Histamines Antihistamines Mast Cells
We have all gotten a scratch now and then, but most people never learn the science involved. If you think about the science, you might not notice that it hurts so much.
|
|
|
|
|
|
This Week's Experiment - #301 Scratch Science
The week's experiment is a result of a question that Lisa asked about
scratches. We have all gotten a scratch now and then, but most people never
learn the science involved. If you think about the science, you might not
notice that it hurts so much. We won't hurt ourselves today, so if you are
itching to know more about how your body works, you will need:
your skin
Have you ever had a mosquito bite? Or been scratched by a thorn, a cat, or
maybe a 70 pound Labrador? What happened to your skin? We can investigate
that under more pleasant conditions. Pick an area of skin that is fairly
tender. I picked the skin on my right side, just at the ribs. Now pretend
that you have a mosquito bite there. If it helps, tell yourself that you
are not allowed to scratch and it will start to itch fairly quickly. Now
scratch the itch. Don't hurt yourself and don't break the skin. Just
scratch the itch. Then watch the skin carefully. If you are light
skinned, you will quickly see the scratches turn red. If your skin is
darker, then you may not see that. Either way, if you look carefully, you
may see that the skin has swollen and risen up slightly along each scratch.
The area will feel warm or even hot. It will be very sensitive to touch.
Why does this happen? Your body contains special cells called mast cells.
When they are irritated, such as being scratched, they release all sorts of
chemicals. One of these is called histamine. Histamine causes tiny blood
vessels to release blood into surrounding tissues. This causes the area to
look red, feel hot and become swollen. The blood cells can help fight
infection in the tissue, but the swelling can put pressure on nerves, causing
more itching or pain. Scratching a mosquito bite releases histamine.
Besides causing swelling, histamines sensitize nerves, making sensations such
as pain or itching more intense. Scratching actually makes the itching
worse. The more you scratch it, the more histamine you release and the more
it itches. A trick that I learned is to use your fingernail to press into
the center of the bite several times, making a star shaped pattern. This
helps disperse the mosquito spit (Yes, the initial itch is caused by mosquito
spit.) without releasing too much histamine.
The histamine reaction can also be triggered by things you are allergic to.
It may just be a yummy strawberry or peanut butter, but if you are allergic,
your body mistakenly identifies it as something dangerous. This triggers
the histamines, and you get a rash or worse. A histamine reaction in the
airway can cause the tissue in your nose, throat and lungs to swell. That
makes it difficult to breath. When that happens, we take something to stop
the histamines, an antihistamine. Many medicines for colds and flu contain
antihistamines. Some people are so allergic that they have to go to the
hospital to control the reaction.
After reading all this, the histamine reaction from your scratching has
probably ended and your skin is back to normal. As long as you don't think
about that imaginary itch, you won't have to scratch any more. In the mean
time, I am not allergic to turkey, so I will have a snack before bedtime.
Have a great week.
From Robert Krampf's Science Education Company
PO Box 60982
Jacksonville, FL 32236-0982
904-388-6381
krampf@aol.com
|
|
|
|
Nicholas Academy Index
|
|
Artists, wars, armour, castle games, recipes, geography, quizzes, fashions, pictures of weapons, music, old world maps, women of medieval times, medicine, language, and more.
|
Arabic, German, Japanese, Spanish, French, Italian, Latin, Russian. Games, free software downloads, free online lessons, newspapers, discussion groups, articles, history, culture, quizzes.
|
Play language arts games, improve your vocabulary, create customized puzzles, make your own book! Download free software in the form of shareware, freeware, and demos.
|
Math games, quizzes, fun websites, printable charts, coloring books, tools. Algebra, geometry, fractions, multiplication.
|
Play music games, take free music lessons, explore music theory and history, find great posters.
|
|
Explore animation, filmmaking, build online cities, create and share works of art, write stories, create your own web site, read creativity articles.
|
Science games and quizzes, fun science websites, posters, coloring books, kits, experiments, forensics labs and more.
|
Coloring books, countries of the world, games and quizzes, software downloads, posters, computer jigsaw puzzles, printables.
|
Science can be fun and understandable. Free Experiment of the Week, featuring experiments that are unusual, safe, dramatic, cheap, and fun. From Robert Kramp's Science Education Co.
|
Fun and affordable space items for kids, including toys, games, kits, food products, and more.
|
|
Educational science kits kids will love! Early science kit, DNA explorer kit, robot challenge, forensic lab, volcano kits, crystals.
|
All in one project labs, light kits, sound kits, motion and metal detectors, clap on/off kit, nerve tester and shocker.
|
Civil rights, African American writers, parts of speech, medieval, periodic table of elements, music, astronomy, world maps with flags, literature, poetry, dinosaurs, biology, cats, Japanese anime.
|
Coloring books for kids and adults. Civil war, plants, animals, states, middle ages, cultures, geometric designs, puzzles.
|
Online, via email or through the regular mail. College, accredited high school, free reading and phonics courses, foreign language, history, religion, and more.
|
|
Test your knowledge with these fast, fun, and educational quizzes. Roman numeral addition, world capitals, presidents in order, the elements, world flags, and more.
|
Roman numerals, addition, multiplication, order of statehood, state and world capitals, order of presidents, chemical elements, parts of speech, spanish numbers.
|
Reading systems, loan programs, flashcard, worksheet and test makers, game creators, board games, percentage calculator, puzzle creator, timeline template.
|
SAT, GED, ACT, practice tests, exam preparation. Standardized test practice, content standards listed by state, sample items, scope and sequence, aptitude, essential skills.
|
New and used low cost books and textbooks. Websites with open source books and loan programs.
|
|
Templates, ideas for personal, educational, children's, business sites, design tips and tools, registration and hosting information, step-by-step instructions, quick and easy web page, web building just for kids.
|
Books, posters, videos, software kits, curriculum, courses. Save on teaching supplies, receive free educational materials.
|
This site map lists nearly every page on our site, along with a short description.
|
|
|
|
Educational Poster Store
Hundreds of educational posters in different subject areas. Parts of speech, medieval, solar system, biology, world maps, Einstein, Martin Luther King. Science, math, literature, art, music, english, geography, social studies. If you don't know exactly what you're looking for, this is great to browse for ideas.
|
NASA Website Links
Educational resources include worksheets such as mazes, coloring pages, shuttle model instructions, crossword puzzles, space food tray instructions and grocery list, and more. See the Space Station Sky Watch, view a NASA Astronaut Application or the Space Shuttle Launch Schedule, learn about the U.S. Space Camp and Women in Spaceflight.
|
Zoobooks
Get a free Zoobooks issue and a tiger poster. Zoobooks are the all-in-one, everything-you-wanted-to-know but-didn’t-know-who-to-ask guide to the world’s most fascinating animals, birds, reptiles, and insects. For kids five to twelve.
|
|
