Problem 83 - Objective Biology for NEET

Question

During diastole, blood (a) Enters the heart (b) Leaves the heart (c) Leaves the ventricle (d) Enters into lungs

Step-by-Step Solution

Answer

During the diastole phase, blood 'Enters the heart'. So, the correct answer is option (a).

Step 1: Understanding Diastole phase

In the diastole phase of the heart cycle, the heart relaxes after contraction (systole) allowing the chambers to fill with blood. Thus, it helps in preparing the heart for the next contraction phase.

Step 2: Matching Diastole phase with options

Now, relating this information with the options given, we can infer that during diastole, blood 'Enters the heart' since the chambers are filling up with blood in this phase. So, option (a) is the correct answer.

Step 3: Final Check

It's important to cross-verify with other options to make sure our answer is correct. Here, options (b), (c) and (d) describes activities that generally happen after the diastole phase so they can be eliminated.

Key Concepts

Heart Cycle

The heart cycle is a continuous process that keeps blood moving throughout the body. It consists of two main phases: systole and diastole. During systole, the heart contracts to pump blood out into the arteries. This is followed by the diastole phase, where the heart muscles relax and allow blood to fill the cardiac chambers. This cycle ensures that oxygen-rich blood flows to vital organs and tissues, while carbon dioxide and waste are transported back to the lungs for expiration. The orderly sequence of contraction and relaxation is regulated by the heart's internal electrical system, ensuring that each chamber plays a timely role. This cycle repeats continuously to sustain life, underlining the heart's role as a relentless pump.

Blood Flow in Heart

Blood flow in the heart follows a precise path to ensure that oxygen and nutrients are delivered effectively throughout the body. Blood enters the heart through two large veins, the superior and inferior vena cava, emptying into the right atrium. From here, it moves to the right ventricle, which pumps it to the lungs via the pulmonary arteries for oxygenation. Oxygen-rich blood then returns to the heart through the pulmonary veins into the left atrium, and subsequently, it is pushed into the left ventricle. Finally, the left ventricle pumps the oxygenated blood out to the body through the aorta. This circulation is vital to maintain homeostasis and support metabolic processes.

Cardiac Chambers

The heart is composed of four main chambers that play a pivotal role in circulating blood. These chambers include the right atrium, right ventricle, left atrium, and left ventricle. The right atrium receives deoxygenated blood from the body and directs it to the right ventricle. The right ventricle then pumps the blood to the lungs for oxygenation. Meanwhile, the left atrium receives oxygen-rich blood from the lungs and transfers it to the left ventricle. The left ventricle is responsible for pumping the oxygenated blood into the systemic circulation through the aorta. Each chamber is separated by valves that ensure unidirectional flow and prevent backflow, highlighting their importance in maintaining efficient and effective heart function.