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Summary The nervous system is divided into two main branches and two divisions: Branches • The Central Nervous system • The Peripheral nervous system Divisions • The efferent division has neurons that carry signals away from the brain and spinal cord to the periphery (the body) • The afferent division contains neurons that carry impulses from the periphery to the CNS. Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins 2

Function of the Autonomic Nervous System • The ANS is an involuntary system responsible for the control of smooth muscle. • The connection between neurons and organs or tissues relies on neurotransmitters and synaptic transmission. • The autonomic nervous system (ANS) is subdivided into: • Sympathetic nervous system (SNS) • Parasympathetic nervous system (PNS) Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins 3

Autonomic Nervous System: Sympathetic • Central Nervous System (CNS) excitatory sympathetic neuron activation • Responds to stress or danger • Initiate the fight-or-flight response • Chief neurotransmitters are called ADRENERGIC 4 Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins

Alarm or Acute Stress • Adrenal glands release epinephrine to … • Enhance strength and speed • Dilate pupils for better vision • Shunt blood away to the muscles, heart, lungs • Corticosteroids release from the adrenal glands to … • Increase muscle endurance and stamina • Decrease nonessential functions like digestion • Inhibit reproduction, growth and immunity • Endorphins are released to… • Reduce sensitivity to pain and injury. • Interact with opioid receptors in the brain to limit the perception of pain. Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins 5

DIRECT SNS ADRENERGIC DRUGS • The therapeutic uses of sympathetic drugs are related to providing extra-adrenergic stimulation. • One of the most frequent indications for adrenergic agonist drugs is shock: • Tachycardia • Severe hypotension • Circulatory collapse • Shock is the result of inadequate tissue perfusion, leaving the cells without the oxygen and nutrients they need to function normally and survive. Prototype drug: Epinephrine Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins 6

Epinephrine: Core Drug Knowledge • Pharmacotherapeutics • Wide variety of indications—asthma, shock, etc. • Pharmacokinetics • Administered—parenterally, topically, or by inhalation. Metabolism: liver. Absorption: into the tissues. Excreted: kidneys. Duration: 1 to 4 hours. • Pharmacodynamics • It stimulates all adrenergic receptors and causes adverse effects in the cardiovascular system and Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins

Epinephrine • Contraindications and precautions • Absolute contraindications to epinephrine include hypersensitivity, sulfite sensitivity, closed -angle glaucoma, and using during labor. • Adverse effects • Severe adverse effects include hypertensive crisis, angina, cerebral hemorrhage, and cardiac arrhythmias. • Drug interactions • Tricyclic antidepressants, oxytocin, some anesthetics, and beta-adrenergic drugs. Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins

Epinephrine • Maximizing therapeutic effects • Close monitoring of vital signs • Careful monitoring for adverse effects. • Minimizing adverse effects • When treating anaphylactic shock, monitor blood pressure. • Assisting the patient with menu planning may help to promote appetite and counteract the anorectic influence of epinephrine. • Monitor and treat insomnia Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins

Adrenergic Receptor Agonist • Adrenergic receptors located throughout the body are important in blood pressure control: • Alpha-adrenergic (Alpha-1 and Alpha-2) receptors • Beta-adrenergic receptors - antagonists [We will discuss these in more depth later in the semester] Beta-adrenergic Agonist • Dopamine creates norepinephrine with use of other chemicals like beta-hydroxylase. Norepinephrine is a then precursor neurotransmitter to epinephrine. Dopamine is important in emergency cardiac treatment to support circulation, prevent circulatory collapse and raise blood pressure. Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins 10

Cardiogenic Shock https: //www. youtube. com/watch? v=GTZ 8 Zh 8 j. Px. A 11

Autonomic Nervous System: Parasympathetic • The Autonomic Nervous System (ANS) maintains regulatory functions of the body e. g. bowels, bladder, digestion, blood flow, heart rate • Chief neurotransmitters are called CHOLINERGIC • Drugs can have cholinergic effects or side effects [Will be covered in later lectures] Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins 12

SNS and PNS Effects on the Body 13 Copyright © 2012 Wolters Kluwer Health

Neurotransmitters https: //www. youtube. com/watch? v=p 5 z. Fg. T 4 aof. A 14

REVIEW: Agonists and Antagonists Agonists are medications that mimic natural neurotransmitters thus “turning on” their receptors. Antagonists are medications that either: A) block natural chemicals at the postsynaptic neuron, or B) prevent the pre-synaptic neuron from the reuptake of natural neurotransmitters. 15 Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins

Practice Question: A priority nursing assessment for a patient who is to receive an alpha- or beta-adrenergic antagonist would be to: A. Assess heart rate B. Check blood glucose C. Measure urinary output D. Monitor respiratory rate Answer: A. Assess heart rate 16 Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins

Practice Question: A nurse in the intensive care unit is caring for a patient in shock and has started IV administration of dopamine. For a patient in shock, dopamine helps to: A. Decrease heart rate B. Decrease blood pressure C. Increase blood pressure D. Increase body temperature Answer: C. Increase blood pressure 17 Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins

Practice Question: A patient is prescribed regular doses of epinephrine. Which of the following nursing diagnoses is related to comfort and is most appropriate for this patient? A. Imbalanced Nutrition: Less than body requirements B. Disturbed Sleep Pattern: Insomnia due to CNS excitation C. Disturbed Sensory Perception D. Ineffective Tissue Perfusion Answer: B. Disturbed Sleep Pattern Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins 18

Practice Question: A patient has recently been prescribed a drug that treats his hypertension by blocking the sympathetic receptors in his sympathetic nervous system. This action is characteristic of: A. An adrenergic antagonist B. An adrenergic agonist C. A cardiotonic D. A neurotransmitter Answer: A. An adrenergic antagonist Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins 19

Practice Question: A 21 -year-old man experienced massive trauma and blood loss during a motorcycle accident and has been started on a dopamine infusion upon his arrival at the hospital. In light of this drug treatment, what assessment should the care team prioritize? A. Respiratory assessment B. Arterial blood gases C. Cardiac monitoring D. Monitoring of intracranial pressure Answer: C. Cardiac monitoring Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins 20

Practice Question: A resident of a long-term care facility receives a betaadrenergic antagonist (beta-blocker) called metoprolol (Lopressor) at 8 AM and 8 PM daily. Before administering this drug, the nurse should perform and document what assessments? A. Oxygen saturation and respiratory rate B. Heart rate and blood pressure C. Level of consciousness and pain rating D. Temperature and respiratory rate Answer: B. Heart rate and blood pressure Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins 21

Practice Question: Which of the following patients is most likely to benefit from the administration of an adrenergic agonist? A. A man who is in cardiogenic shock following a myocardial infarction (“heart attack”) B. A man who has a diagnosis of primary hypertension C. A woman who has been admitted with suspected ischemic stroke D. A woman who is in labor and may need a cesarean section Answer: A. A man who is in cardiogenic shock Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins 22