4
Histology
Module 4.1: Introduction to Tissues
Build Your Own Glossary
Key Terms for Module 4.1
Term
Definition
Epithelial tissue
Tissue type composed of epithelial and a thin basal layer of
extracellular matrix; it covers and lines all body surfaces and
hollow organs.
Connective tissue
Tissue characterized by extensive extracellular matrix; functions
in support, protection and transport.
Muscle tissue
Tissue specialized for contraction
Nervous tissue
Tissue that makes up the majority of the brain, spinal cord, and
nerves. Unique extracellular matrix
Extracellular matrix
Substance in a tissue outside of the cells that consists of
extracellular fluid, ground substance, and protein fibers.
Ground substance
Amorphous component of the extracellular matrix containing
water; proteoglycans, glycosaminoglycans, and other molecules.
Collagen fibers
Protein fibers in the extracellular matrix of a tissue that are
composed of the protein collagen and give a tissue tensile
strength.
Elastic fibers
Protein fibers in the extracellular matrix of a tissue that give a
tissue extensibility and elasticity.
Reticular fibers
Thin protein fibers in the extracellular matrix of a tissue that form
“nets” within organs such a spleen and lymph nodes and form
supportive networks around blood vessels and nerves.
Tight junction
Intercellular junctions that hold cells tightly together in a tissue
and make the space between them relatively, impermeable.
Desmosome
Intercellular junctions that hold cells together in a tissue to
increase the tissue’s resistance to mechanical stress.
