The human heart is the most vital muscular organ that ensures the circulation of blood throughout the body. A detailed understanding of the internal structure and sectional anatomy of the heart helps us comprehend how this biological pump maintains life.
In this article, you’ll learn:
- Labeled anatomy of the human heart
- Functions of each internal part
- Path of electrical conduction in the heart
- NEET-ready facts, tables, and FAQs
Overview of the Human Heart
The heart is a four-chambered organ located in the thoracic cavity between the lungs. It has:
- Two atria (upper chambers)
- Two ventricles (lower chambers)
- Valves, tendons, nodes, vessels, and septa that coordinate its functioning
Labeled Diagram: Section of the Human Heart
The image provided clearly illustrates the internal structure of the heart with labels including:
- Right Atrium
- Left Atrium
- Right Ventricle
- Left Ventricle
- Vena Cava
- Pulmonary Veins
- Pulmonary Artery
- Aorta
- Interventricular Septum
- Chordae Tendineae
- Sino-atrial Node (SAN)
- Atrio-ventricular Node (AVN)
- Bundle of His
- Apex
Functions of Each Part in the Heart Diagram
1. Right Atrium
- Receives deoxygenated blood from the superior and inferior vena cava
- Transfers blood to the right ventricle via the tricuspid valve
2. Left Atrium
- Receives oxygenated blood from pulmonary veins
- Sends it to the left ventricle via the bicuspid (mitral) valve
3. Right Ventricle
- Pumps deoxygenated blood to the lungs through the pulmonary artery
- Uses semilunar valves to prevent backflow
4. Left Ventricle
- Pumps oxygenated blood into the aorta
- Thickest chamber due to high pressure needed for systemic circulation
5. Vena Cava (Superior & Inferior)
- Major veins that bring deoxygenated blood from the body to the right atrium
6. Pulmonary Artery
- Carries deoxygenated blood from the right ventricle to the lungs
7. Pulmonary Veins
- Return oxygenated blood from the lungs to the left atrium
8. Aorta
- Largest artery that distributes oxygen-rich blood to the entire body
9. Interventricular Septum
- A muscular wall separating the right and left ventricles
- Prevents mixing of oxygenated and deoxygenated blood
10. Chordae Tendineae
- Tough strings that anchor AV valves to ventricular walls
- Prevent valve inversion during contraction
11. Sino-Atrial Node (SAN)
- Natural pacemaker of the heart
- Located in the right atrium
- Initiates heartbeat and sends impulses to AVN
12. Atrio-Ventricular Node (AVN)
- Receives signals from SAN
- Passes it to ventricles via Bundle of His
13. Bundle of His
- Conducts impulse from AVN to Purkinje fibers in the ventricles
- Ensures coordinated contraction of ventricles
14. Apex
- Tip of the heart pointing downward
- Formed by the left ventricle
Summary Table: Internal Structure of Heart
| Structure | Function |
|---|---|
| Right Atrium | Receives deoxygenated blood |
| Left Atrium | Receives oxygenated blood |
| Right Ventricle | Pumps blood to lungs |
| Left Ventricle | Pumps blood to body |
| Vena Cava | Carries blood from body to heart |
| Pulmonary Veins | Carry oxygenated blood to heart |
| Pulmonary Artery | Sends blood to lungs |
| Aorta | Sends blood to body |
| Interventricular Septum | Separates ventricles |
| Chordae Tendineae | Prevents valve collapse |
| SAN | Initiates heartbeat |
| AVN | Relays signals to Bundle of His |
| Bundle of His | Activates ventricular contraction |
| Apex | Contraction base, directional force |
NEET Relevance & Biology Exam Prep
- Diagram-based questions with labels
- Assertion-reason questions on conduction system
- MCQs on valves, nodes, and blood vessels
NEET Tip: Focus on the sequence: SAN → AVN → Bundle of His → Purkinje fibers
FAQs: Human Heart Structure
Q1. Which chamber has the thickest wall?
A1. Left ventricle, due to high-pressure pumping to the body.Q2. What is the function of chordae tendineae?
A2. They prevent the valve flaps from inverting into the atria during contraction.Q3. Where is the SAN located?
A3. In the upper wall of the right atrium.Q4. What prevents blood from mixing in the heart?
A4. Interventricular and interatrial septa.
