NEET Biology - Human Heart Cheat Sheet

Key Definitions

• Heart: A muscular organ that pumps blood through the circulatory system.

• Cardiac Cycle: The sequence of events in one heartbeat, including contraction (systole) and relaxation (diastole).

• Stroke Volume (SV): The amount of blood pumped by the heart in one contraction.

Important Formulas

• Cardiac Output (CO):

  CO = SV × HR
  

• CO = Cardiac Output (liters/min)

• SV = Stroke Volume (liters)

• HR = Heart Rate (beats/min)

Critical Concepts

• Chambers of the Heart:

• 4 chambers: Right atrium, Right ventricle, Left atrium, Left ventricle.

• Valves:

• Atrioventricular (AV) valves: Tricuspid (right), Mitral (left).

• Semilunar valves: Pulmonary (right), Aortic (left).

• Blood Flow Pathway:

• Deoxygenated blood → Right atrium → Right ventricle → Pulmonary artery → Lungs.

• Oxygenated blood → Left atrium → Left ventricle → Aorta → Body.

Common Mistakes to Avoid

• Confusing the right and left sides of the heart.

• Forgetting the direction of blood flow (deoxygenated vs. oxygenated).

• Misunderstanding the function of heart valves.

Quick Memory Tricks/Mnemonics

• "LARS":

• Left Atrium → Right Ventricle → Systemic circulation.

• "TRAMP":

• Tricuspid, Right, Atrium, Mitral, Pulmonary.

Key Diagrams

• Heart Structure:

     +---------+
     |  L.A.   | ← Left Atrium
     +---------+
           |
           v
     +---------+       +---------+
     |  L.V.   | ← Left Ventricle
     +---------+       +---------+
           |                |
           v                v
     +---------+       +---------+
     | R.A.    | ← Right Atrium
     +---------+
           |
           v
     +---------+       +---------+
     | R.V.    | ← Right Ventricle
     +---------+       +---------+

• Blood Flow:

• Use arrows to indicate the flow:

• Deoxygenated (blue) → Oxygenated (red).

Tip: Understand the heart's electrical conduction system (SA node, AV node) as it regulates heartbeats.