Anatomy Chapter 18 Flashcards

Questions and Answers

What is the function of the coronary circulation?

Provide a blood supply to the heart

What is the ligament arteriosum?

A remnant of the ductus arteriosus

What chamber of the heart exits into the pulmonary trunk?

Right ventricle

Identify the ear-like flaps that are attached to the top chambers of the heart.

Auricle Signup and view all the answers

The first branch off the arch of the aorta is the brachiocephalic artery in both the sheep and the human.

True Signup and view all the answers

The base of the heart is located at the bottom of the heart.

False Signup and view all the answers

Which of the following would increase cardiac output?

Epinephrine Signup and view all the answers

Which of the following would decrease stroke volume?

Increasing afterload Signup and view all the answers

Calculate stroke volume.

Subtract the ESV from the EDV Signup and view all the answers

Which of the following descriptions does not describe atrioventricular (AV) valves?

Formed from pocket-like cusps Signup and view all the answers

Which statement regarding cardiac muscle structure is accurate?

Myofibrils of cardiac muscle tissue vary in diameter and branch extensively. Signup and view all the answers

What does the interatrial septum do?

Divides the two atria of the heart Signup and view all the answers

What do atrioventricular valves do?

Control blood flow into the ventricles Signup and view all the answers

What is an electrocardiogram?

A test that records the electrical activity of the heart Signup and view all the answers

What does tachycardia mean?

A faster than normal heart rate Signup and view all the answers

Why is a patent ductus arteriosus a cause for concern?

The higher pressure in the aorta will push extra blood through the ductus arteriosus into the child's pulmonary circulation. Signup and view all the answers

Which of the following abnormalities is not a direct result of right ventricular failure?

Pulmonary edema Signup and view all the answers

Which statement is correct regarding the ventricles?

True Signup and view all the answers

Cardiac tamponade results in ineffective pumping of blood by the heart. This is because the excessive amount of fluid in the pericardial cavity will ______.

prevent the heart from filling properly with blood Signup and view all the answers

What is the epicardium?

Serous layer covering the heart muscle Signup and view all the answers

What is myocardium?

Heart muscle Signup and view all the answers

What is endocardium?

The inner lining of the heart Signup and view all the answers

What is the parietal layer?

The outermost layer of the serous pericardium Signup and view all the answers

The parietal pericardium ________.

lines the internal surface of the fibrous pericardium Signup and view all the answers

Pectinate muscles are found in the ________.

atria only Signup and view all the answers

The foramen ovale ________.

connected the two atria in the fetal heart Signup and view all the answers

Which is NOT a vessel that brings blood directly into the right atrium?

Pulmonary vein Signup and view all the answers

Which valve is located between the right atrium and ventricle?

Tricuspid valve Signup and view all the answers

The role of the chordae tendineae is to open the AV valves at the appropriate time.

False Signup and view all the answers

What does the aortic semilunar valve do?

Prevents backflow into the left ventricle Signup and view all the answers

What does the tricuspid valve do?

Prevents backflow into the right atrium. Atrioventricular (AV) valve with three flaps Signup and view all the answers

What does the mitral (bicuspid) valve do?

Prevents backflow into the left atrium. Atrioventricular (AV) valve with two flaps Signup and view all the answers

What does the pulmonary semilunar valve do?

Prevents backflow into the right ventricle Signup and view all the answers

Which chamber of the heart has the highest probability of being the site of a myocardial infarction?

Left ventricle Signup and view all the answers

If the mitral valve is unable to close properly, ________.

blood could flow back into the left atrium Signup and view all the answers

Which heart chamber receives oxygenated blood from the lungs?

Left atrium Signup and view all the answers

Arterial blood supply to heart muscle is continuous whether the heart is in systole or diastole.

False Signup and view all the answers

The left side of the heart pumps the same volume of blood as the right.

True Signup and view all the answers

Which coronary artery is most responsible for supplying blood to the myocardial tissue of the left atrium?

Circumflex artery Signup and view all the answers

What does it mean that the left ventricle is thicker than the right ventricle?

It pumps blood against a greater resistance Signup and view all the answers

What is the term for pain associated with deficient blood delivery to the heart?

Angina pectoris Signup and view all the answers

What effects does the presence of an incompetent tricuspid valve have?

Reduced efficiency in the delivery of blood to the lungs Signup and view all the answers

What structures connect the individual heart muscle cells?

Intercalated discs Signup and view all the answers

If cardiac muscle is deprived of its normal blood supply, damage would primarily result from ________.

Decreased delivery of oxygen Signup and view all the answers

If the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells, ________.

Tetanic contractions might occur, which would stop the heart's pumping action Signup and view all the answers

Compared to skeletal muscle, cardiac muscle has gap junctions that allow it to act as a functional syncytium.

True Signup and view all the answers

What does the QRS wave of the electrocardiogram (ECG) represent?

Ventricular depolarization Signup and view all the answers

Which structure receives the depolarization wave from the atria?

AV node Signup and view all the answers

What would happen to the SA node if a chemical blocker was used to reduce transport of Na+ into the pacemaker cells?

The SA node would depolarize more slowly, reducing the heart rate Signup and view all the answers

Electrical impulses pass through the conduction system of the heart in the following sequence:

SA node, AV node, bundle of His, bundle branches, and Purkinje fibers Signup and view all the answers

What does the P wave on an electrocardiogram represent?

Atrial depolarization Signup and view all the answers

In an ischemic heart, the affected cardiac muscle cells are likely to have an altered ______.

Resting membrane potential Signup and view all the answers

Which chambers of the heart contain oxygenated blood?

Left atrium and left ventricle Signup and view all the answers

Which of the following is NOT part of the intrinsic conduction system of the heart?

Atrioventricular (AV) valve Signup and view all the answers

What causes the 'pacemaker potential' of pacemaker cells?

The opening of slow Na+ channels at the end of an action potential Signup and view all the answers

What is the plateau phase of an action potential in cardiac muscle cells due to?

Influx of Ca2+ through slow Ca2+ channels Signup and view all the answers

Besides cardiac muscle, what muscle tissue type is involuntary and displays autorhythmicity?

Smooth muscle Signup and view all the answers

What is the period during the cardiac cycle when the valves leading to and from the ventricles are completely closed?

Isovolumetric contraction phase Signup and view all the answers

At what point in the cardiac cycle is pressure in the ventricles the highest?

Ventricular systole Signup and view all the answers

During which stage are the aortic and pulmonary valves open?

Phase 2b Signup and view all the answers

What causes heart sounds?

Heart valve closure Signup and view all the answers

Which best describes the isovolumetric contraction phase of the cardiac cycle?

As ventricular systole starts, the AV valves are closed and the semilunar valves are closed. Signup and view all the answers

The first heart sound is caused by __________.

Closure of the atrioventricular valves Signup and view all the answers

Which of the following terms is correctly matched to its description?

Quiescent period: period of total heart relaxation Signup and view all the answers

As soon as ventricular pressure falls below atrial pressure, the AV valve will open and ventricular filling will begin.

True Signup and view all the answers

An abnormal P wave could be indicative of ______.

Enlarged atria Signup and view all the answers

What does ischemia mean?

Heart muscle is deprived of oxygen Signup and view all the answers

What is the quiescent period?

Total heart relaxation Signup and view all the answers

What does infarction refer to?

Death of heart muscle cells Signup and view all the answers

What is ectopic focus?

An abnormal pacemaker Signup and view all the answers

What does fibrillation mean?

A condition of rapid and irregular or out-of-phase contraction of heart muscle cells Signup and view all the answers

During the isovolumetric relaxation phase of the cardiac cycle, AV, aortic, and pulmonary valves are closed.

True Signup and view all the answers

Which of the following receive(s) blood during ventricular systole?

Both the aorta and pulmonary trunk Signup and view all the answers

When are the atrioventricular (AV) valves closed?

When the ventricles are in systole Signup and view all the answers

What happens during the period of ventricular filling?

Blood flows mostly passively from the atria through the atrioventricular (AV) valves into the ventricles Signup and view all the answers

The second heart sound is heard during which phase of the cardiac cycle?

Isovolumetric relaxation Signup and view all the answers

Which of the following would cause a DECREASE in cardiac output (CO)?

Decreasing thyroid function (thyroxine) Signup and view all the answers

Which of the following INCREASES stroke volume?

Exercise Signup and view all the answers

What best describes afterload?

Back pressure exerted by arterial blood Signup and view all the answers

As your skeletal muscles contract during physical activity, what happens to preload?

Preload would be increased, which would result in a larger cardiac output Signup and view all the answers

Increasing end-diastolic volume (EDV) or end-systolic volume (ESV) will increase stroke volume.

False Signup and view all the answers

Which of the following descriptions of cardiac pacemaker cells is INCORRECT?

Rapid depolarization is due to Na+ influx Signup and view all the answers

What could hypercalcemia cause?

Prolonged T wave Signup and view all the answers

Which of the following cannot trigger tachycardia?

Increased vagal tone Signup and view all the answers

What does a patent ductus arteriosus permit?

Blood to flow from the aorta into the pulmonary trunk Signup and view all the answers

What does the Frank-Starling Law state?

A higher end diastolic volume will produce a higher stroke volume Signup and view all the answers

What is the expected heart rate when a heart is removed from a living body?

100 beats / minute Signup and view all the answers

What is a correct statement about cardiac output?

A slow heart rate increases end diastolic volume, stroke volume, and force of contraction. Signup and view all the answers

If the vagal nerves to the heart were cut, the result would be that ______.

The heart rate would increase by about 25 beats per minute Signup and view all the answers

How does norepinephrine act on the heart?

Causing threshold to be reached more quickly Signup and view all the answers

What is cardiac reserve?

Difference between resting and maximal cardiac output Signup and view all the answers

What does bradycardia mean?

An abnormally slow heart rate Signup and view all the answers

What does vagal tone refer to?

Heart rate at rest under both autonomic divisions signaling Signup and view all the answers

What happens during hemorrhage with a large loss of blood?

A lowering of blood pressure due to change in cardiac output Signup and view all the answers

Which of the following is NOT an age-related change affecting the heart?

Thinning of the valve flaps Signup and view all the answers

When released in large quantities, thyroxine causes a sustained increase in heart rate.

True Signup and view all the answers

If blood volume decreased dramatically due to massive bleeding, the autonomic nervous system will attempt to maintain cardiac output by increasing the heart rate.

True Signup and view all the answers

Suppose a patient develops a myocardial infarction that disables the sinoatrial node. Would the heart still pump blood to the aorta and the pulmonary trunk?

True Signup and view all the answers

What structure is most responsible for the synchronized contraction of cardiac muscle tissue?

Gap junctions Signup and view all the answers

Trace the pathway of stimulation through the heart. Which of these pathways shows stimulation in the correct order?

AV node, AV bundle, interventricular septum, subendocardial conducting network Signup and view all the answers

Study Notes

Coronary Circulation and Cardiac Anatomy

Coronary circulation provides essential blood supply to the heart muscle.
The ligament arteriosum is a remnant of the ductus arteriosus, linked to fetal circulation.
Right ventricle is responsible for pumping blood into the pulmonary trunk.

Heart Structure

Auricles are ear-like flaps attached to the atria, aiding in expansion.
The interatrial septum divides the two atria, ensuring separate blood flow.
Pectinate muscles are specific to the atria, providing structural support.

Valvular Function

Atrioventricular (AV) valves prevent backflow into the atria during ventricular contraction; includes the tricuspid and mitral valves.
Semilunar valves (aortic and pulmonary) ensure blood does not flow back into the ventricles after ejection.
Chordae tendineae help maintain valve positions but do not actively open AV valves.

Cardiac Cycle

Stroke volume calculation is key: subtract end-systolic volume (ESV) from end-diastolic volume (EDV).
Ventricular systole occurs when pressure in the ventricles rises, ejecting blood into the aorta and pulmonary artery.
Isovolumetric contraction phase features all valves closed while ventricles contract, raising pressure without volume change.

Electrical Activity

SA node serves as the natural pacemaker, initiating electrical impulses, followed by the AV node and subsequent pathways.
The QRS wave on an electrocardiogram (ECG) represents ventricular depolarization.
Abnormalities, such as enlarged atria or altered resting membrane potential, can indicate underlying heart issues.

Cardiac Output and Regulation

Cardiac output can increase due to factors like epinephrine or physical exercise.
Afterload refers to the resistance the heart must overcome to eject blood, influenced by arterial pressure.
Frank-Starling Law indicates that increased end-diastolic volume leads to higher stroke volume.

Heart Conditions and Responses

Myocardial infarctions commonly occur in the left ventricle due to its thicker muscle and higher workload.
Bradycardia describes a heart rate slower than normal, potentially harmful if severe.
Autonomic responses adjust heart rate based on blood volume changes or external stimuli such as hormones.

Miscellaneous Terms

Angina pectoris is pain due to reduced blood flow to cardiac tissue.
Fibrillation is described as chaotic heart muscle contractions, leading to ineffective pumping.
Cardiac reserve indicates the capacity for increased output beyond resting levels during physical activity.

Summary of Cardiovascular Dynamics

Blood flow dynamics involve continuous supply under varying heart states; contraction phases influence blood movement significantly.
Gap junctions in cardiac muscle tissue ensure synchronized contractions, essential for effective heart function.
Thyroxine can significantly impact heart rate when released in high quantities, leading to sustained increases.

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Test your knowledge of the heart's anatomy with these flashcards focusing on coronary circulation, ligaments, and heart chambers. Ideal for students studying human anatomy or preparing for exams.