1.
Where does hematopoiesis takes place?
Correct Answer
A. Bone marrow
Explanation
Hematopoiesis is the process of producing new blood cells. It primarily takes place in the bone marrow, which is a soft tissue found inside the bones. The bone marrow contains stem cells that can differentiate into different types of blood cells, including red blood cells, white blood cells, and platelets. The liver, kidney, and lungs do not play a significant role in hematopoiesis.
2.
Which of these is not a kind of blood cell?
Correct Answer
B. Hepatocyte
Explanation
The correct answer is Hepatocyte. Hepatocytes are liver cells and are not a type of blood cell. Erythrocytes are red blood cells, leukocytes are white blood cells, and thrombocytes are platelets, all of which are types of blood cells.
3.
What is the process by which red blood cells are produced?
Correct Answer
A. Erythropoiesis
Explanation
Erythropoiesis is the process by which red blood cells are produced. It takes place in the bone marrow and is regulated by the hormone erythropoietin. During erythropoiesis, stem cells in the bone marrow differentiate into red blood cells. This process involves several stages, including the loss of the nucleus and other organelles, the synthesis of hemoglobin, and the formation of a biconcave shape. Erythropoiesis is essential for maintaining adequate oxygen levels in the body and is regulated by various factors, such as oxygen levels, iron availability, and hormonal signals.
4.
Which of these is not a lymphocyte?
Correct Answer
C. Helper cells
Explanation
"Helper cells" is not a specific type of lymphocyte. Instead, helper cells, also known as helper T-cells, are a subset of T-cells that play a critical role in the immune system by assisting other immune cells in their functions. The other options, T-cells, B-cells, and natural killer cells, are all types of lymphocytes.
5.
Which of these negatively alter the genetic expression of hematopoietic factors?
Correct Answer
A. Mutation
Explanation
Mutations can negatively alter the genetic expression of hematopoietic factors. Mutations are changes in the DNA sequence that can result in the production of abnormal proteins or the loss of normal protein function. In the context of hematopoietic factors, mutations can disrupt the normal regulation of gene expression, leading to abnormal production or function of these factors. This can have detrimental effects on the development and function of blood cells, potentially leading to disorders such as leukemia or anemia.
6.
Which of these refers to mature red blood cells?
Correct Answer
D. Erythrocytes
Explanation
Erythrocytes are mature red blood cells. They are responsible for carrying oxygen throughout the body and removing carbon dioxide. Erythrocytes have a unique biconcave shape that allows them to efficiently transport oxygen. They lack a nucleus and other organelles, making more space for hemoglobin, the protein that binds to oxygen. Erythrocytes have a lifespan of about 120 days before being removed by the spleen. They are constantly produced in the bone marrow to maintain a stable number in the bloodstream.
7.
Which of these is not part of the lymphatic system?
Correct Answer
D. Bone marrow
Explanation
The lymphatic system is a network of tissues, organs, and vessels that help to remove toxins, waste, and other unwanted materials from the body. The liver, spleen, and lymph nodes are all part of the lymphatic system as they play a role in filtering and cleansing the lymph fluid. However, the bone marrow is not part of the lymphatic system. It is responsible for producing red and white blood cells, but it does not directly participate in the filtration or transportation of lymph fluid.
8.
Which of these cells is concerned with clotting?
Correct Answer
B. Thrombocytes
Explanation
Thrombocytes, also known as platelets, are the cells responsible for clotting. When there is an injury or damage to a blood vessel, thrombocytes gather at the site and form a plug to stop bleeding. They release chemicals that help in the formation of a blood clot, preventing excessive blood loss and promoting healing. Lymphocytes, leucocytes, and hepatocytes are not directly involved in clotting.
9.
Which of these refers to the death of hematopoietic cells?
Correct Answer
A. Necrosis
Explanation
Necrosis refers to the death of hematopoietic cells. Necrosis is a type of cell death that occurs due to external factors such as injury, infection, or toxins. It is characterized by cell swelling, rupture, and inflammation. In the context of hematopoietic cells, necrosis can occur due to various factors such as ischemia, radiation, or certain diseases. Unlike apoptosis, which is a programmed cell death that occurs naturally as part of normal cellular processes, necrosis is an uncontrolled and pathological cell death. Proliferation refers to the rapid multiplication of cells, while erythropoiesis is the process of formation of red blood cells.
10.
Which of these is irrelevant to hematopoiesis?
Correct Answer
D. Second messenger mechanism
Explanation
Hematopoiesis is the process of blood cell formation. Growth factors play a crucial role in regulating hematopoiesis by stimulating the proliferation and differentiation of blood cells. Cell fate determination is also relevant as it determines the specific lineage and type of blood cell that will be produced. Transcription factors are essential for regulating gene expression and controlling the differentiation of blood cells. However, the second messenger mechanism is not directly involved in hematopoiesis. It is a signaling pathway that transmits signals from cell surface receptors to the inside of the cell, but it does not directly influence the process of blood cell formation.