connective tissues

connective tissues
General Features:
Contain three basic elements: cells, ground substance and fibers (Extracellular Matrix).
Matrix which may be fluid, semi-fluid, gelatinous, fibrous or calcified is usually secreted by the connective tissue cells
Do not usually occur on free surfaces.
Have a nerve supply.
Highly vascular.
Cells in connective tissue are derived form mesenchymal cells.

• Tissue à Collection of cells with a similar structure and function.

• Tissue cells are often separated by non-living, intercellular materials that cells produce. This substance is called the matrix.

• The study of tissues is known as histology

? Basic tissues types

Table 1: Main characteristics of the four basic types of tissues

Tissue Cells Extracellular matrix Main function
Epithelial Aggregated polyhedral cells Very small amount Lining of surface or body cavities, glandular secretion.
Connective Several types of fixed and wandering cells Abundant amount Support and protection
Muscle Elongated contractile cells Moderate amount Movement
Nervous Intertwining elongated processes None Transmission of nervous impulses

? Epithelial Tissue
• Types and locations
– Epithelium is divided into two types:
• Membranous (covering or lining) epithelium
• Glandular epithelium
– Locations
• Membranous epithelium covers the body and some of its parts; lines the body cavities, blood and lymphatic vessels, and respiratory, digestive, and genitourinary tracts
• Glandular epithelium: secretory units of endocrine and exocrine glands