The human heart is a complex organ that serves as the center of the cardiovascular system. It is responsible for pumping blood throughout the body via a vast network of blood vessels. But what happens when you remove the blood from this vital organ? What color does the heart become without the red oxygenated blood flowing through it? In this article, we will examine the anatomy of the heart, the purpose of blood, and reveal the true color of the untouched human heart.
Anatomy of the Human Heart
The heart is located in the chest cavity just left of the breastbone and superior to the diaphragm. It is enclosed in a protective sac called the pericardium which anchors it to structures within the chest. The heart is roughly the size of a fist and has a conical shape.
There are four chambers within the heart:
- Right atrium – Upper right chamber which receives deoxygenated blood from the body via the vena cava and pumps it to the right ventricle.
- Right ventricle – Lower right chamber which pumps deoxygenated blood to the lungs via the pulmonary arteries.
- Left atrium – Upper left chamber which receives oxygenated blood from the lungs via the pulmonary veins and pumps it into the left ventricle.
- Left ventricle – Lower left chamber which pumps oxygenated blood to the body via the aorta.
The right side and left side of the heart are separated by a muscular wall called the septum. This separation allows the oxygen-rich blood from the lungs to be pumped to the body without mixing with the deoxygenated blood being pumped to the lungs.
There are four valves within the heart that prevent backflow and keep blood flowing in one direction:
- Tricuspid valve – Between the right atrium and right ventricle
- Pulmonary valve – Between the right ventricle and pulmonary artery
- Mitral valve – Between the left atrium and left ventricle
- Aortic valve – Between the left ventricle and aorta
The contractions of the heart are controlled by electrical impulses that originate in the heart’s internal pacemaker called the sinoatrial node. This node sends signals through the conduction system which stimulates the cardiac muscle cells to contract and pump blood.
Now that we have reviewed the basic anatomy, let’s look at the purpose of blood within the cardiovascular system.
Purpose of Blood
Blood is a specialized bodily fluid that delivers essential substances like oxygen, nutrients, and hormones to cells throughout the body while simultaneously collecting waste products. Blood consists of a liquid portion called plasma and three major types of cells suspended within it:
- Red blood cells (erythrocytes) – Contain hemoglobin which binds to oxygen and transports it to tissues. They give blood its red color.
- White blood cells (leukocytes) – Help fight infection in the body.
- Platelets – Assist in blood clotting.
Blood picks up oxygen in the lungs which is carried by the red blood cells. It then circulates through the heart to be pumped to the rest of the body via the arteries. As it reaches the body’s tissues, oxygen and nutrients pass into the cells and carbon dioxide waste is collected. The deoxygenated blood returns to the heart through the veins to be sent back to the lungs to reload on oxygen. This oxygenated blood is what gives the heart its bright red color.
Without blood flowing through it, the true color of the human heart is revealed.
The Color of the Heart Without Blood
Appearance
So what color is the heart without any blood within it? The untouched heart is not actually red but more of a brownish tan color. This is the natural color of the cardiac muscle tissue itself without the red blood cells. The outer surface takes on a dull, pinkish-gray appearance as some blood remains on the surface after drainage. But internally, the chambers appear a very light tan.
This color results from the composition of the heart wall comprising differing ratios of two proteins:
- Myoglobin – This protein stores oxygen within muscle cells and contains reddish pigment, giving the heart its red hue when oxygenated blood flows through it.
- Collagen – The main structural protein found in connective tissues. It provides strength to heart muscle but is not red.
Without blood, the darker myoglobin and lighter collagen fibers give the heart its tan-brown natural color.
Cause
So why does the heart change color when blood is removed? Hemoglobin contained in red blood cells makes blood appear red as it carries oxygen. This hemoglobin is what stains the muscle fibers of the heart giving it its bright crimson color.
When blood is drained from the heart, only the natural color of the muscle tissue remains. The lack of red-blood cell hemoglobin bound to oxygen is responsible for the dramatic change from red to tan.
Clinical Applications
Visualizing the heart without blood has some clinical importance:
- Improved imaging – Removing blood allows for clearer visualization during ultrasound or MRI exams.
- Assess damage – A heart attack can be identified by lighter areas indicating dead muscle.
- Transplants – A heart’s viability for transplant is checked by color and contractions after blood is flushed.
Seeing the heart’s true color provides insight that can improve cardiac diagnoses and treatments.
Table Comparing Heart With and Without Blood
| Heart filled with blood | Heart without blood (drained) |
|---|---|
| Bright red color | Brownish-tan color |
| Oxygenated hemoglobin in blood colors muscle tissue red | Lack of hemoglobin reveals natural tan muscle tissue |
| Appears red and vibrant | Dull, pinkish-gray exterior with light tan interior |
This table summarizes the key differences in appearance between a blood-filled heart versus an emptied, bloodless heart.
Conclusion
In summary, the human heart without blood does not maintain its bright red color. Once blood is drained from the chambers and vessels, the heart reverts to a tan-brownish color resulting from the cardiac muscle tissue itself without the red blood cells. This reveals the heart’s natural pigmentation distinct from the coloring provided by hemoglobin in the blood. Understanding why the heart changes color provides insight into the relationship between blood and cardiac anatomy. Next time you picture a heart, imagine it in its natural state as a light brown organ ready to facilitate the vital flow of life-giving blood.