Michael Anderson EXSC 224-001 SummerProf. Thompson June 7th, 2016Assignment # 31) Cletus is at rest. His heart rate is 68 bpm and is under parasympathetic control.A) What is the neurotransmitter associated with the parasympathetic system and the receptor it will bind to in the heart to regulate heart rate?Acetylcholine (ACH); M2 Cholinergic receptorWhat happens to the heart rate when we administer a drug that blocks this neurotransmitter from binding to its receptor (i.e., block parasympathetic activity)?Acetylcholine will not be able to bind to its receptor and will be unable to slow the heart rate; leaving control of the heart solely up to the sympathetic system, meaning the heart rate will increase. B) Cletus plans to start exercising. When he starts exercising his heart rate will increase. The increase in heart rate is due to parasympathetic withdrawal and increased sympathetic activity. What is the neurotransmitter secreted by the sympathetic neurons and the name of the adrenergic receptor it bind to?Norepinephrine (NE); Beta 1 adrenergic receptorHow does the sympathetic nervous system increase heart rate? How will this increased heart rate affect ventricular filling time?Norepinephrine causes the sodium leakage channels of the SA Node to become more active and allows the atria to become depolarized more rapidly. The increased heart rate will decrease the filling time of the ventricles; the higher rate would cut down on the typically time allotted for ventricular diastole. C) During exercise the rhythmic contraction/relaxation of skeletal muscle will enhance venous blood returning to the heart. What effect will this have on stroke volume? And Why?If we were to increase the rate of venous return we will also increase the stroke volume. The increased rate of return would cause an increase in End Diastolic Volume (EDV). The increased EDV would result in a larger stretching of the cardiac myofibers, this increased stretching would result in a larger number of cross bridges formed at contraction and would result in a higher stroke volume output as according got the Frank- Starling law of the heart. D) What factors will contribute to the increased cardiac contractility during exercise?Intrinsic factors for this increased contractility include the before mention increased EDVand the Frank-Starling Law of the Heart. Extrinsic factors at play I this situation includegreater sympathetic activity brought on by the exercise. Sympathetic nerve fibers release the neurotransmitter Norepinephrine which calls for the opening of CA channels in the plasma membranes and on the SR, both allowing more calcium cytosol to bind to troponin C, freeing the more myosin binding sites and increasing the number of cross bridges formed; ultimately leading to an increased stroke volume. 2) Bob was recently been diagnosed with hypertension and was put on the following medications; Beta-1 adrenergic receptor blocker and a Nitric Oxide supplement. A1) Where in the body does each medication act?The Beta 1 Blocker would act on the heart, meaning the SA and AV nodes, and Ventricular MyocytesThe Nitric Oxide would act on the Blood Vessels A2) How will these medications help his hypertension? Hypertension is condition of sustained elevated Mean Arterial Pressure of 140/90 or higher. The Beta Blocker will cause a decrease in heart rate. Decreased heart rate will cause a drop in cardiac output. Since Mean Arterial Pressure can be calculated by multiplying Cardiac output by a Resistance (third of Pulse Pressure) it would ultimately result in a decrease in Bob’s Mean Arterial Pressure. The NO will cause vasodilation of blood vessels and would lead to a decrease in Resistance, again leading to a decrease in Mean Arterial Pressure. B) Which medication has a relationship to Poiseuille’s Law?The Nitric Oxide. 3) A typical resting blood pressure is 120/80 mmHg. When we assess blood pressure using the sphygmomanometer (blood pressure cuff) in the arm, we assume that this pressure reflects pressures in the aorta during systole (SBP) and diastole (DBP). A) What is the functional significance of DBP (as discussed in class)? The pressure the left ventricle must exceed to open the Aortic Semi-lunar Valve. B) Calculate pulse pressure? Mean arterial pressure (MAP)? Pulse Pressure= SBP – DBP = 120 – 80 = 40 mmHGMAP= DBP + 1/3 (PP) = 80 + 13.3 = 93.3 mmHGC) If DBP increases to 100 mmHg, how will this affect Q? Why?Cardiac Output (Q) can be calculated by MAP / Resistance. The Increase DBP would change the MAP from 93.3 to 86. 6. Any Decrease in MAP will result in a lowered Cardiac Output4) At rest Sally has a heart rate of 70 bpm, an end systolic volume of (ESV) of 50 mL, and an end diastolic volume (EDV) of 120 mL of blood. What is Sally’s stroke volume in mL? SV= EDV – ESV = 120 – 50 = 70 mL Calculate Sally’s Q in L/min. What is her Ejection fraction (%EF)? Based on her ejection fraction, is her heart functioning normally?Q= HR x SV = 70bpm x 70 mL = 4900 mL/min = 4.9 L/minEjection function (%) = EDV – ESV / EDV x 100 = 120 – 50 / 120 x 100 = 58.3 %Based on Sally’s Ejection Fraction (58.3 %) her heart is functioning with in normal