Selina solutions concise biology class 9 icse Solutions for Chapter 13 skin the jack of all trades

The statements given below have some parts printed in bold face. In case these parts are incorrect, rewrite these in correct form.

1. All mammals are ectothermal.

2. Hibernation is also known as summer sleep.

3. Human body temperature normally is 98.6°F(37°C)

4. Vigorous activity on a cold day overheats you.

5. The principal heat-regulating centre is located in thyroid.

6. Increased body heat causes vasoconstriction.

7. Facial hair in humans contributes to sex differences.

Match the items in Column I with those in Column II.

Column I Column II

(i) Air spaces a. Hair

(ii) Mammary glands b. Sebaceous glands

(iii) “Goose-flesh” c. Rudimentary in males

(iv) Traces of urea d. Races of hot countries

(v) More numerous sweat pores e. Gray hair

(vi) Oily secretion f. Sweat

How do hairs provide the sensation of touch?

How is the outer surface of the skin made waterproof?

The statements given below have some parts printed in bold face. In case these parts are incorrect, rewrite these in correct form.

1. All mammals are ectothermal.

2. Hibernation is also known as summer sleep.

3. Human body temperature normally is 98.6°F(37°C)

4. Vigorous activity on a cold day overheats you.

5. The principal heat-regulating centre is located in thyroid.

6. Increased body heat causes vasoconstriction.

7. Facial hair in humans contributes to sex differences.

If for some reason the sebaceous glands fail to function: (a) The body will not be able to regulate the body temperature (b) The skin will turn darker with more melanin (c) The hairs will fail to grow (d) The skin will turn dry and rough

Which one of the following pairs include the abnormal conditions of skin pigmentation? (a) Leukoderma, Ringworm (b) Albinism, Leukoderma (c) Baldness, Albinism (d) Rickets, Baldness

Which one of the organs listed below, functions in regulating our body temperature most actively? (a) Heart (b) Lungs (c) Skin (d) Stomach

Sweat glands are situated in: (a) Epidermis (b) Dermis (c) Both (d) None of the above

The epidermis is highly thickened in: (a) Eyelid (b) Thigh (c) Lip (d) Palm

Name the principal body heat regulating centre in our brain

Name any one modified sweat gland and any one modified sebaceous gland.

Name the skin glands which when inflamed cause acne.

State any two functions of the mammalian skin other than those concerned with heat regulation.

What is “goose-flesh”? How is it brought about?

Name the body structure concerned with the given functional activity:

(a) Prevents food from entering the trachea during swallowing

(b) Transports oxygen to the body cells

(c) Helps to increase the volume of the chest activity lengthwise

(d) Combines with the oxygen in the lungs

(e) Protects the lungs from mechanical injuries

(f) Provides actual diffusion of respiratory gases in lungs.

What is the difference between leucoderma and albinism?

Name any two glands found in the human skin. State their functions.

An otherwise normal healthy young man started perspiring while it was intensely cold outside. What could have been one reason for it?

Enumerate in a tabular form the different structures found in the epidermis and dermis of the human skin

Explain the terms “vasodilation” and “vasoconstriction”. How do these processes contribute in the regulation of the body temperature?

How does our skin provide protection to our body against the following?

(a) Entry of germs

(b) Excessive loss of heat in severe cold

(c) Entry of harmful ultra-violet rays

Draw a labeled diagram of the generalized vertical section of the mammalian skin

Given below is a diagrammatic sketch of the vertical section of the human skin.

(a) Label the parts numbered from 1 to 9.

(b) State one main function of each of the following parts:

Part 2. __________ Part 3. __________

Part 4. __________ Part 9. ______\__

Name any one of the above parts which has at least three functions.

(c) Part 4 may add to one’s good appearance or the “figure”. State one example of this function which may be common to both men and women.