Question

Choose epithelial, connective OR muscle tissue.

For the tissue category of your choice, pick two specific tissues. Compare and contrast the two specific tissues in terms of how their form fits their function.

Answer 1

Epithelial tissue :- Epithelial tissue consist of various shaped cells closely arranged in one or more layers .There is a little intercellulat material between the cells.The epithelial tissue consist of a basal surface and a free surface .The basal surface lies in contact with a noncellular layer and basement membrane .Epithelial tissue usually lie on the non cellular basement membrane consist of two layer :- Basal lamina and Fibrous or Reticular lamina .Epithelial tissues can be classified into two groups -Simple and compound ..Simple epithelial consist of a single layer of cell resting on a basement membrane .It functions as a lining body cavaties,ducts and tubes .On the basis of structure ,simple epithelial can be divided into :-

i)Squamous epithelium-It consist of single layer of flattened cells with irregular boundaries.The cells are closely fitted .It can be found in the walls of blood vessels,air sacs of lungs,loop of henle of nephrons etc.

ii)Cuboidal epithelium:-It consist of single layer of cube like cells lying on a basement membrane in which nuclei are rounded and lie in the center .It is found in ducts of glands,germinal epithelium,epithelium of proximal convoluted tubule

iii) Columnar epithelium:- It consist of tall ,slender cells in which nuclei are somewhat elongated and nuclei lie near the bases of the cell.Some of this cell produce mucus and are called goblet cells .It is found in lining of stomach and intestine and helps in absorptions and secretion .

iv)Cilitiated Epithelium:-If the columnar or cuboidal cells bear cilia on their surface ,they are called ciliated epithelium .It helps in expelling the mucus in respiratory tract and passage of ovum through fallopian tube.

v)Pseudostratified epithelium-This cells are columnar but unequal in size .It is found in urethra of human male and ducts of parotid glands .Psuedostratified ciliated columnar epithelium is found in trachea and large bronchi.

vi)Glandular epithelium -This cells of epothelium are specialized for secretion .They are of two types on the basis of cell number -unicellular and multicellular.On the basis of mode of secretion ,they are of two type-Exocrine and Endocrine.

Connective tissue :- It is the most abundant and widely distributed tissue in the body of animal.A connective tissue is made up of three components -matrix,cells and fibres.The connective tissue can be classified into three types :-Loose connective tissue ,Dense connective tissue and specialized tissue ..

Loose connective tissue :-It consist of cells and fibres loosely arranged in a semi fluid ground substance and it can be further divided into areolar and adipose connective tissue .Areolar tissue is present beneath the skin .It joins skin to muscles ,fills spaces insides organs and is found around muscles,blood vessels and nerves .Adipose tissue is basically an aggregation of fat cells or adipose cells .It is present where fats are stored and it acts asan insulator ,fat reservior .

Dense connective tissue :- It consist of fibres and fibroblast cells which are compactly packed in the matrix .It is of two types -Dense regular and dense irregular connective tissue .Examples of dense regular are tendons and ligaments and dense irrgular connective tissue is present in the skin .

Specialized connective tissue :- It include Solid connective tissue like cartilage and bone and fluid connective tissue like blood and lymph.Solid connective is the connective tissue in which the extracellular ground substance is solid .It supports the body,various organs and help in locomotion.It is of two types -cartilage and bone .Cartilage is elastic harder then dense connective tissue but softer than bone .The matrix of cartilage is solid and in the matrix are present fluid filled spaces called lacunae .Cartilage is present in the tip of nose ,outer ear joints etc.and also provides support and flexibility to the body parts .Bone is the hardest connective tissue due to the presence of calcium phosphate and calcium carbonate etc  and proteins like ossein etc.It is made up of 30% organic matter and 70% inorganic matter .The matrix is present in the form of layers called lamellae in which ring shaped fluid filled spaces called lacunae is present and the lacunae contain bone cells called osteocytes .Bones serve as a storage site for calcium and phosphate and provides structural framework to the body.

Fluid connective tissue :-It is made up of fibre free fluid matrix and specialized living cells that can neither divide nor secrete matrix .It is of two type blood and lymph which helps in transporting nutrients and gaseous to all parts of the body

Differences between epithelial tissue and connective tissue are -

Epithelial tissue	Connective tissue
Cells are closely packed together	Cells are scattered throughout an extracellular matrix
Found above the basement membrane	Found below the basement membrane
Developed from ectoderm,endoderm and mesoderm	Developed from mesoderm
Serves as a barrier over microoragnisms and dehydration while secreting,excreting and absorbing substance .	Supports and connects organs and tissues
Found in skin,glands ,mucous membranes,and organs like kidneys,lungs etc.	Found in adipose ,bone,ligaments ,tendons.cartilage and muscles etc.