The Life of a Red Blood Cell
Blood pulsated, pealing among deafening heart beats. Quivering cells, burdened
with many duties, hurried along the rivulets, tending to the over-quenched body tissues
and organs. Great white blood cells kept their watch, rising; en-masse, as a foreign
stranger lurked within the ‘roadway,’ inducing onslaughts upon the over-crowded ‘city.’
Within the sternum, a red blood cell of Destiny is born. Though appearance may
be altered, the very essence remains.
~~~
“Grandpa!” young Erythro shouted with glee.
“Ah, nice to see you, young one!” Mr. Erythrocyte proclaimed.
“Grandpa…where do red blood cells come from?”
“Err… uh…” Mr. Erythrocyte sighed, “if you wish to know, perhaps I should
inform you, before it is too late.”
~~~
“I was born within the sternum, where a pluripotential hematopoietic stem cell is
present. All blood cells: Red blood cells, White blood cells, and platelets, are produced
in this type of cell. The pluripotential hematopoietic stem cell group has the potential to
form any of the different types of blood cells, and also to reproduce itself. This cell then
forms committed stem cells that will form specific types of blood cells.”
“Is it true that I had a nucleus when I was being born? That’s what RBC told
me.” Erythro questioned.”
“Yes, as the red blood cell matures in the bone marrow, they manufacture
hemoglobin, and the nucleus is squeezed out of the cell. The hemoglobin is what gives
red blood cells the red colour. Nearby macrophages (a cell that consumes and digests
debris and invading microorganisms) ingest the nucleus. The red blood cell then leaves
the bone marrow, and enters the blood vessels.” Mr. Erythrocyte explained.
“So that’s why I don’t have a nucleus!”
“The red blood cell then travels along a roadway that is often described to be very
elastic. Valves are placed along the road just in case we accidentally travel in the wrong
direction. These valves ensure the one-way traffic we pass by daily. Eventually, the red
blood cell will enter the heart. First, the cell will enter the atri-..”
“The heart!? RBC told me a few very scary stories about the heart! I heard that
this one cell entered the heart, and never returned…” Erythro attempted to stop
quivering, for he was in the presence of his grandfather.
Mr. Erythrocyte nodded slightly, “Erythro, let me tell you of a short story about
your father, Erythrocyte Jr. You see, it was a usual day as always. Your father and I
were performing our duties, and approached the heart. Erythrocyte Jr. thought it would
be amusing if he went ahead, and impelled me to chase after him. Laughing with glee, he
entered the right atrium before me. Suddenly, a massive door blocked me off from your
father, and sadly, that was the last I saw of him. Your father always enjoyed a good
laugh… perhaps too much. If only I caught him in time…”
“It wasn’t your fault grandpa. There was nothing you could do.”
“I know. It was another valve in the chamber. I had no control what-so-ever over
the valve. Now, let’s continue. A red blood cell enters the heart, and heads first to the
first chamber, the right atrium. The blood cell would enter the right side of the heart
because it is born deoxygenated. The blood then carries the cell to the right ventricle, and
turns to enter the pulmonary trunk. In the pulmonary trunk, the blood separates and
travels to the left or right pulmonary arteries. The red blood cell is then carried to the
lungs. In the lungs, there are small sacs called alveoli, in which are surrounded by blood
vessels. Here, a red blood cell would exchange the carbon dioxide it’s carrying, and the
hemoglobin, and iron aid it to obtain the oxygen given by the alveoli. After the gas
exchange, the red blood cell is now carrying oxygen, so the blood is considered
oxygenated blood. The pathway of blood is reversed, after the exchange, and travels to
the left or right pulmonary veins.”
“They have to go back to the heart?!” Erythro questioned.
“Yes, Erythro. Even though it is dreadful at first, it is essential for a red blood
cell to travel back to the heart. It enters the left atrium, and is pushed to the left ventri-..”
“Grandpa, can you show me the pathway I must take to do my job?”
Mr. Erythrocyte laughed, “You young ones always try to act all grown-up! Sure,
I will finish my story and show you at the same time!”
Mr. Erythrocyte and Erythro traveled along the vein that lead to the heart. As
they approached the muscle, Erythro hesitated. The throbbing and loud pulsating noices
overwhelmed him. The valve before them closed, and they waited.
“I have gone past this chamber numerous of times, so I am adapted to its rhythm
of closing and opening.”
The valve opened, and they traversed into the heart. First, they entered the right
atrium, and then went on to the right ventricle.
“It’s so loud in here!” Erythro shouted above all the noise.
“The valves in the heart make that noise when they open and close to let blood
through!” Mr. Erythrocyte shouted back.
They quickly left the heart, and traveled through the left pulmonary artery, and
made their way to the left lung.
“Hello, Mr. Alveoli.” Erythro teased. “Grandpa, how am I supposed to exchange
with it?”
“Just follow whatever I do.” Mr. Erythrocyte allowed the alveoli to take the
carbon dioxide, and in exchange, he received oxygen.
“How am I supposed to get oxygen?”
“The hemoglobin you were born with aids you in this process, just let it do its
job.” Mr. Erythrocyte proclaimed.
“All right. Hemoglobin, do your thing!”
At that moment, the hemoglobin in Erythro picked up the oxygen.
“Why do we have to do this?”
“The person we reside in needs our help. When they breathe in through their
nose, the blood vessels in their sinuses heat up the air, and provide moisture for it. The
air contains oxygen, other gas particles, and even some pollutants. The air then is filtered
through the cilia, and mucus that is lined within the trachea. The air then travels through
the bronchi, and then branches out into the bronchioles. At the end of each bronchiole,
there is a sac of alveoli, much like this one. We exchange gases, so that we are able to
obtain the oxygen they breathe in, and we drop off the wastes, which in our case, is
carbon dioxide. The person then breathes out the carbon dioxide, and the process
continues. They also breathe out any excess water alongside the carbon dioxide when the
person exhales. Now that we are oxygenated, we must return to the heart.”
Mr. Erythrocyte and Erythro turned around, and reversed their path. They then
entered left atrium from the left pulmonary vein. They were then pushed into the left
ventricle.
“Up straight ahead is where the aorta is. Just relax, and let the heart slide you
through!” Mr. Erythrocyte smiled.
The heart contracted, and the red blood cells were pushed through the aorta,
where they saw three arteries that would lead to the head, neck, shoulders, and arms.
They continued to travel to the lower body.
“Now, I will teach you how to give the body tissues’ cells oxygen, and take away
their waste, which is most likely to be carbon dioxide. First, let’s travel to the very
bottom, the feet.”
The two red blood cells continued along the artery to the feet.
“You see this web we are approaching?”
“Yeah,” Erythro answered back.
“These are capillaries. We are able to travel through even the smallest of vessels,
such as capillaries due to our shape. Red blood cells can bend, squish, and squeeze
ourselves through. In the capillaries, we pick up carbon dioxide, and drop off the oxygen
we received from the lungs. We only have to drop off oxygen where the levels of it are
low, such as in tissue. Now, let’s drop off our oxygen, and pick up the ‘trash.’”
“Grandpa! This one gave me salts and nutrients!” Erythro complained.
“Erythro, just accept it. Blood is also responsible for picking up nutrients and
other wastes, alongside our major functions.”
“Ah, all right.”
“I’ll tell you about a little event that happened not too long ago. In the meantime,
let’s continue on our way, until we reach the small intestine. About 26 days ago, an event
occurred that shocked me! The heart started to pump so much blood! More than I’ve
ever seen! It was so chaotic in here. I was concerned that a blood vessel might burst, for
we would have had some horrendous tragedies. Fortunately, the capillaries I passed
through dilated, and allowed more blood to travel through. I believe that when this event
occurs, the person we reside in will get a pink tone in their skin. Oh yes, our wastes are
also excreted by the skin. When the person sweats, they are excreting excess water, and
salts, such as minerals. Oh, we have arrived!”
The two red blood cells approach the small intestine.
“The blood’s duty here is to receive the nutrients that the villi pick up during
absorption. The nutrients are broken down, and are small enough to be released into the
blood. Villi are finger-like projections that are inside the small intestine.”
“Fingers? Wouldn’t they tickle the person from the inside though?”
“No, no. They only look like fingers, and are miniature in size.”
The two red blood cells pick up the nutrients supplied by the villi, in which they
will deliver to those muscles and tissues that require, or have low amounts of it. The two
cells continue along.
“Okay, our next stop… the liver!”
“RBC told me that old red blood cells die, and get recycled in the liver.”
Mr. Erythrocyte nodded slightly. “RBC is quite right. A red blood cell lives up
to 120 days maximum. After the cell has passed away, its remnants are recycled in the
liver. The iron it once contained is passed on to new red blood cells, and the hemoglobin
is converted and distributed into the bile.”
“Grandpa… how old are you?”
“Approximately 198 days old.”
“Will you be recycled soon…?”
Mr. Erythrocyte sighed. “I’m afraid so. But hey, all good things must come to an
end, right?”
“I guess…” Erythro whispered.
~~~
Mr. Erythrocyte quavered, and collapsed.
“Grandpa! Not now… I need you. I don’t know what to do!”
Mr. Erythrocyte whispered, “Head to the kidneys. Once there, drop off the waste
you collected, and retrace your path…”
~~~
“Grandpa died that day…”
Alone, and with little content, Erythro continued along the path, and headed
towards the liver first, alongside Mr. Erythrocyte’s remnants. While in the liver, he
tossed the deceased cell into the ‘abyss’ where he could be reprocessed into new red
blood cells.
Following his grandfather’s words, Erythro moved on to the kidneys. The
kidneys possessed an odd shape; much like a bean. RBC, his best friend, once told him
that all blood passes through the kidneys to get filtered out. It just appeared to him that
RBC knew a great deal about the functions of a red blood cell.
Erythro dropped off the waste he collected from the tissue he tended to. No one
ever told him what happened to the waste, once they were dropped off into the kidneys.
It struck him that he gained a lot of knowledge from his deceased grandfather, and
wished to learn more. But, all will be revealed in due time. For the time being, he will
just have to value the words of Mr. Erythrocyte, and perform his duty daily, and to his
full extent.
Erythro then went on to travel back to the heart. From there, he will retrace his
steps, and do what red blood cells do best! Erythro will perform his duty well,
particularly in the gas exchange of oxygen and carbon dioxide in the lungs. And perhaps,
he might meet a young red blood cell along the way, and pass down the knowledge of his
grandfather.
And, who knows… Erythro might be residing in you!
Laura White
Block A