Circulatory System — Set 2
Biology · परिसंचरण तंत्र · Questions 11–20 of 50
Which metal ion is essential for the process of blood clotting?
Correct Answer: C. Calcium
Calcium ions (Ca2+) act as a vital cofactor in the complex chemical cascade of blood coagulation. They help convert prothrombin into thrombin, which is necessary for forming a clot. Without sufficient calcium, blood fails to thicken properly at injury sites.
The rhythmic contraction and expansion of arteries felt at the wrist is called?
Correct Answer: D. Pulse
The pulse is the physical expansion of an artery caused by the surge of blood from the heart. It is most commonly measured at the radial artery in the wrist. A resting pulse rate for adults is usually between 60 and 100 beats per minute.
Which blood vessel carries oxygenated blood from the lungs back to the heart?
Correct Answer: D. Pulmonary vein
The pulmonary veins are the only veins in the human body that carry oxygen-rich blood. They deliver this blood from the lungs directly into the left atrium. There are typically four such veins in a healthy adult.
Which of the following is an iron-rich protein that helps in the transport of oxygen?
Correct Answer: D. Hemoglobin
Hemoglobin is found inside red blood cells and binds with oxygen molecules. It gives blood its characteristic red color when oxygenated. A deficiency of this protein leads to a condition known as anemia.
The state of the heart when it is relaxed and filling with blood is known as?
Correct Answer: B. Diastole
Diastole is the phase of the cardiac cycle when the heart muscles relax to allow the chambers to fill. This phase occurs between heartbeats. It is reflected as the lower number in a blood pressure reading.
Which system of the body returns excess tissue fluid back into the bloodstream?
Correct Answer: D. Lymphatic system
The lymphatic system acts as a secondary drainage system for the body. It collects 'lymph' fluid and filters it through nodes before returning it to the blood. This process is essential for maintaining fluid balance and immune function.
What is the scientific name for the red blood cells?
Correct Answer: C. Erythrocytes
Erythrocytes are the most numerous cells in the blood and lack a nucleus at maturity. Their biconcave shape increases the surface area for efficient gas exchange. They are produced in the red bone marrow of large bones.
Which of the following blood vessels have valves to prevent the backflow of blood?
Correct Answer: B. Veins
Veins contain one-way valves that assist in moving blood toward the heart against gravity. These valves are particularly important in the lower limbs. Failure of these valves can lead to conditions like varicose veins.
The hepatic portal vein carries blood from the digestive tract to which organ?
Correct Answer: C. Liver
The hepatic portal system allows the liver to process nutrients and toxins before they enter the general circulation. This organ acts as a chemical processing plant for the body. It is a vital step in human metabolism and detoxification.
Which vitamin is essential for the synthesis of blood clotting factors in the liver?
Correct Answer: A. Vitamin K
Vitamin K is required by the liver to produce several proteins needed for blood coagulation. A deficiency in this vitamin can lead to excessive bleeding after a minor injury. It is naturally produced by beneficial bacteria in the human intestine.