The Bone Marrow
Bone marrow
Episode 4
Vital statistics
Czech Title Kostní dřeň
Original (French) Title La Moelle osseuse
Episode guide
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The Body's Sentinels The Blood
The Bone Marrow is the fourth episode of Once Upon a Time... Life. This episode centers around production of blood cells that occurs in the titular organ.

Plot Edit

The episode begins with the narrator introducing the bone marrow to the viewer, explaining its purpose and then listing the number of blood cells produced per day:

  • 200 billion red blood cells
  • 15 billion white blood cells
  • 500 billion platelets

The scene switches to the insides of a hematopoietic stem cell in process of preparing to create a red corpuscle. The chief of genetic central calculates number of necessary nucleotides, but is interrupted by a curious Enzyme, at who he ends up yelling to finish arithmetics. Inside of the nucleus, Maestro's assistants are observing the growing number of created erythrocytes as it almost reaches 200 billion. Suddenly, the screen gets stuck and one of them kicks it, resulting in it counting one too many. Soon afterwards, the red blood cell is formed and enters the bloodstream. Once the newborn red corpuscles enter the blood vessel, they are introduced to Globus, Globin and Hemo.

The next scene focuses on hematopoiesis of white corpuscles. After examining that the daily counter is nearly achieved, Maestro explains that hematopoiesis is a serious procedure, and that if a flaw appears the consequences could be fatal. Then, an Enzyme works on the DNA and decides to have fun and plays with it as if on a swing. However, the chain breaks and genes reform in a new chain. Maestro is shocked to see someone fooling around with heredity programming and dismisses the guilty-feeling Enzyme for playing with genes. He requests help from Ligase Enzymes and they soon reform the original blueprint. They generate a white blood cell. Maestro then takes a nap while the assistants have to observe hematopoiesis of platelets.

In the headquarters of body's sentinels, a few young leukocytes are hanging out until they're told to quickly investigate nasal mucus. Four vehicles set off and reach the destination where they find a group of viruses. A female leukocyte, knowing what to do, dismisses her colleagues and solves the situation by herself, using the Antibodies and then performs mitosis. Soon after this, the Colonel receives a report. After reading it, visibly shocked, he declares the alert that the newly created troops are not aligned anymore.

In one of creation halls, leukocytes start forming more frequently than intended and they enter the bloodstream. Compared to the normal leukocytes, they look dull and malicious, also preventing the normal blood flow by mistreating the red blood cells and nutrients. Soon, Lieutenant Jumbo requests their HLA cards and finds out that they don't correspond to the stem tissue of the body, but they ignore him and quickly rush through.

In the nucleus, Maestro is worried when he discovers that the number of generated white blood cells just keeps growing (by now it has increased 15 times). He states that this is too many and contacts the Enzymes to abort hematopoiesis through DNA, but they fail. In the meantime, Globus, Hemo, Globin and two newborn red blood cells sit exhausted by the wall of the blood vessel. The female newborn says that she feels sick.

Scene cuts to Peter's Sister, sitting on the floor and visibly sick, with all of the previous scenes happening in her body. Mum puts the laundry aside, touches her forehead and discovers that she has a temperature and calls the doctor. After Doctor Maestro's arrival, Peter's Sister exclaims that she hurts everywhere, down in her legs especially. To find out what is happening, Doctor has to perform a blood test. He takes the sample, puts it on the glass slide and under the microscope, where he discovers the rampaging leukocytes.

Mum asks is the situation serious, and Doctor sadly admits that the situation is very serious; it turned out the disease that has struck Peter's Sister is leukemia, which presents the high number of abnormal, immature leukocytes. Mum is worried, but Doctor informs her that they have a way to cure her daughter. In a sterile room, Doctor declares a very serious anemia with his colleague and starts the purification process — he inserts the liquid in her arm, which quickly begins to purge most of blood cells in the body, including all the immature leukocytes.

The only flaw is that she no longer has a way to be protected and he reveals the second part of therapy to Mum; Peter will give her a number of his bone marrow cells considering that they both have similar genetic characteristics. A worried but determined Peter comes, and then, in the sterile room, Doctor extracts his hematopoietic cells and injects his sister with them.

The transplanted hematopoietic cells make their way from basilic vein to the heart, then pulmonary circulation and then spread all over Peter's Sister's body, soon reforming the bone marrow. In a matter of time, she is healed, the leukocytes are produced at the normal pace again and they come to world without a flaw.

Trivia Edit

  • This is the first episode to feature a story that takes place in body of Peter's Sister.
  • Maestro debuted as a doctor.
  • The soundtrack used during PS's diagnosis and bone marrow transplantation is known under the names of Omega I, II and III from Once Upon a Time... Space.
    • The mentioned soundtrack fits in the scene to describe the seriousness and battle for life.
  • This is the first episode to feature the body's sentinels becoming attackers.
  • This episode marks the first time we see a genetic accident.

Biology Edit

Bone marrowEdit

Bone-marrow-he edited-1

  • Bone marrow is a semi-solid tissue that fills the space in spongy bone tissues.
  • In adult humans, bone marrow can usually be found in the ribs, sternum, vertebrae and the pelvic complex.
  • There are two main types of bone marrow:
    • Red bone marrow is the most common type of bone marrow in childhood and has the role of hematopoiesis.
    • Yellow bone marrow replaces some of red bone marrow tissue in adulthood and it generates fat cells.
  • Bone marrow transplants are useful not only for leukemia, but also for curing diseases such as IBD.



  • Leukemia (coming from the Greek leukos = white and aima = blood), also pronounced as leukaemia (or also known as "blood cancer") is a type of cancers that is characterized by malignancy of bone marrow's cells which results in a huge number of abnormal white blood cells.
  • The exact cause of leukemia is unknown, but it's speculated to be the result of a genetic mutation during hematopoiesis.
  • These are the most common symptops of leukemia:
    • Fever
    • Weight loss
    • Weakness
    • Pain or tenderness in bones and joins
    • Fatigue
    • Scattered reddish-purple spots (petechiae) on skin
  • Despite many methods of discovering leukemia, many people have not yet been diagnosed thanks to many symptoms being vague or non-specific. In conclusion, the ACS (American Cancer Society) estimates that at least one-fifth of the people with leukemia have not yet been diagnosed.
  • Curing leukemia itself is difficult and it may be carried out by chemotherapy, radiation therapy, targeted therapy and bone marrow transplant.