Karch's PrepU (Pharm) CH. 19 Intro to Nerves and the Nervous System
Which is the most primitive area of the brain and contains the brain stem? Midbrain Hindbrain Limbic system Forebrain
Hindbrain Explanation: The hindbrain, which runs from the top of the spinal cord into the midbrain, is the most primitive area of the brain and contains the brain stem, where the pons and medulla oblongata are located.
The nursing student knows that the function of the thalamus is most accurately described by which statement? It relays motor impulses from the cerebral cortex to the spinal cord. It is responsible for voluntary movement. It continually adjusts body temperature, blood pressure, and heart rate. It helps maintain red blood cell production.
It relays motor impulses from the cerebral cortex to the spinal cord. Explanation: The thalamus relays motor impulses from the cerebral cortex to the spinal cord. It also relays impulses carrying sensations to the cortex.
When levels of serotonin are high in the RAS, the system shuts off and what occurs? Arousal Sleep Memory loss Pain
Sleep Explanation: When levels of serotonin become high in the RAS, the system shuts down and sleep begins to occur. The medulla absorbs serotonin from the RAS; when the levels are low enough, consciousness or arousal results.
What areas are mainly responsible for coordinating internal and external responses? Thalamus and hypothalamus Pituitary and adrenal glands Temporal and frontal lobes Pia mater and dura mater
Thalamus and hypothalamus Explanation: The thalamus and hypothalamus coordinate internal and external responses and direct information into the cerebral cortex.
Neurotransmitters are chemical substances that: are found only in the hypothalamus. carry messages from one neuron to another. consist solely of acetylcholine and norepinephrine. are composed solely of Schwann cells.
carry messages from one neuron to another. Explanation: Neurotransmitters are chemicals found throughout the body that are used to relay, amplify, and modulate signals (messages) between a neuron and another cell. Schwann cells are a variety of glial cells that mainly provide myelin insulation to axons in the peripheral nervous system of jawed vertebrates. The chemical substances are not limited to acetylcholine and are not composed solely of Schwann cells.
The nurse is assessing a client experiencing changes with ambulation. Which neurotransmitter would the nurse suspect is affected in this client? serotonin dopamine epinephrine norepinephrine
dopamine Explanation: Neurotransmitters are chemicals produced by a nerve and released when the nerve is stimulated. Dopamine is involved in the coordination of motor impulses and response. Serotonin plays a role in arousal and sleep, preventing depression, and promoting motivation. Epinephrine and norepinephrine are catecholamines released by nerves in the sympathetic branch of the autonomic nervous system and are classified as hormones.
After studying for a test on the brain and spinal cord, the students demonstrate understanding when they identify the spinal cord as being made up of how many pairs of nerves? 31 24 12 8
31 Explanation: The spinal cord is made up of 31 pairs of spinal nerves.
The neurological nurse is caring for a diverse group of clients. For which client would the role of the blood-brain barrier be most significant during treatment? A client who has been diagnosed with an infection of brain tissue A client who had an ischemic stroke 36 hours ago and is being stabilized A client who has ataxia resulting from cerebellar damage A client being treated for a closed head injury
A client who has been diagnosed with an infection of brain tissue Explanation: The blood-brain barrier presents a challenge to the delivery of medications from the circulatory system into the central nervous system. A client with a brain infection would require the delivery of antibiotics through or behind the barrier. It would be less significant in the treatment of clients who have had strokes or head injuries since these do not normally involve the delivery of medications beyond the barrier.
Magnetic resonance imaging of a client's brain indicates a lesion in Wernicke's area. What assessment should the nurse perform when gauging the effects of this lesion? Assess the client's ability to comprehend spoken instructions. Ask the client to walk in a straight line with his or her eyes closed. Ask the client to draw the face of a clock identifying the current time. Assess the client's ability to discern cold from hot sensations.
Assess the client's ability to comprehend spoken instructions. Explanation: Wernicke's area is known to regulate speech comprehension. It is not directly involved in sensation, coordination or complex tasks such as drawing a clock.
What part of the brain controls and coordinates muscle movement? Cerebellum Cerebrum Midbrain Brain stem
Cerebellum Explanation: The cerebellum, which is located behind and below the cerebrum, controls and coordinates muscle movement.
A client's left adrenal medulla has been injured in a motor vehicle accident. What is a possible implication of this injury? Disruptions in the levels of norepinephrine and epinephrine Dopamine deficiency Impaired action potential Disruption of the sodium-potassium pump
Disruptions in the levels of norepinephrine and epinephrine Explanation: The adrenal medulla produces epinephrine and norepinephrine, but not dopamine. Impaired adrenal medullary functions would be unlikely to affect action potentials or the function of the sodium potassium pump throughout the nervous system.
A client has a diagnosis of Parkinson disease, a health problem that has effects on motor function and cognition. What neurotransmitter is most likely deficient in this client's CNS? Dopamine Norepinephrine Acetylcholine Gamma-aminobutyric acid (GABA)
Dopamine Explanation: Dopamine levels are disrupted in Parkinson disease, as evidenced by the profound effects of motor function and cognition. Norepinephrine, acetylcholine and GABA do not have this combination of motor and cognitive functions.
Which substance is required for brain cell metabolism? Glucose Serotonin Bile Oxytocin
Glucose Explanation: Glucose is required as an energy source for brain cell metabolism.
What occurs when the cell returns to the resting membrane potential? Depolarization Synapse Myelinization Repolarization
Repolarization Explanation: Using the sodium-potassium pump, the cell then returns that section of membrane to the resting membrane potential. Depolarization means that the sodium channels open in response to the stimulus, and sodium ions rush into the cell, following the established concentration gradient. A synapse is the junction between a nerve and an effector. Myelinization of nerve fibers allows the electrical impulse to increase in speed.
Nerve stimulation has caused the release of serotonin into many of a client's synaptic clefts, causing stimulation of the effector cell. How will the effector cell be returned to a resting state so that it can be stimulated again? Serotonin will be reabsorbed by the axon of the presynaptic nerve Acetylcholine will be released, which has a contrary effect to serotonin Dopamine will be released, which negates the effect of serotonin Serotonin molecules will spontaneously break down in a fraction of a second
Serotonin will be reabsorbed by the axon of the presynaptic nerve Explanation: To return the effector cell to a resting state so that it can be stimulated again, if needed, neurotransmitters must be inactivated. Neurotransmitters may be either reabsorbed by the presynaptic nerve in a process called reuptake (a recycling effort by the nerve to reuse the materials and save resources) or broken down by enzymes in the area. Other neurotransmitters do not perform this role.
Information is being carried into a client's neuron from other neurons. What component of the neurologic system will perform this function? axon dendrite nucleus soma
dendrite Explanation: Dendrites carry information to the nerve and axons; they also carry information from a nerve to be transmitted to effector cells, which are found in muscles, glands, or another nerve. Soma refers to the cell body. The nucleus is the central part of a cell, which is responsible for the cell's growth, reproduction, and metabolism.
A nurse is reviewing the structure and function of the blood--brain barrier . This anatomical feature would have the greatest effect on what aspect of nursing care? Administering antibiotics to treat brain infections Assessing a client's cranial nerve function Determining the site of damage after a traumatic brain injury Obtaining accurate electroencephalography readings
Administering antibiotics to treat brain infections Explanation: The blood-brain barrier is a functioning boundary that keeps toxins, proteins, and other large structures out of the brain and prevents their contact with the sensitive and fragile neurons. It also makes it more difficult for medication to penetrate to locations beyond the barrier. It has no significant effect on assessing cranial nerve function, determining sites of injury or performing EEG's.
Assessment of a client with a complex neurologic history reveals that the client follows instructions but is unable to produce clear speech despite making great effort to do so. The nurse recognizes that diagnostic imaging is likely to reveal a lesion in what location? Broca's area Limbic system Extrapyramidal system Central sulcus
Broca's area Explanation: Broca's area is also known as the motor speech area and regulates the ability to articulate speech. The limbic system is primarily involved with emotion and extrapyramidal system coordinates unconscious motor activity. The central sulcus is a landmark between the parietal and frontal lobes.
A comatose client is being cared for by a critical care nurse who documents that the client responds only to very painful stimuli by fragmentary, delayed reflex withdrawal. The nurse knows that reflexes in the body are centered in the: pons. medulla oblongata. spinal cord. midbrain.
spinal cord. Explanation: The spinal cord functions as a passageway for ascending sensory and descending motor neurons. Its two main functions are to provide centers for reflex action and to serve as a pathway for impulses to and from the brain. Reflex centers are not in the pons, the medulla or the midbrain.
After teaching a group of students about the functions of the nervous system, the instructor determines that the students need additional teaching when they identify this as a function: Analysis of incoming stimuli Control of body functions Integration of responses Prevention of stimulus exposure
Prevention of stimulus exposure Explanation: The nervous system does not prevent stimulus exposure. Rather, the nervous system is responsible for analyzing incoming stimuli, controlling the functions of the human body, and integrating internal and external responses.
A client is experiencing major depressive disorder. Which neurotransmitter is most likely implicated? Serotonin Dopamine GABA Norepinephrine
Serotonin Explanation: Serotonin abnormalities are thought to be involved in mental depression and sleep disorders.
The nurse is caring for a client whose unpredictable emotions are due to an infarct in the limbic system. What hormone(s) are considered relevant to this impairment? Select all that apply. epinephrine serotonin gamma-aminobutyric acid norepinephrine dopamine acetylcholine
epinephrine serotonin norepinephrine Explanation: The limbic system contains high levels of epinephrine, norepinephrine, and serotonin. Dopamine, acetylcholine, and gamma-aminobutyric acid are found in the brain but not primarily in the limbic system.
The CNS structure containing groups of neurons responsible for vital cardiac, respiratory, and vasomotor functions is the: reticular activating system. limbic system. medulla oblongata. hypothalamus.
medulla oblongata. Explanation: Only the medulla oblongata controls autonomic functions and relays nerve signals between the brain and spinal cord. It is also responsible for controlling several major points and autonomic functions of the body.
The nurse is caring for a client whose recent ultrasound of the carotids diagnosed a 90% occlusion of the right carotid artery and a 92% occlusion of the left carotid artery. The client asks the nurse, "If one of these arteries becomes completely occluded will I have a stroke?" What is the nurse's best response? "A common vessel receiving all blood to the head called the circle of Willis will distribute blood from other arteries to the brain as needed." "A stroke is caused by lack of blood supply to a part of the brain, so if your right carotid artery becomes blocked, you'll have a stroke on the right side of your brain." "It is hard to predict exactly what will happen, so you'll have to wait until your provider sees you because only the provider can answer that question." "With only 10% of the blood needed getting through your right artery and 8% through your left artery, you could have a
"A common vessel receiving all blood to the head called the circle of Willis will distribute blood from other arteries to the brain as needed." Explanation: All the arteries that supply blood to the head deliver blood to a common vessel at the bottom of the brain called the circle of Willis, which distributes the blood to the brain when it is needed. The role of the circle of Willis becomes apparent when someone has an occluded carotid artery. Although the passage of blood through one of the carotid arteries may be negligible, the areas of the brain on that side will still have a full blood supply because of the blood sent to those areas through the circle of Willis. All other options are incorrect.
A client is recovering from an ischemic stroke that caused a significant brain infarction and loss of neurons. The client's family member asks the nurse, "How long will it take before new brain cells replace the ones that died?" What is the nurse's best response? "Unfortunately, the destruction of nerves is permanent and they're unable to reproduce." "The rate of recovery depends on many factors including blood supply, location and health of surrounding brain tissue." "Regrowth of new nerves is hard to predict, but starting rehabilitation early is beneficial." "It normally takes between six and eighteen months, depending on the client's age."
"Unfortunately, the destruction of nerves is permanent and they're unable to reproduce." Explanation: Neurons are unable to reproduce, and their loss is permanent. Early rehabilitation is beneficial, but it does not cause the growth of new nerves.
A client's nerve transmission has reached the end of an axon. What event will take place next? An enzyme will be released. An electrical impulse will stimulate a dendrite. The synaptic gap will close. A neurotransmitter will be released.
A neurotransmitter will be released. Explanation: The nerve axon, called the presynaptic nerve, releases a chemical called a neurotransmitter into the synaptic cleft; the neurotransmitter reacts with a very specific receptor site on the postsynaptic cell to cause a reaction that increases synaptic transmission. Communication between nerves occurs through the action of neurotransmitters, not enzymes or electrical activity. Synaptic gaps never physically close.
In response to a stimulus, a client's nerve has released a neurotransmitter. From what component of the nerve would the neurotransmitter be released? Axon Efferent fibers Schwann cell Soma
Axon Explanation: The presynaptic nerve is the nerve that releases a chemical, a neurotransmitter, from the axon terminal into the synaptic cleft. Efferent fibers are nerve axons that carry nerve impulses from the CNS to the periphery to stimulate muscles or glands. Schwann cells are cells located at specific intervals along nerve axons to allow nerve conduction. The soma is the cell body of the neuron.
A nurse is preparing to assess a patient's cerebellar function. What would the nurse expect to test? Remote memory Sensation Mental status Balance
Balance Explanation: Balance and coordination are functions of the pyramidal and extrapyramidal tracts of the motor and cerebellar systems. Remote memory and mental status exam provide information about the patient's cognitive ability. Testing for sensation would address issues with specific cranial nerves or problems involving the parietal lobe.
Dendrites route information away from the nerve cell while axons bring information to the nerve. True False
False Explanation: Axons route information away from the nerve cells; dendrites bring information to the nerve.
After teaching a group of students about major divisions of the brain, the instructor determines that additional teaching is needed when the students identify what as part of the hindbrain? Hypothalamus Reticular activating system Swallowing center Respiratory control center
Hypothalamus Explanation: The hypothalamus is part of the midbrain. The reticular activating system is part of the hindbrain. The swallowing center is part of the hindbrain. The respiratory control center is part of the hindbrain.
The nurse is planning the care of a client who has been diagnosed with a cerebellar disorder. What should the nurse prioritize in this client's plan of care? Implement falls precautions. Reorient the client as needed. Monitor the client for seizure activity. Assess mood and affect once per shift.
Implement falls precautions. Explanation: The cerebellum coordinates posture and balance. As a result, pathologies involving this part of the brain create a risk for falls. Cognitive deficits, seizures, and mood disorders are less likely to result from a disruption to normal cerebellar function.
Which is an important function of serotonin? Coordination of impulses Prevention of over-excitability Prevention of depression Communication between nerves and muscles
Prevention of depression Explanation: Serotonin, which is found in the limbic system, is important to arousal and sleep, as well as in preventing depression and promoting motivation. Dopamine is involved in the coordination of impulses and responses, both motor and intellectual. Gamma-aminobutyric acid is important in preventing over-excitability or stimulation such as a seizure. Acetylcholine communicates between nerves and muscles.
The nursing instructor is talking with their clinical group about the central nervous system. What should the instructor tell the students about the function of the spinal cord? Provides centers for planned action Extends through the whole vertebral column Serves as a conduit for impulses to and from the brain Supports the skeletal system
Serves as a conduit for impulses to and from the brain Explanation: The spinal cord functions as a passageway for ascending sensory and descending motor neurons. Its two main functions are to provide centers for reflex action and to serve as a pathway for impulses to and from the brain. The spinal cord ends between the first and second lumbar vertebrae. The spinal column supports the skeletal system.
A signal has reached the terminus of a client's nerve and is in the space where the nerve is closest to the effector cell in a muscle. At what location is this signal? Synapse Schwann cell Neuron Soma
Synapse Explanation: The synapse refers to the junction between a nerve and an effector such as a gland, muscle, or other nerve. The neuron is the basic structural unit of the nervous system. Soma refers to the cell body of a neuron. A Schwann cell is a specialized insulating cell on nerve axons.
The nurse is caring for a client with a brain abscess. Which cerebral structure would the nurse expect to be considered when medications are being identified to treat the client's infection? meninges brain stem cerebellum blood-brain barrier
blood-brain barrier Explanation: The blood-brain barrier consists of unique capillary characteristics and the astrocytes, which are a type of neuroglial cell. The endothelial cells in the capillaries supplying brain neurons have tight or overlapping junctions, which decrease capillary permeability. This can slow and control the diffusion of most substances, except for water, carbon dioxide, and oxygen. The blood-brain barrier represents a therapeutic challenge to drug treatment of brain-related disorders because a large percentage of drugs are carried bound to plasma proteins and are unable to cross into the brain. The meninges is a membrane that covers the nerves in the brain and spine. The brain stem controls basic vital sign functions. The cerebellum coordinates motor function.
The CNS structure involved in all higher order functions, including conscious processes containing both motor and sensory areas, is the: thalamus. hypothalamus. cerebral cortex. corpus callosum.
cerebral cortex. Explanation: The thalamus is the brain region that serves as a switching center for sensory signals passing from the brain stem to other brain regions. The main function of the hypothalamus is homeostasis, or maintaining the body's status quo. The corpus callosum is a structure of the mammalian brain that connects the left and right hemispheres. The cerebral cortex is a region of the brain that plays an important role in the integration of sensory perception and motor control and is responsible for many "higher-order" functions, such as language and information processing.
After teaching a group of students about the functions of the nervous system, the instructor determines that the teaching was effective when the students identify that a function is: control of body functions. generation of incoming stimuli. separation of responses. prevention of stimulus exposure.
control of body functions. Explanation: The nervous system is responsible for controlling body function, analyzing incoming stimuli, and integrating internal and external responses.
A client is diagnosed with pheochromocytoma, which causes hypertension due to excessive hormone release from the adrenal medulla. This client's symptoms are due to disruptions in the level of what hormone? ephedrine norepinephrine dopamine acetylcholine
norepinephrine Explanation: Norepinephrine and epinephrine are catecholamines, which are released by nerves in the sympathetic branch of the autonomic nervous system and are classified as hormones when they are released from cells in the adrenal medulla. The other listed options are not released from the adrenal medulla.
The cell body of one of a client's nerves is intact but communication with the muscle which it normally innervates has been severed by a laceration. The nurse teaches the client that normal resumption of nerve function will depend on: regeneration of the nerve's axon. restoration of the nerve's dendrites. generation of new nerves. replacement of an afferent fiber with an efferent fiber.
regeneration of the nerve's axon. Explanation: The axon runs from the nerve's cell body to the synaptic cleft near the effector cell, which is a muscle in this case. Dendrites carry impulses into the cell body. Nerves do not replace themselves. Afferent and efferent fibers are not interchangeable.
The nurse is providing an overview of the structure and function of the nervous system to a client with a new diagnosis of multiple sclerosis. The nurse describes how a stimulus normally travels down the axon of a nerve and stimulates an effector cell by: releasing one or more neurotransmitters into the synapse. depolarizing the dendrite of the effector cell. stimulating the effector's dendrite that touches the nerve's axon. chemically stimulating the effector cells' Schwann cells.
releasing one or more neurotransmitters into the synapse. Explanation: Electrical communication of a nerve signal ends at terminus of the axon, which does not physically touch the dendrite of the effector cell. Instead, chemical transmission takes place by the release of neurotransmitters into the synapse. The effector's dendrite is stimulated chemically, not electrically. Nerve to nerve transmission does not involve the role of Schwann cells.
