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Biol 2110 Autonomic Case Study 3 Due July 25 Day of Final YOU must turn in a hard copy on the day of the final, it will not be accepted late. Name: Eboni Cook 1. Answer all questions with material that explains your answers. Yes/no answers receive NO credit. 2. Submit this as a hard copy, typed. 3. Late papers will not be accepted 4. Total possible points = 35 points This exercise is to explain the ANS, its neurons and the type of neurotransmitters involved NOT cardiac. Concentrate your answers on the Autonomic Nervous system.

During a routine physical a 56 year old retired case worker was found to have hypertension. The patient did not experience any unusual symptoms and had no complaints. Upon examination, chest x rays showed an enlarged left atrium and left ventricle. Blood pressure readings were 154/93mmHg. ( normal BP is 120/80mmHg. With hypertension defined as 140/90mmHg or greater). Cardiac evaluation resulted in the following information: Cardiac output (CO) 3.4L/min. ( Normal ~ 5.4 liters/ min Blood pressure (BP) 154/93 mm Hg ( normal 120/70) Heart sounds revealed no valvular regurgitation. Upon follow up appointments she was diagnosed with chronic hypertension. The doctor prescribes prazosin hydrochloride which is an alpha adrenergic-blocking agent and propranolol with is a beta adrenergic-blocking agent. Follow up visits reveal normal BP for the patient.

Autonomic Nervous System Analysis 1. Explain the anatomical differences between the Somatic Nervous system and the ANS. What does dual innervation mean? You may use a diagram. (8 points )  The somatic nervous system includes sensory input from the special senses, skin, muscles and joints, and motor output to control skeletal muscle. The somatic nervous system (SNS) is the part of the peripheral nervous system associated with the voluntary control of body movements through the skeletal muscles and mediation of involuntary reflex arcs. The SNS nerves are predominately composed of motor neurons in the spinal cord and allow for voluntary control of

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the skeletal muscle. They consist of a single efferent neuron whose axon terminal always releases acetylcholine which means its effect is always excitatory. The autonomic nervous system includes involuntary motor output to cardiac muscle, smooth muscle, and glands and respond to sensory input from visceral sensory components. The autonomic nervous system (ANS) is the part of the peripheral nervous system that controls visceral functions that occur below the level of consciousness. The ANS can be subdivided into the parasympathetic nervous system (PSNS) and the sympathetic nervous system (SNS). The ANS can either release acetylcholine or norepinephrine and can result in an excitatory or inhibitory response. Dual innervation occurs in many effectors of the Autonomic Nervous System and it means that they are innervated by post ganglionic axons from both parasympathetic and sympathetic divisions. They usually result in either antagonist or cooperative effects. Antagonist effects oppose each other such as the control of heart rate, control of muscular activity in the gastrointestinal track, and control of pupil diameter in the iris of the eye.

2. What neurotransmitters are released by somatic neurons? What neurotransmitters are released by preganglionic sympathetic neurons, postganglionic sympathetic neurons, preganglionic parasympathetic neurons and postganglionic parasympathetic neurons? (6 points)  Somatic neurons secrete the neurotransmitter acetylcholine (ACh). Preganglionic sympathetic neurons secrete acetylcholine (ACh) which bind to the cholinergic nicotinic receptor. Postganglionic sympathetic neurons secrete either ACh or norepinephrine (NE). ACh binds to cholinergic muscarinic receptors while NE binds to adrenergic (alpha or beta) receptors. Most postganglionic sympathetic neurons are adrenergic and some are cholinergic. Preganglionic parasympathetic neurons only secrete ACh which binds to cholinergic nicotinic receptors. Postganglionic neurons always secrete ACh and bind to cholinergic muscarinic receptors. 3. What is an adrenergic neurotransmitter? What ANS system releases this type of neurotransmitter? (6 points)  An adrenergic neurotransmitter is norepinephrine. Adrenergic neurons synthesize and secrete norepinephrine. Receptors who bind to NE are known as adrenergic receptors and are divided into alpha and beta divisions. Most other sympathetic post ganglionic neurons release adrenergic neurotransmitters 4. Adrenergic receptors are classified as either Alpha or Beta. What neurotransmitters bind to a ( alpha ) and b (beta ) receptors. (6 points)  The neurotransmitters norepinephrine and epinephrine bind to alpha and beta adrenergic receptors. “Signaling molecules such as neurotransmitters and hormones are called ligands when they bind to specific receptors in the plasma membrane. The class of ligands that bind to adrenergic receptors in neurons are called biogenic amines. One category of biogenic amines are catecholamines because of the presence of a catechol ring structure in the molecule.

Catecholamines include dopamine, norepinephrine, and epinephrine”. The ANS pathway being employed is the sympathetic nervous system because adrenergic receptors are only located in some post ganglionic sympathetic neurons. The sympathetic nervous system houses alpha and beta receptors which are found in the arteries and heart. Once stimulated they cause the arteries to constrict increasing blood pressure and the heart rate. 5. What is the mechanism of action of the 2 drugs? (8points)  The patient was given prazosin hydrochloride which is an alpha-adrenergicblocking agent and propranolol which is a beta adrenergic-blocking agent. Alpha receptors are mostly involved in the stimulation of effector cells and constriction of blood vessels. On the other hand, beta receptors are mostly involved in the relaxation of effector cells and dilatation of blood vessels. Though beta receptors regulate our body’s relaxation functions, when the heart organ is involved, they make our heart beat faster and more forcefully. Alpha-receptors are located on the arteries. When the alpha receptor is stimulated by epinephrine or norepinephrine, the arteries constrict. This increases the blood pressure and the blood flow returning to the heart. Beta 1 receptors are located in the heart. When Beta 1 receptors are stimulated they increase the heart rate and increase the heart's strength of contraction or contractility. Prazosin is used with or without other medications to treat hypertension or high blood pressure. Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. Prazosin belongs to a class of medications called alpha blockers. It works by relaxing and widening blood vessels so blood can flow more easily. Propranolol is a beta-blocker. Beta-blockers affect the heart and circulation (blood flow through arteries and veins). These beta blockers slow down the activity of the heart by preventing messages from being sent to the heart from some nerves, and by blocking the beta adrenergic receptors on the heart. Propranolol is used to treat tremors, angina (chest pain), hypertension (high blood pressure), heart rhythm disorders, and other heart or circulatory conditions. It is also used to treat or prevent heart attack, and to reduce the severity and frequency of migraine headaches. References: 1. “Adrenergic Neurotransmitter.” The Free Dictionary, Farlex, medical-dictionary.thefreedictionary.com/adrenergic neurotransmitter. 2. “ADRENERGIC PHARMACOLOGY.” What Is an Insect?, www.uky.edu/~mtp/OBI836AR.html. 3. Boundless. “Boundless Anatomy and Physiology.” Lumen, Open SUNY Textbooks, courses.lumenlearning.com/boundless-ap/chapter/introductionto-the-autonomic-nervous-system/. 4. Boundless. “Boundless Biology.” Lumen, Open SUNY Textbooks, courses.lumenlearning.com/boundlessbiology/chapter/the-peripheral-nervous-system/.

5. “Prazosin.” DrugBank, www.drugbank.ca/drugs/DB00457....