Tissue and Its Classification

Question 1

What are tissues?

Answer 1

Tissues are aggregates or groups of cells organized to perform one or more specific function

Question 2

How do the cells within the tissues communicate?

Answer 2

Cells within tissues communicate through specialized intercellular junctions (gap junctions) which allow the cells to operate as a functional unit

Question 3

What are the four basic types of tissue and their functions?

Answer 3

• epithelial tissue: covers body surfaces, lines body cavities and forms glands
• connective tissue: underlies or supports the other three basic tissues both structurally and functionally
• muscle tissue: made up of contractile cells and is responsible for movement
• nerve tissue: receives, transmits and integrates information from outside and inside the body to control the activities of the body

Question 4

What are the characteristics of epithelial tissue?

Answer 4

• close cell apposition
• presence at a free surface
• the intercellular space between epithelial cells is minimal and devoid of any structure except where junctions attachments are present
• free surfaces are characteristic of the exterior of the body, the outer surface of many internal organs, the lining of body cavities, tubes and ducts and those the communicate with the exterior of the body and those that are enclosed
• enclosed body cavities and tubes including the pleural, pericardial and peritoneal cavities as well as the cardiovascular system is lined by epithelium

Question 5

How is epithelial tissue classified?

Answer 5

Depending on layers:

• single layer
• multilayer (stratified)

Depending on shape:

• squamous
• cuboidal
• columnar

Question 6

What are the characteristics of connective tissue?

Answer 6

• cells are conspicuously separated from one another
• the intervening spaces are occupied by material produced by the cells
• this extracellular material is called the extracellular matrix
• the nature of the cells and matrix varies according to the function of the tissue

Question 7

What are the types of connective tissue?

Answer 7

• loose connective tissue: the extracellular matrix of loose connective tissue contains loosely arranged collagen fibers and numerous cells
• dense connective tissue: where only strength is require, collagen fibers are more numerous and densely packed

Question 8

what are the characteristics of muscle tissue?

Answer 8

• categorized on the basis of a functional property, the ability of its cells to contract
• characterized by large amounts of the contractile proteins actin and myosin in their cytoplasm and by their particular cellular arrangement in the tissue
• they are typically elongated
• most muscle cells are aggregated into distinct bundles that are easily distinguished from the surrounding tissue

Question 9

what are the types of muscle tissue?

Answer 9

• smooth
• skeletal
• cardiac

Question 10

what is the histogenesis of tissue in general?

Answer 10

The three germ layers: ectoderm, mesoderm and endoderm give rise to all the tissues and organs of the body and are derived from the embryo proper or inner cell mass.