Class 9 Skin Mock Test (ICSE)

Topics in Skin

• Structure of skin
• Functions of skin
• Regulation of body temperature
• Care of skin

Skin practice questions with answers

1. Q1Multiple choice·1 mark
   Which of the following practices is recommended for maintaining healthy skin?

   1. (a)Squeezing pimples to clear the blocked oil glands
   2. (b)Sharing a towel with family members after bathing
   3. (c)Bathing in very hot water to open the skin pores
   4. (d)Bathing daily with mild soap and clean water
   Show answer and step marks

   1. Correct option: (d) Bathing daily with mild soap and clean water+1

   Answer: (d)
2. Q2Multiple choice·1 mark
   Which layer of the skin contains blood vessels, nerve endings, and sweat glands?

   1. (a)Dermis
   2. (b)Epidermis
   3. (c)Subcutaneous layer
   4. (d)Stratum corneum
   Show answer and step marks

   1. Correct option: (a) Dermis+1

   Answer: (a)
3. Q3Multiple choice·1 mark
   In response to a cold environment, how do the arrector pili muscles in the skin help in regulating body temperature?

   1. (a)They contract to pull hair upright, trapping an insulating layer of air.
   2. (b)They dilate blood vessels to release trapped body heat.
   3. (c)They relax to allow maximum blood flow to the epidermis.
   4. (d)They stimulate sweat glands to produce cooling moisture.
   Show answer and step marks

   1. Correct option: (a) They contract to pull hair upright, trapping an insulating layer of air.+1

   Answer: (a)
4. Q4Multiple choice·1 mark
   Which of the following substances are eliminated from the body through sweat produced by the skin?

   1. (a)Carbon dioxide and excess oxygen
   2. (b)Glucose, proteins, and urea
   3. (c)Bile pigments and uric acid only
   4. (d)Urea, water, and mineral salts
   Show answer and step marks

   1. Correct option: (d) Urea, water, and mineral salts+1

   Answer: (d)
5. Q5Long answer·4 marks
   Explain how the human skin regulates body temperature under varying conditions: (a) Describe the action of blood vessels in the skin when the surrounding temperature is very high. (b) State the condition of sweat glands and blood vessels when the body needs to conserve heat in a cold environment. (c) Name the specific region of the brain which acts as the thermoregulatory centre.
   Show answer and step marks

   1. (a) The blood vessels (capillaries) in the skin dilate (vasodilation).+1
   2. (a) More blood flows close to the skin surface, so more heat is lost to the surroundings by radiation, conduction and convection.+1
   3. (b) Sweat glands become inactive, secreting little or no sweat.+0.5
   4. (b) Blood vessels in the skin constrict (vasoconstriction), reducing blood flow to the skin and so reducing heat loss.+0.5
   5. (c) Hypothalamus.+1

   Answer: (a) Skin blood vessels dilate (vasodilation), bringing more blood to the surface so more heat is lost. (b) Sweat glands become inactive and skin blood vessels constrict (vasoconstriction). (c) Hypothalamus.

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