A&P II Cardiac Cycle and Heart Sounds
37 flashcards covering A&P II Cardiac Cycle and Heart Sounds for the ANATOMY-PHYSIOLOGY-2 A&P II Systems section.
The cardiac cycle refers to the sequence of events in one heartbeat, encompassing the contraction and relaxation of the heart chambers, which is crucial for understanding cardiovascular physiology. The American Association of Colleges of Nursing (AACN) outlines this concept in its curriculum for Anatomy and Physiology II, emphasizing the importance of heart sounds and the phases of the cardiac cycle in maintaining effective circulation and diagnosing cardiac conditions.
In practice exams and competency assessments, questions about the cardiac cycle often focus on identifying the phases of the cycle, the associated heart sounds (S1, S2), and their clinical significance. Common traps include confusing the timing of heart sounds with the phases of the cycle or misidentifying the physiological changes that occur during systole and diastole. A frequent oversight among clinicians is neglecting to correlate abnormal heart sounds with specific cardiac conditions, which can lead to missed diagnoses.
Terms (37)
- 01
What is the cardiac cycle?
The cardiac cycle is the sequence of events that occur during one heartbeat, including the contraction (systole) and relaxation (diastole) of the heart chambers, resulting in blood flow through the heart and into the circulation (Marieb, Anatomy and Physiology).
- 02
How many phases are in the cardiac cycle?
The cardiac cycle consists of two main phases: diastole, when the heart relaxes and fills with blood, and systole, when the heart contracts and pumps blood out (Tortora, Anatomy and Physiology).
- 03
What occurs during atrial systole?
During atrial systole, the atria contract, pushing blood into the ventricles, which are in diastole at this time (Saladin, Anatomy and Physiology).
- 04
What is the role of the AV valves during the cardiac cycle?
The atrioventricular (AV) valves prevent backflow of blood into the atria during ventricular contraction (systole) (Marieb, Anatomy and Physiology).
- 05
What are the heart sounds associated with the cardiac cycle?
The heart sounds, commonly referred to as 'lub' and 'dub', correspond to the closure of the AV valves and semilunar valves, respectively (Tortora, Anatomy and Physiology).
- 06
What causes the first heart sound (S1)?
The first heart sound (S1) is caused by the closure of the mitral and tricuspid valves at the beginning of ventricular systole (Saladin, Anatomy and Physiology).
- 07
What is the second heart sound (S2) associated with?
The second heart sound (S2) is associated with the closure of the aortic and pulmonary valves at the end of ventricular systole (Marieb, Anatomy and Physiology).
- 08
What is isovolumetric contraction?
Isovolumetric contraction is the phase of the cardiac cycle where the ventricles contract with no change in volume because all valves are closed (Tortora, Anatomy and Physiology).
- 09
How does the heart rate affect the cardiac cycle?
An increase in heart rate shortens the duration of the cardiac cycle, leading to less time for diastole and potentially affecting filling of the ventricles (Saladin, Anatomy and Physiology).
- 10
What is the significance of the cardiac output?
Cardiac output is the volume of blood pumped by the heart per minute, which is a critical measure of the heart's efficiency and overall health (Marieb, Anatomy and Physiology).
- 11
What factors influence stroke volume?
Stroke volume is influenced by preload, afterload, and contractility, affecting the amount of blood ejected from the heart during systole (Tortora, Anatomy and Physiology).
- 12
What is preload in the context of the cardiac cycle?
Preload refers to the degree of stretch of the cardiac muscle fibers at the end of diastole, which affects stroke volume (Saladin, Anatomy and Physiology).
- 13
What is afterload?
Afterload is the resistance the ventricles must overcome to eject blood during systole, impacting stroke volume and cardiac output (Marieb, Anatomy and Physiology).
- 14
Which phase of the cardiac cycle is longest?
Diastole is the longest phase of the cardiac cycle, allowing for adequate filling of the heart chambers (Tortora, Anatomy and Physiology).
- 15
What is the role of the sinoatrial (SA) node?
The sinoatrial (SA) node acts as the primary pacemaker of the heart, initiating the electrical impulses that trigger the cardiac cycle (Saladin, Anatomy and Physiology).
- 16
How does the autonomic nervous system affect heart rate?
The autonomic nervous system regulates heart rate through sympathetic stimulation (increasing heart rate) and parasympathetic stimulation (decreasing heart rate) (Marieb, Anatomy and Physiology).
- 17
What is the significance of the P wave on an ECG?
The P wave on an electrocardiogram (ECG) represents atrial depolarization, which occurs just before atrial contraction (Tortora, Anatomy and Physiology).
- 18
What does the QRS complex indicate in the cardiac cycle?
The QRS complex indicates ventricular depolarization, which precedes ventricular contraction (Saladin, Anatomy and Physiology).
- 19
What is the T wave in an ECG?
The T wave represents ventricular repolarization, occurring during ventricular diastole (Marieb, Anatomy and Physiology).
- 20
What happens during ventricular diastole?
During ventricular diastole, the ventricles relax and fill with blood from the atria, facilitated by the opening of the AV valves (Tortora, Anatomy and Physiology).
- 21
How does venous return affect cardiac output?
Increased venous return enhances preload, which can increase stroke volume and subsequently cardiac output (Saladin, Anatomy and Physiology).
- 22
What is the function of the semilunar valves?
The semilunar valves (aortic and pulmonary) prevent backflow of blood into the ventricles during diastole (Marieb, Anatomy and Physiology).
- 23
What is the effect of increased contractility on the cardiac cycle?
Increased contractility enhances the force of ventricular contraction, leading to increased stroke volume and cardiac output (Tortora, Anatomy and Physiology).
- 24
What is the relationship between heart rate and stroke volume?
Heart rate and stroke volume together determine cardiac output; as one increases, the other may adjust to maintain efficient blood circulation (Saladin, Anatomy and Physiology).
- 25
What is the significance of the cardiac reserve?
Cardiac reserve is the difference between resting and maximal cardiac output, indicating the heart's capacity to increase output during increased activity (Marieb, Anatomy and Physiology).
- 26
What is a heart murmur?
A heart murmur is an abnormal sound during the heartbeat cycle, often indicating turbulent blood flow due to valve abnormalities (Tortora, Anatomy and Physiology).
- 27
What is the effect of exercise on the cardiac cycle?
Exercise increases heart rate and contractility, leading to increased cardiac output to meet the body's higher metabolic demands (Saladin, Anatomy and Physiology).
- 28
How often should a resting heart rate be measured?
A resting heart rate should be measured regularly, typically at least once per year during routine health assessments (Marieb, Anatomy and Physiology).
- 29
What is the impact of aging on the cardiac cycle?
Aging can lead to decreased heart rate responsiveness and changes in cardiac structure, affecting the efficiency of the cardiac cycle (Tortora, Anatomy and Physiology).
- 30
What is the role of baroreceptors in heart function?
Baroreceptors detect changes in blood pressure and help regulate heart rate and vascular resistance through the autonomic nervous system (Saladin, Anatomy and Physiology).
- 31
What is the function of the chordae tendineae?
Chordae tendineae are fibrous cords that anchor the AV valves to the papillary muscles, preventing valve prolapse during ventricular contraction (Marieb, Anatomy and Physiology).
- 32
What is the significance of the Frank-Starling law?
The Frank-Starling law states that the stroke volume of the heart increases in response to an increase in the volume of blood filling the heart (preload) (Tortora, Anatomy and Physiology).
- 33
What is the effect of sympathetic stimulation on the heart?
Sympathetic stimulation increases heart rate and contractility, enhancing cardiac output during stress or exercise (Saladin, Anatomy and Physiology).
- 34
What is the role of the cardiac conduction system?
The cardiac conduction system coordinates the electrical impulses that regulate the timing of heart contractions, ensuring efficient blood flow (Marieb, Anatomy and Physiology).
- 35
What occurs during the rapid filling phase of the ventricles?
During the rapid filling phase, blood flows passively from the atria into the ventricles, occurring early in diastole (Tortora, Anatomy and Physiology).
- 36
What is the purpose of cardiac auscultation?
Cardiac auscultation is performed to listen to heart sounds and assess the function of the heart valves and overall heart health (Saladin, Anatomy and Physiology).
- 37
How does the body respond to low blood pressure during the cardiac cycle?
The body responds to low blood pressure by increasing heart rate and contractility through sympathetic nervous system activation (Marieb, Anatomy and Physiology).