Robert J Samples Loc: Round Rock, Texas

It was a calm day and until the alarm sounded, there had been almost so much calm, the men on duty had resorted to either card games of darts. But then when the claxon sounded, they jumped to action immediately. What the alarm was about was a severe crash below decks that was allowing a flow of fluids that were critical for the operation of their ship.

The senior member of their team immediately sized up the extent of the damage and immediately ordered the necessary lumber and other supplies to staunch the flow of fluids and how the crew would commence the repairs. While there would be a lot of signs where the contusion occurred, the damage had been held to only a small part of the wall of the ship.

It would remain just a reminder of the damage for about ten days to two weeks, when a second crew of experienced workmen came and removed the repaired material. In its place they would cover the entire ruptured area with new material as they removed the lumber and scaffolding that held it in place. Within another week to ten days, there was little to show that there had ever been an accident that had render the gash in the side of the ship, just a visible scar!

Read the following description of how the human body sends troops to staunch a wound and stop the bleeding, the repair the damage. Read the following for an amazing complex, but satisfactory system of wound remediation.

The Coagulation Cascade: Blood Clotting in More Detail

Blood clotting occurs in a multi-step process known as the coagulation cascade. The process involves many different proteins. The cascade is a chain reaction in which one step leads to the next. In general, each step produces a new protein which acts as an enzyme, or catalyst, for the next step.

The coagulation cascade is often classified into three pathways—the extrinsic pathway, the intrinsic pathway, and the common pathway.

The extrinsic pathway is triggered by a chemical called tissue factor that is released by damaged cells. This pathway is "extrinsic" because it's initiated by a factor outside the blood vessels. It's also known as the tissue factor pathway.

The intrinsic pathway is triggered by blood coming into contact with collagen fibers in the broken wall of a blood vessel. It's "intrinsic" because it's initiated by a factor inside the blood vessel. It's sometimes called the contact activation pathway.

Both pathways eventually produce a prothrombin activator. The prothrombin activator triggers the common pathway in which prothrombin becomes thrombin followed by the conversion of fibrinogen to fibrin.
Although dividing the coagulation process into extrinsic and intrinsic pathways is a useful approach to the topic and is a widely used tactic, scientists say that it's not completely accurate. For many students of this complex process, however, it's the best solution for understanding blood clotting.

The Classical Blood Coagulation Pathway

A summary of the intrinsic and extrinsic pathways in the coagulation cascade; recent studies have found that additional reactions and clotting factors are involved in the pathways, but this diagram gives a general idea of the process.

Graham olm, via Wikimedia Commons, CC BY-SA 3.0 License
The Roman numerals in a coagulation cascade diagram represent clotting or coagulation factors. These factors are chemicals that are required in the chain of reactions that make up the blood clotting process.

Clotting Factors

The chemicals involved in the coagulation cascade are called clotting or coagulation factors. There are twelve clotting factors, which are numbered with Roman numerals and given a common name as well. The factors are numbered according to the order in which they were discovered and not according to the order in which they react.
Other chemicals are needed for blood clotting in addition to those numbered in the coagulation cascade. For example, vitamin K is an essential chemical in the blood clotting process.
Names and Sources of the Clotting or Coagulation Factors
Coagulation Factor Common Name Source
Factor l Fibrinogen Liver
Factor ll prothrombin Liver
Factor lll tissue factor or thromboplastin Damaged tissue cells release tissue thromboplastin. Platelets release platelet thromboplastin.
Factor lV calcium ions bone, and absorption through the lining of the small intestine
Factor V proaccelerin or labile factor liver and platelets
Factor Vl (unassigned) No longer used N/A
Factor Vll proconvertin or stable factor Liver
Factor Vlll anti-hemophilic factor platelets and the lining of blood vessels
Factor lX Christmas factor Liver
Factor X Stuart Prower factor Liver
Factor Xl plasma thromboplastin antecedent Liver
Factor Xll Hageman factor Liver
Factor Xlll fibrin stabilizing factor Liver
The Factor Vl name is no longer assigned after it was discovered that the chemical that was given the name was actually activated Factor V. The name is traditionally retained in a table of coagulation factors, however.


Studying the Blood Clotting Process

At the high school level, the discussion of blood clotting often begins with the prothombin activator and the previous steps before its formation are ignored or summarized very briefly. At the college or university level, a more detailed knowledge of the process may be needed.

Students sometimes find that studying the coagulation cascade is a challenge, especially when reactions in the cascade must be memorized. Videos from a reliable source can be helpful because they show the blood clotting process visually and can be paused and replayed, as necessary. It may be useful to make notes based on a video and then ask an instructor for clarification if necessary. Making frequent diagrams of the cascade can also help a student to memorize the reactions.

A Summary of Hemostasis

Anti-Clotting Mechanisms in the Body

Though the ability to coagulate blood is essential, it can be dangerous if it occurs inappropriately. The body has ways to prevent this from happening.

The endothelium is the layer of cells that lines the inside of a blood vessel wall. The smooth surface of the endothelium discourages clot formation when there is no injury. In addition, there is no exposed collagen inside a blood vessel. Collagen is a fibrous protein that provides strength to tissues. When blood contacts collagen, the clotting process is stimulated.
Another factor that prevents unwanted clots from forming is the fact that the clotting proteins in the blood are present in an inactive form. They only become active when the body is wounded.
A chemical called Protein C acts as an anticoagulant by inactivating two of the activated coagulation factors (Factor Va and Factor Vllla). Protein S helps Protein C do its job. The two proteins are very useful for preventing blood clotting.

Stabilization of the fibrin network over a wound by Factor Xlll. Fibrin must be broken down once it's done its job.



Removing Blood Clots

When a blood clot has served its function and the tissue underneath it has been repaired, the clot needs to be removed. In addition, it's important that any clots inside a blood vessel don't become large enough to block the vessel. Fortunately, the body can deal with these problems.
Fibrinolysis is the process in which fibrin is destroyed by an enzyme called plasmin. Plasmin cuts the fibrin threads up into smaller pieces, which can then be further broken up by other enzymes and removed from the body in the urine.

An Impressive and Vital Process

A healthy body protects us by clotting blood when we're injured, removing clots when they're no longer needed, and preventing clots from growing too big. The normal blood clotting process is certainly complicated, but it's also amazing. Learning more about the process may help researchers discover ways to improve coagulation as well as prevent it from occurring inappropriately.

Now, doesn’t that make you feel better about your body, all healthy human bodies are so capable of handing wounds in such an organized manner. Of course, it does not mean you should avoid medical attention. There are several reasons for medical attention, such as possible infection, tetanus, and even suturing to repair of the injury. Just Sayin…RJS

ripogenu Loc: norfolk, MA

perhaps the title is misleading RJ. there is really nothing "mysterious" about how the natural mechanisms of most warm blooded creatures functions. I noticed that you neglected to mention the role that the natural bacteria, that are an important part of life forms , plays in the scenario that you have laid out. The first line of defense in the human body is the protective bacteria that we have on our skin, in our nasal passages, and our digestive system. while some think we are the top of the predator/food chain, we would not be able to hold that position without the help of our microscopic friends. Just sayin............

ripogenu Loc: norfolk, MA

BTW no offense is meant here, as some others here think I'm "dismissive"

Robert J Samples Loc: Round Rock, Texas

Ripogenu: You are right, but I was concerned about the length of this post as it was. I tried to make it shorter, but did not know where to cut. Natural bacteria both outside and inside our guts, is vital to our survival.


Other than that, how did you like the article? Just Sayin...RJS

Fredfish Loc: Prospect CT.

I thought it was fascinating RJ. I've forgotten a lot since High School Biology class.

ripogenu Loc: norfolk, MA

I always enjoy seeing posts that actually tell you something you may not know," learn something every day and your brain will stay young"

Robert J Samples Loc: Round Rock, Texas

So, tell me that all this happened by evolution! i believe in a supreme creator, God. we are created beings, wounderfully and carefully made. Just Sayin...RJS

Catfish hunter Loc: Riggins idaho (Paradise)

Thanks Robert. Very informative as usual. 👍

Smokypig Loc: Cheyenne, wyoming

Quick survival tip. An injury in the wild can cause a lot of blood loss. Spider webs are a magic treatment.

ripogenu Loc: norfolk, MA

so while bleeding to death I need to find a spider web...........in the winter?

Smokypig Loc: Cheyenne, wyoming

Nah. Start humming taps...

Robert J Samples Loc: Round Rock, Texas

Well, if you are severly wounded, moss, dry grass, crushed leaves, even dirt would work in a pinch to save one's life. It pays to hunt with a companion to help in the case of a real need. I hunted for years with a surgeon and always kidded him about never carrying any gloves, or other medical supplies. I usually had a small first aid kit in my car. Just Sayin....RJS