NCERT SAMPLE QUESTIONS IX SCIENCE
1)Write one function each of the following.
a)squamous epithelium
b)Fluid CONNECTIVE tissue
c)ciliated columnar epithelium 3M.
2)what is a nervous tissue?Give its functions.Explain the structure of a neuron with a diagram. 5M
3)which type of muscles are found in the iris of the eye ,smooth or striated?why are smooth muscles called involuntary muscles?In what way they are different from striated muscles with respect to number of nuclei? 3M
4)Differentiate between axon and dendron. 1M
5)Draw well labelled diagram s of various types of muscles found in human body. 5M
Answers
Answer:
Animal tissues are classified into four types based on the functions they perform:
(i) Epithelial
(ii) Connective
(iii) Muscular
(iv) Nervous
(i) Epithelial tissues
They form the covering of the external surfaces, internal cavities and organs of the animal body.
Epithelial tissue cells are tightly packed and form a continuous sheet.
The skin, the lining of the mouth, the lining of blood vessels, lung alveoli and kidney tubules are all made of epithelial tissue.
Functions of Epithelial Tissue:
(i) Epithelitum covers most organs and cavities within the body.
(ii) It also forms a barrier to keep different body systems separate.
(iii) The permeability of the cells of various epithelia play an important role in regulating the exchange of materials between the body and the external environment.