Questions and Answers
The difference between the maximum and resting cardiac output is called __________.
Cardiac Reserve
Correctly sequence the pathway of blood flow through the heart, beginning with the venae cavae.
Venae cavae → Right atrium → Right ventricle → Pulmonary arteries → Lungs → Pulmonary veins → Left atrium → Left ventricle → Aorta
Which term refers to relaxation of the heart?
Diastole
The AV valves close in response to __________.
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Action potentials received directly from the __________ stimulate the papillary muscles to contract, allowing for the proper __________ of the AV valves.
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The part of the cardiac conduction system which acts as the pacemaker is the __________ node.
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What is the double-walled sac that surrounds the heart called?
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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?
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When atrial pressure is greater than ventricular pressure, the _____ valves open.
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The rate of ventricular conduction is best determined by __________ on an ECG.
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Which of the following is the correct formula for calculating cardiac output?
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Study Notes
Cardiac Anatomy and Blood Flow
- Cardiac Reserve is the difference between maximum and resting cardiac output.
- Blood flow sequence starts from venae cavae into the heart chambers and out to the body.
- Key internal structures of the heart include four chambers, valves (AV and semilunar), and specialized muscle tissues.
Cardiac Cycle and Heart Function
- Diastole refers to the relaxation phase of the heart.
- AV valves close due to ventricular contraction, triggered by increased pressure in the ventricles.
- The semilunar valves open when ventricular pressure exceeds arterial pressure during the late ventricular systole phase.
Heart Valves and Electrical System
- Major heart valves include the AV and semilunar valves, which prevent backflow during contraction and relaxation.
- The cardiac conduction system consists of the sinoatrial (SA) node, atrioventricular (AV) node, and Purkinje fibers, regulating heart rhythm by conducting electrical impulses.
Cardiac Muscle Characteristics
- Cardiac muscle has unique structural features, including intercalated discs that facilitate communication between cells and synchronize contractions.
- Action potentials in cardiomyocytes initiate contraction, marked by specific ion channel activities involving sodium, calcium, and potassium ions.
Physiological Concepts
- Stroke volume can be influenced by factors such as preload and inotropic agents, which affect the force of contraction.
- The Frank-Starling law describes that increased ventricular filling leads to more forceful contractions.
Electrocardiogram (ECG) Interpretation
- An ECG records electrical currents of the heart, showing P waves (atrial depolarization), QRS complexes (ventricular depolarization), and T waves (ventricular repolarization).
- Third-degree AV blocks manifest as irregularities in the ratio of P waves to QRS complexes.
Heart Rate Regulation
- Heart rate increases with sympathetic stimulation, exercise, and stress, while it decreases in response to vagal tone and specific pharmacological interventions.
- Cardiac output (CO) is calculated using the formula: CO = Heart Rate (HR) x Stroke Volume (SV).
Pathological Considerations
- Mitral valve prolapse can lead to increased left atrial pressure, impacting overall heart function.
- Cardiac dysfunctions can be monitored through ECG changes, indicative of various conduction blocks or abnormal heart rhythms.
Pericardium and External Anatomy
- The pericardium is a double-walled sac surrounding the heart, providing protection and facilitating movement during contraction and relaxation.
- Knowledge of both external and internal structures of the heart is vital for understanding its function and diagnosing diseases.
Miscellaneous
- Post-exercise venous return increases, influencing the right ventricular workload and contributing to overall cardiovascular dynamics.
- Positive inotropic agents enhance cardiac output by decreasing end-systolic volume, while negative inotropes reduce cardiac workload during hypertension.
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Description
Test your knowledge of the heart's anatomy and functions with these flashcards for A&P II Exam 1. Cover topics including cardiac output, blood flow pathways, and key terms related to the heart's physiology. Perfect for students preparing for exams and wanting to reinforce their learning.
