Homeostasis is the process through which living organisms maintain a stable internal environment despite changes in their external surroundings. It is essential for survival, as it regulates water balance, temperature, pH levels, and the concentration of important chemicals in the body.
In this chapter, you will learn how plants and humans maintain homeostasis, understand the structure and function of the human urinary system, and explore common kidney disorders. These notes are designed for exam preparation and include MCQs, short questions, and long questions to help students revise effectively and score well.
Important MCQs – Chapter 11 Homeostasis
1.What is homeostasis in plants?
(a) Rapid growth mechanism
(b) Constant internal condition maintenance ✅
(c) Absorption of light energy
(d) Production of chlorophyll
2. Extra water in plants is mostly removed by:
(a) Respiration
(b) Guttation
(c) Photosynthesis
(d) Transpiration ✅
3. At night, transpiration usually does not occur because:
(a) Leaves fal loff
(b) Roots stop working
(c) Stomata are closed ✅
(d) Photosynthesis increases
4. Which substances are removed through sweat by skin?
(a) Salts and carbon dioxide
(b) Urea, uric acid, water, and salts ✅
(c) Oxygen and nitrogen
(d) Glucose and oxygen
Short Questions – Chapter 11
1. What are the major organs involved in homeostasis in human body? State the roles of eachoftheseorgans.
Answer:
The major organs involved in homeostasis are:
- Kidneys
- Lungs
- Skin
2.What is homeostasis in plants?
Answer:
The maintenance of internal conditions (like water, gases, and salts) in plants despite environmental changes is called homeostasis.
2. What is guttation?
Answer:
The appearance of water drops at the tips or edges of leaves due to high root pressure is called guttation.
3. What is the shape and average size of a human kidney?
answer:
Kidney is bean-shaped; about 10 cm long, 5 cm wide, and weighs 120 grams.
Long Questions – Chapter 11
Q.1:What is homeostasis? Describe the role of skin, lungs, and kidneys in maintaining homeostasis in humans.
➤ Introduction:
- Homeostasis is the ability of the body to maintain a stable internal environment despite changesintheexternalsurroundings.
- In humans, several organs work together to control the levels of water, salts, body temperature,andcarbondioxide.
Roles of Organs in Homeostasis:
1. Lungs
-
Remove extra carbon dioxide (CO₂) from blood.
-
CO₂ travels from cells → blood → lungs → out of body.
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Keeps blood acid-base balanced.
2. Skin
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Controls temperature: Sweating cools body; fat layer & goosebumps conserve heat.
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Excretes waste: Sweat removes water, salts, urea, and uric acid.
3. Kidneys
-
Filter blood to remove water, salts, urea, uric acid.
-
Make urine and keep fluid, salt, and blood pressure balanced.
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