The Heart
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68 terms
Terms | Definitions |
|---|---|
 If the connection between the SA node and AV node becomes blocked, | the ventricles will beat more slowly |
| The long plateau phase of the cardiac muscle action potential is due to | calcium channels remaining open |
| An increase in the rate of action potentials from baroreceptors will reflexly lead to | both decrease in heart rate and decrease in blood pressure. |
| During the T wave of the electrocardiogram, the ventricles are | both repolarizing and relaxing |
| Depolarization of the atria corresponds to the EKG's | P wave |
| As a result of the long refractory period in the cardiac action potential, cardiac muscle cannot exhibit | tetany |
| Cardiac cells damaged by infarction will show which of the following? | release of troponin T and I into the circulation. switch to anaerobic metabolism. release of enzymes into the circulation. release of MB-CK into the circulation. |
| Analysis of the electrocardiogram can reveal all of the following, except the | stroke volume |
| A heart murmur might be caused by | aortic valve stenosis or mitral valve insufficiency or pulmonic valve insufficiency. |
| The relaxation phase of the cardiac cycle is called ________. | diastole |
| ________ is when the heart can't maintain adequate cardiac output. | Heart failure |
| As the heart rate slows, ________ gets longer. | diastole |
| If the connection between the vagus nerve and the heart is cut, which of these changes will occur? | None of the above |
| During the isovolumetric phase of ventricular systole, the | atrioventricular valves and semilunar valves are closed. |
| The closing of the left AV valve occurs near the beginning of __________. | ventricular systole |
| The majority of ventricular filling occurs while the ventricles and atria are in what state(s)? | ventricular and atrial diastole |
| Which of the following most correctly describes end-diastolic volume? | \the volume of the ventricle when it is most full |
| Left ventricular filling occurs __________. | while the AV valve is open |
| Heart valves are in what state during isovolumetric contraction? | AV valves and semilunar valves are closed |
| The decrease in left ventricular pressure at the end of ventricular systole causes __________. | the semilunar valves to close |
| Ventricular diastole begins with the closing of the semilunar valves. What phase of the cardiac cycle happens between this event and the later opening of the AV valves? | isovolumetric relaxation |
| The contraction phase of the cardiac cycle is called ________. | systole |
| Compared to the right ventricle, which of these statements about the left ventricle is false? | it ejects more blood |
| During the cardiac cycle, the | both QRS complex of the ECG precedes the increase in ventricular pressure and first heart sound coincides with the QRS complex of the ECG. |
| Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________. | ventricular diastole |
| Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________. | Most blood flows passively into the ventricles through open AV valves |
| Describe the pressures in the atria and ventricles that would cause the opening of the AV valves. | Pressure in the atria would be greater than the pressure in the ventricles. |
| What causes the aortic semilunar valve to close? | greater pressure in the aorta than in the left ventricle |
| Put the phases of the cardiac cycle in the correct order, starting after ventricular filling. | isovolumetric contraction, ventricular ejection, isovolumetric relaxation |
| Increased pressure in the ventricles would close what valve(s)? | AV valves only |
| The backward flow of blood from a ventricle to its atrium or from a outflow vessel to its ventricle is called ________. | regurgitation |
| Which of the following would increase heart rate? | decreased parasympathetic stimulation of nodal fibers increased levels of epinephrine increased sympathetic stimulation of SA node faster depolarization of the pacemaker potential |
| Each of the following factors will increase cardiac output, except | increased parasympathetic stimulation |
| Cardiac output is increased by | more sympathetic stimulation and increased stroke volume. |
| Drugs that block the beta-one adrenergic receptors will | decrease the heart rate |
| If a patient's tricuspid valve was leaking during systole, what would happen? | regurgitation into the right atrium |
| The amount of blood returning to the heart is the ________. | venous return |
| The ________ is the volume of blood in a ventricle at the beginning of systole. | end-diastolic volume |
| The phase in the cardiac cycle when the mitral valve is closed and the aortic valve is open is the | systolic ejection phase |
| The first heart sound ("lub") | is associated with the closing of the mitral valve |
| Pacemaker cells isolated from the SA node generate action potentials at ________ beats per minute. | 80-100 |
| During ventricular systole, | AV valves are closed |
| Which of the following would increase cardiac output to the greatest extent? | increased heart rate and increased stroke volume |
| Which of the following would increase heart rate? | norepinephrine and epinephrine |
| How would an increase in the sympathetic nervous system increase stroke volume? | increased contractility |
| By what mechanism would an increase in venous return increase stroke volume? | increased end-diastolic volume |
| How would a decrease in blood volume affect both stroke volume and cardiac output? | decreased stroke volume and no change in cardiac output |
| The heart is innervated by ________ nerves. | both parasympathetic and sympathetic |
| The volume of blood ejected from each ventricle during a contraction is called the | stroke volume |
| Drugs known as calcium channel blockers such as nifedipine can be used to | decrease blood pressure. decrease the force of cardiac contraction. produce a negative inotropic effect. dilate the coronary arteries. |
| Stroke volume depends on | end diastolic volume, the contractility of the ventricle, and the pressure required to pump blood into the aorta. |
| Heart rate is controlled by neurons of the cardiovascular center located in the | medulla oblongata |
| Which of these would cause stroke volume to increase? | both when venous return is increased and when diastolic blood pressure is decreased |
| In mitral valve prolapse, the cusps of the mitral valve are pushed into the ________ atrium. | left |
| Cardiac output can be increased by all of the following except one. Choose the exception. | decreasing ejection fraction |
| "An increase in end-diastolic volume increases the stroke volume" is a way of stating | Starling's law of the heart |
| Which of these is not needed to determine cardiac output? | blood pressure |
| Acetylcholine slows the heart because it | opens potassium ion channels in SA node cells and causes the pacemaker potential to depolarize more slowly. |
| Which of these is true about the atrial reflex? | depends on sympathetic innervation triggered by atrial mechanoreceptors also called Bainbridge reflex triggered by increasing venous return |
| Pacemaker cells in the SA node | both show a slow spontaneous depolarization and are connected by gap junctions to atrial myocytes. |
| Which of the following would be greater? | the end-diastolic volume when the heart rate is 60 beats/minute (as opposed to 150 bpm) |
| Activation of which kind of receptor causes heart rate to increase? | beta-one receptor |
| The cardioacceleratory center activates sympathetic neurons and the cardioinhibitory center controls parasympathetic neurons. | Both parts of the statement are true and relate to brainstem control of heart rate. |
| David suffers from a prolapsed mitral valve. This condition would cause | both increased effort by the left ventricle and systolic murmur. |
| The ________ is the amount of blood in a ventricle after it has contracted and before it begins to refill. | end-systolic volume |
| The principle that increasing the end-diastolic volume results in a corresponding increase in the stroke volume is known as ________. | Starling's law of the heart |
| Cells that spontaneously make action potentials make up ________ tissue. | pacemaker |
| The cardiac ________ is the difference between the resting and maximal cardiac output. | reserve |
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