|Erythrocyte, Red Blood Cell with Type A+B Antigens|
In the spirits of Halloween, SleuthSayers brings you a bloody fine tutorial, the basics of what an author needs to know about blood.
As crime writers, we often deal with blood, splatter, DNA and alleles in fiction and non-fiction. Today, we investigate a bleedin’ serious topic.
|A+B Antibodies Schematic (Type O blood)|
Erythrocyte is the technical name for a red blood cell. Scientists describe the shape as a biconcave disc or a toroid without a nucleus, meaning they’re vaguely shaped like a plastic kiddie pool or a fresh out-of-the-pack condom.
The cells contain the pigment hemoglobin that makes erythrocytes appear red. A cell’s primary duty is to carry oxygen from the lungs to other parts of the body and transport carbon dioxide back to the lungs where the breathing process of ‘gas exchange’ takes place.
- An antigen induces an immune response stimulating the production of antibodies. Blood antigens comprise types A and B. Either one, both or neither may appear as part of our blood cells.
- The specific surface features of an antigen type are called epitopes. It’s debatable which is the key and which the lock, so it may be convenient to think of matching antigens and antibodies as jigsaw puzzle tabs. For convenience, our schema employs shapes of letters A and B to represent type A and B antigens.
- Triggered by an immune response, antibodies individually key to epitopes. A particular antibody locks onto the shape of an antigen (A and/or B). Antibodies explain why care is exercised when matching blood donors.
|❤︎||ABO||ABO blood constituents|
|Erythrocytes (Red Blood Cells)|
|Red Blood Cell Antigens|
|Blood Type Results||Erythrocytes with neither antigen but plasma containing both type antibodies.||Erythrocytes with type A surface antigens and plasma with type B antibodies.||Erythrocytes with type B surface antigens and plasma with type A antibodies.||Erythrocytes with both surface antigens but plasma without either antibody.|
If you vampires think your honey’s blood is sweet, you have a point– the ‘A’s and ‘B’s in blood types are sugars. Moreover, under an SEM (scanning electron microscope), antigens lend red blood cells a sugary gumdrop look, quite unlike the glossy renderings we usually see.
Types A, B, and AB feature antigens on the surfaces of their cells. Notice how antibodies are ‘keyed’ to lock onto a particular type of antigen, kind of a socket. Antibodies in plasma can attack the wrong type antigens introduced into the blood stream.
Mayhap you feel it’s better to giveth than to receive. Not to be sanguine about these matters, we practice safe blood-letting. To help take the ‘ick’ out of ichor, following is a convenient Béla Lugosi table of tasty platelets for those special moments.
|❤︎||blood||r e c i p i e n t|
This explains why blood donations are carefully matched. A person with, say, type B antibodies in the plasma can’t mix blood with type B antigens (blood type B or AB): Only type A or O will serve. For practical purposes, a type O donor can give blood to everyone.
Contrarily, an AB- patient can receive from nearly anyone. Because of AB antigens, an AB donor can give blood only to another AB recipient.
——— Factoids ———
Famously, Mr. Spock exhibited faintly green skin, purportedly because Vulcan blood flowed with copper-based hemocyanin rather than iron-based hemoglobin. Beyond Star Trek, other blood colors can be found. In fact, you’ve likely eaten some of them.
Creature copper carriers include shrimp, lobsters, certain crabs, some snails, crayfish, and squid. Octopuses are known for their copper-protein blood, albeit blue rather than green.
The New Guinea skink bleeds green, not because of copper, but because of staggering levels of biliverdin and bilirubin. The ocellated icefish, with neither iron or copper, carries clear blood in its veins.
Blue Bloods… and Green
Mention ‘blue bloods’ today and people think police. In centuries past, the term connoted nobility. Initially, ’sangre azul’ referred to Spanish royalty, whereupon the phrase spread throughout Europe. But why blue?
Serfs, slaves, and commoners typically labored outdoors in fields and forests, accumulating muscles, thicker skin, and tanned flesh. Such ‘rednecks’ looked markedly different from the aristocracy, usually known for their pale, sunless skin revealing blue veins.
Two other hypotheses about royal blue bloods prove difficult to verify. One suggestion premised that royalty often suffered from hæmophilia, rendering the skin and veins even paler. A somewhat more intriguing idea set forth the notion that a lifetime of exposure to silver serving dishes, wine cups, and table utensils, may have given the skin a pale blue cast.
Tomorrow, grab that sphygmomanometer. We’re bringing you more bloody information.