Notes in 3 Properties of the Heart/Cardiac Muscle Physiology

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Published	10/07/2024	Definition of TermsA. Intercalated discs: dark areas crossing cardiac muscleB. Intercalated discs: fused cell membranes that form permeable communicat…
Published	10/07/2024	4 phases of cardiac muscle contractionA. (0) Initial repolarization → (1) Depolarization → (2) Rapid repolarization → (3) Plateau → (4) Resting Membra…
Published	10/07/2024	Correct about the velocity of conduction of excitatory action potential signalA. Along atrial and ventricular muscle fibers: 0.3 to 0.5 m/secB. Along …
Published	10/07/2024	What happens if the mitral valve fails to close properly?A. Blood flows back into the left atriumB. Blood flow to the lungs increases
Published	10/07/2024	The following are properties of cardiac muscle, exceptA. Involuntary and striatedB. Controlled by voluntary nervesC. Contains intercalated discsD. Con…
Published	10/07/2024	What is the function of intercalated discs in cardiac muscle?A. Separate atria and ventriclesB. Prevent blood flow back into the atriaC. Allow rapid t…
Published	10/07/2024	T/FCardiac muscle cells have syncytial interconnections to allow synchronized contraction.Gap junctions prevent the flow of ions between cells.
Published	10/07/2024	T/FARF is shorter than RRF.ARF is longer than RRF
Published	10/07/2024	T/FA. Sarcoplasmic reticulum of cardiac muscle is more developed than that of skeletal muscle T-tubules of cardiac muscle is more developed than …
Published	10/07/2024	What ion is primarily responsible for the depolarization phase (Phase 0) of the cardiac action potential?A. Potassium (K⁺)B. Sodium (Na⁺)C. Calcium (C…
Published	10/07/2024	The plateau phase of the cardiac action potential is caused by calcium ion influx.Potassium ion permeability decreases during the plateau phase.
Published	10/07/2024	What happens if calcium channels in cardiac muscle are blocked?A. Contraction force decreasesB. The resting membrane potential becomes more positive
Published	10/07/2024	Which factors influence the force of contraction in cardiac muscle?I. Calcium influx during the plateau phaseII. Sodium influx during depolarizationII…
Published	10/07/2024	Compared to the RMP of ventricular muscles, the RMP of sinus nodal fibers is _______, which causes the fast Na+ channels to be inactivatedA. -15 mVB. …
Published	10/07/2024	AV blockA. Happens when the SA node is not transmitting action potentials efficiently to the AV nodeB. Manifested as no rhythmicity (e.g. atria beatin…
Published	10/07/2024	Which is the correct match?A. Manual defibrillators: pulseless ventricular tachycardia and ventricular fibrillationsB. Cardiopulmonary resuscitation (…
Published	10/07/2024	T/FDuring the ejection phase, the ventricular volume remains constant.The isovolumic contraction phase is characterized by a rapid increase in ventric…
Published	10/07/2024	Which valves close at the beginning of ventricular systole?A. Aortic and pulmonary valvesB. Mitral and tricuspid valvesC. Mitral and aortic valvesD. T…
Published	10/07/2024	T/FDuring the absolute refractory period, no new action potential can be generated.During the relative refractory period, an action potential can be g…
Published	10/07/2024	What happens if action potentials are generated during the relative refractory period?A. Tachycardia may developB. Bradycardia occurs
Published	10/07/2024	The atria contract during ventricular diastole to help fill the ventricles.The closing of the semilunar valves produces the second heart sound ("dub")…
Published	10/07/2024	What occurs during the isovolumic relaxation phase?I. Ventricular pressure decreasesII. Ventricular volume decreasesIII. Both AV and semilunar valves …
Published	10/07/2024	T/FThe rapid ejection phase is responsible for ejecting approximately 70% of the stroke volume.The heart spends more time in diastole than in systole …
Published	10/07/2024	Which of the following events occurs last in the cardiac cycle?A. Isovolumic relaxationB. Ventricular fillingC. Atrial contractionD. Isovolumic contra…
Published	10/07/2024	What happens when ventricular pressure exceeds aortic pressure?A. The aortic valve opens, and blood is ejectedB. The ventricles relax
Published	10/07/2024	T/FThe ejection phase of systole is when blood is pumped out of the ventricles.The isovolumic contraction phase involves changes in volume but no chan…
Published	10/07/2024	What happens if there is increased ventricular afterload?A. The heart must work harder to eject bloodB. Cardiac output decreases
Published	10/07/2024	What factors affect cardiac output?I. Heart rateII. Stroke volumeIII. Blood pressureIV. Venous returnA. IB. I, IIC. I, II, IIID. I, II, III, IV
Published	10/07/2024	What mechanism explains the increased contraction force when the heart is filled with more blood?A. Frank-Starling mechanismB. Bainbridge reflexC. Sym…
Published	10/07/2024	T/FIncreased venous return increases atrial stretching, which increases heart rate through the Bainbridge reflex.The Frank-Starling mechanism refers t…
Published	10/07/2024	What happens if the Frank-Starling mechanism is impaired?A. The heart cannot increase contraction force with increased venous returnB. Stroke volume r…
Published	10/07/2024	What happens during the isovolumic relaxation phase?I. Ventricular pressure drops rapidlyII. Ventricular volume remains constantIII. Both the AV and s…
Published	10/07/2024	What effect does sympathetic stimulation have on the heart?A. Decreases heart rate and contractilityB. Increases heart rate and contractilityC. Increa…
Published	10/07/2024	T/FIncreased potassium levels in the blood can cause the heart to become flaccid and dilated.Increased calcium levels lead to spastic heart contractio…
Published	10/07/2024	What is the normal end-diastolic volume (EDV) of the left ventricle?A. 70-80 mLB. 100-120 mLC. 120-140 mLD. 150-160 mL
Published	10/07/2024	Prevents backflow during systoleA. AV valveB. SV valveC. AV & SV valvesD. None
Published	10/07/2024	Which is not a description of the first heart sound?A. AV valves closingB. Rapid snapC. Long-lastingD. All are description of the first heart sound
Published	10/07/2024	Identify
Published	10/07/2024	Pressure that the ventricle has to overcome to unload blood into the systemic systemI. AfterloadII. PreloadIII. Diastolic pressureIV. Systolic pressur…
Published	10/07/2024	Arterial pressure beyond 150 - 200 mmHg, except:A. CO decreaseB. Heart decompensatesC. Ventricles can’t pump bloodD. Give vasoconstrictors
Published	10/07/2024	Effects of hyperkalemia, exceptA. DilatationB. FlaccidityC. SpasticityD. Decreased heart rate
Published	10/07/2024	Blocked ANS + exposure to dinitrophenolI. almost no change in arterial pressureII. almost four-fold increase of the cardiac outputIII. profound fall i…
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