the synaptic cleft must be tightly regulated for neurons to function properly. Which cells is most responsible for siding in this regulation? astrocytes What does the central nervous system use to determine the strength of stimulus? frequency of action potentials If a postsynaptic cell is stimulated to threshold by temporal summation this implies that a presynaptic neuron is sending frequent EPSP Correct statement regarding chemical synapses The synaptic cleft uses the action potential to transmit a chemical signal to the post synaptic cell. The depolarization phase of an action potential is punctuated by the closing of inactivation gates in the voltage gated sodium ion channels. What is not a consequence of the closing of inactivating gates? This allows for the flux (diffusion out) of potassium ions, resulting in the depolarization of the cell Which is false? A.) A nerve impulse occursif the excitatory and inhibitory effects are equal B.) An inhibitory postsynaptic potential occurs if the inhibitory effect is greater than the excitatory, causing hyper polarization of the membrane C.) An excitatory postsynaptic potential occurs if the excitatory effect is greater than the inhibitory effect but less than threshold A nerve impulse occurs if the excitatory and inhibitory effects are equal A second nerve impulse cannot be generated until . the membrane potential has been reestablished Loss of function in the enzyme acetylcholine esterase would result in what? Inability to destroy and remove acetylcholine from the synaptic cleft Collections of nerve cell bodies outside the central nervous system are called . ganglia The period after an initial stimulus when a neuron is not sensitive to another stimulus is the absolute refractory period Which is true about the movement of ions across excitable living membranes? Sodium gates in the membrane can open in response to electrical potential changes An action potential is regarded as an example of positive feedback. Which example best illustrates the positive feedback aspect of an action potential? A threshold stimulus will cause the opening of voltage gated sodium ion channels that will cause further depolarizing stimulus. This stimulus will open still more voltage gated sodium ion channels Which is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle? acetylcholine When a neurotransmitter like GABA is acting in an inhibitory manner which is likely a result of the GABA acting on the postsynaptic cell? hyper polarization of the postsynaptic cell membrane Which of the choices below describes the ANS? A.) sensory and motor neurons that supply the digestive tract B.) motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands C.) Motor fibers that conduct nerve impulses from the CNS to skeletal muscle D.) Sensory neurons that convey information from somatic receptors in the head, body wall, and limbs and from receptors from the special senses of vision, hearing, taste, and smell to the CNS motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands When a sensory neuron is excited by some form of energy, the resulting graded potential is called a(n) . generator potential Which describes the excitatory postsynaptic potential? short distance depolarization Saltatory conduction is made possible by . myelin sheath Bipolar neurons are commonly . found in the retina of the eye