Patho Exam 3 CH 31 Cardiac
Occlusion of the left anterior descending artery during a myocardial infarction would interrupt blood supply to which structures? A. Left and right ventricles and much of the interventricular septum B. Left atrium and the lateral wall of the left ventricle C. Upper right ventricle, right marginal branch, and right ventricle to the apex D. Posterior interventricular sulcus and the smaller branches of both ventricles
A The left anterior descending artery (LAD), also called the anterior interventricular artery, delivers blood to portions of the left and right ventricles and much of the interventricular septum.
Which cardiac chamber has the thinnest wall and why? A. The right and left atria; they are low-pressure chambers that serve as storage units and conduits for blood. B. The right and left atria; they are not directly involved in the preload, contractility, or afterload of the heart. C. The left ventricle; the mean pressure of blood coming into this ventricle is from the lung, which has a low pressure. D. The right ventricle; it pumps blood into the pulmonary capillaries, which have a lower pressure compared with the systemic circulation.
A The two atria have the thinnest walls because they are low-pressure chambers that serve as storage units and conduits for blood that is emptied into the ventricles. This selection is the only option that correctly identifies which heart chambers have the thinnest walls and why that helps cardiac function
Within a physiologic range, what does an increase in left ventricular end-diastolic volume (preload) result in? A. Increase in force of contraction B. Decrease in refractory time C. Increase in afterload D. Decrease in repolarization
A This concept is expressed in the Frank-Starling law; the cardiac muscle, like other muscles, increases its strength of contraction when it is stretched.
Which statements are true concerning the method in which substances pass between capillaries and the interstitial fluid? (Select all that apply.) A. Substances pass through junctions between endothelial cells. B. Substances pass through pores or oval windows (fenestrations). C. Substances pass between vesicles by active transport across the endothelial cell membrane. D. Substances pass across the endothelial cell membrane by osmosis. E. Substances pass through endothelial cell membranes by diffusion.
A, B, C, E Substances pass between the capillary lumen and the interstitial fluid in several ways: (1) through junctions between endothelial cells, (2) through fenestrations in endothelial cells, (3) in vesicles moved by active transport across the endothelial cell membrane, or (4) by diffusion through the endothelial cell membrane.
Which intracardiac pressure is generated by the atrial contraction? A. A wave B. C wave C. Y descent D. X descent
A. A wave Atrial pressure curves are made up of only the A wave, which is generated by atrial contraction.
As stated in the Frank-Starling law, a direct relationship exists between the _____ of the blood in the heart at the end of diastole and the _____ of contraction during the next systole. A. Pressure; force B. Volume; strength C. Viscosity; force D. Viscosity; strength
B As stated in the Frank-Starling law, the volume of blood in the heart at the end of diastole (the length of its muscle fibers) is directly related to the force (strength) of contraction during the next systole.
What can shorten the conduction time of action potential through the atrioventricular (AV) node? A. Parasympathetic nervous system B. Catecholamines C. Vagal stimulation D. Sinoatrial node (SA)
B Catecholamines speed the heart rate, shorten the conduction time through the AV node, and increase the rhythmicity of the AV pacemaker fibers.
What is the process that ensures mitral and tricuspid valve closure after the ventricles are filled with blood? A. Chordae tendineae relax, which allows the valves to close. B. Increased pressure in the ventricles pushes the valves to close. C. Trabeculae carneae contract, which pulls the valves closed. D. Reduced pressure in the atria creates a negative pressure that pulls the valves closed.
B During ventricular relaxation, the two atrioventricular valves open and blood flows from the higher pressure atria to the relaxed ventricles. With increasing ventricular pressure, these valves close and prevent backflow into the atria as the ventricles contract.
If the sinoatrial (SA) node fails, then at what rate (depolarizations per minute) can the atrioventricular (AV) node depolarize? A. 60 to 70 B. 40 to 60 C. 30 to 40 D. 10 to 20
B If the SA node is damaged, then the AV node will become the heart's pacemaker at a rate of approximately 40 to 60 spontaneous depolarizations per minute.
What enables electrical impulses to travel in a continuous cell-to-cell fashion in myocardial cells? A. Sarcolemma sclerotic plaques B. Intercalated disks C. Trabeculae carneae D. Bachmann bundles
B Only intercalated disks, thickened portions of the sarcolemma, enable electrical impulses to spread quickly in a continuous cell-to-cell (syncytial) fashion.
Which complex (wave) represents the sum of all ventricular muscle cell depolarizations? A. PRS B. QRS C. QT interval D. P
B Only the QRS complex represents the sum of all ventricular muscle cell depolarizations.
Oxygenated blood flows through which vessel? A. Superior vena cava B. Pulmonary veins C. Pulmonary artery D. Coronary veins
B Only the four pulmonary veins, two from the right lung and two from the left lung, carry oxygenated blood from the lungs to the left side of the heart
What causes depolarization of a cardiac muscle cell to occur? A. Decrease in the permeability of the cell membrane to potassium B. Rapid movement of sodium into the cell C. Decrease in the movement of sodium out of the cell D. Rapid movement of calcium out of the cell
B Phase 0 consists of depolarization, which lasts 1 to 2 milliseconds (ms) and represents rapid sodium entry into the cell.
Pressure in the left ventricle must exceed pressure in which structure before the left ventricle can eject blood? A. Superior vena cava B. Aorta C. Inferior vena cava D. Pulmonary veins
B Pressure in the ventricle must exceed aortic pressure before blood can be pumped out during systole. The aorta is the only structure in which pressure must be less than the amount of blood in the left ventricle for ejection to occur.
Reflex control of total cardiac output and total peripheral resistance is controlled by what mechanism? A. Parasympathetic stimulation of the heart, arterioles, and veins B. Sympathetic stimulation of the heart, arterioles, and veins C. Autonomic control of the heart only D. Somatic control of the heart, arterioles, and veins
B Reflex control of total cardiac output and peripheral resistance includes (1) sympathetic stimulation of the heart, arterioles, and veins; and (2) parasympathetic stimulation of the heart only.
What is the major effect of a calcium channel blocker such as verapamil on cardiac contractions? A. Increases the rate of cardiac contractions. B. Decreases the strength of cardiac contractions. C. Stabilizes the rhythm of cardiac contractions. D. Stabilizes the vasodilation during cardiac contractions.
B The L-type, or long-lasting, channels are the predominant type of calcium channels and are the channels blocked by calcium channel-blocking drugs (verapamil, nifedipine, diltiazem). The major effect of these medications is to decrease the strength of cardiac contraction.
An early diastole peak caused by filling of the atrium from peripheral veins is identified by which intracardiac pressure? A. A wave B. V wave C. C wave D. X descent
B The V wave is an early diastolic peak caused by the filling of the atrium from the peripheral veins.
Regarding the heart's valves, what is a function of the papillary muscles? A. The papillary muscles close the semilunar valve. B. These muscles prevent backward expulsion of the atrioventricular valve. C. They close the atrioventricular valve. D. The papillary muscles open the semilunar valve.
B The papillary muscles are extensions of the myocardium that pull the cusps together and downward at the onset of ventricular contraction, thus preventing their backward expulsion into the atria.
Which statement does not accurately describe the pericardium? A. The pericardium is a double-walled membranous sac that encloses the heart. B. It is made up of connective tissue and a surface layer of squamous cells. C. The pericardium protects the heart against infection and inflammation from the lungs and pleural space. D. It contains pain and mechanoreceptors that can elicit reflex changes in blood pressure and heart rate.
B The pericardium is made up of a surface layer of mesothelium over a thin layer of connective tissue.
The resting heart rate in a healthy person is primarily under the control of which nervous system? A. Sympathetic B. Parasympathetic C. Somatic D. Spinal
B The resting heart rate in healthy individuals is primarily under the control of parasympathetic stimulation.
A wave produced in early sytole and may represent bulging of the mitral valve into the left atrium during early systole A. V wave B. C wave C. Y descent D. X descent
B. C wave Pg. 1089
Which statement accurately describes blood flow through the heart? Blood flows from the left atrium through the tricuspid valve to the left ventricle. Blood flows from the right atrium through the aortic valve to the right ventricle. Blood flows from the right ventricle through the pulmonic semilunar valve. Blood flows from the left ventricle through the bicuspid valve.
Blood flows from the right atrium through the tricuspid valve to the right ventricle. Blood then travels from the right ventricle through the pulmonic semilunar valve to the pulmonary circulation. Once in the pulmonary circulation, it is oxygenated and travels to the left atrium through the bicuspid valve to the left ventricle. Blood leaves the left ventricle through the aortic valve and enters the systemic circulation.
What is the most important negative inotropic agent? A. Norepinephrine B. Epinephrine C. Acetylcholine D. Dopamine
C Chemicals affecting contractility are called inotropic agents. The most important negative inotropic agent is acetylcholine released from the vagus nerve. The most important positive inotropic agents produced by the body are norepinephrine released from the sympathetic nerves that supply the heart and epinephrine released by the adrenal cortex. Other positive inotropes include thyroid hormone and dopamine. Many medications have positive or negative inotropic properties that can have profound effects on cardiac function.
Which function of the cardiovascular system is often affected by ischemia? A. Cardiac output (CO) B. Stroke volume (SV) C. Heart rate (HR) D. Cardiac index (CI)
C Common causes of an abnormal heart rate include ischemia, electrolyte imbalance, and drug toxicity.
During the cardiac cycle, which structure directly delivers action potential to the ventricular myocardium? A. Sinoatrial (SA) node B. Atrioventricular (AV) node C. Purkinje fibers D. Bundle branches
C Each cardiac action potential travels from the SA node to the AV node to the bundle of His (AV bundle), through the bundle branches, and finally to the Purkinje fibers and the ventricular myocardium, where the impulse is stopped. The refractory period of cells that have just been polarized prevents the impulse from reversing its path. The refractory period ensures that diastole (relaxation) will occur, thereby completing the cardiac cycle.
The significance of the atrial kick is that it affects the contraction of the: A. Right atria, which is necessary to open the tricuspid valve. B. Right atria, which is necessary to increase the blood volume from the vena cava. C. Left atria, which increases the blood volume into the ventricle. D. Left atria, that is necessary to open the mitral valve.
C Left atrial contraction, the atrial kick, provides a significant increase of blood to the left ventricle.
Which factors determine cardiac output? Parasympathetic and sympathetic activity Preload and afterload Incorrect Heart rate and stroke volume Correct Right and left atrial pressure
Cardiac output is directly related to the heart rate and stroke volume. Changes in either variable affect the cardiac output. Preload is the pressure generated in the left ventricle at the end of diastole (end-diastolic volume). Afterload is the resistance or impedance to the ejection of blood from the left ventricle. Although the parasympathetic stimulation has a bradycardic effect and sympathetic nervous system increases the frequency of the cardiac pacemaker and may influence cardiac output, these factors are not used in the cardiac output formula; neither are atrial pressures.
Cycles of attachment, movement, and dissociation of thin filaments during the attachments of actin to myosin
Cross-bridge Theory With the attachment of actin to myosin at the cross-bridge, the myosin head molecule undergoes a position change, exerting traction on the rest of the myosin bridge, causing the thin filaments to slide past the thick filaments. During contraction, each cross-bridge undergoes cycles of attachment, movement, and dissociation from the thin filaments
The coronary ostia are located in the: A. Left ventricle B. Aortic valve C. Coronary sinus D. Aorta
D Coronary arteries receive blood through openings in the aorta, called the coronary ostia.
Which event occurs during phase 1 of the normal myocardial cell depolarization and repolarization? A. Repolarization when potassium moves out of the cells B. Repolarization when sodium rapidly enters into the cells C. Early repolarization when sodium slowly enters the cells D. Early repolarization when calcium slowly enters the cells
D Phase 1 is early repolarization and the only time during which calcium slowly enters the cell.
Which phase of the normal myocardial cell depolarization and repolarization correlates with diastole? A. Phase 1 B. Phase 2 C. Phase 3 D. Phase 4
D Potassium is moved out of the cell during phase 3, with a return to resting membrane potential only in phase 4. The time between action potentials corresponds to diastole.
Occlusion of the circumflex artery during a myocardial infarction would interrupt blood supply to which area? A. Left and right ventricles and much of the interventricular septum B. Posterior interventricular sulcus and the smaller branches of both ventricles C. Upper right ventricle, right marginal branch, and right ventricle to the apex D. Left atrium and the lateral wall of the left ventricle
D The circumflex artery supplies blood to the left atrium and the lateral wall of the left ventricle. The circumflex artery often branches to the posterior surfaces of the left atrium and left ventricle.
The cardiac electrical impulse normally begins spontaneously in the sinoatrial (SA) node because it: A. Has a superior location in the right atrium. B. Is the only area of the heart capable of spontaneous depolarization. C. Has rich sympathetic innervation via the vagus nerve. D. Depolarizes more rapidly than other automatic cells of the heart.
D The electrical impulse normally begins in the SA node because its cells depolarize more rapidly than other automatic cells.
When the volume of blood in the ventricle at the end of diastole increases, the force of the myocardial contraction during the next systole will also increase, which is an example of which law or theory about the heart? A. Laplace's law B. Poiseuille law C. Cross-bridge theory D. Frank-Starling law
D This concept is expressed only in the Frank-Starling law; the cardiac muscle, like other muscles, increases its strength of contraction when it is stretched.
During the cardiac cycle, why do the aortic and pulmonic valves close after the ventricles relax? A. Papillary muscles relax, which allows the valves to close. B. Chordae tendineae contract, which pulls the valves closed. C. Reduced pressure in the ventricles creates a negative pressure, which pulls the valves closed. D. Blood fills the cusps of the valves and causes the edges to merge, closing the valves.
D When the ventricles relax, blood fills the cusps and causes their free edges to meet in the middle of the vessel, closing the valve and preventing any backflow.
What physical sign is the result of turbulent blood flow through a vessel? A. Increased blood pressure during periods of stress B. Bounding pulse felt on palpation C. Cyanosis observed on excretion D. Murmur heard on auscultation
D Where flow is obstructed, the vessel turns or blood flows over rough surfaces. The flow becomes turbulent with whorls or eddy currents that produce noise, causing a murmur to be heard on auscultation, such as occurs during blood pressure measurement with a sphygomanometer.
What is the effect of epinephrine on β3 receptors on the heart? A. Decreases coronary blood flow. B. Supplements the effects of both β1 and β2 receptors. C. Increases the strength of myocardial contraction. D. Prevents overstimulation of the heart by the sympathetic nervous system.
D β3 receptors are found in the myocardium and coronary vessels. In the heart, stimulation of these receptors opposes the effects of β1- and β2-receptor stimulation and negative inotropic effect. Thus β3 receptors may provide a safety mechanism that decreases myocardial contractility to prevent overstimulation of the heart by the sympathetic nervous system.
Which intracardiac pressure is produced because of the descent of the tricuspid valve ring and by the ejection of blood from both ventricles? A. V wave B. C wave C. Y descent D. X descent
D. X descent The X descent follows an A wave and is produced because of the descent of the tricuspid valve ring and by the ejection of blood from both ventricles.
Which is the function of the pericardium? (Select all that apply.) Prevents displacement of the heart during gravitational acceleration or deceleration. Physical barrier that protects the heart against infection and inflammation. Forms a lining that is continuous with the arteries, veins, and capillaries of the body. Contains pain receptors and mechanoreceptors that affect blood pressure. Creates a continuous closed circulatory system.
Functions of the pericardium are: (1) to prevent the displacement of the heart during gravitational acceleration or deceleration, (2) to provide a physical barrier that protects the heart against infection and inflammation from the lungs and pleural space, and (3) to provide pain receptors and mechanoreceptors that can elicit reflex changes in blood pressure and heart rate. The endocardium is the lining that is continuous with the arteries, veins, and capillaries of the body and creates a continuous closed circulatory system.
Relationship of wall tension, intraventricular pressure, internal radius, and wall thickness
Laplace's law, wall tension is directly related to the product of intraventricular pressure and internal radius and inversely to the wall thickness.
Which statement is true regarding the thoracic duct? The thoracic duct is the major source of venous return to the heart. The thoracic duct receives lymph from most of the body. The thoracic duct receives lymph from the right arm, head, and thorax. Blood is dumped into the right atrium through the thoracic duct.
Lymph is primarily water and small amounts of protein. It is reabsorbed through the lymph nodes and delivered to either the right lymphatic duct (lymph from right arm, head, and thorax) or the thoracic duct (rest of the body). These structures, in turn, dump the lymph into the inferior vena cava and superior vena cava (major sources of venous return to the heart), which conduct blood to the right atrium.
Phases of myocardial cell depolarization and repolarization
Phase 1 Early repolarization - Ca slowly enters the cell Phase 2 Plateau - continuation of repolarization, slow entry of Ca and Na into cell Phase 3 K moves out of cell Pahse 4 Return to resting membrane potential. Diastole
Relationship among blood flow, pressure, and resistance
Poiseuille law for resistance to fluid flow through a tube takes into account the length of the tube, the viscosity of the fluid, and the radius of the tube's lumen.
Which statement correctly defines preload? Resistance to the ejection of blood from the left ventricle Wall tension that is related to internal blood vessel radius Lower tension curve than normal—a major characteristic Pressure generated by the end-diastolic volume
Preload is the pressure generated in the left ventricle at the end of diastole (end-diastolic volume). Afterload is the resistance or impedance to the ejection of blood from the left ventricle. Wall tension is directly related to the product of the intraventricular pressure and internal radius, and inversely related to the wall thickness (Laplace's law). A tension curve lower than normal is characteristic of congestive heart failure.
Heart - blood circulation
RT atrium - Tricuspid - RT Ventricle - Pulmonic Semilunar valve - Pulmonary circulation L atrium - Bicuspid valve - L ventricle - aortic valve - systemic circulation
Increased heart rate from increased volume
The Bainbridge reflex Causes changes in the heart rate after intravenous infusions of blood or other fluid.
Length-tension relationship of cardiac muscle
The Frank-Starling law states that the cardiac muscle, like other muscles, increases its strength of contraction when it is stretched.
Which two items are related in the Frank-Starling law of the heart? Resting sarcomere length to tension generation Resting sarcomere length to end-diastolic volume Tension generation and left ventricular pressure Incorrect Tension generation and diastolic filling pressures
The Frank-Starling law of the heart relates resting sarcomere length (expressed as the volume of blood in the heart at the end of diastole or end-diastolic volume) to tension generation (development of left ventricular pressure). In summary, this means the volume of blood in the heart at the end of diastole is directly related to the force of contraction of the next systole.
Which cardiac event represents the measure of time from the onset of atrial activation to the onset of ventricular activation? PR interval QRS complex ST interval QT interval
The PR interval measures the time of onset of atrial activation to the onset of ventricular activation. The QRS complex represents the sum of all ventricular muscle cell depolarization. The ST interval is the time when the entire ventricular myocardium is depolarized. The QT interval is often called electrical systole.
Which cardiac chamber has the thickest wall? Left atrium Right atrium Left ventricle Right ventricle
The atria are approximately 1 to 2 mm thick. The right ventricle is 4 to 5 mm thick, and the left ventricle, the most muscular chamber, is approximately 12 to 15 mm thick.
Which artery travels in the coronary sulcus between the left atrium and the left ventricle? Left anterior descending Circumflex Right coronary Left coronar
The circumflex artery travels in the coronary sulcus. The left anterior descending artery travels down the anterior surface of the interventricular septum. The right coronary artery originates from an ostium behind the right aortic cusp and travels behind the pulmonary artery. The left coronary artery passes between the left atrial appendage and the pulmonary artery and generally divides into two branches.
Which process is responsible for slowing the heart rate? Sympathetic excitation Parasympathetic excitation Correct Bainbridge reflex Baroreceptor reflex
The parasympathetic excitation slows the heart rate and is often referred to as the cardioinhibitory center. The sympathetic stimulation is often called the cardioexcitation center because the heart rate increases. The Bainbridge reflex causes the heart rate to increase after intravenous infusions of blood or fluid. The baroreceptor reflex facilitates blood pressure changes and heart rate changes.
Which part of the heart is responsible for electrical impulse stimulation? Atrioventricular node Incorrect Sinus node Correct Bundle of His Right bundle branch
The sinus node, the pacemaker of the heart, is the site of impulse formation. The atrioventricular node is the junction of the electrical transmission between the atria and the ventricles. The impulse then travels to the bundle of His and, finally, to the right and left bundle branches. The terminal branches are the Purkinje fibers.
What is an expected change in the cardiovascular system that occurs with aging? A. Arterial stiffening B. Decreased left ventricular wall tension C. Decreased aortic wall thickness D. Arteriosclerosis
A Arterial stiffening occurs with aging even in the absence of clinical hypertension.
What period follows depolarization of the myocardium and represents a period during which no new cardiac potential can be propagated? A. Refractory B. Hyperpolarization C. Threshold D. Sinoatrial (SA)
A During the refractory period, no new cardiac action potential can be initiated by a stimulus
The Bainbridge reflex is thought to be initiated by sensory neurons in which cardiac location? A. Atria B. Aorta C. Sinoatrial (SA) node D. Ventricles
A The Bainbridge reflex causes changes in the heart rate after intravenous infusions of blood or other fluid. The changes in heart rate are thought to be caused by a reflex mediated by volume receptors found only in the atria that are innervated by the vagus nerve.
The coronary sinus empties into which cardiac structure? A. Right atrium B. Left atrium C. Superior vena cava D. Aorta
A The cardiac veins empty only into the right atrium through another ostium, the opening of a large vein called the coronary sinus.
What is the ratio of coronary capillaries to cardiac muscle cells? A. 1:1 (one capillary per one muscle cell) B. 1:2 (one capillary per two muscle cells) C. 1:4 (one capillary per four muscle cells) D. 1:10 (one capillary per ten muscle cells)
A The heart has an extensive capillary network, with approximately 3300 capillaries per square millimeter (ca/mm2) or approximately one capillary per one muscle cell (muscle fiber).
After the baroreceptor reflex is stimulated, the resulting impulse is transmitted from the carotid artery by which sequence of events? A. Vagus nerve to the medulla to increase parasympathetic activity and to decrease sympathetic activity B. Glossopharyngeal cranial nerve through the vagus nerve to the medulla to increase sympathetic activity and to decrease parasympathetic activity C. Glossopharyngeal cranial nerve through the vagus nerve to the medulla to increase parasympathetic activity and to decrease sympathetic activity D. Glossopharyngeal cranial nerve through the vagus nerve to the hypothalamus to increase parasympathetic activity and to decrease sympathetic activity
C Neural impulses are transmitted over the glossopharyngeal nerve (ninth cranial nerve) from the carotid artery and through the vagus nerve from the aorta to the cardiovascular control centers in the medulla. These centers initiate an increase in parasympathetic activity and a decrease in sympathetic activity, causing blood vessels to dilate and the heart rate to decrease. Glossopharyngeal (IX) - Carotid artery - Vagus nerve (aorta) - CV centers in medulla
What is the major determinant of the resistance that blood encounters as it flows through the systemic circulation? A. Volume of blood in the systemic circulation B. Muscle layer of the metarterioles C. Muscle layer of the arterioles D. Force of ventricular contraction
C Of the options available, only the thick, smooth muscle layer of the arterioles is a major determinant of the resistance blood encounters as it flows through the systemic circulation.
Continuous increases in left ventricular filing pressures result in which disorder? A. Mitral regurgitation B. Mitral stenosis C. Pulmonary edema D. Jugular vein distention
C Pressure changes are important because increased left ventricular filling pressures back up into the pulmonary circulation, where they force plasma out through vessel walls, causing fluid to accumulate in lung tissues (pulmonary edema).
Which chamber of the heart endures the highest pressures? A. Right atrium B. Left atrium C. Left ventricle D. Right ventricle
C Pressure is greatest in the systemic circulation, driven by the left ventricle.
Where in the heart are the receptors for neurotransmitters located? A. Semilunar and atrioventricular (AV) valves B. Endocardium and sinoatrial (SA) node C. Myocardium and coronary vessels D. Epicardium and AV node
C Sympathetic neural stimulation of the myocardium and coronary vessels depends on the presence of adrenergic receptors, which specifically bind with neurotransmitters of the sympathetic nervous system. The β1 receptors are found mostly in the heart, specifically the conduction system (AV and SA nodes, Purkinje fibers) and the atrial and ventricular myocardium, whereas the β2 receptors are found in the heart and also on vascular smooth muscle. β3 receptors are also found in the myocardium and coronary vessels.
In the normal electrocardiogram, what does the PR interval represent? A. Atrial depolarization B. Ventricular depolarization C. Atrial activation to onset of ventricular activity D. Electrical systole of the ventricles
C The PR interval is a measure of time from the onset of atrial activation to the onset of ventricular activation; it normally ranges from 0.12 to 0.20 second. The PR interval represents the time necessary to travel from the sinus node through the atrium, the atrioventricular (AV) node, and the His-Purkinje system to activate ventricular myocardial cells.
Where is the major cardiovascular center in the central nervous system? A. Frontal lobe B. Thalamus C. Brainstem D. Hypothalamus
C The major cardiovascular control center is in the brainstem in the medulla with secondary areas in the hypothalamus, the cerebral cortex, the thalamus, and the complex networks of exciting or inhibiting interneurons (connecting neurons) throughout the brain
The right lymphatic duct drains into which structure? A. Right subclavian artery B. Right atrium C. Right subclavian vein D. Superior vena cava
C The right lymphatic duct drains lymph only into the right subclavian vein.
Reflects the rapid flow of blood from the great veins and right atrium into the right ventricle A. V wave B. C wave C. Y descent D. X descent
C. Y descent