INTRODUCTION TO NERVES & THE NERVOUS SYSTEM

The client is diagnosed with myasthenia gravis, a condition in which antibodies block, alter, or destroy the receptors for acetylcholine. What symptom would the nurse expect this client to display? A) Muscle dysfunction B) Seizures C) Depression D) Coma

Ans: A Feedback: Acetylcholine communicates between nerves and muscles so inability of this neurotransmitter to function properly, whether blocking, altering, or destroying the receptors, would result in muscle dysfunction, but not coma. Inadequate gamma-aminobutyric acid would result in seizures. Serotonin is important in preventing depression.

A client's muscle weakness has been found to result from a lack of neurotransmitter communication between nerves and muscles. What neurotransmitter is most likely deficient? A) Acetylcholine B) Dopamine C) Gamma-aminobutyric acid (GABA) D) Serotonin

Ans: A Feedback: Acetylcholine communicates between nerves and muscles. Dopamine is involved in the coordination of impulses and responses, both motor and intellectual. GABA inhibits nerve activity. Serotonin is important in arousal and sleep.

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) "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." B) "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." C) "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." D) "With only 10% of the blood needed getting through your right artery and 8% through your left artery, you could have a stroke now."

Ans: A Feedback: 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 has a neurologic disorder that affects the structure and function of the myelin sheath and Schwann cells. What effect will this client likely experience? A) Slower than normal nerve conduction B) Personality changes C) Chronic pain D) Lack of coordination

Ans: A Feedback: Myelinated nerves have Schwann cells, which speed up nerve conduction. Their absence does not cause personality changes, pain or lack of coordination.

What client is likely to be experiencing a heightened ability to learn? A) A client who gave birth 12 hours ago B) A client who is experiencing extreme anxiety C) A client who has slept for the past 11 hours and recently awoken D) A client who is thrilled to hear of a good prognosis

Ans: A Feedback: Oxytocin and mild stress act to increase actual learning. Childbirth is the only time that oxytocin levels increase, and this phenomenon is not clearly understood. Extreme anxiety, excitement, and prolonged sleep do not increase learning.

The nurse is caring for a client whose emotions often swing from one extreme to the other. The client's spouse tells the nurse these mood swings started when the client awoke from a coma following a serious head trauma. What area of the brain does the nurse suspect was damaged? A) The limbic system B) The forebrain C) The hindbrain D) The cerebellum

Ans: A Feedback: Stimulation of the limbic system, which appears to be responsible for the expression of emotions, may lead to anger, pleasure, motivation, and stress. The forebrain is where thinking and coordination of sensory and motor activity occur. The hindbrain controls vital functions and arousal. The cerebellum controls motor functions that regulate balance.

The nurse is caring for a client with a malignant brain tumor. The client asks the nurse why the tumor is being treated with radiation instead of chemotherapy. The nurse's explanation involves what important information? A) "Medications have difficulty crossing the blood-brain barrier." B) "Neurons in the brain are easily damaged by chemotherapy." C) "Tumors arising from nervous tissue are not impacted by chemotherapy." D) "Chemotherapy reduces nerve transmission and cannot be used."

Ans: A Feedback: The blood-brain barrier is a functioning boundary that plays a defensive role by keeping toxins, proteins, and other large structures out of the brain and preventing their contact with the sensitive and fragile neurons. As a result, medications like chemotherapy can have difficulty crossing this barrier to reach the tumor. The other answers are neither true nor the correct option.

A nurse is caring for a client who is having adverse effects from long-term antipsychotic treatment. The client is experiencing tremors, shuffles when walking, and is having difficulty sitting up in bed. What disruption to the neurologic system should the nurse suspect? A) An interference with the extrapyramidal system B) A faulty engram C) An alteration in the reticular activating system D) An interference with a neurotransmitter

Ans: A Feedback: The extrapyramidal system coordinates unconscious motor activity that regulates control of position and posture. An engram is a reverberating circuit of action potentials that becomes a long-term, permanent memory in the presence of the proper neurotransmitters and hormones. The reticular activating system, which is located in the hindbrain, controls arousal and awareness of stimuli and contains the sleep center. A neurotransmitter is a chemical that stimulates postsynaptic cells either by exciting or by inhibiting them.

A client's dysphagia has been attributed to damage to the client's swallowing center. This client has dysfunction in what part of the brain? A) Hindbrain B) Right hemisphere C) Forebrain D) Left hemisphere

Ans: A Feedback: The pons and medulla oblongata are in the hindbrain and control basic, vital functions, such as the respiratory centers, which control breathing; the cardiovascular centers, which regulate blood pressure; the chemoreceptor trigger zone and emetic zone, which control vomiting; and the swallowing center, which coordinates the complex swallowing reflex.

The sensory nerves enter the brain and react with related nerves to cause a reaction. What mediates this reaction? A) Muscles or glands B) The limbic system C) The cerebral cortex D) Neurotransmitters

Ans: A Feedback: The sensory nerves that enter the brain react with related motor nerves to cause a reaction mediated by muscles or glands. The motor impulses that leave the cortex are further regulated or coordinated by the pyramidal system, which coordinates voluntary movement, and the extrapyramidal system, which coordinates unconscious motor activity that regulates control of position and posture. Therefore, the other options are incorrect.

A nurse is reviewing the function of the forebrain before assessing a client on the neurological unit. The nurse should identify what functions of this part of the brain? Select all that apply. A) Coordination of speech and communication B) Learning C) Housing of the extrapyramidal motor system D) Housing the cranial nerves E) Containing the swallowing center

Ans: A, B, C Feedback: The forebrain is made up of two cerebral hemispheres joined together by the corpus callosum. The two hemispheres contain the sensory and motor neurons. It also contains areas that coordinate speech and communication and is thought to be where learning takes place. Cranial nerves emerge from the hindbrain, which is where the swallowing center is located as well.

The nurse is caring for a client whose unpredictable emotions are due to an infarct in the limbic system. The nurse should be aware that this part of the brain contains high levels of what neurotransmitters? Select all that apply. A) Epinephrine B) Serotonin C) Gamma-aminobutyric acid D) Norepinephrine E) Dopamine F) Acetylcholine

Ans: A, B, D Feedback: 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.

2. A client's neuron is stimulated and depolarization of the nerve has occurred. The nurse should anticipate what subsequent action? A) Calcium rushes into the cell. B) Sodium rushes into the cell. C) Potassium rushes into the cell. D) Sodium and potassium are actively pumped out to the cell.

Ans: B Feedback: When depolarization occurs, sodium rushes into the cell. During repolarization, potassium is pumped out of the cell and the resting membrane potential is reestablished. Calcium ions decrease the cell membranes' permeability to sodium and increase the threshold needed to depolarize the cell.

Information is being carried into a client's neuron from other neurons. What component of the neurologic system will perform this function? A) Axon B) Dendrite C) Nucleus D) Soma

Ans: B Feedback: 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.

What is the purpose of the myelin sheath? A) Protects the nerve from damage B) Speeds electrical conduction C) Produces Schwann cells D) Secretes neurotransmitters

Ans: B Feedback: Long nerves are myelinated: they have a myelin sheath that speeds electrical conduction and protects the nerves from the fatigue that results from frequent formation of action potentials, not from damage. Although myelin sheaths have Schwann cells, they do not produce these cells and the myelin sheath does not secrete neurotransmitters.

A client has 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? A) Ephedrine B) Norepinephrine C) Dopamine D) Acetylcholine

Ans: B Feedback: 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 nurse is caring for a client with meningitis who is not responding to the prescribed antibiotic and whose condition continues to deteriorate. The nurse should provide which rationale to explain why the client is not responding? A) The meninges do not have a blood supply. B) The blood-brain barrier prevents the antibiotics from crossing into the brain. C) The circle of Willis redirects the antibiotic elsewhere. D) The pressure in the hindbrain prevents antibiotic entry into the skull.

Ans: B Feedback: The blood-brain barrier works to keep large molecules out of the brain and away from the nerves. Most antibiotics are protein bound and cannot pass through the blood-brain barrier. When the infection becomes severe, the blood- brain barrier will stop being effective and the antibiotics can pass into the brain. The brain has a unique blood supply to protect the neurons from lack of oxygen and glucose. After the blood-brain barrier allows the antibiotic to pass through, the circle of Willis distributes the blood to the areas of need. If someone has an occluded carotid artery, which could build pressure up in the area, the circle of Willis can redirect the blood supply and provide a full blood supply to the affected areas.

The nurse is caring for a client who has an injured hindbrain. When assessing the client, the nurse should anticipate abnormal findings in what domain? A) Arousal and awareness B) Basic vital functions C) Coordination and motor activity D) Learning and motivation

Ans: B Feedback: The hindbrain contains centers that control basic vital functions (e.g., blood pressure, respirations, vomiting). The reticular activating system in the medulla controls arousal and awareness. Learning and motivation occur in the cerebral cortex. Coordination and motor activity are controlled through the cerebellum and basal ganglia.

A client's nerves have been stimulated and the signal has reached the axon. How will communication continue? A) Through the production of an electrical signal. B) By the release of a neurotransmitter. C) By physically stimulating the nerve on the other side of the synapse. D) The nerve signal will cease at this point.

Ans: B Feedback: The transmission of information between two nerves or between a nerve and a gland or muscle is chemical, achieved by the release of a neurotransmitter. Communication is not electrical or physical, and communication does not necessarily cease at the axon.

The nurse is preparing to perform a neurologic assessment of a new client. What provides required energy to the nerves? Select all that apply. A) Dopamine B) Oxygen C) Potassium D) Acetylcholine E) Serotonin F) Glucose

Ans: B, F Feedback: Nerves require energy (i.e., oxygen and glucose) and the correct balance of the electrolytes sodium and potassium to maintain normal action potentials and transmit information into and out of the nervous system. Energy required by the nerves is not provided by dopamine, potassium, acetylcholine, or serotonin.

3. A client has experienced a seizure. A deficiency in what neurotransmitter may have caused the client's seizure activity? A) Acetylcholine B) Dopamine C) Gamma-aminobutyric acid (GABA) D) Serotonin

Ans: C Feedback: GABA is found in the brain and inhibits nerve activity. It is important in preventing overexcitability or stimulation such as seizure activity. Acetylcholine communicates between nerves and muscles. Dopamine is involved in the coordination of impulses and responses, both motor and intellectual. Serotonin is found in the limbic system and is important in arousal and sleep as well as in preventing depression and promoting motivation.

What is the major inhibitory neurotransmitter in the CNS? A) Acetylcholine B) Dopamine C) Gamma-aminobutyric acid (GABA) D) Serotonin

Ans: C Feedback: GABA, which is found in the brain, inhibits nerve activity and is important in preventing overexcitability or stimulation such as seizure activity. Acetylcholine, which communicates between nerves and muscles, is also important as the preganglionic neurotransmitter throughout the autonomic nervous system and as the postganglionic neurotransmitter in the parasympathetic nervous system and in several pathways in the brain. Dopamine is involved in the coordination of impulses and responses, both motor and intellectual. Acetylcholine, dopamine, and serotonin are not the major inhibitory neurotransmitter in the CNS. Serotonin is important in arousal and sleep.

A client who nearly drowned is brought to the emergency department. The paramedics tell the nurse the client was anoxic for approximately 5 minutes. Because of this anoxia, what might happen to the nerve cells? A) The nerves may repolarize too quickly. B) The nerves might not be able to depolarize. C) The nerves might not be able to maintain the sodium-potassium pump. D) The nerves may release inappropriate neurotransmitters.

Ans: C Feedback: If a person has anoxia or hypoglycemia, the nerves might not be able to maintain the sodium-potassium pump, and with continued lack of oxygen and/or glucose, the nerve cell will die. It will not repolarize too quickly, be unable to depolarize or release inappropriate neurotransmitters.

The nurse is caring for a client who is believed to be greatly deficient in serotonin. What assessment is a nursing priority? A) Vital signs B) Assessment of falls risk C) Assessment for suicide risk D) Deep tendon reflexes

Ans: C Feedback: Serotonin prevents depression. Restoration of serotonin levels is a cornerstone of depression therapy, and low levels could constitute a suicide risk. This deficiency would not cause disruptions in balance, vital signs, or reflexes.

A nurse is working on a surgical unit and has several clients who require preoperative teaching. Which client demonstrates behavior indicating this is an appropriate time to begin teaching? A) A client who is wide eyed and extremely frightened about being "put to sleep." B) A client who appears to be unconcerned about what is happening and wants to watch their favorite TV show. C) A client who is clearing their throat several times while asking the nurse questions during conversation and who appears to be slightly stressed. D) A client who is getting up and down from the bed, talking very fast, and appears to be extremely anxious.

Ans: C Feedback: Several substances appear to affect learning. Antidiuretic hormone (ADH), which is released during reactions to stress, is one such substance. Although too much stress prevents learning, feeling slightly stressed may increase a person's ability to learn. A client who is a little nervous about upcoming surgery, for example, seems to display a better mastery of facts about the surgery and postoperative procedures than a client who is very stressed and scared or one who appears to show no interest or concern.

The nurse is preparing to provide health education to a client. The client's learning will take place in what brain region? A) The area that coordinates sensation B) The area that coordinates movement C) The areas that coordinate speech and communication D) The areas that communicate between motor and sensory neurons

Ans: C Feedback: The forebrain is made up of two cerebral hemispheres that contain areas that coordinate speech and communication and are thought to be the area where learning takes place. The forebrain does not coordinate sensation or movement or communicate between the sensory and motor systems.

A client has experienced a stroke affecting the right side of their brain. What assessment finding is most likely attributable to this health problem? A) Inability to recall the name of a best friend B) Inability to state their telephone number C) Inability to distinguish a spoon from a fork D) Inability to recall how to apply makeup

Ans: C Feedback: The right side of the brain is the artistic side and is concerned with forms and shapes. This client could have difficulty distinguishing the roundness of the spoon with the straight line of the top of the fork. The left side of the brain is more analytical and is concerned with names, numbers, and process.

A client has suffered damage to the thalamus as a result of a stroke. The client would exhibit deficits with what neurological function? A) Relaying motor impulses from the cortex to the spinal cord B) Coordinating voluntary movement C) Conveying information about sensations to the cerebrum D) Regulating emotions

Ans: C Feedback: The thalamus sends direct information into the cerebrum to transfer sensations, such as cold, heat, pain, touch, and muscle sense. Motor fibers from the cortex cross to the other side of the spinal cord before emerging to interact with peripheral effectors. In this way, motor stimuli coming from the right side of the brain affect motor activity on the left side of the body. The thalamus does not regulate emotions or coordinate movement.

The nurse is caring for a client who experienced damage to the midbrain during neurologic surgery. The nurse will expect the client to exhibit what sign? A) Chronic insomnia B) Sensorineural hearing loss C) Difficulty in distinguishing hot and cold D) Slurred speech

Ans: C Feedback: The thalamus, located in the midbrain, is responsible for temperature control. The client will have difficulty distinguishing hot and cold. Centers of control for sleep and hearing are found in the hindbrain, and areas that control speech and communication are found in the forebrain

What client is most likely to have sustained damage to his or her limbic system? A) A client who requires mechanical ventilation following a head injury B) A client whose gait is unbalanced and who frequently falls C) A client whose moods are described as "volatile" and "unpredictable" D) A client whose sense of smell no longer exists

Ans: C Feedback: The limbic system is responsible for the expression of emotions. The limbic system does not regulate balance, special senses, or respiration.

When a person learns, this action begins as an electrical circuit called what? A) Impulse B) Synapse C) Memory D) Engram

Ans: D Feedback: Learning begins as an electrical circuit called an engram, a reverberating circuit of action potentials that eventually becomes a long-term, permanent memory in the presence of the proper neurotransmitters and hormones.

What brings information from the central nervous system (CNS) to the peripheral nervous system (PNS)? A) Motor nerves B) Synapses C) Afferent neurons D) Sensory nerves

Ans: D Feedback: The PNS is composed of sensory receptors that bring information into the CNS and motor nerves that carry information away from the CNS to facilitate response to stimuli. Synapses are the gaps between neurons. Afferent fibers are nerve axons that run from the peripheral receptors into the CNS.

The nurse is describing the structure and function of the two hemispheres of the brain to a recent graduate. What regulatory function should the nurse describe? A) Regulation of the electrical conduction system of the brain B) Regulation of the afferent conduction system C) Regulation of the efferent conduction system D) Regulation of communication between sensory and motor neurons

Ans: D Feedback: The cerebral cortex consists of two hemispheres, which regulate the communication between sensory and motor neurons and are the sites of thinking and learning. The regulatory functions of the hemispheres do not focus electrical, afferent, or efferent conduction

A client sustained a closed-head injury 4 hours ago and now presents to the emergency department with difficulty breathing. The nurse should suspect damage to what part of the brain? A) Thalamus B) Cerebrum C) Pituitary D) Medulla oblongata

Ans: D Feedback: 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 brainstem, where the pons and medulla oblongata are located. This area of the brain controls basic vital functions such as the respiratory centers, which control breathing; the cardiovascular centers, which regulate blood pressure; the chemoreceptor trigger zone and emetic zone, which control vomiting; the swallowing center, which coordinates the complex swallowing reflex; and the reticular activating system (RAS), which controls arousal and awareness of stimuli and contains the sleep center. The midbrain contains the thalamus and hypothalamus and the limbic system that transfer sensations into the cerebrum and control temperature. The pituitary gland is known as the master gland, controlling other glands with hormones secreted here.

A client's nerve transmission has reached the end of an axon. What event will take place next? A) An enzyme will be released. B) An electrical impulse will stimulate a dendrite. C) The synaptic gap will close. D) A neurotransmitter will be released.

Ans: D Feedback: 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.