Epithelial and Connective Tissue Notes

Tissue: group of cells found together in the body, sharing a common origin and features, and are arranged in an orderly pattern that creates function 

Histology: study of tissue structure, organization, and function 

Connective tissue: binds cells and organs together for protection and support

Epithelial tissue: cells that cover external surfaces and internal cavities

Nervous tissue: propagates and transports communication throughout the body

Muscle tissue: responsive to stimulation and provide movement

Mucous (epithelial tissue): membranes that line tracts that are “exposed” to the external environment; covered with mucous 

Serous (epithelial tissue): membranes that line cavities closed to the external environment

Cutaneous (epithelial tissue): ”dry,” covers the body surface

Synovial (epithelial tissue): line joint cavities and produce fluid inside the joint; Connective tissue 

Common structural features of epithelial tissue: Highly cellular, little extracellular material; Apical Surface - ‘exposed’ surface, superior side; Basement Membrane - secreted connective tissues that holds it together; Nearly completely avascular (no blood vessels cross over from basement membrane, so nutrients must pass via diffusion or absorption.

Squamous description: outside of nucleus is squashed [flat]

Cuboidal description: outside of nucleus are equal around (like a cube)

Columnar description: outside of nucleus is like a column 

Simple squamous epithelium: Location-- heart, blood vessels, and lymphatic vessels; Function-- allows materials to pass through by diffusion and filtration, and secretes lubricating substance

Stratified squamous epithelium: Location lines the esophagus, mouth, and vagina; Function protects against abrasion 

Simple columnar epithelium: Location-- ciliated tissues in bronchi, uterine tubes, and uterus: smooth (ciliated) are in digestive tract, bladder; Function-- absorbs: also secretes mucous and enzymes 

Stratified columnar epithelium: Location-- male urethra and the ducts of some glands; Function-- secretes and protects 

Simple cuboidal epithelium: Location-- in ducts and secretory portions of small glands and in kidney tubes; Function-- secretes and absorbs 

Stratified cuboidal epithelium: Location-- sweat glands, salivary glands, and the mammary glands; Function-- protective tissue 

Pseudostratified columnar epithelium: Location-- lines the trachea and much of the upper respiratory tract; Function-- secretes mucus; ciliated tissue moves mucus 

Functions of connective tissue: connects body parts; protects, supports, and binds other tissues together 

Extracellular matrix (shorten this): Non-living substance that makes up connective tissue; produced by connective tissue and then secreted to the exterior; made up of--Structureless ground substance - “glue” that keeps the tissue together AND Fibers - collagen, elastic, and reticular fibers; Forms a soft packing tissue around other organs, bears weight, and can withstand stretching and abrasion; Ranges from fat tissue to bones and cartilage.

Bone: Bone cells are in cavities called lacunae, which are surrounded by layers of layers of a very hard matrix of calcium salts and large numbers of collagen fibers; Awesome ability to protect and support.

Dense Connective Tissue: Mostly collagen fibers with rows of fibroblasts

Tendons (dense connective tissue): connect muscle to bone

Ligaments (dense connective tissue): connect bone to bone

Loose connective tissue: Softer, more cells, less fibrous than other connective tissues (except blood).

Areolar tissue (loose connective tissue): most widely distributed; holds organs together & in place.

Adipose tissue (loose connective tissue): aka fat; insulates the body from extreme heat & cold; under skin.

Reticular Connective Tissue: forms internal framework for free blood cells and spleen, lymph nodes, & bone marrow.

Blood: is a tissue because it consists of blood cells surrounded by a fluid matrix called blood plasma; Protein molecules are soluble fibers; Atypical connective tissue since it is a transport vehicle instead of a structure.

Hyaline (cartilage): lots of collagen fibers; blue and white appearance; covers ends of bones, forms larynx, attaches ribs to breastbone 

Fibrocartilage (cartilage): highly compressible; between vertebrae discs 

Elastic (cartilage): where elasticity is desired; holds structure but you can move/wiggle it; ex. external ear and nose