Chapter 34: Organization and Control of Neural Function-Patho taken from http://thepoint.lww.com/Book/Show Level 3
Which of the following statements best conveys an aspect of the role of cerebrospinal fluid (CSF)? a) CSF distributes plasma proteins throughout the superficial gray matter of the CNS. b) It provides physical protection for the brain and ensures leukocytes and erythrocytes are evenly distributed in the CNS. c) CSF cushions the brain and provides a near-water medium for diffusion of nutrients. d) It ensures the high metabolic and oxygenation needs of the brain are met, as well as absorbing physical shocks.
CSF cushions the brain and provides a near-water medium for diffusion of nutrients. In addition to providing a cushion for the CNS, CSF provides a medium that is 99% water in which nutrients, electrolytes and wastes can be diffused. It is not centrally involved in the distribution of oxygen, plasma proteins or blood cells.
A client has developed shock and the physician has instructed the nurse to begin the administration of intravenous dopamine. The nurse anticipates that the medication will: a) Cause vasoconstriction of the renal system b) Cause alteration in the level of consciousness c) Cause vasodilatation of the coronary blood vessels d) Cause vasoconstriction of the splanchnic vessels
Cause vasodilatation of the coronary blood vessels Dopamine, which is an intermediate compound in the synthesis of norepinephrine, also acts as a neurotransmitter. It is the principal inhibitory transmitter of interconnecting neurons in the sympathetic ganglia. It also has vasodilator effects on renal, splanchnic, and coronary blood vessels when given intravenously and is sometimes used in the treatment of shock. Level of consciousness is not affected.
Myelinated neurons are found in which of the following component(s) of the nervous system? a) Central b) Peripheral c) Central and peripheral d) Gray matter
Central and peripheral Myelin formation is essentially the same in both the central (CNS) and peripheral nervous systems (PNS). Two types of neuroglial cells (oligodendrocytes in the CNS and Schwann cells in the PNS) produce the myelin used to insulate nerve cell processes and increase the velocity of nerve impulse conduction. Myelin has a high lipid content, which gives it a whitish color, and the name "white matter."
Which of the following catecholamines may have a vasodilator effect on the renal blood vessels and be prescribed for clients in shock who are experiencing renal insufficiency manifestations? a) Acetylcholine b) Enkephalin c) Norepinephrine d) Dopamine
Dopamine The catecholamines, which include norepinephrine, epinephrine, and dopamine, are synthesized in the sympathetic nervous system and are the neurotransmitters for most postganglionic sympathetic neurons. Dopamine, which is an intermediate compound in the synthesis of norepinephrine, also acts as a neurotransmitter. It is the principal inhibitory transmitter of interconnecting neurons in the sympathetic ganglia. It also has vasodilator effects on renal, splanchnic, and coronary blood vessels when given intravenously and is sometimes used in the treatment of shock. -Endorphins and enkephalins are involved in pain sensation and perception. -Acetylcholine is the transmitter for all preganglionic neurons, for postganglionic parasympathetic neurons, and for selected postganglionic sympathetic neurons.
Which one of the following meninges provides the major protection for the brain and spinal cord? a) Pia mater b) Dura mater c) Arachnoid membrane d) Tentorium cerebelli
Dura mater All surfaces of the spinal cord, brain, and segmental nerves are covered with a delicate connective tissue layer called the pia mater. A second, very delicate, nonvascular, and waterproof layer, called the arachnoid, encloses the entire central nervous system. Immediately outside the arachnoid is a continuous sheath of strong connective tissue, the dura mater, which provides the major protection for the brain and spinal cord. The tentorium cerebelli is the inner layer of the dura that anchors the brain to the skull
Which of the following types of synapse allows the quickest transmission from one neuron to another? a) Inhibitory b) Chemical c) Electrical d) Excitatory
Electrical Electrical synapses premit the passage of current-carrying ions through small openings called gap junctions. The gap junctions allow an action potential to pass directly and quickly from one neuron to another. Chemical synapses are the slowest component in progressive communication through a sequence of neurons. Chemical synapses are divided into two types: excitatory and inhibitory.
Which of the following catecholamines is formed in the adrenal gland? a) Norephinephrine b) Acetylcholine c) Dopamine d) Epinephrine
Epinephrine The catecholamines, which include norepinephrine, epinephrine, and dopamine, are synthesized in the axoplasm of sympathetic nerve terminal endings from the amino acid tyrosine. During catecholamine synthesis, tyrosine is hydroxylated to form dopamine, and dopamine is hydroxylated to form norephinephrine. In the adrenal gland, an additional step occurs during which norephinephrine is methylated to form epinephrine. Acetylcholine is not a catecholamine.
Which of the following potentials, when combining a neurotransmitter with a receptor site, causes partial depolarization of the postsynaptic membrane? a) Threshold b) Inhibitory postsynaptic c) Resting membrane d) Excitatory postsynaptic
Excitatory postsynaptic A neurotransmitter can cause an excitatory or an inhibitory-graded potential. When the combination of a neurotransmitter with a receptor site causes partial depolariztion of the postsynaptic membrane, it is called an excitatory postsynaptic potential. -Threshold potential and resting membrane potential are terms associated with membrane action potentials.
A client is having an upper endoscopy to determine the presence of a gastric ulcer. After the procedure is performed, the nurse instructs the client that he cannot have anything to eat or drink until the return of the gag reflex. Which nerve is the nurse testing for return of function? a) Hypoglossal b) Glossopharyngeal c) Trigeminal d) Abducens
Glossopharyngeal The glossopharyngeal nerve innervates the stylophargeus muscle, posterior external ear, taste buds of posterior half of tongue, oral pharynx, parotid gland, pharyngeal muscles, and the stylopharyngeus muscle. It affects the function of proprioception, somesthesia, taste, gag reflex, salivary reflex, and assists in swallowing.
Nutrition students are studying the nervous system, which has a high rate of metabolism. Which of the following is its major fuel source? a) Protein b) Electrolyes c) Glucose d) Ketones
Glucose Glucose is the major fuel source for the nervous system, but neurons have no provision for storing glucose. Ketones can provide for limited, temporary energy requirements; however, these resources are rapidly depleted.
The nurse measures a blood glucose level of 40 mg/dL for a client with diabetes type I. Why would it be important for the nurse to institute an intervention to elevate the glucose level in this client? a) Glucose is not stored in the brain and is a major fuel source for brain function. b) It is not necessary for glucose to be replaced immediately because the client will have enough stores to function for a while. c) Small amounts of glucose may be stored in the brain for a short period of time but are rapidly metabolized. d) The nurse should administer a food source of protein in order to increase the glucose level for improved cardiac function.
Glucose is not stored in the brain and is a major fuel source for brain function. Glucose is the major fuel source for the nervous system but neurons have no provision for storing glucose. Ketones can provide for limited temporary energy requirements. However, these sources are rapidly depleted.
A client has sustained damage to cranial nerve VIII. The nurse recognizes that the client may experience difficulty with: a) Taste b) Motor c) Smell d) Hearing
Hearing Cranial nerve VIII (vestibulocochlear nerve) is associated with hearing. The other options involve different nerves.
A client arrives in the clinic after having a tongue piercing performed and is unable to control the movement of the tongue. The nurse is aware that which nerve may have been damaged from the piercing? a) Abducens b) Vagus c) Hypoglossal d) Trigeminal
Hypoglossal The general somatic efferent LMNs of the lower segments of the medulla supply the extrinsic and intrinsic muscles of the tongue by means of the hypoglossal nerve (CN XII). Damage to the hypoglossal nerve results in weakness or paralysis of tongue muscles. When the tongue is protruded, it deviates toward the damaged and therefore weaker side because of the greater protrusion strength on the normal side
A client is unable to stick out his tongue as a result of injury to cranial nerve XII. The nurse recognizes that the client has sustained as damage to which nerve? a) Hypoglossal b) Trigeminal c) Vestibular d) Gustatory
Hypoglossal The name of cranial nerve XII is the hypoglossal nerve. It is responsible for the client's ability to stick out his or her tongue without deviation.
Maintenance of blood gas concentrations, water balance, and food consumption are controlled by which of the following parts of the brain? a) Cerebral hemispheres b) Hypothalamus c) Basal ganglia d) Cerebellum
Hypothalamus The hypothalamus is the area of master level integration of homeostatic control of the body's internal environment. Maintenance of blood gas concentrations, water balance, food consumption, and major aspects of endocrine and autonomic nervous system control require hypothalamic function.
Maintenance of blood gas concentrations, water balance, and food consumption are controlled by which of the following parts of the brain? a) Cerebral hemispheres b) Hypothalamus c) Basal ganglia d) Cerebellum
Hypothalamus The hypothalamus is the area of master level integration of homeostatic control of the body's internal environment. Maintenance of blood gas concentrations, water balance, food consumption, and major aspects of endocrine and autonomic nervous system control require hypothalamic function.
Neurotransmitters are small molecules that exert their actions through specific proteins, called receptors, embedded in the postsynaptic membrane. Where are neurotransmitters synthesized? a) In the dendrite terminal b) In the postsynaptic junction c) In the presynaptic junction d) In the axon terminal
In the axon terminal Neurotransmitters are synthesized in the cytoplasm of the axon terminal. The other answers are incorrect.
When reviewing the purpose/action of neurotransmitters as they interact with different receptors, the nursing instructor gives an example using acetylcholine. When acetylcholine is released at the sinoatrial node in the right atrium of the heart, it is: a) Inhibitory. b) Overstimulated. c) Dormant. d) Positively charged.
Inhibitory. The action of a transmitter is determined by the type of receptor to which it binds. Acetylcholine is excitatory when it is released at a myoneural junction, and it is inhibitory when it is released at the sinoatrial node in the heart
The sympathetic and the parasympathetic nervous systems are continuously at work in our bodies. This continual action gives a basal activity to all parts of the body. What is this basal activity referred to as? a) Relaxation b) Tone c) Strength d) Tension
Tone The sympathetic and parasympathetic nervous systems are continually active. The effect of this continual or basal (baseline) activity is referred to as tone.
A client comes to the emergency department stating she is having severe pain on the left side of her face. The client states that the pain started after being outdoors in the cold. The nurse observes lacrimation of the right eye. Which nerve does the nurse recognize is affected? a) Hypoglossal b) Trigeminal c) Abducens d) Glossopharyngeal
Trigeminal The trigeminal nerve (CN V), which has both sensory and motor subdivisions, exits the brain stem laterally on the forward surface of the pons. The trigeminal is the main sensory nerve conveying the modalities of pain, temperature, touch, and proprioception to the superficial and deep regions of the face. Regions innervated include the skin of the anterior scalp and face, the conjunctiva and orbit, the meninges, the paranasal sinuses, and the mouth, including the teeth and the anterior two thirds of the tongue.
The vertebral column provides protection for the spinal cord, spinal nerves, and supporting structures. a) False b) True
True
The arachnoid membrane is the middle layer of the three meninges. a) False b) True
True- the arachnoid membrane is the middle layer of the three meninges.
Dopamine is an intermediate compound made during the synthesis of norepinephrine. It is the principal inhibitory transmitter of the internuncial neurons in the sympathetic ganglia. What other action does it have? a) Vasodilates renal and coronary blood vessels when given intravenously b) Vasoconstricts renal and coronary blood vessels when given intravenously c) Acts as a neuromodulator in the hindbrain d) Acts as a neuromodulator in the forebrain
Vasodilates renal and coronary blood vessels when given intravenously Dopamine, which is an intermediate compound in the synthesis of norepinephrine, also acts as a neurotransmitter. It is the principal inhibitory transmitter of internuncial neurons in the sympathetic ganglia. It also has vasodilator effects on renal, splanchnic, and coronary blood vessels when given intravenously and is sometimes used in the treatment of shock.
A 21 year old male is brought to the ED following a night of partying in his fraternity. His friends found him "asleep" and couldn't get him to respond. They cannot recall how many alcoholic beverages he drank the night before. While educating a student nurse and the roommates in the fraternity, the nurse begins by explaining that alcohol is: a) Able to reverse the transport of some substances to remove them from the brain. b) Very likely to cause sedation and therefore the patient just needs to sleep it off. c) Very lipid soluble and rapidly crosses the blood-brain barrier. d) Water-soluble compound that is easily absorbed by the gastric lining of the stomach.
Very lipid soluble and rapidly crosses the blood-brain barrier. The blood-brain barrier prevents many drugs from entering the brain. Most highly water-soluble compounds are excluded from the brain. Many lipid-soluble molecules cross the lipid layers of the blood-brain barrier with ease...Alcohol, nicotine, and heroin are very lipid soluble and rapidly enters the brain. Alcohol toxicity can kill patients, especially if they are not use to consuming beverages. These patients should never be left alone to "sleep it off".
Ion channels in nervous system cells generate action potentials in the cells. What are the ion channels guarded by? a) Voltage-dependent gates b) Ligand gates c) Leyte cells d) Schwann cells
Voltage-dependent gates These membrane channels are guarded by voltage-dependent gates that open and close with changes in the membrane potential. The other answers are incorrect.
Which of the following types of reflex is stimulated by a nociceptive stimulus? a) Carotid sinus baroreflex b) Stretch reflex c) Myotatic reflex d) Withdrawal reflex
Withdrawal reflex The withdrawal reflex is stimulated by a damaging (nociceptive) stimulus. -The myotatic, or stretch reflex, controls muscle tone and helps maintain posture. -The carotid sinus baroreflex assists adjustment of the cardiovascular system at the level of the brain stem.
Which drug, administered by the nurse to a client with a heart rate of 40 and syncope, is a muscarinic blocking drug that will increase the heart rate? a) Atropine b) Dopamine c) Lidocaine d) Epinephrine
• Atropine The drug atropine is an antimuscarinic or muscarinic cholinergic blocking drug that prevents the action of acetylcholine at excitatory and inhibitory muscarinic receptor sites. Because it is a muscarinic blocking drug, it exerts little effect at nicotinic receptor sites.
Which cranial nerves that have their origin in the pons assist with the manipulation of the jaw during chewing and speech? Select all that apply. a) Cranial nerve VI b) Cranial nerve VIII c) Cranial nerve I d) Cranial nerve VII e) Cranial nerve III
• Cranial nerve VI • Cranial nerve VII • Cranial nerve VIII In the pons, the reticular formation is large and contains the circuitry for manipulating the jaw during chewing and speech. Cranial nerves VIII, VII, and VI have their origin in the pons. -Axons of the olfactory nerve, or cranial nerve I, terminate in the most primitive portion of the cerebrum—the olfactory bulb, where initial processing of olfactory information occurs. The outflow from the midbrain passes through the oculomotor nerve (cranial nerve III) to supply the pupillary sphincter muscle of each eye and the ciliary muscles that control lens thickness for accommodation.
Which structures are part of the brain stem? Select all that apply. a) Pons b) Midbrain c) Cerebellum d) Medulla oblongata
• Medulla oblongata • Pons • Midbrain The term brain stem is often used to include the medulla, pons, and midbrain. The cerebellum is not part of the brain stem.
Which of the following are the main neurotransmitters of the autonomic nervous system (ANS)? Select all that apply. a) Norepinephrine b) Acetylcholine c) Monoamine oxidase d) Tyrosine e) Epinephrine
• Norepinephrine • Acetylcholine • Epinephrine The main neurotransmitters of the ANS are acetylcholine and the catecholamines epinephrine and norepinephrine. Monoamine oxidase is found in the nerve endings to degrade catecholamines. Tyrosine is an amino acid that is a precursor to catecholamines
The vertebral column provides protection of: Select all that apply. a) Supporting structures b) Tendons c) Spinal nerves d) Spinal cord e) Muscles
• Spinal cord • Spinal nerves • Supporting structures The vertebral column provides protection for the spinal cord, spinal nerves, and supporting structures.
While assessing a critically ill patient in the emergency department, the nurse notes on the cardiac monitor an R-on-T premature ventricular beat which develops into ventricular tachycardia (VT). Immediately, the patient became unresponsive. The nurse knows that based on pathophysiologic principles, the most likely cause of the unresponsiveness is: a) Interruption of the blood/oxygen supply to the brain. b) Massive cerebrovascular accident (CVA) resulting from increased perfusion. c) A blood clot coming from the heart and occluding the carotid arteries. d) Metabolic acidosis that occurs spontaneously following any dysrhythmias.
Interruption of the blood/oxygen supply to the brain. The brain receives 15-20% of the total resting cardiac output and consumes 20% of its oxygen. The brain cannot store oxygen or engage in anaerobic metabolism. An interruption of blood supply or oxygen to the brain rapidly leads to clinically observable signs/symptoms. Unconsciousness occurs almost simultaneously with cardiac arrest. Metabolic acidosis will occur later in the cardiac arrest but not immediately and is not responsible for the patients unresponsiveness. CVAs can be caused by thrombosis formation or plaque occlusions, but is not the primary reason for unconsciousness in VT.
The health care provider is performing a spinal tap on a client with suspected infection. The provider would perform the procedure at: a) S3 or S4 b) C3 or C4 c) L3 or L4 d) T3 or T4
L3 or L4 A pocket of CSF, the dural cisterna spinalis, extends from approximately L2 to S2. Because this area contains an abundant supply of CSF and the spinal cord does not extend this far, the area often is used for sampling the CSF. A procedure called a spinal tap, or puncture, can be done by inserting a special needle into the dural sac at L3 or L4. The spinal roots, which are covered with pia mater, are in little danger of trauma from the needle used for this purpose
The region of the brain involved in emotional experience and control of emotional behavior is the: a) Limbic system b) Occipital lobe c) Parietal lobe d) Cerebral hemisphere
Limbic system The limbic region of the brain is involved in emotional experience and in the control of emotion-related behavior. Stimulation of specific areas in this system can lead to feelings of dread, high anxiety, or exquisite pleasure. It also can result in violent behaviors, including attack, defense, or explosive and emotional speech. - The occipital lobe plays an important role in the meaningfulness of visual experience, including experiences of color, motion, depth perception, pattern, form, and location in space. -The parietal lobe is necessary for perceiving the meaningfulness of integrated sensory information from various sensory systems, especially the perception of "where" the stimulus is in space and in relation to body parts. -Axons of the olfactory nerve, or cranial nerve I, terminate in the most primitive portion of the cerebrum—the olfactory bulb, where initial processing of olfactory information occurs.
The nurse is aware that the primary function of the sympathetic nervous system is: a) Maintenance of organ function during periods of minimal activity b) Conservation of energy and resource replenishment c) Suppression of responses during threatened periods d) Maintenance of vital functions and responding when there is a critical threat to the integrity of the individual
Maintenance of vital functions and responding when there is a critical threat to the integrity of the individual The sympathetic division maintains vital functions and responds when there is a critical threat to the integrity of the individual—the "fight-or-flight" response. The parasympathetic nervous system is concerned with conservation of energy, resource replenishment, and maintenance of organ function during periods of minimal activity.
The nurse knows which of the following phenomena listed below is an accurate statement about axonal transport? a) The unidirectional nature of the axonal transport system protects the CNS against potential pathogens. b) Materials can be transported to the nerve terminal by either fast or slow components. c) Anterograde and retrograde axonal transport allow for the communication of nerve impulses between and neuron and the central nervous system (CNS). d) Axonal transport facilitates the movement of electrical impulses but precludes the transport of molecular materials.
Materials can be transported to the nerve terminal by either fast or slow components. The bidirectional axonal transport system allows for the transport of molecular materials (as opposed to electrical impulses); anterograde transport has both slow and fast components.
Since catecholamines can be degraded by enzymes, the medication category usually prescribed to treat a Parkinson disease client, thereby controlling this interaction, is: a) β-Adrenergic blocker b) Epinephrine c) Dopamine d) Monoamine oxidase (MAO) inhibitor
Monoamine oxidase (MAO) inhibitor Catecholamines also can be degraded by enzymes, such as catechol-O-methyltransferase (COMT) in the synaptic space or monoamine oxidase (MAO) in the nerve terminals. COMT inhibitors and MAO inhibitors are used in the treatments of various conditions, such as Parkinson disease, major depression, and anxiety. The other medications listed do not perform this function.
A client has been brought to the emergency department following an overdose of insulin that resulted in unconsciousness. When explaining the rationale for this to the family, the nurse will emphasize that neurons: a) Must rely on glucose from the blood to meet their energy needs b) Store glycogen within the brain cavity c) Can cause the liver to convert triglycerides into energy if needed quickly d) Require many amino acids in order to produce enough energy to function properly
Must rely on glucose from the blood to meet their energy needs Nervous tissue has a high rate of metabolism. Glucose is the major fuel source for the nervous system. Unlike muscle cells, neurons have no glycogen stores and must rely on glucose from the blood or the glycogen stores of supporting glial cells to meet their energy needs. Persons receiving insulin for diabetes may experience signs of neural dysfunction and unconsciousness when blood glucose drops because of insulin excess. Neither amino acid production nor liver conversion of triglycerides will produce the quick energy that the brain requires to function properly.
Which of the following is the primary component of white matter? a) Dendrites b) Myelinated fibers c) Cell bodies d) Demyelinated lesions
Myelinated fibers Myelin has a high lipid content, which gives it a whitish color, and the name "white matter" is given to the masses of myelinated fibers in the spinal cord and brain. The other options are not myelinated
During embryonic development, which of the following structures develops into the central nervous system (CNS)? a) Neural crest cells b) Ectoderm c) Neural tube d) Notochord
Neural tube During embryonic development, the neural tube develops into the CNS, whereas the notochord becomes the foundation around which the vertebral column ultimately develops. As the neural tube closes, ectoderm cells called neural crest cells, migrate away from the dorsal surface of the neural tube to become progenitors of the neurons and supporting cells of the parasympathetic nervous system. The surface ectoderm separates from the neural tube and fuses over the top to become the outer layer of skin.
While explaining the role of skeletal muscle relaxants, such as succinylcholine, used during anesthesia, the faculty mentions that these effects are caused by blocking: a) N2, neuronal-type receptor, a type of nicotinic acetylcholine receptor b) Norepinephrine c) Nicotinic acetylcholine receptors, muscle-type receptor (NM) d) Muscarinic acetylcholine receptors
Nicotinic acetylcholine receptors, muscle-type receptor (NM) Some skeletal muscle relaxants, such as succinylcholine, can be used to induce muscle relaxation and short-term paralysis in anesthesia by blocking NM receptors at the neuromuscular junction. The drug atropine is a competitive antagonist for the muscarinic acetylcholine receptor that prevents the action of acetylcholine at excitatory and inhibitory muscarinic receptor sites. Norepinephrine is released at most sympathetic nerve endings.
Spinal nerves that form complex nerve networks are called which of the following? a) Plexuses b) Choroid plexus c) Reticular formations d) Rami
Plexuses Spinal nerves do not go directly to skin and muscle fibers; instead, they form complicated nerve networks called plexuses. A plexus is a site of intermixing nerve branches. - After emerging from the vertebral column, the spinal nerve divides into two branches, or rami. -The choroid plexus produces cerebrospinal fluit in the lateral, third and fourth ventricles. -Reticular formation is the location of many important reflex circuits of the spinal cord and brain stem.
Which parts of the brain make up the brain stem? a) Cerebellum and reticular system b) Circle of Willis and hypothalamus c) Pons and medulla oblongata d) Limbic and diencephalons
Pons and medulla oblongata The brain stem consists of the pons and the medulla
When educating a patient about to undergo a pacemaker insertion, the nurse explains the normal phases of cardiac muscle tissue. During the repolarization phase, the nurse will stress that membranes must be repolarized before they can be re-excited. Within the cell, the nurse understands that: a) Potassium channels open and while sodium channels close causing repolarization to the resting state. b) Only the electrical activity within the heart will determine when repolarization occurs. c) The cell membranes need to stay calm resulting in muscle tissue becoming refractive. d) The influx of calcium is the primary stimulus for the repolarization of cardiac tissue.
Potassium channels open and while sodium channels close causing repolarization to the resting state. Repolarization is the phase during which the polarity of the resting membrane potential is re-established. This occurs with the closure of the sodium channels and opening of the potassium channels.
Release of neurotransmitters occurs at which of the following locations in the neuron? a) Postsynaptic membrane b) Presynaptic terminal c) Synaptic cleft d) Endoneurium
Presynaptic terminal Chemical synapses involve special presynaptic and postsynaptic membrane structures, separated by the synaptic cleft. The presynaptic terminal secretes one and often several chemical transmitter molecules. The secreted neurotransmitters diffuse into the synaptic cleft and bind to receptors on the postsynaptic membrane. Each of the Schwann cells along a peripheral nerve is encased in a continuous tube of basement membrane, which in turn is surrounded by a multilayer sheath of loose connective tissue known as the endoneurium.
Neurotransmitters exert their actions through specific proteins that are known as: a) Transformers b) Receptors c) Antibodies d) Autoantigens
Receptors Neurotransmitters exert their actions through specific proteins that are known as called receptors, embedded in the postsynaptic membrane.
Neurons communicate with each other through which of the following structures? a) Neural crest cells b) Cell bodies c) Synapses d) Dendrites
Synapses Neurons communicate with each other through structures known as synapses. -Cell bodies and dendrites are covered in synapses. -Neural crest cells migrate aways from the forming neural tube and are progenitors to the parasympathetic nervous system.
After neurotransmitters are synthesized, in which of the following structures are they stored in the axon terminal? a) Synaptic vesicles b) Synaptic cleft c) Axon hillock d) Postsynaptic receptor
Synaptic vesicles After synthesis, the neurotransmitter molecules are stored in the axon terminal in tiny, membrane bound sacs called synaptic vesicles. After a nerve impulse stimulates the presynaptic neuron, the vesicles move to the cell membrane and release the neurotransmitter into the synaptic cleft. The neurotransmitter moves across the cleft and binds to postsynaptic receptors. The axon hillock is the initial segment of the axon where the action potential is initiated.
A badly burned firefighter has been in an induced coma for three weeks. When he awakens, he thanks his son for singing Happy Birthday to him a week earlier. Which part of the brain is responsible for allowing him to hear and comprehend while comatose? a) Corpus callosum b) Hypothalamus c) Basal ganglia d) Thalamus
Thalamus Coordination and integration of peripheral sensory stimuli occur in the thalamus, along with some crude interpretation of highly emotion-laden auditory experiences that not only occur but also can be remembered. For example, a person can recover from a deep coma in which cerebral cortex activity is minimal and remember some of what was said at the bedside. Inferior to the thalamus, and representing the ventral horn portion of the diencephalon, is the hypothalamus; it is the area of master-level integration of homeostatic control of the body's internal environment. -The corpus callosum is a massive commissure, or bridge, of myelinated axons that connects the cerebral cortex of the two sides of the brain. -The basal ganglia lie on either side of the internal capsule, just lateral to the thalamus; they supply axial and proximal unlearned and learned postures and movements, which enhance and add gracefulness to UMN-controlled manipulative movements
The nurse is aware that some drugs may be prevented from entering the brain as a function of: a) Elimination by the kidneys b) Rapid absorption in the gastric mucosa c) Detoxification by the liver d) The blood-brain barrier
The blood-brain barrier The blood-brain barrier prevents many drugs from entering the brain. Most highly water-soluble components are excluded from the brain, especially molecules with high ionic charge, such as many of the catecholamines.
College students were given various amounts of alcohol within a specified timeframe and then asked to drive an obstacle course. The rationale for poor performance in driving as the amount of alcohol intake increased includes, "The blood-brain barrier: a) Interacts negatively with the potassium-sodium pump, allowing alcohol to freely flow into the capillaries of the brain." b) Allows alcohol, a very lipid-soluble molecule to rapidly enter the brain." c) Allows more bilirubin to cross the barrier producing brain damage." d) Excludes water-based compounds from crossing the brain with the exception of alcohol."
Allows alcohol, a very lipid-soluble molecule to rapidly enter the brain." The blood-brain barrier prevents many drugs from entering the brain. Most highly water-soluble compounds are excluded from the brain, especially molecules with high ionic charge, such as many of the catecholamines. In contrast, many lipid-soluble molecules cross the lipid layers of the blood-brain barrier with ease. Alcohol, nicotine, and heroin are very lipid soluble and rapidly enter the brain.
Neuromodulators can produce slower and longer-lasting changes in membrane excitability by acting on postsynaptic receptors. What do neuromodulators do? a) Alter the release of or response to neurotransmitters b) Alter the inhibitory response of postsynaptic electrical receptors c) Alter the ligand gate response to electrical activity d) Alter the metabolic function of Schwann cells
Alter the release of or response to neurotransmitters Neuromodulator molecules react with presynaptic or postsynaptic receptors to alter the release of or response to neurotransmitters. The other answers are incorrect.
Which components of the nervous system make up the central nervous system? a) Astrocytes and Schwann cells b) Brain and spinal cord c) Dendrites and axons d) Neurohormones and neurosecretory granules
Brain and spinal cord The brain and the spinal column make up the central nervous system. The peripheral nervous system lies outside of these two structures.
An increased blood pressure is detected by the carotid sinus baroreceptor and results in stimulation of the vagus nerve to decrease the heart rate. At which of the following levels of the nervous system does this reflex adjustment occur? a) Spinal cord b) Brain stem (medulla and pons) c) Cerebral cortex d) Hypothalumus
Brain stem (medulla and pons) Reflex adjustment of cardiovascular and respiratory function occur at the level of the brain stem (medulla and pons). The other options do not provide autonomic control of the cardiovascular system.
A practitioner is preparing to do a lumbar puncture on a patient with suspected meningitis. Which of the following areas on the spine does the practitioner choose to obtain a cerebrospinal fluid (CSF) sample? a) Between T1 and T2 b) Between T12 and L1 c) Between C7 and C8 d) Between L3 and L4
Between L3 and L4 The adult cord usually terminates at the inferior border of L1. The arachnoid and its enclosed subarachnoid space, which is filled with CSF, do not close down on the filum terminale until they reach the second sacral vertebra. This results in a formation of a pocket of CSF, the dural cisterna spinalis, which extends from approximately L2 to S2. Because this has an abundant supply of CSF and the spinal cord does not extend this far, the area (L3 or L4) is often used to perform a lumbar puncture to obtain CSF
Following a stroke, injury to nerve cells within the central nervous system needs to be repaired. The health care provider knows that which of the following processes explains how this occurs? a) The microglia are responsible for cleaning up debris after cerebral infection, or cell death. b) Oligodendrocytes are responsible for integrative metabolism. c) Ependymal cells are responsible for phagocytosis. d) Astrocytes fill up the space to form a glial scar, repairing the area and replacing the CNS cells that cannot regenerate.
Astrocytes fill up the space to form a glial scar, repairing the area and replacing the CNS cells that cannot regenerate. Astrocytes are the largest and most numerous of neuroglia and are particularly prominent in the gray matter of the CNS. They form a network within the CNS and communicate with neurons to support and modulate their activities. Astrocytes are also the principal cells responsible for repair and scar formation in the brain. -The microglia is a small phagocytic cell that is available for cleaning up debris after cellular infection or cell death. -The ependymal cell forms the lining of the neural tube cavity, the ventricular system. -The oligodendrocytes form the myelin in the CNS. Instead of forming a myelin covering for a single axon, these cells reach out with several processes, each wrapping around and forming a multilayered myelin segment around several different axons.
Which of the following cell types are responsible for repair and scar formation (also called gliosis)in the brain? a) Schwann cells. b) Astrocytes. c) Microglia. d) Oligodendrocytes.
Astrocytes. Astrocytes, the most numerous of the neuroglial cells, are the principle cells responsible for repair and scar formation in the brain. This process is called gliosis. -Microglia, another neuroglial cell of the CNS, is a small phagocytic cell that is available for cleaning up debris after cellular damage, infection or cell death. -Oligodendrocytes are neuroglial cells that form myelin in the CNS. -Schwann cells are also neuroglial cells that produce myelin in the PNS.
The parasympathetic nervous system is part of which of the following systems? a) Central nervous system b) Autonomic nervous system c) Somatic nervous system d) Thoracolumbar nervouse system
Autonomic nervous system The efferent outflow from the autonomic nervous system has two divisons: the sympathetic nervous system and the parasympathetic nervous system.
Drugs like diazepam (Valium), a benzodiazepine, exert their action on ion channels. These drugs do not open the GABA-operated ion channel, but they: a) Change the effect that GABA has when it binds to the channel at the same time as the drug b) Modulate the peripheral sympathetic nerves and can have both a transmitter and modulator function c) Play a necessary role in the long-term survival of presynaptic neurons d) Modulate the release from axon terminals
Change the effect that GABA has when it binds to the channel at the same time as the drug Amino acids, such as glutamine, glycine, and GABA, serve as neurotransmitters at most CNS synapses. GABA mediates most synaptic inhibition in the CNS. Drugs such as the benzodiazepines (e.g., the tranquilizer diazepam) and the barbiturates exert their action by binding to their own distinct receptor on a GABA-operated ion channel. The drugs by themselves do not open the channel, but they change the effect that GABA has when it binds to the channel at the same time as the drug. -Another class of messenger molecules, known as neuromodulators, also may be released from axon terminals. In contrast to neurotransmitters, neuromodulators do not directly activate ion channel receptors but bring about long-term changes that subtly enhance or depress the action of the receptors. -Neuromodulators, such as dopamine, serotonin, acetylcholine, histamine, and others, may act at either presynaptic or postsynaptic sites.
Cerebrospinal fluid (CSF) is produced by which of the following structures? a) Arachnoid mater b) Choroid plexus c) Falx cerebri d) Dura mater
Choroid plexus The CSF is produced by tiny reddish masses of specialized ependymal cells and capillaries, called the choroid plexus, which projects into the ventricles. The other options do not produce CSF
Select the function of the occipital lobe. a) Discrimination of sounds entering opposite ears b) Determination of objects through the sense of touch c) Anticipation and prediction of consequences of behavior d) Color, motion, and depth perception
Color, motion, and depth perception The occipital lobe is associated with the ability to experience color, depth, and motion perception. -The temporal lobe is responsible for behavior, -The parietal lobe helps us to determine objects through the sense of feel.
Which of the following characterizes a function of the parasympathetic nervous system (PNS)? a) Conservation of energy b) Blood sugar increase c) Constriction of the stomach and intestine sphincters d) Blood flow shifting from the skin and gastrointestinal tract to the skeletal muscles and brain
Conservation of energy The functions of the PNS are concerned with conservation of energy, resource replenishment and storage, and maintenance of organ function during periods of minimal activity—the rest-digest response. All other options are functions of the sympathetic nervous system
describes the midbrain
Conveys the senses of pain, temperature, touch, and proprioception to the superficial and deep regions of the face
The cerebellum, separated from the cerebral hemispheres by the tentorium cerebelli, lies in the posterior fossa of the cranium. What is one of the functions of the cerebellum? a) Contains the main motor pathways between the forebrain and the pons b) Coordinates smooth and accurate movements of the body c) Contains the pontine nuclei d) Conveys the senses of pain, temperature, touch, and proprioception to the superficial and deep regions of the face
Coordinates smooth and accurate movements of the body The cerebellum compares what is actually happening with what is intended to happen. It then transmits the appropriate corrective signals back to the motor system, instructing it to increase or decrease the activity of the participating muscle groups so that smooth and accurate movements can be performed. Answer B describes the trigeminal nerve, which exits the brain stem. Answer C describes the pons. Answer D describes the midbrain.
The thick area of myelinated axons that connects the two sides of the cerebral cortex is known as which of the following components? a) Striatum b) Corpus callosum c) Caudate nucleus d) Globus pallidus
Corpus callosum The thick area of myelinated axons that connects the two sides of the cerebral cortex is known as the corpus callosum. The remaining options are all components of the basal ganglia
While walking down the street, a cat jumps out of an alley into the pathway of an adult. They note that his heart is "racing." This response is primarily due to: a) Parasympathetic effects on the vagus nerve b) The cell body of the first motor neuron that lies in the brain stem c) Reflex circuitry produced by the ANS reflexes d) Secretions of sympathetic neurotransmitters produced in the adrenal medulla
Reflex circuitry produced by the ANS reflexes The organization of many life-support reflexes occurs in the reticular formation of the medulla and pons. These areas of reflex circuitry, often called centers, produce complex combinations of autonomic and somatic efferent functions required for the cough, sneeze, swallow, and vomit reflexes, as well as for the more purely autonomic control of the cardiovascular system. One of the striking features of ANS function is the rapidity and intensity with which it can change visceral function. Within 3 to 5 seconds, it can increase heart rate to approximately twice its resting level. -The vagus nerve provides parasympathetic innervation for the heart, trachea, lungs, esophagus, etc. -The adrenal medulla, which is part of the sympathetic nervous system, contains postganglionic sympathetic neurons that secrete sympathetic neurotransmitters directly into the bloodstream. -The cell body of the first motor neuron, called the preganglionic neuron, lies in the brain stem or the spinal cord.
Which of the following is the period during repolarization when a portion of the recovery period is where the membrane can be excited, although only by a stronger-than-normal stimulus? a) Hypopolarization b) Hyperpolarization c) Absolute refractory period d) Relative refractory period
Relative refractory period During repolarization, the membrane remains refractory until repolarization is approximately one third complete and is called the absolute refractory period. During a portion of the recovery period, the membrane can be excited, although only by a stronger-than-normal stimulus, and is called a relative refractory period. -The excitability of neurons can be affected by conditions that alter the resting membrane potential, moving it either closer (hypopolarization) or further (hyperpolarization) from the threshold potential.
Potassium outflow from the cell is characteristic of which of the following phases of the action potential? a) Threshold potential b) Repolarization c) Resting membrane potential d) Depolarization
Repolarization Repolarization is the phase during which the polarity of the resting membrane potential is reestablished. This is accomplished with closure of the sodium channels and opening of the potassium channels. The outflow of the positively charged potassium ions across the cell membrane returns the membrane potential to negativity. During depolarization and resting membrane potential, potassium does not flow out of the cell. A threshold potential represents the membrane potential at which neruon or other excitable tissues are stimulated to fire
Contains the pontine nuclei
describes the pons.
