Tissues

Q45. Draw a labelled diagram of a neuron.

Ans. 

Image From NCERT

Q46. Complete the table:

Ans. 

Q47. Name the regions in which parenchyma tissue is present.

Ans. Parenchyma is a simple permanent tissue of angiospermic plants. It is present in cortex and pith of stem and roots. It is also present in the mesophyll of leaves.

 
Q48. What is the role of epidermis in plants?

Ans. The epidermis in plants forms an uninterrupted and continuous layer that has no intercellular spaces. It provides protection to underlying tissues.

Q49. Name the tissue responsible for movement in our body.

Ans. The functional combination of nerve and muscle tissue is fundamental to most animals. This combination enables animals to move rapidly in response to stimuli.

Q50. How does the cork act as a protective tissue?

Ans. Cells of cork are dead and compactly arranged without intercellular spaces. They also have a chemical called suberin in their walls that makes them impervious to gases and water.

 
Q51. Water hyacinth float on water surface. Explain.

Ans. Water hyacinth has spongy petioles which enclose a lot of air in its aerenchyma. Air makes the plant lighter than water so that it is able to float on surface of water.

Q52. If a potted plant is covered with a glass jar, water vapours appear on the wall of glass jar. Explain why?

Ans. This happens due to the phenomenon of transpiration. During transpiration water escapes from the stomatal openings of the leaf. These vapours appear on the glass jar if a potted plant is covered with the glass jar.

Q53. Fill in the blanks.
(a) Lining of blood vessels is made up of _____.
(b) Lining of small intestine is made up of _____.
(c) Lining of kidney tubules is made up of _____.
(d) Epithelial cells with cilia are found in_____ of our body.

Ans. (a) squamous epithelium

(b) columnar epithelium

(c) cuboidal epithelium

(d) respiratory tract

Q54. Animals of colder regions and fishes of cold water have thicker layer of subcutaneous fat. Describe why?

Ans. In animals, subcutaneous fat functions as an insulating layer that prevents heat loss from the body in cold environment. So animals in cold areas and fishes of cold water possess thicker layer of subcutaneous fat. Fat also functions as reserve food during periods of food scarcity.

Q55. What is the specific function of the cardiac muscle?

Ans. Functions: 

1. Cardiac muscles contract and relax rapidly, rhythmically and tirelessly throughout a life time.

2. The contraction and relaxation of the heart muscles help to pump and distribute blood to various parts of body.

Q56. Write true (T) or false (F)
(a) Epithelial tissue is protective tissue in animal body.
(b) The lining of blood vessels, lung alveoli and kidney tubules are all made up of epithelial tissue.
(c) Epithelial cells have a lot of intercellular spaces.
(d) Epithelial layer is permeable layer.

(e) Epithelial layer does not allow regulation of materials between body and external environment.

Ans. a. True

b. True

c. False

d. True

e. False

Q57. Which structure protects the plant body against the invasion of parasites?

Ans. The entire surface of a plant has outer covering of epidermis. It protects all the parts of the plant. Epidermal cells on the aerial parts of the plant often secrete a waxy, water-resistant layer on their outer surface. This aids in protection against loss of water, mechanical injury and invasion by parasitic fungi.

Q58. Give reasons for
(a) Meristematic cells have a prominent nucleus and dense cytoplasm but they lack vacuole.
(b) Intercellular spaces are absent in sclerencymatous tissues.
(c) We get a crunchy and granular feeling, when we chew pear fruit.
(d) Branches of a tree move and bend freely in high wind velocity.
(e) It is difficult to pull out the husk of a coconut tree.

Ans. (a) They are undergoing divisions (by mitosis) and do not store food.

(b) They have lignified walls and form bundles for mechanical function.

(c) It has stone cells or sclereids.

(d) Collenchyma provides them flexibility.

(e) Sclerenchyma fibres are tightly packed.

Q59. What are the functions of the stomata?

Ans. Small pores here and there in the epidermis of the leaf are called stomata. Stomata are enclosed by two kidney-shaped cells called guard cells. They are necessary for exchanging gases with the atmosphere. Transpiration (loss of water in the form of water vapour) also takes place through stomata.

Q60. Identify the type of tissue in the following: skin, bark of tree, bone, lining of kidney tubule, vascular bundle.

Ans. (a) Skin—Striated squamous epithelium

(b) Bark of tree—Cork, Protective tissue

(c) Bone—Connective tissue

(d) Lining of kidney tubule—Cuboidal epithelium tissue

(e) Vascular bundle—Conducting tissue

Q61. How are simple tissues different from complex tissues in plants?

Ans. Simple Tissues: These tissues are composed of cells which are structurally and functionally similar. Thus, these tissues are all made of one type of cells.

Complex Tissues: The complex tissues consist of more than one type of cells having a common origin. All these cells coordinate to perform a common function.

Q62. Name the following.
(a) Tissue that forms the inner lining of our mouth.
(b) Tissue that connects muscle to bone in humans.
(c) Tissue that transports food in plants.
(d) Tissue that stores fat in our body.
(e) Connective tissue with a fluid matrix.
(f) Tissue present in the brain.

Ans. (a) Squamous epithelium

(b) Tendons

(c) Phloem

(d) Adipose tissue

(e) Blood

(f) Nervous tissue