Mammalian Body Systems and Tissues

What specialized extracellular material is secreted by epithelial cells and connective tissue cells?

In epithelial tissues, where are the most metabolically active cells typically located?

How do gases and nutrients reach the epithelial cells in avascular epithelia?

In what type of glands do some epithelial tissues lack both free surfaces and basal surfaces with a basement membrane?

What allows adjacent epithelial cells to bind together?

Which property allows epithelial cells to replace damaged cells with new ones?

What is the main function of muscular tissues in the body?

Which type of tissue covers the body and organ surfaces, and also forms glands?

What is the function of nervous tissues in the body?

Which statement is true about connective tissues?

What is histology the study of?

Which type of tissue secretes an intercellular matrix that can be liquid, semi-solid, or solid?

Epithelial Tissue

Covers the body surface, lining of digestive tract, vessels, body cavities, and forms structures such as glands (e.g. salivary glands)
Most epithelial tissues have one free surface not associated with other cells and a basal surface attached to a basement membrane
Some epithelial tissues do not have a free surface or basal surface with a basement membrane (e.g. cells of some endocrine glands)

Characteristics of Epithelial Tissue

Consists almost entirely of cells with little extracellular materials between them
Specialized cell contacts such as tight junctions and desmosomes bind adjacent cells together

Basement Membrane

A specialized type of extracellular material secreted by epithelial cells and connective tissue cells
Blood vessels do not penetrate the basement membrane to reach the epithelium
Gases and nutrients in the blood reach the epithelium by diffusing across the basement membrane from blood vessels in the underlying connective tissues

Epithelial Cell Function

Cells die as they move further away from the basement membrane
Cells close to the basement membrane are most metabolically active
Epithelial cells retain the ability to undergo mitosis and replace damaged cells with new ones
Epithelial cells can replace lost cells by cell division as long as they receive nutrients

Tissue Classification

Tissues are classified into 4 main groups: epithelial, muscular, connective, and nervous tissues
Epithelial tissues cover the body and organ surfaces, line body and lumen cavities, and form glands
Muscular tissues contract to bring about movement
Connective tissues include blood, cartilage, bone, cells of connective tissue proper, and their products
Nervous tissues initiate and transmit impulses from one part of the body to another

Explore the important functions and processes within the mammalian body, focusing on cells and tissues. Learn about the relations of tissue structure to functions in the digestive, respiratory, cardiovascular, immune, and musculoskeletal systems. Identify associated malfunctions of these systems and delve into the definition and classification of tissues.