Cardiovascular system - Quiz

Blood transports various components throughout the body, including hormones, oxygen, carbon dioxide, nutrients, and waste products. However, heat is not transported by blood. Heat is mainly transferred through conduction, convection, and radiation. Blood plays a crucial role in maintaining the body's homeostasis and provides the necessary nutrients and oxygen to various organs and tissues. Lymph, on the other hand, is not transported by blood. It has its own set of vessels, and it helps in removing excess fluid and waste products from the tissues.

Hematocrit is the term used to define the amount or percentage of red blood cells (RBCs) present in the blood. It is typically expressed as a percentage, such as 40%, which means that 40% of the volume of blood is occupied by RBCs. Hemoglobin is a protein found in RBCs that carries oxygen, while hemopoiesis is the process of blood cell formation. Myoglobin is a protein found in muscle tissue that helps store and transport oxygen within muscle cells.

Aplastic anemia is a rare condition in which the bone marrow fails to produce enough red blood cells, white blood cells, and platelets. This can occur due to toxic chemicals, radiation, certain medications, or viral infections. Without enough red blood cells, the body cannot get enough oxygen, leading to fatigue, weakness, and shortness of breath. Treatment options may include blood transfusions, medications to stimulate blood cell production, or a bone marrow transplant.

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.

A closed-type circulatory system is a system in which blood is pumped through a continuous network of vessels. Among the given options, only fish belong to the phylum Chordata which has a closed circulatory system. In contrast, phylum Arthropoda and Mollusca have an open circulatory system. Cockroaches and scorpions belong to the class Insecta phylum Arthropoda, which means they have an open circulatory system. Fishes have a two-chambered heart and a closed circulatory system that pumps blood through the gills to oxygenate it before circulating it through the rest of the body. The closed circulatory system enables fish to have a more efficient and higher-pressure circulatory system than animals with an open circulatory system.

The correct answer is option A, 250- 300 gm. The size of the human heart is roughly the same as a clenched fist. An adult human heart usually weighs between 250 to 350 gm, making up approximately 0.45% of the total weight of the body. However, the weight of the heart can vary slightly based on an individual's physical size and sex.
Option B, 250- 350 gm, is close to the actual weight of the human heart, but the range is slightly larger than the typical weight range. Option C, 350- 450 gm, and option D, 300- 400 gm, are outside the typical weight range of the human heart.

The correct answer is option D, Bone Marrow. Bone Marrow is a soft tissue found inside the medullary cavities of bones, primarily in the hip and thigh bones. It generates immature cells called stem cells that can develop into various types of cells later on. There are two types of stem cells: mesenchymal and hematopoietic. While mesenchymal cells develop into fat, cartilage, and bones, hematopoietic cells develop and turn into blood cells, including red blood cells (RBCs), white blood cells (WBCs), and platelets.
Options A, Heart, B, Lymph Nodes, and C, Liver, are not involved in the production of red blood cells. The heart is a muscular organ that pumps blood throughout the body, lymph nodes are small bean-shaped structures that help filter lymph fluid and fight infections, and the liver is a large organ that produces bile and plays a role in detoxification and metabolism.

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.

Blood platelets, also known as thrombocytes, are small, disc-shaped cells that are essential for blood clotting. When a blood vessel is damaged, platelets rush to the site of injury and stick to the damaged area, forming a plug to stop the bleeding. This process is called hemostasis and is crucial for preventing excessive blood loss. Platelets also release chemicals that attract other clotting factors to the site of injury, leading to the formation of a stable clot. Therefore, the primary function of platelets is to aid in the coagulation of blood.
While platelets play a role in the immune response by releasing chemicals that attract white blood cells to the site of infection or inflammation, they do not ingest bacteria. Additionally, platelets do not carry hemoglobin or transport CO2, which are functions performed by red blood cells.