NEET 2025 MCQ with Answer Explanation : “Body fluid and Circulation”.

Here below some basic MCQ’s about “Body fluid and circulation” with answer which is explained in details. Let’s check one by one which is given below.

MCQ 1:
Which of the following is the primary component of blood?

A) Plasma
B) White blood cells
C) Platelets
D) Red blood cells

Answer: A) Plasma

Explanation: Plasma makes up about 55% of blood volume and is primarily composed of water, electrolytes, proteins, and other substances. While red blood cells, white blood cells, and platelets are important, they are present in smaller proportions compared to plasma.

MCQ 2:
What is the role of hemoglobin in the blood?

A) Clotting
B) Oxygen transport
C) Immune response
D) Nutrient transport

Answer: B) Oxygen transport

Explanation: Hemoglobin is a protein in red blood cells that binds to oxygen in the lungs and carries it to tissues throughout the body. While it plays a minor role in carbon dioxide transport, its primary function is oxygen transport.

MCQ 3:
Which type of blood vessel carries oxygenated blood away from the heart?

A) Veins
B) Arteries
C) Capillaries
D) Lymphatic vessels

Answer: B) Arteries

Explanation: Arteries carry oxygenated blood away from the heart to the body (with the exception of the pulmonary arteries, which carry deoxygenated blood to the lungs). Veins carry deoxygenated blood back to the heart.

MCQ 4:
The cardiac cycle includes which of the following phases?

A) Systole and diastole
B) Inspiration and expiration
C) Contraction and relaxation
D) A and C

Answer: D) A and C

Explanation: The cardiac cycle consists of systole (the contraction phase) and diastole (the relaxation phase). Together, these phases allow for the pumping of blood through the heart and circulation.

MCQ 5:
Which hormone is primarily responsible for regulating blood pressure?

A) Insulin
B) Adrenaline
C) Aldosterone
D) Estrogen

Answer: C) Aldosterone

Explanation: Aldosterone is a hormone produced by the adrenal glands that helps regulate blood pressure by increasing sodium and water reabsorption in the kidneys, thereby increasing blood volume. Adrenaline can affect heart rate but is not the primary regulator of blood pressure.

MCQ 6:
Which of the following is the largest component of blood?

A) Red blood cells
B) White blood cells
C) Plasma
D) Platelets

Answer: C) Plasma

Explanation: Plasma constitutes about 55% of blood volume, making it the largest component, while red blood cells, white blood cells, and platelets make up the remaining 45%.

MCQ 7:
What is the main function of platelets?

A) Oxygen transport
B) Blood clotting
C) Immune response
D) Nutrient transport

Answer: B) Blood clotting

Explanation: Platelets are small cell fragments that play a crucial role in hemostasis, the process of blood clotting, preventing excessive bleeding when injuries occur.

MCQ 8:
What component of blood is responsible for transporting carbon dioxide?

A) Hemoglobin
B) Plasma
C) White blood cells
D) Fibrinogen

Answer: A) Hemoglobin

Explanation: Hemoglobin can bind to carbon dioxide as well as oxygen, transporting CO2 from tissues back to the lungs for exhalation.

MCQ 9:
Which part of the heart receives deoxygenated blood from the body?

A) Left atrium
B) Right atrium
C) Left ventricle
D) Right ventricle

Answer: B) Right atrium

Explanation: The right atrium receives deoxygenated blood from the body via the superior and inferior vena cavae.

MCQ 10:
The heart is divided into how many chambers?

A) Two
B) Three
C) Four
D) Five

Answer: C) Four

Explanation: The human heart has four chambers: two atria (left and right) and two ventricles (left and right).