Questions and Answers
What is the function of the coronary circulation?
Provide a blood supply to the heart
What is the ligamentum arteriosum?
A remnant of the ductus arteriosus
Which chamber of the heart exits into the pulmonary trunk?
Identify the ear-like flaps that are attached to the top chambers of the heart.
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The first branch off the arch of the aorta is the brachiocephalic artery in both the sheep and the human.
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The base of the heart is located at the bottom of the heart.
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Identify the most muscular chamber of the heart.
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Name the inner lining of the heart.
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Identify the valve found between the left atrium and left ventricle.
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What heart chamber pushes blood through the aortic semilunar valve?
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Name the irregular ridges of muscle lining the ventricles.
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What fibrous structure functions to anchor the atrioventricular valves in a closed position?
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Blood on the right never mixes with blood on the left, once the heart is fully developed.
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Name the ridged bundles of muscle found projecting inside the right atrium.
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Identify the right atrioventricular valve.
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Identify the valve located at the exit of the right ventricle.
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The moderator band is found on both the right and left side of the heart.
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Oxygenated blood flows through the right side of the heart.
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Action potentials generated by autorhythmic cells spread to contractile cells through what structures in the membrane?
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One of the changes that occurs in the pacemaker potential in the SA node is a decreased efflux of what ion?
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When threshold is reached at the SA node, what channels open causing further depolarization of the membrane?
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Repolarization of an autorhythmic cell is due to the opening of which channels?
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What causes the depolarization of the contractile cells?
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Which part of the conduction system initiates the depolarizing impulse, which spreads throughout the heart?
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What does the ECG wave tracing represent?
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What does the QRS complex represent in the ECG wave tracing?
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Contraction of the atria results from which wave of depolarization on the ECG tracing?
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Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles?
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Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________.
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Most blood flows passively into the ventricles through open AV valves.
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Describe the pressures in the atria and ventricles that would cause the opening of the AV valves.
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What causes the aortic semilunar valve to close?
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Put the phases of the cardiac cycle in the correct order, starting after ventricular filling.
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Increased pressure in the ventricles would close what valve(s)?
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Which of the following would increase cardiac output?
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Which of the following is NOT a factor that increases stroke volume?
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Calculate the stroke volume if the end diastolic volume (EDV) is 135 mL and the end systolic volume (ESV) is 60 mL.
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What structures connect the individual heart muscle cells?
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Myofibrils of cardiac muscle tissue vary in diameter and branch extensively.
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Study Notes
Coronary Circulation
- Provides blood supply specifically to the heart and pericardium.
- Ensures adequate oxygen and nutrient delivery to cardiac tissues.
Ligamentum Arteriosum
- A remnant structure of the ductus arteriosus found post-birth.
- Connects the pulmonary artery to the aorta.
Heart Chambers
- Right ventricle is responsible for exiting blood into the pulmonary trunk.
- Left ventricle is the most muscular chamber, pushing blood to systemic circulation through the aortic semilunar valve.
Heart Structures
- Auricles are ear-like flaps attached to the atria, increasing atrial volume.
- Endocardium is the inner lining of the heart, providing a smooth surface for blood flow.
- Trabeculae carneae are irregular muscle ridges found in the ventricles, aiding in contraction efficiency.
Valves of the Heart
- Bicuspid (mitral) valve separates the left atrium from the left ventricle.
- Tricuspid valve is the right atrioventricular valve.
- Pulmonary semilunar valve is located at the exit of the right ventricle and prevents backflow.
Cardiac Cycle
- Blood flow into ventricles occurs passively through open AV valves, with most filling occurring before atrial contraction.
- Ventricular diastole involves isovolumetric relaxation and filling phases.
- Increased ventricular pressure leads to closure of the AV valves and opens the semilunar valves during systole.
Electrical Conduction System
- SA node initiates the depolarizing impulse, which spreads throughout the heart muscle.
- AV node briefly delays impulses before transmitting to the ventricles.
- ECG wave tracing, representing electrical activity, shows P wave for atrial contraction, QRS complex for ventricular depolarization, and T wave for repolarization.
Ion Movement in Action Potentials
- Pacemaker potential involves decreased potassium efflux in SA node cells.
- Fast calcium channels open upon reaching threshold, contributing to depolarization.
- Repolarization occurs due to the opening of voltage-gated potassium channels.
- Depolarization of contractile cells is triggered by positive ion flow from adjacent cells.
Stroke Volume and Cardiac Output
- Stroke volume is calculated by subtracting end systolic volume from end diastolic volume (e.g., EDV of 135 mL minus ESV of 60 mL results in 75 mL).
- Factors increasing cardiac output include sympathetic stimulation and hormones like epinephrine.
- Increasing afterload is a factor that does not enhance stroke volume.
Structural Features of Cardiac Muscle
- Myofibrils in cardiac muscle vary in diameter and branch, contributing to contraction efficiency.
- Intercalated discs connect cardiac muscle cells, facilitating synchronized contractions.
Blood Flow Pathways
- Blood enters the heart through the right atrium, passes through the tricuspid valve, and flows into the right ventricle.
- Blood moves from the aorta through systemic arteries to capillaries and returns to the right atrium via systemic veins.
General Heart Function
- Proper pressure differences between atria and ventricles ensure valve operation during the cardiac cycle.
- Oxygen-rich blood returns to the heart and enters the left atrium before flowing to the left ventricle and then out to the body through the aorta.
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Description
Test your knowledge on the cardiovascular system with these flashcards focusing on coronary circulation and anatomical structures like the ligamentum arteriosum. This quiz will help reinforce your understanding of vital heart functions and developmental remnants.
