Chapter 29 PrepU Pharmacology (m)

The nurse is caring for a client with asthma who has been administered albuterol in order to promote bronchodilation and relieve shortness of breath. When giving this medication, the nurse has affected the client's autonomic nervous system by:

stimulating beta2-receptors. Explanation: Stimulation of beta2-receptors causes bronchial dilation. Manipulation of acetylcholine levels does not cause this effect, not does increasing norepinephrine levels. Antagonizing the alpha2-receptors would not have this effect.

A patient exercises for 30 minutes today. The client has not been on an exercise regimen for many years. The exercise will result in what autonomic neurotransmitter to be released?

Acetylcholine Explanation: Acetylcholine is released from postganglionic sympathetic neurons that innervate the sweat glands and from motor neurons of somatic nervous system that innervate the skeletal muscles. Norepinephrine is synthesized from the amino acid tyrosine by a series of enzymatic conversions that also produce dopamine and epinephrine. Epinephrine regulates blood pressure and cardiac function, but has limited effect on skeletal muscles of exercise. The release of insulin regulates blood sugar and is not a neurotransmitter, but a hormone.

A patient is using his incentive spirometer during the postoperative period. The skeletal muscles during the use of the incentive spirometer are stimulated by which neurotransmitter?

Acetylcholine Explanation: When acetylcholine acts on body cells that respond to parasympathetic nervous stimulation, it interacts with two types of cholinergic receptors: nicotinic and muscarinic. Nicotinic receptors are located in motor nerves and skeletal muscle. Dopamine is a catecholamine neurotransmitter that elevates blood pressure. Epinephrine is responsible for maintaining blood pressure. Norepinephrine is released to manage severe hypotension.

Deactivation of norepinephrine (NE) occurs by breakdown of NE by which enzyme?

COMT Explanation: Deactivation of NE occurs by breakdown of NE by the enzyme COMT or, most importantly, by reuptake into the presynaptic neuron, where it may be used or inactivated by another enzyme, monoamine oxidase (MOA).

A client is experiencing a stress response. Which would the nurse expect to assess?

Diminished bowel sounds Explanation: In the stress or fight-or-flight response, the nurse would assess diminished bowel sounds, tachycardia, hypertension, and pupil dilation.

Which is NOT a function of the body's homeostatic control systems?

Feed cells under stress Explanation: In many areas, the parasympathetic nervous system works in opposition to the SNS. 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.

Which structure is responsible for the secretion of adrenocorticotropin hormone?

Hypothalamus Explanation: The hypothalamus causes the secretion of adrenocorticotropin hormone, 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.

Norepinephrine is the main neurotransmitter in the sympathetic nervous system. Which enzyme metabolizes norepinephrine?

Monoamine oxidase Explanation: Following its release from adrenergic nerve endings, most of the norepinephrine that does not return to the nerve endings is either absorbed by the surrounding tissue or metabolized by monoamine oxidase (MAO) or catechol-O-methyltransferase (COMT).

Adrenergic nerves use tyrosine from the diet to make which neurotransmitters?

Norepinephrine

Muscarinic receptors would be found most likely at which location?

Sweat glands Explanation: Muscarinic receptors are located in visceral effector organs such as the gastrointestinal tract, bladder, and heart; in sweat glands; and in some vascular smooth muscle. Nicotinic receptors would be found in the adrenal medulla, neuromuscular junction, and CNS.

The nurse is caring for a client who is known to have deficient levels of dopamine because of a dietary lack of tyrosine. The nurse should expect to assess for evidence of:

decreased adrenergic response. Explanation: Dopamine is a precursor to norepinephrine, which is one of the two major postganglionic neurotransmitters of the sympathetic nervous system. Consequently, low levels of dopamine could plausibly lead to a decreased adrenergic response. This would not affect the function of cholinergic neurons. Hypofunction, not hyperfunction, of the SNS would be likely.

The nurse prepares to administer a preoperative anticholinergic to a client. What is a desired effect based upon the characteristics of the prescribed medication?

dry mucous membranes Explanation: Anticholinergic medications block the actions of the endogenous neurotransmitters of the parasympathetic stimulation. The medication would lead to drying of mucous membranes, a desired effect for a preoperative drug. The other listed responses of wheezing, which is because of bronchoconstriction; heart rate of 50, which is bradycardia; and pupils' constriction and increase in mucous secretions would be present when a client receives a cholinergic medication resulting from the activation of the parasympathetic nervous system.

A nurse is caring for client experiencing pain. The client describes the pain as "9" on a scale of 1 to 10, with 10 being the worst pain. Which are expected SNS responses by the client? Select all that apply.

increased blood pressure increased rate of respiration pupillary dilation Explanation: The SNS is stimulated by physical or emotional stress, such as strenuous exercise or work, pain, hemorrhage, intense emotions, and temperature extremes. The client is experiencing an increase in blood pressure, cardiac output, respiratory rate, blood glucose, muscle strength, and pupillary dilation to aid vision.

Which neurotransmitter is involved in pre- and postganglionic activity in the parasympathetic nervous system?

Acetylcholine Explanation: In the PNS, the neurotransmitter involved in pre- and postganglion activity is acetylcholine. Norepinephrine is involved in postganglionic activity of the SNS. Epinephrine is involved in the adrenergic response, being secreted directly into the bloodstream by the adrenal medulla. Dopamine is converted to norepinephrine in the adrenergic cells.

The anatomy and physiology instructor is discussing adrenergic receptors with the nursing class. What adrenergic receptor would the instructor tell the students is found in the blood vessels, iris, and urinary bladder?

Alpha1 Explanation: B1 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. Beta2 receptors are found in smooth muscle in blood vessels, in the bronchi, in the periphery, and in uterine muscle.

Which is a sympathetic nervous system response? (Select all that apply.)

Bronchial dilation Increased sweating Pupil dilation Explanation: Sympathetic nervous system responses include bronchial dilation, pupil dilation, increased sweating, piloerection, and decreased activity of the GI tract.

A client has had a stroke and computed tomography reveals infarcts in multiple brain regions. An infarct in which region is most likely to affect the function of the client's autonomic nervous system?

Hypothalamus Explanation: The hypothalamus plays a major role in the coordination of autonomic nervous system function. The parietal cortex primarily regulates touch and sensation. The amygdala contributes to memory and decision making. The ventricular system contributes to the production and distribution of cerebrospinal fluid.

Alpha-1 receptors have which actions?

Increase blood pressure Explanation: Aplpha1 receptors are found in blood vessels, in the iris, and in the urinary bladder. In blood vessels, they can cause vasoconstriction and increase peripheral resistance, thus raising blood pressure. In the urinary bladder, they cause the increased closure of the internal splinter. Beta-2 receptors are responsible for bronchial dilation, uterine smooth muscle relaxation, and increased lipolysis.

Which would be assessed with parasympathetic nervous system stimulation?

Increased gastric motility Explanation: With parasympathetic nervous stimulation, gastric motility increases, secretions increase, pupils constrict, and the rectal and urinary sphincters relax to allow elimination.

The anatomy and physiology instructor is discussing the role of neurotransmitters in the autonomic nervous system. Which would the instructor identify as the main adrenergic neurotransmitter?

Norepinephrine Explanation: Adrenergic refers to the sympathetic nervous system. The main neurotransmitter of the sympathetic nervous system is norepinephrine.

A nurse administers a decongestant that stimulates alpha-1 receptors. What would most likely occur?

Pupil dilation Explanation: Pupil dilation results from stimulation of alpha-1 receptors. Increased heart rate occurs with beta-1 stimulation. Bronchodilation results from stimulation of beta-2 receptors. Decreased GI activity results from stimulation of beta-2 receptors.v

The nurse is caring for a client with asthma who has been experiencing shortness of breath and who has been administered a medication to cause bronchodilation. What aspect of autonomic nervous function has the nurse most likely influenced?

Stimulation of beta-adrenergic receptors Explanation: Stimulation of beta receptors causes bronchodilation, which is the therapeutic effect of several medications for asthma. The bronchi are not primarily affected by the presence of acetylcholine receptors. Inhibiting the alpha adrenergic receptors does not cause bronchodilation.

A nurse is caring for a client who has excessive salivation. Which muscarinic receptor is responsible for activation of the salivary glands?

muscarinic1 Explanation: Muscarinic1 receptor is expressed primarily in the central nervous system (CNS), autonomic ganglia, and the gastric and salivary glands. Muscarinic2 inhibits adenly cyclase in the heart, smooth muscle, and brain. Muscarinic3 is expressed in the CNS, smooth muscle, glands, and heart. Muscarinic4 inhibits acetylcholine release in the stratum and contributes to the development of Parkinson's disease. Muscarinic5 dilates cerebral arteries and arterioles and facilitates dopamine release.

A client has begun to experience post-operative pain and the client's heart rate has increased from 72 beats per minute to 96 beats per minute. The nurse should attribute this change to the effect of:

stimulation of beta1 receptors in the sympathetic nervous system. Explanation: Stimulation of beta1 receptors increases heart rate. Reuptake of norepinephrine limits the sympathetic response. Stimulation of muscarinic receptors would cause a decrease in heart rate. Dopamine is converted to norepinephrine in the SNS; norepinephrine is not converted to dopamine.

Which is a parasympathetic response of the lacrimal glands?

Increased secretions Explanation: A parasympathetic reaction of the lacrimal glands would be an increased amount of secretions.

When working with a client who is experiencing a stress response, the nurse should anticipate what effects? Select all that apply.

Tachycardia Pupil dilation Diaphoresis Explanation: In the stress response, tachycardia, pupil dilation, hypertension, decreased bowel sounds, and diaphoresis would be noted.

The nurse is conducting an assessment of a newly admitted client. What assessment finding should suggest to the nurse that the client's muscarinic cholinergic receptors are being stimulated?

The client has "pinpoint" pupils. Explanation: Pupil constriction is among the effect of parasympathetic stimulation of muscarinic cholinergic receptors. Pain and cognition are not affected by these receptors. The client's blood pressure is well within acceptable ranges; there is no obvious indication of parasympathetic stimulation.

A famous magician is known for his outlandish feats, such as being underwater for 10 minutes while removing handcuffs. Some have postulated that he has control over his autonomic nervous system in ways that most people do not. What would be an example of an autonomic response he may have control over?

The rate of his heart beat Explanation: The autonomic nervous system controls functions essential to the life of the organism and not consciously controlled, including heart rate, blood pressure, and gastrointestinal activity. Speech, income, and oxygen diffusion within cells are not controlled by the autonomic nervous system.

After teaching a group of students about the differences between the sympathetic nervous system and the parasympathetic nervous system, the instructor determines that the students have understood the information when they state:

The sympathetic nervous system preganglionic fibers are short, while those in the parasympathetic nervous system are long. Explanation: The SNS preganglionic fibers are short; the PNS preganglionic fibers are long. The SNS ganglia are located in chains along the spinal cord; those of the PNS are located close to or within the effector tissue. The SNS is the system involved in the stress response, while the PNS is the rest and digest system. The PNS contains nicotinic and muscarinic receptors.

Which would occur if a drug stimulated beta-2 receptors?

Vasodilation Explanation: Vasodilation, as well as bronchodilation and uterine relaxation, occur as a result of beta-2 stimulation. Piloerection results from stimulation of alpha-1 receptors.