Circulatory System — Set 3
Biology · परिसंचरण तंत्र · Questions 21–30 of 50
What is the average lifespan of a human red blood cell?
Correct Answer: D. 120 days
The correct answer is '120 days'. Red blood cells circulate in the body for approximately four months. After this period, they are broken down in the spleen and liver. The iron from the old cells is recycled by the body to make new cells.
Which chamber of the heart receives deoxygenated blood from the entire body?
Correct Answer: B. Right atrium
The right atrium receives oxygen-poor blood through the superior and inferior vena cava. This blood is then pushed into the right ventricle. It marks the starting point of the pulmonary circulation cycle.
The smallest blood vessels where the exchange of gases and nutrients takes place are?
Correct Answer: B. Capillaries
Capillaries have extremely thin walls, often just one cell thick, to allow diffusion. They form vast networks throughout the body's tissues. This is the only site where blood truly interacts with individual body cells.
Which blood type is considered the 'Universal Recipient'?
Correct Answer: D. AB positive
AB positive blood contains both A and B antigens and the Rh factor. Consequently, the plasma does not contain antibodies against these antigens. A person with this blood type can safely receive blood from any other group.
Which hormone is produced by the kidneys to stimulate red blood cell production?
Correct Answer: B. Erythropoietin
Erythropoietin (EPO) is released by the kidneys when oxygen levels in the blood are low. It signals the bone marrow to increase the production of erythrocytes. This hormone is vital for adaptation to high altitudes.
The first successful human-to-human blood transfusion was performed by?
Correct Answer: B. James Blundell
James Blundell, a British obstetrician, performed the first successful human blood transfusion in 1818. Before his work, animal blood was often used with fatal results. This paved the way for modern transfusion medicine.
A decrease in the number of platelets in the blood is called?
Correct Answer: C. Thrombocytopenia
Thrombocytopenia can lead to symptoms like easy bruising and prolonged bleeding from small cuts. Platelets are essential for sealing damaged blood vessels. This condition can be caused by various medications or bone marrow disorders.
Which part of the brain controls the heart rate and blood pressure automatically?
Correct Answer: D. Medulla oblongata
The medulla oblongata contains the cardiovascular center that regulates autonomic functions. It adjusts the heart rate based on the body's physical activity and carbon dioxide levels. This ensures the brain receives a constant supply of blood regardless of body position.
The process by which the heart muscle itself receives blood is called?
Correct Answer: A. Coronary circulation
Coronary circulation involves the arteries and veins that supply the heart tissue with oxygen. Blockage in these specific arteries can lead to a heart attack. The heart uses a significant portion of the body's total oxygen supply.
Which of the following helps in maintaining the osmotic pressure of the blood?
Correct Answer: C. Albumin
Albumin is the most abundant protein in the blood plasma. It prevents water from leaking out of the blood vessels into the surrounding tissues. This balance is crucial for maintaining proper blood volume and pressure.