200 Lab 12 The Vascular System CHEMICAL STIMULATION sodilation vessels and surro
ID: 99613 • Letter: 2
Question
200 Lab 12 The Vascular System CHEMICAL STIMULATION sodilation vessels and surrounding point of stimulation, a spreading Chemical stimulation of the vessels can cause either vasoconstriction or va of the arterioles. Some chemicals stimulate the triple response in the vessels and surrounidi tissues. This triple response consists of a red reaction at the flare from the red area and a wheal or raised area over the red reaction. This wheal is caus by an increase in vessel permeability and the movement of water from the vessels to the ed surrounding tissues. 7. Describe the triple response of inflammation and the mechanisms that produce each response. Procedure Test the action of the following chemicals on the blood vessels by placing a drop of 1:3,000 histamine, a drop of 1:1,000 epinephrine and a drop of water on the anterior surface of the forearm. Gently scratch the skin through the drop of liquid with a sterile pin. Use a different sterile pin for each drop. Let the solutions stay on the skin for 2 minutes before wiping off any excess fluid. . Observe the color changes and any triple response immediately and after ten minutes. Place the used pins in the beaker labeled as such. * 8. What was the response of histamine to the skin? 9. How would histamine change the diameter of the arterioles?Explanation / Answer
7) Triple response of inflammation, is also called the triple response of Lewis. It is a cutaneous response and it is caused when skin is firmly stroke with something.
Triple response has 3 manifestations : at first an initial red line is formed on the skin, then a flare forms around the line followed by formation of a wheal.
These responses are caused due to a compound called histamine. Histamine is stored in mast cells and basophils granules. It is obtained by decarboxylation of an amino acid called histidine and is found in high concentrations in skin, lungs and gastrointestinal tract. It is basically a dibasic vasoactive amine.
Histamine is particularly associated with tissyes that are in close vicinity with blood vessels and nerves. The release of histamine by a cut causes triple response by these mechanisms:
Capillary dilatation by action on nerves causes red spot.
Axon reflex is mediated by areriolar dilatation which causes flare.
Due to cuts, fluids exudate from capillaries and venules.This leads to wheal and inflammation.
8) Histamine causes triple response by binding to histamine receptors on the tissues associated with blood vessels on the anterioir surface of the forearm. The response elicited were : formation of a red line, formation of a flare around the red line followed by formation of a wheal giving rise to overall inflammatory response.
9) Histamine in binding to histamine receptors on the blood vessels below the skin causes dilatation of the blood veesels. That is, the diameter of the capillaries increases.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.