KnowledgeBoat Logo
OPEN IN APP

Chapter 7

Allergy

Class 7 - Concise Biology Selina


Review Questions

Question 1

Define the term "allergy".

Answer

Allergy is defined as a number of conditions caused by hypersensitivity of one's immune system to allergens like dust, spores, pollen, insect stings, certain types of food and cloth, etc.

Question 2

Name the inflammatory chemical released by the basophils causing skin reaction and constriction of bronchioles.

Answer

The inflammatory chemical released by the basophils causing skin reaction and constriction of bronchioles is histamine.

Question 3

How the allergy causing chemical is naturally removed from the body?

Answer

The level of allergy causing chemical decreases in the body with time if the person avoids the allergens. Vitamin C rich food also helps to decrease histamine present in the body. In serious condition anti-histamine or anti-allergic medicines are recommended.

Question 4

Match the items given under column I with those given under column II:

Sl.
No.
Column IColumn II
1.Dust allergyNuts
2.Food allergyPollen
3.Seasonal allergyAsthma

Answer

Sl.
No.
Column IColumn II
1.Dust allergyAsthma
2.Food allergyNuts
3.Seasonal allergyPollen

Question 5

Name any three routes by which allergens normally enter in our body.

Answer

Three routes by which allergens normally enter in our body are:

  1. Skin
  2. Mouth
  3. Nose

Question 6

What are allergens? Name any three allergens.

Answer

The substances that cause allergies are called allergens. Three common allergens are:

  1. Dust
  2. Spores
  3. Insect sting

Question 7

Name the two tests generally used to diagnose allergy and describe any one of them.

Answer

The two tests generally used to diagnose allergy are:

  1. Skin prick test.
  2. Blood testing

Blood testing — A sample of patient's blood is sent to a laboratory for analysis. Multiple allergens can be detected with a single blood sample. The test measures the concentration of specific antibodies in the blood. The quantitative allergy blood result can help determine what a patient is allergic to, help predict and follow the disease development, estimate the risk of a severe reaction, and explain cross-reactivity.

Question 8

Which test is mostly favoured for testing allergy, prick test or blood test? Why?

Answer

Blood test is mostly favoured for testing allergy. An allergy blood test is quick and simple, and can be ordered by a licensed health care provider. Unlike skin-prick testing, a blood test can be performed irrespective of age, skin condition, medication, symptom, disease activity, and pregnancy. Thus, we can say that blood test is a better test as compared to prick test.

PrevNext