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Where Does Blood Come From? - The River of Life

Born and raised in a Catholic home, Reina is deeply passionate about sharing her faith with all people. She is interested in apologetics.

I have always been wondering. Where does blood come from? Sure, you can get bags of blood from the blood bank. There are kind people who willingly donate their blood. But, how do these people get so much blood to give away?


Anatomy of the Blood

Students at Washington State University asked Dr. Universe. Why do we have blood? He answers that blood helps keep all the body parts alive. Blood moves around the body like your local postal service.

  • Blood is made up of four different components. Each has its own specific function. The red blood cells deliver oxygen throughout the body. White blood cells protect the body from invaders.
  • Consider red blood cells like your package delivery guy. They bring the oxygen from your lungs to different parts of your body. It also takes along all other nutrients your body needs.
  • White blood cells are like your local policemen and platelets are medics. They help keep you from losing blood when you get a cut by closing up the wound. The red liquid that we see coming out of the wound is called plasma.

Blood is formed from stem cells inside the bones. The bone marrow produces these blood cells. It is the heart that pumps the blood out into the body. It takes a force as strong as squeezing a tennis ball.

Journey from the Heart

The blood is like a stream the flows inside the human body. Water forms the plasma that makes it move across the veins and blood vessels throughout all body parts. It springs from the heart.

Encyclopedia Britannica features the story of the journey of a red blood cell. It begins with a single heartbeat at the right side of the heart. The video shows real footage of blood cells flowing through blood vessels across the body.

The red blood cell travels from the right side of the heart into the lungs to get oxygen. It returns to the left side carrying the oxygen with it. With another heartbeat, it pushes upwards distributing oxygen to all the other parts of the body.

The cells return to the heart with depleted oxygen. The cycle gets repeated and a red blood cell begins another journey from the heart. This animated video explains how the heart works in the circulatory system.

There is a river whose streams make glad the city of God, the holy habitation of the Most High. God is in the midst of the city; it shall not be moved; God will help it when the morning dawns.

— Psalm 46:4-5 | New Revised Standard Version Catholic Edition

Movement of the Heart

The human heart is the most hardworking organ in the body. It pumps about five quarts of blood every minute and beats about a hundred thousand times in one day. Every heartbeat is a continuous cycle of contraction and relaxation of the heart muscle.

  • Systole- Contraction of the heart squeezes the ventricles pushing the blood into the vessel. Blue blood in the right ventricle travels to the lungs to get oxygen. It turns red and returns to the heart into the left atrium Red blood in the left ventricle goes through the aorta into all the other parts of the body.
  • Diastole - When the heart relaxes, the upper chambers called the left and right atria release blood into the ventricles. Blue blood from the right atrium gets deposited into the right ventricle. It turns red as it reaches the lungs and receives oxygen. This red blood enters the left atrium which releases it to the left ventricle.

The right atrium consists of an electrical wiring system that ignites the beating of the heart. Every heartbeat makes a cycle of blue blood coming out of the heart into the lungs and red blood entering the heart from the lungs. Four valves control the movement of blood in the heart. They are like gates that open and close with every heartbeat.

How Blood Cells Are Formed

The bone marrow is a soft, spongy tissue found at the center of some bones. It contains stem cells that may grow into red blood cells, white blood cells, and platelets. Stem cells are raw materials for the body to create new cells.

There are two types of bone marrow. The yellow bone marrow consists mainly of fats and contains stem cells that make cartilage. The red bone marrow holds the stem cells that form the cellular components of blood.

It takes two days for a red blood cell to take shape. The body makes about two million red blood cells every second. These red blood cells can enter the right atrium through the many blood vessels in the bone.

My Two Cents

A word from the Book of Psalms in the Bible comes to mind. There is like an entire city inside the human body. Blood is the river that flows around that city. It's amazing how it works.

Blood is truly the river of life, and how it's made still remains a mystery. Who shaped those tiny cells inside the body? Who gives the strength that makes the heartbeat? In all this, I can only marvel at the beauty and wisdom of God's creation.


© 2021 Reina Mendoza

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