The Human Heart: A Comprehensive Guide

The Human Heart

The heart is a special muscle that serves as the engine of the body.
It is located slightly to the left of the center of the chest, between the lungs, in an oblique (diagonal) position.
Its primary function is to pump blood throughout the body.

Blood carries oxygen and nutrients to all the cells in the body, which are essential for sustaining life.

The heart functions as a pump, similar to those used to inflate tires, but instead of air, it pumps blood.

The heart is divided into two parts: the right and left sides.
These two parts are separated by a cellular wall, ensuring there is no internal connection.
Each side of the heart has two chambers or cavities:
- Upper cavities: Right and left atrium.
- Lower cavities: Right and left ventricle.
The heart contains four valves that act as doors.
- These valves open to allow blood to flow in and close to prevent backflow.

The process begins in the right atrium, where deoxygenated blood (blood with low oxygen and nutrient levels) enters the heart.
The deoxygenated blood then passes through the first valve to reach the right ventricle.
From the right ventricle, the heart pumps the blood directly to the lungs.
In the lungs, the blood becomes oxygenated and enriched with nutrients.
Once oxygenated, the blood returns to the heart, entering the left atrium.
From the left atrium, the blood passes through the third valve into the left ventricle.
Finally, the heart sends the oxygenated blood through the fourth and last valve out to the rest of the body, completing the cycle.
The heart's beating action can be visualized by imagining a hand opening and closing.
- Opening the hand corresponds to the heart filling with blood.
- Closing the hand represents the heart pumping blood out.

Blood flows through the body via blood vessels, which include three types:
- Arteries: Carry oxygen and nutrient-rich blood from the heart to the body's organs.
- Veins: Carry blood with low oxygen levels back to the heart.
- Capillary Vessels: Small vessels connecting arteries and veins, facilitating nutrient and waste exchange at the cellular level.

The average human heart weighs approximately 450 grams (almost half a kilogram).
The heart is a powerful muscle capable of beating over 100,000 times a day.