histology

what are the characteristics of epithelium?

• ells very tightly packed together

• cell polarity

• absence of blood vessels

• direct contact with the basement membrane

• high regenerative capacity

what are the main functions of the epithelium?

• protection against friction

• nutrient absorption

• substance secretion

• sensation

• excretion

where is epithelium (epithelial tissue) found?

found predominantly in the lining of body surfaces and cavities such as skin and the digestive and respiratory tracts, they also form glands.

what is the lamina propria composed of?

connective tissue

what are the characteristics of connective tissue?

• composed of cells, fibers, and amorphous ground substance

• divided into loose and dense

• it is vascularized and innervated

• acts as a pathway for nutrients, waste products, and immune cells throughout the body

• it originates from the embryonic mesoderm

what are the differences between loose and dense connective tissue? to which subdivision of connective tissue do they belong?

• connective tissue itself.

• dense: rich in collagen fibers, more resistant and divided into modeled (organized fibers) and unmodeled

• loose: predominantly composed of cells and amorphous ground substance

what are the differences between loose and dense connective tissue? to which subdivision of connective tissue do they belong?

• connective tissue itself.

• dense: rich in collagen fibers, more resistant and divided into modeled (organized fibers) and unmodeled

• loose: predominantly composed of cells and amorphous ground substance

what are the differences between cells and fibers?

• cells: living units of tissues that have the ability to divide and respond to stimuli.

• fibers: inactive protein structures that do not divide, being secreted and maintained by cells. they perform various functions such as resistance and elasticity

what are the main types of body tissues?

muscular, epithelial, connective and nervous tissues

what are the cells that make up connective tissue?

• fibroblasts: produce extracellular matrix (collagen fibers, elastin, and ground substance)

• macrophages: phagocytize debris and microorganisms

• mast cells: release histamine

• plasma cells: produce antibodies

what is the extracellular matrix and what are its characteristics?

• it is a network of macromolecules (proteins and polysaccharides)

• secreted by the cells

• present in all tissues

• provide structural support

• cell communication

• regulation of cell behavior

• most abundant in connective tissues

what are the main divisions of connective tissue?

• connective tissue proper: loose or dense (regulated or irregular)

• supporting tissues: cartilage and bone

• fluids: blood and lymph

what are the main divisions of epithelial tissue?

• regarding cell shape: simple (1 layer), stratified, or pseudostratified

• regarding form: squamous, cuboidal, or prismatic/columnar

• glandular: specialized in secretion