science

Triple response of Lewis

Triple response of Lewis is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Triple response of Lewis rather than just read about it. In short: The triple response of Lewis is a cutaneous response that occurs from firm stroking of the skin. This produces an initial red line, followed by a flare around that line, and then finally a wheal.

Key takeaways

Triple response of Lewis belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Triple response of Lewis to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Triple response of Lewis from memory before moving on to harder problems.

Reference excerpt

The triple response of Lewis is a cutaneous response that occurs from firm stroking of the skin. This produces an initial red line, followed by a flare around that line, and then finally a wheal.

Signs The triple response consists of three aspects:

Red spot, caused by capillary vasodilation. Flare, a redness in the surrounding area due to arteriolar dilation mediated by axon reflex. Wheal, caused by exudation of extracellular fluid from capillaries and venules. The red spot emerges within 15 seconds. Flare can take up to 45 seconds to begin. Wheal can take up to 3 minutes to begin.

Cause The triple response is caused by firm stroking of the skin with a pointed object. but some time at caused by capillary vasodilation. The triple response of Lewis is particularly sensitive in people with dermatographia urticaria. Some form of dermatographia is present in around 5% of the population.

Mechanism The triple response of Lewis is due to the release of histamine. Histamine, or 2-(imidazol-4-yl)ethanamine, is a dibasic vasoactive amine that is located in most body tissues but is highly concentrated in the lungs, skin, and gastrointestinal tract. Histamine is a small molecule, stored in granules of mast cells and basophils. Mast cells and basophils are the effector cells involved in the immediate hypersensitivity response. Found in tissues throughout the body, they are particularly associated with blood vessels and nerves, and are in proximity to surfaces that border the external environment.

Hunting response of Lewis

The underlying pathophysiology of frostbite is a combination of freezing, vascular insufficiency (constriction and occlusion) and damage due to inflammatory mediators. As extremities cool, the ‘hunting response of Lewis’ (alternating vasoconstriction and vasodilation) occurs, ending with vasoconstriction.

See also Skin disease List of cutaneous conditions Thomas Lewis (cardiologist)

References

Illustrations

Worked examples

Example 1 — a first encounter with Triple response of Lewis

Start with the simplest possible case. Write down what Triple response of Lewis claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Triple response of Lewis before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Triple response of Lewis ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Triple response of Lewis

In research: Triple response of Lewis appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Triple response of Lewis in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Triple response of Lewis is common in secondary-school and first-year university syllabi. It links to neighbouring topics Dermatologic terminology, so understanding it makes those chapters shorter.
In everyday life: Look for Triple response of Lewis outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Triple response of Lewis in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Triple response of Lewis means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Triple response of Lewis out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Triple response of Lewis in simple terms?

The triple response of Lewis is a cutaneous response that occurs from firm stroking of the skin. This produces an initial red line, followed by a flare around that line, and then finally a wheal.

Why does Triple response of Lewis matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Triple response of Lewis?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Triple response of Lewis.