The Heart Show
•Circulatory system •Cardiovascular system
Heart Location In the thoracic cavity, between the lungs in the mediastinum Size, Shape and Position of the Heart •Located in thoracic cavity •Base - broad
superior portion Pericardium •Double walled membraneous sac •Parietal pericardium •Pericardial cavity- space between parietal & visceral pericardium Pericardium Problems •Pericarditis Heart Wall •Epicardium (a.k.a. visceral pericardium) •Myocardium - thick muscular layer •Endocardium- smooth inner lining Spiral Orientation of Myocardial Muscle See image Heart Chambers •4 chambers •Right and left atria •Right and left ventricles Heart External Anatomy- Anterior Chambers See image Question: The chamber of the heart most affected by cardiac tamponade is the ____? Right ventricle due to the tilt/gravity of the heart Sulci •Grooves on outside of heart •Atrioventricular (AV) or coronary
sulcus External Anatomy- Anterior See image External Anatomy- Posterior See image Heart Chambers- Internal •Interatrial septum Which circuit carries blood from the right ventricle to the lungs for gas exchange and returns it to the left atrium of the heart? Pulmonary Heart Internal Anatomy See image Heart Internal Anatomy- Anterior See image Heart Valves •Ensure one-way blood flow •Semilunar valves- control flow into great arteries Blood Flow Through Heart 1-Superior
& Inferior Vena Cava What is the study of the heart and its disorders called? Cardiology What are the thick inferior chambers of the heart that pump blood into the arteries called? Ventricles The passage of blood from the atria to the ventricles is regulated by which valves? Atrioventricular What is the ability to rhythmically depolarize without outside stimulation called? Autorhythmic Valve Mechanics AV valves hang open & semilunar valves are closed when the ventricles are relaxed Operation of AV Valves See image Operation of Semilunar Valves See image Coronary Circulation •Heart is 0.5% of body weight, but uses 5% of the circulating blood •Left coronary artery (LCA) •Right coronary artery (RCA) Venous Drainage •Route by which
blood leaves an organ Coronary Vessels- Anterior View See image Coronary Vessels- Posterior View See image Question: A blockage in the ______ would cause the most damage to the heart. Left coronary artery because it supplies the left side of the heart which gets blood out to the entire body Myocardial Infarction •Heart attack- sudden death of heart tissue Identify each of the heart valves. See image Angina Pectoris Heart pain due to temporary and reversible myocardial ischemia Identify each component of the electrical conduction system of the heart. See image Coronary Atherosclerosis •Fatty deposits form in a coronary artery •Corrected by: Structure of Cardiac Muscle •Involuntary; striated •Myocytes, cardiomyocytes or cardiocytes •Intercalated discs- join myocytes end to end The AV valves close in response to the __________. Contraction of the ventricles and the resulting rise in ventricular pressure Action potentials received directly from the __________ stimulate the papillary muscles to contract, allowing for the proper __________ of the AV valves. Subendocardial conducting network (Purkinje fibers); closing Mitral valve prolapse severe enough to cause regurgitation may directly cause __________ pressure in the __________ atrium. Increased; left Intercalated Disks Specialized cell junctions in the myocardium where one muscle cell connects to the next Metabolism of Cardiac Muscle •Aerobic respiration Place each label representing a specific electrical event on the appropriate region of the ECG. See image Cardiac Conduction System •Myogenic- heartbeat originates within heart, not brain •Conduction system Which region of the ECG image aligns with the electrical changes related to atrial repolarization? Region B A first-degree block is caused by __________. delay of the action potential between the SA and subendocardial conducting network (Purkinje fibers) Cardiac Rhythm •Systole = contraction; Diastole = relaxation •Sinus rhythm - normal rhythm set by SA node •Ectopic foci - region other than SA node sets rhythm •Arrhythmia - abnormal cardiac rhythm •Ventricular fibrillation (V-fib)- uncoordinated contraction
The rate of ventricular conduction is best determined by __________ on an ECG. The number of QRS complexes present within a specific unit of time An ECG tracing from someone with a third-degree AV block is best described as a tracing with a __________. 2:1 ratio of P waves to QRS complexes Correctly label the following parts of the pericardium and the heart walls. See image Correctly sequence the pathway of blood flow through the heart, beginning with the venae cavae. See image Contraction of Myocardium •Myocytes have stable resting potential of -90 mV •Depolarization (very brief) •Plateau- 200 to 250 msec, sustains contraction •Repolarization - membrane returns to resting potential Action Potential of a Ventricular Cardiocyte See image SA Node Potentials See image Indicate whether each structure is part of the systemic or pulmonary circuit. See image Electrocardiogram (ECG/EKG) •Composite of all action potentials of nodal and myocardial cells detected, amplified and recorded by electrodes on arms, legs & chest •Invaluable for diagnosing: ECG Components •P wave -
SA node fires Drag each label to the location of each structure described. See image Drag each statement to the appropriate position to identify the valve being described. See image Drag each statement to the appropriate position to identify the valve being described. See image Principles of Pressure and Flow •Pressure causes fluid to flow •Resistance opposes flow Drag each label to the location of each structure described. See image Drag each label to the appropriate position to identify whether the structure contains oxygenated or deoxygenated blood. Oxygenated - Coronary arteries, descending arteries, carotid arteries, left ventricle Deoxygenated - Jugular vein, pulmonary trunk, pulmonary arteries, right atrium, superior vena cava, great cardiac vein Electrical Activity of the Myocardium See image Correctly label the pathway for the cardiac conduction system. See image Place a single word into each sentence regarding the heart's conduction system. See image Question: A heart rate of 45 bpm and no P wave on an ECG indicates ______? SA node damage ECG Diagnostics See image ECGs, Normal & Abnormal See image ECGs, Abnormal See image Abnormal ECG •Extrasystole or PVC Heart Sounds •Auscultation- listening to sounds made by the body •Heart Murmur - sound of blood
flowing backward due to valvular insufficiency Place a single word into each sentence to make it correct. Then rearrange the sentences into the correct order to explain the process of the cardiocyte action potential. The action potential of a ventricular CARDIOMYOCYTE beings with opening a voltage gated sodium ion channel. Na+ inflow depolarizes the membrane, triggering the opening of more channels causing a POSITIVE feedback cycle. Channels will then close when the voltage reaches +30mV. Depolarization is then prolonged via slow CALCIUM ION channels. Once these channels close, potassium ions flow out quickly and restore the RESTING membrane potential. Place a single word into each sentence to make it correct. Electrical CURRENTS in the heart can be detected by means of electrode applied to the skin. An instrument called the electrocardiograph AMPLIFIES these signals and produces a record on a moving paper chart. The chart includes three principle deflections above and below the baseline; the P wave, QRS complex and the T wave. The P wave is produced when a signal from the SA node spreads through the atria and DEPOLARIZES them. The QRS complex is produced when the signal from the AV node spreads through the VENTRICULAR myocardium and depolarizes the muscle. The T wave is generated by ventricular repolarization immediately before DIASTOLE. Place a single word into each sentence to make it correct. See image Phases of Cardiac Cycle •1. Ventricular filling •2. Isovolumetric Contraction of Ventricles •3. Ventricular Ejection •4. Isovolumetric Relaxation of Ventricles Classify the following images into the phase of the cardiac cycle they represent. See image Indicate the heart chamber responsible for the given function. See image Overview of Volume Changes End-systolic volume (ESV) 60 ml Listed are two heart conditions, increased heart rate and decreased heart rate. Classify whether each given factor would increase or decrease heart rate. Increased Heart Rate- Epinephrine, nicotine, Blood acidosis (decline in pH), thyroid hormone, Hypercapnia (high carbon dioxide levels) Decreased Heart rate- Hyperkalemia (high potassium concentrations in the ECF), hypercalcemia, Acetylcholine Congestive Heart Failure (CHF) 1) Right ventricular output exceeds left ventricular output 2) Pressure backs up 3) Fluid accumulates in pulmonary tissue Congestive Heart Failure (CHF) 1) Left ventricular output exceeds right ventricular output 2) Pressure backs up 3) Fluid accumulates in systemic tissue Question: In an angiogram, the blood vessels are injected with a dye so that they may be visualized. The angiogram is used to detect ______? Atherosclerosis Classify whether each given factor would increase or decrease heart rate. Increased Heart Rate- cutting the vagus nerve, exercise, sympathetic stimulation, psychological stress Decreased Heart Rate- Vagal tone, SA node Damage, BBB, Calcium Channel blockers Place the labels in order denoting the flow of blood through the pulmonary circuit beginning with the right atrium and ending in the left atrioventricular valve. The first and last structures are given. See image Complete each sentence by dragging the labels to the appropriate blanks. Then place each sentence in a logical order beginning with blood entering the right side of the heart. See image Complete each sentence by dragging the labels to the appropriate blanks. Then place each sentence in a logical order beginning with cardiomyocytes in a resting state. See image Drag each label into the appropriate position to characterize the events of a single heart cycle as seen on an ECG tracing. See image Drag each label into the appropriate position to identify the waves of a normal ECG. See image Place the labels in order denoting the sequence of events of the cardiac cycle beginning with resting membrane potential and ending with the beginning of repolarization. The first and last steps are given. See image Indicate whether each item would increase or decrease contractility. See image Which of the following is caused by ventricular contraction? The atrioventricular valves close, and then the semilunar valves open When the pressure in the ventricles becomes lower than the pressure in the atria, __________. The atrioventricular valves open Which of the following is the correct sequence of events regarding the cardiac cycle? Isovolumic contraction, ejection, isovolumic relaxation, passive ventricular filling, active ventricular filling The atria never contract due to passive ventricular filling. False In the heart, an action potential originates in the __________. Sinoatrial node Which of the following is the correct sequential path of an action potential in the heart? Sinoatrial node, atrioventricular node, atrioventricular bundle, bundle branches, subendocardial conducting network (Purkinje fibers) Which of the following is true concerning the heart's conduction system? Action potentials pass slowly through the atrioventricular node In the ventricles, the action potential travels along the interventricular septum to the apex of the heart, where it then spreads superiorly along the ventricle walls. True Action potentials are carried by the subendocardial conducting network (Purkinje fibers) from the bundle branches to the ventricular walls. True Cardiac muscle is not prone to fatigue because it makes little use of anaerobic fermentation or the oxygen debt mechanism. True Correctly associate the statements with the three distinct features of an intercalated disc. See image Choose the correct statement(s) that accurately explain(s) impulse conduction to the myocardium. Check all that apply. Firing of the SA node excites atrial cardiomyocytes and stimulates the two atria to contract almost simultaneously. In the AV node, the signal slows down to about 0.05 m/sec because the cardiomyocytes have fewer gap junctions over which the signal can be transmitted. Signals travel through the AV bundle and subendocardial conducting network at a speed of 4 m/sec, the fastest in the conduction system. Classify the following statement as belonging to either sympathetic or parasympathetic stimulation of the heart. See image Match the components of the cardiac conduction system with their description. See image As a heart chamber contracts, what happens to the pressure of the fluid within it? It increases Match the action of the AV and semilunar heart valves with the correct statement regarding pressure differences in the heart chambers. See image Which term refers to relaxation of the heart? Diastole Which of the following is the correct formula for calculating cardiac output? HR x SV If a person's heart is pumping 5000 mL of blood in one minute and the heart rate is 50 beats per minute, what is the cardiac output? None of these choices is correct The difference between the maximum and resting cardiac output is called __________. Cardiac reserve The amount of tension in the ventricular myocardium immediately before it contracts is called _________. Preload Which of the following has a strong, positive inotropic effect, meaning it increases the strength of each contraction of the heart? Hypercalcemia If the right ventricle begins to pump an increased amount of blood, this soon arrives at the left ventricle, stretches it more than before, and causes it to increase its stroke volume and match that of the right. This is an example of __________. Preload The Frank-Starling law of the heart states that an additional stretch of the myocardium produces a significant increase in __________ on the next beat. Contraction force As exercise progresses, muscular activity __________ venous return. This increases the __________ on the right ventricle. Increases; preload Exercise has which of the following effects on cardiac output? Check all that apply. The main reason the heart rate increases at the beginning of exercise is that proprioceptors in the muscles and joints transmit signals to the cardiac centers. As the exercise progresses, muscular activity increases venous return. A sustained program of exercise causes hypertrophy of the ventricles, which increases their stroke volume. Which of the following is a recording of all nodal and myocardial action potentials in the heart? ECG Indicate the heart chamber responsible for the given function. See image Drag each label into the appropriate position to identify the segments and intervals of a normal ECG. See image Identify whether each item would increase or decrease stroke volume. See image Complete each sentence by dragging the labels to the appropriate blanks. Then place each sentence in a logical order beginning with blood entering the right side of the heart. See image Complete each sentence by dragging the labels to the appropriate blanks. Then place each sentence in a logical order beginning with the SA node in a resting state. See image Which of the following statements is not true regarding ventricular systole? The ventricles relax The semilunar valves close during __________. Ventricular diastole The atrioventricular valves open during __________. Ventricular diastole The ventricles begin to fill during ventricular diastole. True In a normal ECG, the deflection that is generated by ventricular repolarization is called the __________. T wave Which of the following is a feature shared by cardiac muscle and skeletal muscle? Muscle fiber striations Which of the following carry oxygen-poor blood? Venae cavae and pulmonary arteries The Frank-Starling law of the heart states that stroke volume is proportional to __________. The end-diastolic volume The cardiac plexus and cardiac nerves dominate the innervation of the heart and contain both parasympathetic and sympathetic fibers. True Which of the following is not a feature of cardiac muscle? They have about the same endurance as skeletal muscle fibers Which is the correct path of an electrical excitation from the pacemaker to a cardiomyocyte in the left ventricle (LV)? Sinuatrial (SA) node → atrioventricular (AV) node → atrioventricular (AV) bundle → subendocardial conducting network → cardiomyocyte in LV The plateau in the action potential of cardiac muscle results from the action of __________. Slow Ca2+ channels The __________ valve regulates the flow of blood between the right ventricle and the vessels leading to the lungs. Pulmonary The apex of the heart is found __________ of the midline of the body. To the left Correctly label the following structures related to the position of the heart in the thorax. See image Correctly label the following anatomical features of the thoracic cavity. See image Correctly label the internal anatomy of the heart. See image Correctly label the following internal anatomy of the heart. See image Correctly label the following external anatomy of the anterior heart. See image Correctly label the following external anatomy of the posterior heart. See image Correctly label the following external anatomy of the posterior heart. See image Correctly label the external anatomy of the anterior heart. See image Correctly label the following internal anatomy of the heart. See image Correctly label the following internal anatomy of the heart. See image Correctly label the following vessels leading from and toward the anterior heart. See image Correctly label the following vessels leading from and toward the anterior heart. See image Correctly label the following parts of the pericardium and the heart walls. See image Correctly label the following external anatomy of the posterior heart. See image Correctly sequence the pathway of blood flow through the heart, beginning with the venae cavae. See image Correctly label the following coronary blood vessels of the heart. See image Correctly label the following coronary blood vessels of the heart. See image Correctly label the following coronary blood vessels of the heart. See image Identify the unique structural characteristics of cardiac muscle. See image Identify the unique structural characteristics of cardiac muscle. See image Identify the unique structural characteristics of cardiac muscle. See image Drag each label into the appropriate position to indicate which view is necessary to see the indicated structure. See image Place the labels in order denoting the flow of blood through the systemic circuit beginning with the left atrioventricular valve and ending in the right atrium. The first and last structures are given. See image Cardiac Output (CO) •Amount ejected by each ventricle in 1 minute Cardiology involves the study of the ______ and its disorders. Heart The muscular pump that keeps blood flowing through blood vessels is the ______. Heart Heart Rate •Measured from pulse Chronotropic Effects •Positive chronotropic agents raise HR and negative chronotropic agents lower HR •Cardiac center of medulla oblongata Sympathetic Nervous System •Cardioacceleratory center Parasympathetic Nervous System •Cardioinhibitory center Blood leaves the left side of the heart through the ______. Aorta The _____ side of the heart supplies blood to the pulmonary circuit. Right Which side of the heart supplies blood to the systemic circuit? Left Inputs to Cardiac Center •Higher brain centers affect HR •Chemoreceptors •Proprioceptors •Baroreceptors Chronotropic Chemicals •Neurotransmitters •Drugs •Hormones •Electrolytes-potassium has greatest chronotropic effects Stroke Volume (SV) •Governed by three factors: Which are components of the cardiovascular system? Heart Preload •Amount of tension in ventricular myocardium before it
contracts •Frank-Starling law of heart - Stroke Volume = EDV Contractility •Contraction force for a given preload Afterload •Pressure in arteries above semilunar valves opposes opening of valves Exercise and Cardiac Output •Effect of proprioceptors •Effect of venous return •Effect of ventricular hypertrophy Which region of the heart is indicated by the letter A in the figure? Base The systemic circuit pumps blood from which side of the heart to the body tissues? Left The right side of the heart pumps ______ blood to the lungs. Oxygen-poor As the heart sits in the thoracic cavity, the superior tip end called the ______. Base Which fibrous structure is indicated by the letter A in the figure? Fibrous pericardium What is the inferior tapered end of the heart called? Apex The ______ is a double-walled sac enclosing the heart. Pericardium The heart is ______ the pericardial cavity. Enfolded by The serous fluid called _____ fluid fills the pericardial cavity and lubricates the membranes, allowing the heart to beat with minimal friction. Pericardial What is the double-layered sac that surrounds the heart called? Pericardium Which are layers of the heart wall? Myocardium Which type of epithelium makes up part of the endocardium? Simple squamous What is the space between the parietal and visceral layers of the pericardium called? Pericardial cavity Where does pericardial fluid come from? The serous pericardium What is the outermost layer of the heart wall called? Epicardium The blood vessel indicated by the letter A in the figure is the superior ______ ______. Vena cava Which layer lines the inner chambers of the heart? Endocardium The epicardium is also called what? Visceral layer of the serous pericardium The blood vessel indicated in the figure has several segments. The initial segment that is indicated by the letter A in the figure is the ______ aorta. Ascending The fibrous skeleton of the heart is a ______ of electricity. Nonconductor Which blood vessel is a branch off the pulmonary trunk? Pulmonary artery A fibrous cord that attaches the pulmonary trunk to the aortic arch is the ______. Ligamentum arteriosum Which supports the valves and openings of the great vessels of the heart? Fibrous skeleton The framework of collagenous and elastic fibers found in the walls of the heart form the ______ skeleton. Fibrous What are the ridges of muscle indicated in the figure? Pectinate muscles What are the functions of the fibrous skeleton? Provides structural support for the heart What is the earlike extension of each atrium called? Auricle What are the internal ridges of myocardium found in the right atrium and auricle? Pectinate muscles Which chamber of the heart is indicated here? Right ventricle Pulmonary arteries are branches of the ______. Pulmonary trunk
The thick-walled inferior chambers of the heart that pump blood into the arteries are called ______. Ventricles The groove that extends downward from the coronary sulcus on the front of the heart is the anterior _______ sulcus. Interventricular Which groove encircles the heart, separating the atria from the ventricles? Coronary sulcus Which sulcus overlies the interventricular septum? Anterior interventricular sulcus Which groove extends downward from the coronary sulcus on the back of the heart? Posterior interventricular sulcus Which valve is indicated in the figure? Right atrioventricular The right atrioventricular valve is also called the ______ valve. Tricuspid The finger-like muscle indicated in the figure is a _____ muscle. Papillary The right atrioventricular valve has ______ cusps. Three The left atrioventricular valve has ______ cusps. Two Which valves are attached to papillary muscles? Atrioventricular valves The mitral valve is also known as what? Left AV valve Blood in the left atrium flows directly into the ______. Left ventricle The blood vessels that supply nutrients and oxygen only to the heart muscle make up the specific type of circulation called the _____ circulation. Coronary What are the string-like structures that attach the AV valves to the papillary muscles called? Tendinous cords Which artery travels under the left auricle and then divides into two branches? Left coronary artery Which best represents the correct flow of blood through the heart, immediately after it returns from the venous circulation? Right atrium, right ventricle, left atrium, left ventricle True or false: The coronary blood vessels are part of the the systemic circulation. True The left and right coronary arteries arise from which blood vessel? Aorta Which artery runs along the sulcus and supplies blood to the right atrium and SA node? Right coronary When does blood flow through the coronary circulation increase? Ventricular diastole The right and left coronary arteries arise from the ascending _______. Aorta Which vein collects venous drainage from all of the coronary veins and drains into the right atrium? Coronary sinus During which phase of the cardiac cycle does blood flow through the coronary circulation? Ventricular relaxation _______ are short, thick, branched muscle cells of the heart. Cardiomyocytes At rest, the heart gets about 60% of its energy from which of the following? Fatty acids The vertebrate heartbeat is said to be ______ because the signal originates within the heart muscle itself. Myogenic Cardiomyocytes are jointed end to end by thick connections called ______. Intercalated discs Cardiac muscle relies on which process to produce ATP? Aerobic respiration Which part of the cardiac conduction system acts as an electrical gateway to the ventricles? AV node Which structures are considered to be part of the cardiac conduction system? SA node Where is the SA node located? The wall of the right atrium The part of the cardiac conduction system which acts as the pacemaker is the _____ node. SA Excitation in the cardiac conduction system leaves the AV node by way of the bundle, also known as the ______ bundle of His. Atrioventricular The portion of the cardiac conduction system located in the lower end of the interatrial septum is the _____ node. Atrioventricular When the AV node acts as pacemaker, the slower heartbeat has what type of rhythm? Nodal What is it referred to as when a portion of the heart wall other than the SA node spontaneously depolarizes? Ectopic focus A spontaneously developing local potential that generates action potentials in the SA node is called what? Pacemaker potential When a cell in the SA node is depolarized to threshold, voltage-gated ______ channels open. Calcium In a healthy person at rest, the SA node normally fires about how many times per minute? 70-80 The depolarization of the SA node (from threshold to peak) is due to the inflow of sodium and ______ ions. Calcium Any region of spontaneous firing other than the SA node is a(n) ______ focus. Ectopic The pacemaker potential of SA node cells is due to the influx of which ions? Sodium When the membrane potential of the SA node reaches threshold, voltage-regulated channels for which ions open? Calcium Where does ventricular contraction begin? Apex The depolarization of the SA node (from threshold to peak) is due to the inflow of which ions? Sodium Place the events of an action potential in a ventricular cardiocyte in order. See image Impulse conduction through the cardiac conduction system is slowest through which structure, thereby allowing a pause between atrial contraction and ventricular contraction? AV node The action potential of a cardiocyte has a plateau due to the opening of which channels? Slow calcium Depolarization of a cardiocyte is due to opening of which channels? Sodium Repolarization of a cardiocyte is due to opening of which channels? Potassium The plateau phase in an action potential of a cardiocyte is caused by which of the following? Ca2+ entering the cell The contraction of a cardiocyte occurs during which phase of its action potential? Plateau Depolarization in cardiocytes is prolonged probably because ______ channels are slow to close. Calcium Firing of the SA node occurs at the beginning of which ECG wave? P wave During which stage of an ECG does atrial systole occur? PQ segment What does the PQ interval of an ECG represent? The time required for an impulse to pass from the SA node to AV node Which is a recording of all nodal and myocardial action potentials in the heart? ECG The QRS wave of an ECG represents what event in the heart? Depolarization of the ventricles On an ECG, atrial systole begins during the ____ segment. PQ Ventricular systole begins shortly after which major deflection on an ECG? QRS complex Which of the following best describes what happens during the T wave of an ECG? The ventricles repolarize What is an abnormal cardiac rhythm called? Arrhythmia A difference in pressure creates a pressure ______ that directs the flow of fluids. Gradient Which is a type of arrhythmia? Ventricular fibrillation What is the relationship between pressure and volume? They are inversely proportional With the onset of ventricular contraction, what happens to the pressure within the ventricles? It increases Which instrument is used to measure blood pressure? Sphygmomanometer Fluids always flow from an area of ______ pressure to an area of ______ pressure. Higher, lower True or false: The papillary muscles contract just before the rest of the myocardium in order to tense the tendinous cords prior to the ejection of blood. True Which accounts for the movement of the heart valves during the cardiac cycle? Pressure changes within the chambers What is the role of the papillary muscles? To tense the tendinous cords just prior to ventricular contraction During ventricular contraction, the ejection of blood out of the heart occurs because the pressure within the ______ exceeds the pressure within the ______. Ventricles, great arteries What is the process of listening to sounds made by the body called? Auscultation Which best represents the correct order of the following events? 1. Isovolumetric relaxation 2. Ventricular filling 3. Isovolumetric contraction 4. Ventricular ejection 2,3,4,1 The semilunar valves will open when the pressure within the ______ exceeds the pressure within the ______. Ventricles, great arteries When the ventricles are relaxed and their pressure is low, which valves are open? Atrioventricular The closing of the atrioventricular valves produces which of the heart sounds? The first What is the volume of blood ejected from one ventricular contraction called? Stroke volume The second heart sound is associated with the closing of which valves? Semilunar valves True/False: Each ventricle will eject a volume of blood equal to the amount of blood it received during the ventricular filling phase. True True or false: The left ventricle always pumps more blood per beat than the right ventricle. False The amount of blood ejected by a ventricle is ______ the amount of blood received during ventricular filling. The same as If the volume of blood pumped by the right side of the heart is less than that pumped by the left side of the heart, what would be the result? Systemic edema Which autonomic system(s) innervate(s) the heart? Both sympathetic and parasympathetic nerves The cardiac nerves convey signals from which nervous system to the heart? Sympathetic The vagus nerve conveys signals from which nervous system to the heart? Parasympathetic An increase in stimulation by what branch of the nervous system lowers the heart rate? Parasympathetic Cardiac output is equal to stroke volume ______ heart rate. Times Stimulation of the SA node by the which division of the nervous system raises the heart rate? Sympathetic What term describes a consistently elevated resting heart rate above 100 bpm? Tachycardia What is the difference between the maximum and resting cardiac output? Cardiac reserve Sympathetic stimulation of the heart involves the release of which neurotransmitter? Norepinephrine Which describes parasympathetic stimulation of the heart? Cholinergic What is a persistent, low resting heart rate below 60 bpm called? Bradycardia Which describes sympathetic stimulation of the heart? Adrenergic How does an increase in blood calcium ion levels affect heart rate? It decreases heart rate Which refers to the steady background firing of the vagus nerve to the heart? Vagal tone Which electrolyte has the greatest effect on heart rate? Potassium Glucagon and thyroid hormone ______ heart rate. Increase What effect does hypocalcemia have on heart rate? It elevates the heart rate An increase in venous return to the heart leads to a(n) ______ in preload and therefore a(n) ______ in stroke volume. Increase, increase Nicotine increases heart rate by increasing the secretion of what? Catecholamine Which law states that stroke volume is determined by the end-diastolic volume? Frank-Starling
What is the strength of contraction for a given preload called? Contractility How do positive inotropic agents affect contractility? They increase it An increase in venous return would ______ preload. Increase A decrease in venous return to the heart leads to a(n) ______ in preload, and therefore, a(n) ______ in stroke volume. Decrease, decrease Which term is used to describe the narrowing of the coronary arteries, usually by atherosclerosis? Coronary artery disease Hyperkalemia (high potassium level) reduces the strength of myocardial action potentials, thus reducing the release of calcium. Therefore how will this condition affect contractility? It will decrease contractility How do negative inotropic agents affect contractility? They decrease it How does the drug digitalis affect heart contractility? It increases it Which force impedes the opening of the semilunar valves and opposes ventricular ejection? Afterload What is the most common cause of coronary artery disease? Atherosclerosis Why does digitalis increase heart contractility? It increases sarcoplasmic calcium levels The blood pressure in the great arteries determines which of the following? Afterload Which condition involves compression of the heart by an abnormal accumulation of fluid in the pericardial cavity? Cardiac tamponade Which condition involves abnormal openings in the interatrial or interventricular septa altering blood flow through the heart? Septal defect Which condition involves a seepage of fluid from the pericardium into the pericardial sac? Pericardial effusion Which part of the cardiac conduction system acts as an electrical gateway to the ventricles?The AV node acts as an electrical gateway to the ventricles. The conduction pathways deliver the signals to the ventricles and the ventricles pump blood to the body.
Which of the following is the electrical gateway to the ventricles?The AV (atrioventricular) node
It is the “gateway” between the atria and the ventricles. The AV node channels the signal into the ventricles.
Which heart layer contains part of the cardiac electrical conduction system quizlet?Endocardium- The innermost layer is thin and very smooth, This layer contains part of the cardiac electrical conduction system.
Which part of the cardiac conduction system is responsible for ventricular depolarization quizlet?What part of the cardiac conduction system is responsible for ventricular depolarization? Purkinje fibers are responsible for the rapid conduction of electrical impulses throughout the ventricles, which leads to ventricular depolarization.
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Which part of the cardiac conduction system acts as an electrical gateway to the ventricles quizlet?
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