Heart & Cardiovascular System Anatomy Exam Review

Blood passes from the right atrium to the right ventricle through the tricuspid valve. The tricuspid valve is located between the right atrium and the right ventricle and consists of three flaps or cusps. When the right atrium contracts, the tricuspid valve opens, allowing blood to flow into the right ventricle. When the right ventricle contracts, the tricuspid valve closes to prevent blood from flowing back into the atrium. This one-way flow of blood ensures efficient circulation and prevents backflow.

The correct answer is a) pericardium. The pericardium is the membrane that surrounds and protects the heart. It is a double-layered sac that contains a fluid-filled space between the layers, which helps to reduce friction as the heart beats. The pericardium also helps to hold the heart in place within the chest cavity and protects it from external forces. The other options (b) pleura, (c) myocardium, (d) mediastinum, and (e) endocardium do not refer to the membrane that surrounds and protects the heart.

The myocardium is the middle layer of the heart wall and is composed of cardiac muscle tissue. This layer is responsible for the contraction and relaxation of the heart, allowing it to pump blood throughout the body. The myocardium is thicker in the left ventricle compared to the right ventricle, as the left ventricle needs to generate more force to pump blood to the rest of the body.

The apex of the heart is normally pointed to the left of the midline. This is because the heart is located slightly to the left side of the chest, so its apex naturally points towards the left. This positioning allows for efficient pumping of blood to the rest of the body.

The correct answer is d) SA node, AV node, Bundle of His, Purkinje fibers. The sequence of structures that a cardiac action potential follows in order to excite normal contraction of the heart is as follows: The impulse starts at the sinoatrial (SA) node, which is the natural pacemaker of the heart. From there, it travels to the atrioventricular (AV) node, which acts as a gateway to the ventricles. The impulse then passes through the Bundle of His, which is a specialized pathway that conducts the electrical signals to the ventricles. Finally, the impulse spreads through the Purkinje fibers, which are specialized muscle fibers that cause the ventricles to contract.

The right atrium and right ventricle of the heart contain deoxygenated blood. The right atrium receives deoxygenated blood from the body through the superior and inferior vena cava, and then it contracts to pump the blood into the right ventricle. The right ventricle then pumps the deoxygenated blood to the lungs for oxygenation.

During the cardiac cycle, the term "systole" refers to the period of time when a chamber of the heart contracts and the pressure within the chamber rises. This is a crucial phase as it allows for the ejection of blood from the chamber into the arteries. The other options, such as filling, repolarization, diastole, and fibrillation, do not specifically describe this particular phase of contraction and pressure increase.

The left ventricle is surrounded by the thickest layer of myocardium because it is responsible for pumping oxygenated blood to the rest of the body. This chamber has to generate a greater force to push the blood out into the systemic circulation, which requires a thicker layer of myocardium for stronger contractions.

Pericardial fluid is used to reduce friction between the layers of membranes surrounding the heart. This fluid acts as a lubricant, allowing the membranes to slide smoothly over each other during the heart's contractions and relaxations. This helps to prevent damage to the heart and allows it to function properly.

Stimulation of the vagus nerve reduces heart rate. The vagus nerve is a cranial nerve that plays a significant role in regulating the parasympathetic nervous system. When stimulated, the vagus nerve releases acetylcholine, which slows down the heart rate by inhibiting the electrical activity of the heart. This is why the correct answer is d) Vagus nerve.

Blood leaving the left ventricle is pumped into the aorta, which is the largest artery in the body. The aortic semilunar valve is located between the left ventricle and the aorta, and it prevents the backflow of blood into the ventricle. Therefore, the correct answer is d) Aortic semilunar valve.

An increase in carbon dioxide levels in the blood is detected by chemoreceptors located in the medulla oblongata. The medulla oblongata is responsible for regulating involuntary functions such as heart rate and breathing. When carbon dioxide levels rise, the medulla oblongata sends signals to increase the heart rate in order to deliver more oxygen to the body's tissues. Therefore, the medulla oblongata is the part of the brain that would receive this input and regulate heart rate.

The T wave in an electrocardiogram represents repolarization of the ventricles. During repolarization, the ventricles are resetting and preparing for the next heartbeat. This wave is typically a small, rounded wave that follows the QRS complex. The T wave is important in assessing the overall health and function of the heart, as abnormalities in its shape, size, or timing can indicate underlying cardiac conditions.

The volume of blood ejected from the left ventricle into the aorta each minute is called the cardiac output. This is the amount of blood that is pumped out of the heart and circulated throughout the body in one minute. It is an important measure of the heart's efficiency and is influenced by both the stroke volume (the amount of blood ejected with each heartbeat) and the heart rate (the number of times the heart beats per minute). Therefore, the correct answer is a) cardiac output.

The visceral layer of the serous pericardium is considered to be the epicardium because the epicardium is the outermost layer of the heart wall and is also known as the visceral layer of the serous pericardium. It is a thin, transparent layer that covers the surface of the heart and is composed of connective tissue and a layer of mesothelial cells.

The correct answer is c) heart rate multiplied by stroke volume. Cardiac output is the amount of blood pumped by the heart per minute. It is calculated by multiplying the heart rate (number of heartbeats per minute) by the stroke volume (volume of blood pumped by the heart with each beat). This formula represents the relationship between heart rate and stroke volume in determining cardiac output.

Athletes tend to have higher cardiac reserves because their hearts operate more efficiently due to training. Regular exercise and training can strengthen the heart muscle, improve its ability to pump blood, and increase its overall efficiency. This leads to a higher cardiac reserve, which means that the heart can pump more blood and supply more oxygen to the muscles during intense physical activity. This increased efficiency allows athletes to perform at higher levels and endure longer periods of exercise without experiencing fatigue or cardiovascular strain.

The sinoatrial (SA) node is known as the natural pacemaker of the heart. It is responsible for initiating action potentials that stimulate contraction of the heart. The SA node is located in the upper part of the right atrium and generates electrical impulses at a constant rate of about 100 beats per minute, which sets the rhythm for the entire heart. This makes it the structure that initiates the heart's contraction at a constant rate.

The coronary artery is the blood vessel that is responsible for distributing oxygenated blood to the myocardium. The myocardium is the muscular tissue of the heart, and it requires a constant supply of oxygen to function properly. The coronary artery branches off from the aorta and delivers oxygenated blood to the heart muscle. The other options, such as the coronary vein, coronary sinus, vena cava, and myocardial vein, do not play a role in distributing oxygenated blood to the myocardium.

Cardiac muscle fibers are electrically connected to neighboring fibers by gap junctions. Gap junctions are specialized protein channels that allow for the direct passage of ions and small molecules between adjacent cells. This allows for the rapid spread of electrical signals throughout the cardiac muscle, ensuring coordinated contraction of the heart. Desmosomes and tight junctions are types of cell junctions that provide mechanical strength and prevent leakage between cells, but they do not allow for electrical communication. Interneurons and chordae tendinae are not involved in the electrical connection between cardiac muscle fibers.

The groove found on the surface of the heart that marks the boundary between the right and left ventricles is called the anterior interventricular sulcus.

Cardiac tamponade is a condition where fluid accumulates in the pericardial sac, causing compression of the heart and impairing its ability to pump blood effectively. Pericarditis, inflammation of the pericardium, can lead to the development of cardiac tamponade. When the pericardium becomes inflamed, it can produce excess fluid, which can accumulate and lead to cardiac tamponade. Myocarditis (inflammation of the heart muscle), endocarditis (infection of the inner lining of the heart), palpitation (awareness of one's heartbeat), and tachycardia (abnormally fast heart rate) are not directly associated with the development of cardiac tamponade.

The valves of the heart are composed of dense connective tissue. This type of tissue is characterized by its high density of collagen fibers, which provide strength and support. The valves need to be strong and flexible in order to open and close properly and maintain the flow of blood in the heart. Dense connective tissue is well-suited for this role as it can withstand the constant pressure and movement of the heart.

The pulmonary semilunar valve prevents blood from flowing back into the right ventricle. This valve is located between the right ventricle and the pulmonary artery, and it opens to allow blood to flow from the right ventricle into the pulmonary artery and then to the lungs for oxygenation. After the blood is oxygenated, it returns to the heart and enters the left atrium, passing through the mitral valve to enter the left ventricle. Therefore, the pulmonary semilunar valve is responsible for ensuring that blood flows in one direction, preventing backflow into the right ventricle.

Trauma to the pericardium can cause bleeding into the pericardial cavity, leading to cardiac tamponade. Cardiac tamponade occurs when there is excessive fluid or blood accumulation in the pericardial sac, which compresses the heart and impairs its ability to pump effectively. This can result in decreased cardiac output and potentially life-threatening symptoms such as low blood pressure and decreased perfusion to vital organs. Myocarditis refers to inflammation of the heart muscle, endocarditis refers to inflammation of the inner lining of the heart, and rapid heart rate is a nonspecific symptom that can occur in various cardiac conditions.

The P wave represents atrial depolarization in an electrocardiogram (ECG). Depolarization refers to the electrical activation of the heart muscle, causing it to contract. In the case of the P wave, it represents the depolarization of the atria, which is the first step in the cardiac cycle. The other options (R wave, T wave, S wave, and Q wave) represent different phases of the cardiac cycle or depolarization/repolarization of other parts of the heart, but not specifically atrial depolarization.

The contractile fibers of the heart are depolarized for a longer period of time compared to skeletal muscle fibers. This is because the heart needs to maintain a constant and rhythmic contraction to pump blood effectively, while skeletal muscles only need to contract for short periods of time for movement.

The correct answer is d) Mediastinum. The mediastinum is the anatomical region found between the lungs. It extends from the sternum to the vertebral column and from the first rib to the diaphragm. It contains important structures such as the heart, major blood vessels, esophagus, trachea, and thymus gland.

Cardiac muscle contains the largest number of mitochondria per cell. Mitochondria are responsible for producing energy in the form of ATP, and cardiac muscle cells require a constant supply of energy to contract and pump blood throughout the body. Therefore, cardiac muscle cells have a high number of mitochondria to meet their energy demands.

The correct answer is d) Cardiac conduction system. The cardiac conduction system is a network of specialized cardiac muscle fibers that coordinate the electrical impulses that regulate the heartbeat. It includes the sinoatrial (SA) node, atrioventricular (AV) node, bundle of His, and Purkinje fibers. These structures ensure that each cycle of cardiac excitation progresses through the heart in a coordinated and efficient manner, allowing for the synchronized contraction of the atria and ventricles.

When the atria of the heart contract, blood moves from the atria into the ventricles. This movement of blood is facilitated by the atrioventricular valves, which open to allow the blood to flow from the atria into the ventricles. Therefore, the correct answer is d) through atrioventricular valves.

When the ventricles of the heart contract, blood is pumped out of the heart and into the arteries. The arteries are responsible for carrying oxygenated blood away from the heart and to the rest of the body. Therefore, the correct answer is a) into arteries.

The patient's symptoms, including fever, heart murmur, irregular heartbeat, fatigue, loss of appetite, and night sweats, are consistent with endocarditis. Endocarditis is an infection of the inner lining of the heart, typically caused by bacteria. The other options, such as a virus, autoimmune condition, exposure to radiation, or cancer, are not commonly associated with endocarditis. Therefore, the most likely diagnosis in this case would be endocarditis caused by a bacterial infection.

The difference between a person's maximum cardiac output and resting cardiac output is called the cardiac reserve. Cardiac reserve refers to the ability of the heart to increase its output in response to increased demand, such as during exercise or stress. It represents the additional capacity of the heart to pump more blood when needed. Stroke volume, peripheral resistance, afterload, and venous return are all related to cardiac function but do not specifically refer to the difference between maximum and resting cardiac output.

The foramen ovale is a hole in the fetal heart that allows blood to bypass the lungs. During fetal life, the lungs are not yet functional, so oxygenation of the blood occurs through the placenta. The foramen ovale acts as a shunt, allowing oxygenated blood from the placenta to bypass the non-functioning lungs and flow directly from the right atrium into the left atrium. This oxygenated blood is then pumped out to the rest of the body. After birth, when the lungs become functional, the foramen ovale closes, redirecting blood flow through the pulmonary circulation.

During ventricular systole, the ventricles of the heart contract, forcing blood out of the heart and into the arteries. This is the period when the largest volume of blood enters the arteries. Atrial diastole is the period when the atria are relaxed and filling with blood, but this blood has not yet been pumped into the arteries. Ventricular diastole is the period when the ventricles are relaxed and filling with blood, but again, this blood has not yet been pumped into the arteries. Atrial systole is the period when the atria contract, but only a small amount of blood is pumped into the ventricles. Therefore, the correct answer is d) ventricular systole.

The second heart sound (dupp) closely follows the closing of the semilunar valves. This sound is produced when the aortic and pulmonary valves close, preventing the backflow of blood into the ventricles. The closure of these valves marks the end of ventricular systole and the beginning of diastole. The sound is heard as a low-pitched "dubb" sound and can be auscultated during the second heart sound.

The correct answer is a) Pectinate muscles. Pectinate muscles are muscular ridges that are found on the anterior wall of the right atrium and extend into the auricles. They are responsible for increasing the surface area of the atrium, allowing for more efficient contraction and blood flow. Trabeculae carneae are found in the ventricles, not the atrium. Coronary sulci are grooves on the surface of the heart that contain blood vessels. Papillary muscles and chordae tendinae are structures found in the ventricles that help to anchor the atrioventricular valves.

Increased preload, decreased afterload, and increased contractility would all lead to increased stroke volume. Preload refers to the amount of blood that fills the ventricles during diastole, and increasing preload would lead to a greater stretch of the ventricles and a more forceful contraction during systole, resulting in increased stroke volume. Decreased afterload, which is the resistance the ventricles must overcome to eject blood, would also allow for a more efficient ejection of blood and increased stroke volume. Finally, increased contractility, or the strength of the ventricular contraction, would directly lead to an increase in stroke volume.

Increased potassium levels in plasma can lead to a decreased heart rate because high levels of potassium can disrupt the electrical signals in the heart, causing it to beat more slowly. This condition is known as hyperkalemia and can result in bradycardia, or a slow heart rate.

During heart transplants, the vagus nerves are severed resulting in a faster resting heart rate (approximately 100 beats per minute) after the transplant. The vagus nerves are responsible for regulating the heart rate and when they are severed, the heart loses some of its ability to slow down the heart rate. This leads to a faster resting heart rate after the transplant.

Heart murmurs are abnormal sounds that are heard during a heartbeat and are often associated with abnormalities in the valves of the heart. The valves in the heart play a crucial role in regulating blood flow by opening and closing to allow blood to flow in the correct direction. When there are abnormalities in the valves, such as stenosis or regurgitation, it can disrupt the normal flow of blood and create turbulence, resulting in the characteristic sound of a heart murmur. Therefore, it is common to hear heart murmurs in individuals with valve abnormalities.

Positive inotropic agents increase the contractility of the heart by promoting the inflow of calcium ions. Calcium plays a crucial role in the contraction of cardiac muscle cells. When calcium enters the cells, it binds to specific proteins, triggering a series of events that lead to the contraction of the heart muscle. Therefore, an increase in the inflow of calcium ions enhances the force of contraction, resulting in increased contractility of the heart.

During the isovolumetric contraction phase of the cardiac cycle, the ventricles contract and their pressure increases. However, the ventricular volume remains the same because both the atrioventricular valves and semilunar valves are closed, preventing any blood from entering or leaving the ventricles. This phase allows for the build-up of pressure within the ventricles before the semilunar valves open and blood is ejected into the systemic circulation during ventricular ejection.

The structure found in a fetus that allows blood to flow directly from the pulmonary trunk into the aorta is the ductus arteriosus. This is a temporary blood vessel that connects the pulmonary artery to the descending aorta, bypassing the lungs. The ductus arteriosus is essential in the fetal circulatory system because the lungs are not yet functioning, and it allows oxygenated blood from the placenta to bypass the non-functioning lungs and go directly to the body. After birth, the ductus arteriosus typically closes and becomes a ligament.

The pectinate muscles extend from the atrial internal wall into the pouch-like structures that increase the total filling capacity of the atrium. These structures are known as auricles.

Ventricular ejection occurs when the semilunar valves are open, allowing blood to be ejected from the ventricles into the arteries. It lasts for about 0.25 seconds. During ventricular ejection, the atrioventricular valves are closed to prevent backflow of blood into the atria.

Cardiomyoplasty is a corrective cardiac procedure in which a large piece of the patient's own latissimus dorsi muscle is wrapped around the heart and stimulated by an implanted pacemaker to assist the pumping action of a damaged heart. This procedure is used to improve the pumping function of the heart in patients with heart failure.

A well-trained athlete will usually have a higher cardiac reserve, meaning their heart can pump more blood during exercise. They will also have a higher stroke volume, meaning their heart can pump more blood with each beat. Additionally, they may experience hypertrophy of the heart, which is an increase in the size and strength of the heart muscle. Resting bradycardia refers to a slower resting heart rate, which can be a characteristic of a well-trained athlete. However, a higher resting cardiac output is not typically seen in well-trained athletes. This is because their heart is more efficient at pumping blood, so it does not need to work as hard at rest.

The limbic system is responsible for regulating emotions and behavior. It sends nerve impulses to the cardiovascular center of the medulla oblongata, which in turn increases the heart rate in anticipation of physical activity. This is because the limbic system is involved in the activation of the "fight or flight" response, preparing the body for action. The cerebral cortex, hypothalamus, baroreceptors, and proprioceptors are not directly involved in this anticipatory increase in heart rate.