May 2016 Answers

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(May 29 – June 4) The vagus nerve releases _________ that binds to ________ receptors on the AV node to ________ heart rate?

(E) acetylcholine; muscarinic; decrease. Acetylcholine binds to both muscarinic and nicotinic receptors. It is the muscarinic receptors that are found on the AV node of the heart and through the parasympathetic stimulation of the vagus nerve cause the heart rate to decrease by slowing down the impulse conduction from the atria to the ventricles. Epinephrine causes the heart rate to increase by binding to beta-1 receptors of the heart.

(May 22 – May 28) What type of receptors are found on skeletal muscle?

(F) Nicotinic. These receptors bind to acetylcholine (ACh) being released into the synapse from the neuron at the neuromuscular junction. Beta-1 receptors are found in the heart, specifically in the AV node. By blocking the beta-1 receptors (i.e. Metoprolol) you slow down the electrical conduction from the atria to the ventricles, thereby decreasing the heart rate. Beta-1 receptors are also found in the kidney to increase renin secretion and in fat cells (adipocytes) to increase lipolysis. Alpha-1 receptors are mainly found in the smooth muscle of vessels and also in the eye (causing dilation of the pupil). Beta-2 receptors are important in the bronchioles of the lungs and when stimulated they relax the smooth muscle of the bronchioles so that they dilate and allow more air flow. Nicotinic receptors can be found in synapses in the nervous system and on skeletal muscle.

(May 15 – May 21) For his asthma, Johnny has an albuterol inhaler. Nurse Ema explained to him it works on beta-2 receptors in order to do what?

(F) Relax bronchiolar smooth muscle. Beta-2 receptors are important in the bronchioles of the lungs and when stimulated they relax the smooth muscle of the bronchioles so that they dilate and allow more air flow. Alpha-1 receptors are found in the vascular smooth muscle and upon blocking them, they relax and dilate the blood vessel to allow more blood flow and decrease blood pressure. Beta-1 receptors are found in the AV node of the heart and upon blocking them cause the heart rate to decrease.

(May 8 – May 14) The nursing instructor asked her students, “What receptor can be blocked on the heart to slow its rate down?”

(C) beta-1. These receptors are found in the heart, specifically in the AV node. By blocking the beta-1 receptors (i.e. Metoprolol) you slow down the electrical conduction from the atria to the ventricles, thereby decreasing the heart rate. Beta-1 receptors are also found in the kidney to increase renin secretion and in fat cells (adipocytes) to increase lipolysis. Alpha-1 receptors are mainly found in the smooth muscle of vessels and also in the eye (causing dilation of the pupil). Beta-2 receptors are important in the bronchioles of the lungs and when stimulated they relax the smooth muscle of the bronchioles so that they dilate and allow more air flow. Nicotinic receptors can be found in synapses in the nervous system and on skeletal muscle.

(May 1 – May 7) Prazosin was prescribed to Phil to decrease his blood pressure. It works by inhibiting alpha-1 receptors that causes what to happen?

(F) Relaxation of smooth muscle. Alpha-1 receptors are located on the smooth muscle of cutaneous and splanchnic vessels. When these receptors are activated, they contract the smooth muscle and therefore increase blood pressure. Prazosin was prescribed to decrease blood pressure so therefore it must block the action of the alpha-1 receptors. This means that the drug will relax (dilate) the blood vessels by relaxing the smooth muscles of the blood vessels.

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