Cardiovascular system - Quiz

Serum is the liquid portion of the blood that remains after the blood has clotted and the clot has been removed. It is similar to plasma but without the clotting factors such as fibrinogen. This makes serum useful in many laboratory tests, as it provides a clear sample for analysis. On the other hand, plasma is the liquid part of blood that contains all the blood components, including red blood cells, white blood cells, platelets, and proteins such as albumin, globulin, and fibrinogen. Understanding the differences between serum and plasma is important in the diagnosis and treatment of various diseases and conditions.

Hemopoiesis is the process of forming blood cells and begins in the yolk sac during embryonic development. As the fetus develops, the process also occurs in other organs such as the liver, spleen, thymus, and lymph nodes. However, the yolk sac is the primary site of hemopoiesis in the early stages of embryonic development.

Thalassemia is a type of hemolytic anemia that results from a genetic defect that leads to the destruction of a large number of red blood cells. In thalassemia, the body is unable to produce enough hemoglobin, a protein that carries oxygen in the blood. As a result, the red blood cells become fragile and easily destroyed, leading to anemia. There are two main types of thalassemia, alpha and beta thalassemia, depending on which part of the hemoglobin molecule is affected. The severity of thalassemia can vary, from mild to life-threatening, depending on the number of defective genes inherited. Treatment may include blood transfusions, bone marrow transplants, or medications to remove excess iron from the body.

Angiology is the branch of medicine that deals with the study of the lymphatic and circulatory systems, including the arteries, veins, and lymphatic vessels. It involves the diagnosis and treatment of various illnesses related to these systems, including conditions like varicose veins, blood clots, and lymphedema. Angiologists are medical specialists who specialize in this field and use a variety of diagnostic tools to evaluate and treat patients with circulatory system disorders. Other related fields include cardiology, which focuses on the heart, and hematology, which focuses on blood disorders. Osteology, on the other hand, is the study of bones and skeletal tissues, and is not directly related to the circulatory system.

The correct answer is option C, the Sinus Node, which is also known as the natural pacemaker of the heart. The sinus node is a cluster of myocytes that act as pacemakers, initiating the heart's contractions. The sinus node can generate approximately 70 to 75 action potentials each minute, which trigger the heart muscles to contract.
The Purkinje fibers, option A, are a network of specialized cardiac muscle fibers that relay electrical impulses from the AV node to the ventricles. The AV node, option B, is a region of the heart that slows down the electrical signal coming from the atria before passing it on to the ventricles. The Bundle of His, option D, is a collection of fibers that transmits the electrical impulses from the AV node to the ventricles.

The aorta is the largest artery in the human body and originates from the left ventricle of the heart. It carries oxygenated blood from the heart to the rest of the body. The coronary arteries supply oxygenated blood to the heart muscles, while the pulmonary artery carries deoxygenated blood from the right ventricle of the heart to the lungs for oxygenation. The blood in the pulmonary artery is low in oxygen and high in carbon dioxide. The pulmonary veins return oxygenated blood from the lungs to the left atrium of the heart. Any obstruction in the coronary arteries can cause a heart attack.

The heart contains four valves that work as doors to regulate the blood flow between the chambers of the heart. These valves open and close in sync with the heartbeat to ensure the proper direction of blood flow. The two atrioventricular (AV) valves located between the upper and lower heart chambers prevent the backflow of blood from the ventricles to the atria during contractions. The two semilunar valves located between the ventricles and arteries prevent the backflow of blood from the arteries to the ventricles during relaxation. These valves are crucial for the proper functioning of the heart and to maintain healthy circulation throughout the body.

Blood clotting is initiated by the activation of several clotting factors, which are in turn activated by calcium. Thus, calcium is the mineral ion that plays the main role in blood clotting. In the absence of sufficient calcium, the clotting process may be impaired, leading to excessive bleeding. It is important to note that excessive calcium can also lead to abnormal clotting, so maintaining a proper balance of calcium in the blood is crucial for proper clotting function.

Adrenaline or epinephrine is a hormone produced by the adrenal glands that acts on the sympathetic nervous system to increase heart rate, contractility, and oxygen consumption of the heart. Adrenaline has a positive inotropic effect, which means it increases the force of contraction of the heart. Adrenaline also increases the heart rate, or the number of beats per minute. However, adrenaline does not decrease the myocardial irritability. Rather, it increases the irritability or excitability of the myocardium, which can lead to arrhythmias or irregular heartbeats. Therefore, option (c) is incorrect.

The middle cardiac vein is a vein that runs along the posterior interventricular sulcus on the heart and drains blood from the back of the heart. However, it does not open directly into the right atrium like most veins in the heart. Instead, it empties into the larger coronary sinus, which then opens into the right atrium. The anterior cardiac vein drains the front of the heart and opens directly into the right atrium, while the superior vena cava drains blood from the upper body and also opens into the right atrium. Therefore, the correct answer is option A, the middle cardiac vein, as it does not open directly into the right atrium.