Cardiac output cannot increase indefinitely because (a) available filling time becomes shorter as the heart rate increases. (b) the cardiac center adjusts the heart rate. (c) the rate of spontaneous depolarization decreases. (d) the ion concentrations surrounding pacemaker plasma membranes decrease.

Q: 106 Depolarization (phase 0) of cardiac pacemaker cells is slower than that of ventricular myocytes…

A: Electrochemical potential gradient across the cellular membrane enables the cardiac cells to…

Q: What are Cardiac Action Potentials?

A: Unlike the action potential in skeletal muscle cells, the cardiac nerve impulse isn't initiated by…

Q: Describe the effects of sympathetic neuron stimulation on cardiacmuscle during contraction and…

A: Contraction in cardiac muscle occurs with the help of the sliding filament model of contraction.…

Q: What type of catabolism occurs in the heart?

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Q: What are the mechanisms that assist in returning venous blood to the heart?

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Q: 70. Which of the following phases of the ventricular action potential most closely coincides with…

A: The electrocardiogram is a graphic representation of the electrical activity of the heart recorded…

Q: How is cardiac output calculated?

A: The human heart is situated in the middle of the thoracic cavity in a space called the mediastinum.…

Q: What initiates action potentials in cardiac muscle?

A: Generation of action potential activates the neuron during the generation of stimuli. It is studied…

Q: What is the importance and the physiology of the cardiac conduction system?

A: Cardiac conduction system is also known as the electrical conduction system of the heart. The…

Q: Briefly define 1) Starling’s Law of the heart, 2) the basic cellular mechanism thought to mediate…

A: Introduction: When at rest, the heart pumps between 4 and 6 liters of blood every minute. During…

Q: Choose the correct option

A: The heart has four chambers where the right side deals with the deoxygenated blood and the left side…

Q: Which of the following statements are true? (a) The left ventricle wall is thicker than the right…

A: It is related to the circulatory system

Q: The QRS complex of the ECG is produced when the, (a) atria depolarize. (b) ventricles depolarize.…

A: An electrocardiogram is used necessarily and generally in hospitals to record the electrical signals…

Q: Blood pressure can be significantly affected by (a) cardiac output (b) peripheral resistance (c)…

A: The wall of the arteries experiences a force that is exerted by the blood, this force is called…

Q: The muscle cells of a heart chamber work as a  functional syncytium.  In terms of heart function…

A: The heart is a meso-dermally derived organs. The walls of heart are made up of cardiac muscles.…

Q: Elevated levels of the hormones ADH and angiotensin II will produce (a) increased peripheral…

A: Hormones are chemical messengers which are secreted by endocrine glands and transported through the…

Q: During this experimental activity (effect of stroke volume), the flow rate stayed constant because…

A: Introduction: The volume of the blood pumped out by each ventricle into the circulation per minute…

Q: During isovolumetric ventricular contraction: a) all valves are open and pressure within the…

A: The term isovolumetric contraction includes the prefix word ‘iso’ which means ‘equal’. So, the word…

Q: 23333 The aortic valve opens at which of the following lettered points on the ventricular volume…

A: Aortic valve is present between left ventricle and aorta.  Aortic valve opens during left…

Q: Where is the sinoatrial node located? (A) Between the left atrium and the left ventricle (B)…

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Q: Identify the correct order of the blood flow pathway? (A) the pulmonary arteries carry oxygenated…

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Q: While downhill skiing, Jerry lost control and appeared to hit into a tree, chest first. The ski…

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Q: Parasympathetic stimulation also increases the delay between atrial and ventricular contractions.…

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Q: Why do cardiac enzymes rise after an acute myocardial infarction? a) Cardiac enzymes leak from the…

A: Introduction  The organ that pumps blood throughout your body is the heart, which is about the size…

Q: Define cardiac output.

A: The heart is a pump that beats 60 to 100 times per minute on average. The heart pumps blood…

Q: 1)cardiac output is increased by  A) more sympathetic stimulation only B) more sympathetic…

A: Cardiac output, or the amount of blood pumped by the heart's two ventricles per unit of time, is the…

Q: 30. S₂ occurs at which of the following lettered points on the ventricular volume curve? OA) Volume…

A: S1, S2 are the usual heart sounds which are normally heard when we auscultate the chest. The S1…

Q: Mrs B had a heart transplant and as a result, she no longer has nerve supply to her heart. Keeping…

A: The heart transplant, or a cardiac transplant, is a careful transfer system performed on patients…