Chapter 29: Introduction to the Autonomic Nervous System
What does the body require in order to produce acetylcholine? A) Tyramine B) Tyrosine from the diet C) Choline from the diet D) Bilirubin from the liver
Ans: C Feedback: Acetylcholine (ACh) is an ester of acetic acid and an organic alcohol called choline. Cholinergic nerves use choline, obtained in the diet, to produce ACh. Tyramine and tyrosine are associated with norepinephrine production. Bilirubin is not a neurotransmitter.
The nurse administers a medication that stimulates the muscarinic receptors. What types of manifestations will the nurse assess in this patient that indicate the drug is working? A) Pupil dilation B) Increased activity of bowel sounds C) Increased heart rate D) Muscle contractions
Ans: B Feedback: Stimulation of muscarinic receptors increases gastrointestinal (GI) motility which would cause increased activity of bowel sounds. Other effects include pupil constriction, increased urinary bladder contraction, and a slowing of the heart rate. Stimulation of nicotinic receptors cause muscle contractions.
After the effector cell has been stimulated by acetylcholine (ACh), what enzyme stops this stimulation and allows the effector membrane to repolarize? A) Decarboxylase B) Norepinephrine C) Acetylcholinesterase D) Catecholamine
Ans: C Feedback: After the effector cell has been stimulated by ACh, stimulation of the receptor site must be terminated and destruction of any ACh must occur. The destruction of ACh is carried out by the enzyme acetylcholinesterase. This enzyme reacts with the ACh to form a chemically inactive compound. The breakdown of the released ACh is accomplished in 1/1,000 second, and the receptor is vacated, allowing the effector membrane to repolarize and be ready for the next stimulation. Dopa decarboxylase is an enzyme that converts dopa to dopamine. Norepinephrine is a catecholamine as are dopamine, serotonin, and epinephrine.
An anatomy and physiology instructor scratches chalk across the blackboard causing a screeching sound. Several students get a feeling like their hair is standing on end. This response is part of the sympathetic stress reaction and is called what? A) Diaphoresis B) Diuresis C) Piloerection D) Vasoconstriction
Ans: C Feedback: The goose flesh or hair standing on end reaction that occurs as part of the stress response is called piloerection. Diaphoresis refers to sweating. Diuresis is the loss of water through the kidneys. Vasoconstriction is a muscle contraction in the blood vessel leading to blood vessel narrowing.
The nurse administers a drug that stimulates beta2 receptors. What type of health condition would this drug treat? A) Heart disease B)High lipid levels C) Diabetes D) Respiratory disease
Ans: D Feedback: Beta2-receptors are found in the smooth muscle in blood vessels, in the bronchi, in the periphery, and in uterine muscle. Beta2-receptors also cause dilation in the bronchi. Beta1-receptor stimulation would improve some heart disease and are responsible for increased lipolysis. Because beta2-receptors increase release of glucagon and the breakdown of glycogen, increasing serum glucose levels, stimulation of these receptors would exacerbate diabetes.
The nurse administers a drug to treat hypertension that causes vasodilation of blood vessels. What is the drug stimulating? A) Alpha1-receptors B) Alpha2-receptors C) Beta1-receptors D) Beta2-receptors
Ans: C Feedback: In blood vessels, beta2 stimulation leads to vasodilation. Stimulation of Alpha1-receptors causes vasoconstriction. Beta1 and Alpha2-receptors are not involved with blood vessels
Central nervous system drugs bind to receptors embedded in the cell membranes of neurons. Cholinergic receptors have been classified as what? A) Muscarinic B) Hormones C) Enzymes D) Proteins
Ans: A Feedback: Cholinergic receptors or acetylcholine receptors are found on organs and muscles. They have been classified as muscarinic receptors and nicotinic receptors. Cholinergic receptors are not classified as hormones, enzymes, or proteins.
Neurons that use acetylcholine as its neurotransmitter are what type of neurons? A) Cholinergic B) Dopaminergic C) GABA-ergic D) Serotonergic
Ans: A Feedback: Neurons that use ACh as their neurotransmitter are called cholinergic neurons. Other options are incorrect.
A young woman who lives alone comes home at night to find a man in her apartment. What body responses would be expected for the young woman? A) Increased blood pressure (BP), increased heart rate, and pupil dilation B) Decrease sweating, decreased BP, and increased heart rate C) Pupil constriction, increased respiratory rate, and decreased heart rate D) Increased sweating, decreased respiratory rate, and increased BP
Ans: A Feedback: When stimulated by a stressful or fearful situation, the sympathetic nervous system (SNS) prepares the body to flee or to turn and fight. Cardiovascular activity increases as do blood pressure, heart rate, and blood flow to skeletal muscles. Respiratory rate increases, pupils dilate, and sweating increases. Decrease in sweating, BP, heart rate, respiratory rate, and pupil constriction indicate stimulation of the parasympathetic nervous system, which would not be stimulated by fear.
The control systems of the body act in many ways to maintain homeostasis. These homeostatic control systems regulate the functions of the cell, integrate the functions of different organ systems, and do what else? A) Control vital functions B) Feed cells under stress C) Act on invading organisms D) Shut down the body at death
Ans: A Feedback: In many areas, the parasympathetic nervous system works in opposition to the sympathetic nervous system. This allows the autonomic system to maintain a fine control over vital functions. This is a homeostatic control system. Homeostatic control systems do not feed cells when they are under stress, they do not act on invading organisms, and do they shut down the body at death.
The body makes norepinephrine by using what from the diet? A) Tyrosine B) Thiamine C) Tryptophan D) Trichonosis
Ans: A Feedback: Norepinephrine is made by adrenergic nerves using tyrosine from the diet. Therefore the other options are incorrect.
The nurse administers a drug that causes vasoconstriction, contracted piloerection muscles, pupil dilation, closure of salivary sphincter, and male sexual emission. What receptor is this drug stimulating? A) Alpha1-receptors B) Alpha2-receptors C) Beta1-receptors D) Beta2-receptors
Ans: A Feedback: Stimulation of Alpha1-receptors results in vasoconstriction of blood vessels, increased peripheral resistance with increased blood pressure, contracted piloerection muscles, pupil dilation, thickened salivary secretions, closure of the urinary bladder sphincter, and male sexual emission. None of the other receptors, when stimulated, would have this effect.
What statement correctly explains the nerve impulse transmission? A) The impulse travels from the central nervous system (CNS) to the preganglionic neuron to the ganglia to the postganglionic neuron to the neuroeffector cells. B) The impulse travels from the preganglionic neuron to the CNS to the ganglia to the postganglionic neuron to the neuroeffector cells. C) The impulse travels from the preganglionic neuron to the ganglia to the postganglionic neuron to the CNS to the neuroeffector cell. D) The impulse travels from the CNS, to the neuroeffector cells, to the preganglionic neuron to the ganglia to the postganglionic neuron.
Ans: A Feedback: The autonomic nervous system does not send impulses directly to the periphery. Instead, axons from CNS neurons end in ganglia, or groups of nerve bodies that are packed together, located outside of the CNS. These ganglia receive information from the preganglionic neuron that started in the CNS and relay that information along postganglionic neurons. The postganglionic neurons transmit impulses to the neuroeffector cellsmuscles, glands, and organs.
The nursing student learns that the hypothalamus serves what purpose? A) Causes the secretion of adrenocorticotropic hormone (ACTH) B) Controls voluntary movement C) Secretes norepinephrine D) Helps maintain red blood cell production
Ans: A Feedback: The hypothalamus causes the secretion of ACTH, leading to a release of the adrenal hormones including cortisol, which suppresses the immune and inflammatory reactions to preserve energy that otherwise, might be used by these activities. The hypothalamus does not have a role in controlling voluntary movement. The adrenal glands secrete norepinephrine. Red blood cells are produced in the bone marrow and are stimulated to produce the cells by epoetin secreted by the kidney.
What is another name for the parasympathetic nervous system? A) Craniosacral system B) Cephalocaudal system C) Preganglionic system D) Thoracolumbar system
Ans: A Feedback: The parasympathetic system is sometimes called the craniosacral system because the central nervous system neurons that originate parasympathetic impulses are found in the cranium (one of the most important being the vagus or tenth cranial nerve) and in the sacral area of the spinal cord. The thoracolumbar system is the sympathetic nervous system. The other options are distractors.
The nurse accompanies the physician into the patients room and remains after the patient is told he has cancer and it is likely to be terminal. The patients respirations become rapid and deep, pupils dilate, and measurement of vital signs indicates the patients heart rate and blood pressure are elevated. What type of response is the nurse assessing? A) Sympathetic nervous system (SNS) response B) Parasympathetic nervous system (PNS) response C) Muscarinic receptor stimulation response D) Nicotinic receptor stimulation response
Ans: A Feedback: When stimulated, the SNS prepares the body to flee or to turn and fight. Cardiovascular activity increases, as do blood pressure, heart rate, and blood flow to the skeletal muscles. Respiratory efficiency also increases; bronchi dilate to allow more air to enter with each breath, and the respiratory rate increases. Pupils dilate to permit more light to enter the eye to improve vision in darkened areas. PNS would lower heart rate and blood pressure and would constrict pupils. Stimulation of muscarinic receptors cause pupil constriction, increased gastrointestinal (GI) motility and secretions (including saliva), increased urinary bladder contraction, and a slowing of the heart rate. Stimulation of nicotinic receptors causes muscle contractions, autonomic responses such as signs and symptoms of a stress reaction, and release of norepinephrine and epinephrine from the adrenal medulla.
The nurse administers a drug that stimulates the nicotinic receptors. What assessment findings would indicate effectiveness of the drug? (Select all that apply.) A) Muscle contractions B) Release of norepinephrine from the adrenal medulla C) Signs and symptoms of a stress reaction D) Urinary incontinence E) Hyperactive bowel sounds
Ans: A, B, C Feedback: Stimulation of nicotinic receptors causes muscle contractions, autonomic responses such as signs and symptoms of a stress reaction, and release of norepinephrine and epinephrine from the adrenal medulla. Urinary incontinence would not be associated with stimulation of the nicotinic receptors and increased bowel activity would result from muscarinic receptors.
The nurse is teaching a class about the autonomic nervous system for critical care nurses. What statements, if made by the nurse during the class, are accurate? (Select all that apply.) A) Adrenergic receptors respond to norepinephrine. B) Adrenergic receptors are part of the sympathetic nervous system. C) Cholinergic receptors are part of the parasympathetic nervous system. D) Cholinergic receptors include alpha- and beta- receptors. E) Cholinergic and adrenergic receptors are part of the autonomic nervous system.
Ans: A, B, C, E Feedback: The sympathetic nervous system contains the adrenergic receptors that respond to norepinephrine and include alpha- and beta-receptors. The parasympathetic nervous system contains the cholinergic receptors including the muscarinic and nicotinic receptors that respond to acetylcholine. Together the sympathetic and parasympathetic systems, including cholinergic and adrenergic receptors, make up the autonomic nervous system. Option D is incorrect.
Where are Alpha1-receptors found? (Select all that apply.) A) Blood vessels B) The iris C) Nerve membranes D) Urinary bladder E) Stomach sphincters
Ans: A, B, D Feedback: Alpha1-receptors are found in blood vessels, in the iris, and in the urinary bladder. Alpha2-receptors are located on nerve membranes. Option E is a distracter.
The nurse administers a medication that stimulates the parasympathetic nervous system (PNS). What manifestations would indicate the medication is working? (Select all that apply.) A) Hyperactive bowel sounds B) Increased saliva production C) Elevated heart rate D) Urinary incontinence E) Constricted pupils
Ans: A, B, E Feedback: PNS stimulation results in increased motility and secretions in the gastrointestinal (GI) tract to promote digestion and absorption of nutrients: decreased heart rate and contractility to conserve energy and provide rest for the heart; constriction of the bronchi, with increased secretions; relaxation of the GI and urinary bladder sphincters, allowing evacuation of waste products; pupillary constriction, which decreases the light entering the eye and decreases stimulation of the retina. While urinary sphincters relax, they do not lose control so incontinence would not be an expected manifestation.
When muscarinic receptors are stimulated, what happens physiologically in the body? (Select all that apply.) A) Pupil constriction B) Pupil dilation C) Increased secretions D) Increased bladder contraction E) Increased heart rate
Ans: A, C, D Feedback: Stimulation of muscarinic receptors causes pupil constriction, increased gastrointestinal (GI) motility and secretions (including saliva), increased urinary bladder contraction, and a slowing of the heart rate. Pupils are constricted, not dilated and heart rate slows, it does not increase.
The patient is undergoing chronic stress and has a prolonged sympathetic response. What type of drug could this patient receive to reduce the sympathetic response? (Select all that apply.) A) A drug that reduces sympathetic response B) A drug that increases sympathetic response C) A drug that reduces parasympathetic response D) A drug that increases parasympathetic response E) A drug that reduces central nervous system (CNS) response
Ans: A, D, E Feedback: Decreasing sympathetic response would reduce the stress response, whereas increasing parasympathetic response would have the same effect. Although not optional, a medication that slowed down the entire nervous system would also work. In many areas, the parasympathetic nervous system works in opposition to the sympathetic nervous system (SNS). This allows the autonomic system to maintain a fine control over internal homeostasis. For example, the SNS increases heart rate, whereas the parasympathetic nervous system decreases it. Thus, the autonomic nervous system can influence heart rate by increasing or decreasing sympathetic activity or by increasing or decreasing parasympathetic activity.
The nurse administers a parasympathetic stimulator that only stimulates nicotinic receptors. What effects would the nurse expect to assess? (Select all that apply.) A) Muscle contraction B) Slowing heart rate C) Increased bladder contraction D) Signs and symptoms of a stress reaction E) Release of epinephrine from adrenal medulla
Ans: A, D, E Feedback: Stimulation of nicotinic receptors causes muscle contractions, autonomic responses such as signs and symptoms of a stress reaction, and release of norepinephrine and epinephrine from the adrenal medulla. Stimulation of muscarinic receptors causes pupil constriction, increased gastrointestinal (GI) motility and secretions (including saliva), increased urinary bladder contraction, and a slowing of the heart rate.
A patient is being admitted to the floor following a motor vehicle accident. Because of the stressful nature of the event, the nurse anticipates the patient will continue to have a sympathetic stress reaction during the postoperative period. When monitoring the patients serum electrolytes, what will the nurse closely monitor? A) Increased calcium B) Decreased potassium C) Increased chloride D) Decreased sodium
Ans: B Feedback: Aldosterone, also released with adrenal stimulation, retains sodium and water and causes the excretion of potassium in the urine. As water is retained, sodium is also retained, therefore increasing serum levels. Chloride levels are unlikely to change significantly. Calcium is not involved.
When there is stimulation of the sympathetic nervous system (SNS), blood is diverted away from the gastrointestinal (GI) tract. What might the nurse assess that would indicate this diversion of blood flow to the GI tract? A) Increased blood glucose levels B) Decreased bowel sounds C) Increased blood pressure D) Decreased immune reactions
Ans: B Feedback: When blood is diverted away from the GI tract, bowel sounds decrease and digestion slows dramatically, sphincters are constricted, and bowel evacuation cannot occur. Increased blood glucose levels, elevated blood pressure, and decreased immune reaction are due to SNS stimulation but are not concerned with the GI tract.
The nurse administers a drug that stimulates the parasympathetic nervous system. What physiological response would indicate the drug is working? A) Vasoconstriction B) Increased gastrointestinal (GI) motility C) Increased heart rate D) Pupil dilation
Ans: B Feedback: When the parasympathetic nervous system is stimulated, the result is increased GI motility, decreased GI secretions, decreased heart rate, and pupillary constriction, which all result from stimulation of the sympathetic nervous system.
What helps to prevent overstimulation of effector sites on nerve membranes? A) Alpha1-receptors B) Alpha2-receptors C) Beta1-receptors D) Beta2-receptors
Ans: C Feedback: Alpha2-receptors are located on nerve membranes and act as modulators of norepinephrine release. When norepinephrine is released from a nerve ending, it crosses the synaptic cleft to react with its specific receptor site. Some of it also flows back to react with the alpha-receptor on the nerve membrane. This causes a reflex decrease in norepinephrine release. In this way, the Alpha2-receptor helps to prevent overstimulation of effector sites.
The sympathetic nervous system (SNS) is associated with a fight-or-flight reaction. What reaction is the parasympathetic nervous system is associated? A) Recover and repair B) Respond and return C) Rest and digest D) Calm and peace
Ans: C Feedback: Although the SNS is associated with the stress reaction and expenditure of energy, the parasympathetic nervous system is associated with activities that help the body to store or conserve energy, a rest-and-digest response.
The nurse administers a drug to the patient whose heart rate is bradycardic aimed at increasing heart rate and myocardial activity. What adrenergic receptor is this drug stimulating? A) Alpha1 B) Alpha2 C) Beta1 D) Beta2
Ans: C Feedback: Beta1-receptors are found in cardiac tissue where they can stimulate increased myocardial activity and increased heart rate. Alpha1-receptors are found in blood vessels, in the iris, and in the urinary bladder. Alpha2-receptors are located on nerve membranes and act as modulators of norepinephrine release. Beta1-receptors are found in smooth muscle in blood vessels, in the bronchi, in the periphery, and in uterine muscle.
When the nurse administers a drug that stimulates the nicotinic receptors, what manifestation would indicate the drug is working? A) Increased gastrointestinal (GI) motility B) Decrease in heart rate C) Muscle contraction D) Pupil constriction
Ans: C Feedback: Nicotinic receptors are located in the central nervous system (CNS), the adrenal medulla, the autonomic ganglia, and the neuromuscular junction. Stimulation of nicotinic receptors causes muscle contractions, autonomic responses, and release of norepinephrine from the adrenal medulla. Increased GI motility, decreased heart rate, and pupil constriction are the result of stimulation of the muscarinic receptors.
Which of these is a neurotransmitter? A) Calcium B) Cholinesterase C) Acetylcholine (ACh) D) Monoamine oxidase
Ans: C Feedback: The last step in the production of the neurotransmitter involves choline acetyltransferase, an enzyme that is also produced within cholinergic nerves. Just like norepinephrine, the ACh is produced in the nerve and travels to the end of the axons, where it is packaged into vesicles. Calcium is an electrolyte and not a neurotransmitter. Cholinesterase breaks down acetylcholine and is an enzyme, not a neurotransmitter. Monoamine oxidase is an enzyme that breaks down norepinephrine.
The nurse assesses that the patient is having a sympathetic response when noting what manifestations? A) Decrease in sweating, decrease in respirations, and pupil constriction B) Decrease in heart rate and perfusion, and an increase in inflammatory reactions C) Increase in blood pressure, bronchodilation, and decreased bowel sounds D) Increased motility and secretions in the GI tract, and constriction of bronchi and pupils
Ans: C Feedback: When stimulated, the sympathetic nervous system prepares the body to flee or to turn and fight (Figure 29.3). Cardiovascular activity increases, as do blood pressure, heart rate, and blood flow to the skeletal muscles. Respiratory efficiency also increases; bronchi dilate to allow more air to enter with each breath, and the respiratory rate increases. Pupils dilate to permit more light to enter the eye, to improve vision in darkened areas (which helps a person to see to fight or flee). Sweating increases to dissipate heat generated by the increased metabolic activity.
Muscarinic and nicotinic receptors are part of what system? A) The limbic system B) The reticular activating system C) The sympathetic nervous system D) The parasympathetic nervous system
Ans: D Feedback: Cholinergic receptors or acetylcholine receptors of the parasympathetic nervous system are found on organs and muscles. They have been classified as muscarinic receptors and nicotinic receptors. Because these receptors are part of the parasympathetic nervous system, all other options are incorrect.
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 presynaptic junction C) In the postsynaptic junction D) In the axon terminal
Ans: D Feedback: Norepinephrine is made by the nerve cells using tyrosine, obtained in the diet. Dihydroxyphenylalanine (dopa) is produced by a nerve, using tyrosine from the diet and other chemicals. With the help of the enzyme dopa decarboxylase, the dopa is converted to dopamine, which in turn is converted to norepinephrine in the axon terminals of adrenergic cells. The norepinephrine then is stored in granules or storage vesicles within the cell.
The central nervous system (CNS) cells, where the impulses for the sympathetic nervous system (SNS) originate, are located where? A) Cranium and sacral area of the spinal cord B) Hypothalamus and the medulla C) Nerve membranes D) Thoracic and lumbar sections of the spinal cord
Ans: D Feedback: The SNS is also called the thoracolumbar system because the CNS cells, where the impulses for the SNS originate, are located in the thoracic and lumbar sections of the spinal cord. The parasympathetic nervous system (PNS) is called the craniosacral system because the CNS neurons, where the impulses for the PNS originate, are found in the cranium and the sacral area of the spinal cord. Alpha2-receptors are located on nerve membranes and the hypothalamus and medulla are located where the main nerve centers for the autonomic nervous system (ANS) are located.