(Sounds of heartbeat and blood moving through vessels)
Blood moves through the body with speed and grace. Each heartbeat propels it along well-known routes.
Think of these routes as highways.
(Sounds of highways come up and stay low underneath; heartbeat and fluid sounds mix briefly then fade out)
Traffic zips by, on its way from one place to the next.
(semi sounds)
Each red blood cell is like a semi, hauling oxygen and carbon dioxide.
(cop siren)
White blood cells are like cops, out on patrol. Their main job is to fight infections.
Also on this highway are little cell fragments or platelets that mop up wounds and stop the bleeding, like an ambulance.
(ambulance siren)
(Highway sounds fade out)
SAMARAS: Yeah, yeah that could probably work (AG: Does it hold up?) Laughter
Dr. Christy Samaras is a good sport about using this traffic metaphor. She’s a blood doctor—a hematologist—at the Cleveland Clinic.
But there are a couple things to know right off the bat, she says. Cells—those trucks and cops—make up about half the body’s total blood volume; the rest is a watery mess—called plasma—filled with proteins and hormones and nutrients and enzymes and salts.
Red blood cells are the most plentiful cell type—there are millions of them in a single drop of blood—and they’re real workhorses. They’re stuffed full of oxygen—and they’ll deliver it to even the far flung parts of the body. So when a red blood cell brings oxygen to your fingertips, it’s like UPS dropping off a package to your cousins in North Dakota.
To visualize one of these oxygen-toters, Samaras says think of a squished m&m. Let a red one sit out in the sun and
SAMARAS: If you put your thumbs on both sides of it and push your thumbs together—not quite touching—what you end up with is something that looks like a red blood cell. (AG: And sticky fingers.) And sticky fingers that are good to lick off.
White blood cells come in all shapes and sizes.
SAMARAS: They look like a blob.
Chances are, you’ve seen ‘em in action.
SAMARAS: If you’ve ever had a boil, that pus you see is actually just a group of white blood cells.
Gross, yes, but Samaras says,
SAMARAS: Pus is a good thing.
It means the immune system is in full force, fighting off the infection.
She’s equally taken with the beauty of platelets.
SAMARAS: There’s an old story about a little boy that stuck his finger in the dike.
And, so the story goes, this saved his city from flooding.
SAMARAS: I think of platelets in that way. They’re the stopgap.
Platelets have little “fingers” (called pseudopods) and when they go to a wound, they’ll clasp on to other platelets—think, a big group hug—and make a plug in that area, to stop the bleeding.
(Music starts low and stays underneath: Sufjan Stevens’ You Are the Blood)
Healing wounds, hauling vital gases, fighting infection…blood is integral to the body.
SAMARAS: Simply speaking, it keeps us living and breathing...All of the other systems of the body are dependent on blood for their own health.
You know that little heel stick a newborn gets? In our next report we’ll tell you about all that can be learned from those five drops of blood.