Hemostasis

by Greg Crowther

The words "hemostasis" and "homeostasis" look and sound very similar and, in fact, hemostasis may be considered one particular form of homeostasis. When a blood vessel breaks and bleeding occurs, the body takes a series of steps to limit the loss of blood (and thus maintain blood pressure, etc.) and restore homeostasis, as outlined below (taken from Erin Amerman's Human Anatomy & Physiology textbook). The 1st verse gives an overview of the overall process, while the 2nd verse offers more detail on the clotting cascade part.

Remember that old sheriff who was shot?
Well, he survived the shooting, thanks to clots....

When a vessel is cut,
There's a leakage of blood,
A vascular spasm,
And a platelet plug.
Fibrin sews up the clot;
Then the clot retracts.
It's dissolved by thrombolysis
To bring homeostasis back....

Hemostasis will conserve your blood!
Hemostasis will conserve your blood!

In the clotting cascade,
Which the platelets foment,
There are two different paths
To turn on Factor Ten.
Then, with calcium's help,
And Factors Ten and Five,
Activation of prothrombin
Brings fibrinogen alive....

Hemostasis will conserve your blood!
Hemostasis will conserve your blood!

• karaoke

• MP3 (demo)

• music video

• sheet music (with melody play-back)

Songs like this one can be used during class meetings and/or in homework assignments. Either way, the song will be most impactful if students DO something with it, as opposed to just listening.

An initial, simple follow-up activity could be to answer the study questions below. A more extensive interaction with the song might entail (A) learning to sing it, using an audio file and/or sheet music as a guide, and/or (B) illustrating it with pictures, bodily poses, and/or bodily movements. The latter activity could begin with students identifying the most important or most challenging content of the song, and deciding how to illustrate that particular content.

(1) As bleeding starts, five steps ensure hemostasis. List these five steps (1-2 words per step).

(2) Which of these steps is/are impaired in people with hemophilia?

(3) Explain the meaning of the word thrombolysis in terms of its roots "thromb" and "lysis."

(4) Why is the clotting process referred to as a "cascade"?

(5) The lyrics state, "There are two different paths to turn on Factor Ten." What are these two different paths?

(6) The lyrics state, "Activation of prothrombin brings fibrinogen alive." What does that mean?