Tissue Types

Histology

The study of tissues

Epithelial

Covering

Connective

Support

Muscle

Movement

Nerve

Communication/control

Epithelia: Simple squamous

One layer flat cells.

Multinucleate

Functions: Secretion, absorption, and filtration.

Found in the lungs

Epithelia: Simple cuboidal

One layer cube-like cells.

Spherical nuclei.

Functions: Secretion and absorption.

Found in the kidneys.

Epithelia: Simple columnar

One layer, tall cells.

Spherical nuclei. Arranged at the basal end of cells. Ciliated or not.

Functions: Secretion and absorption.

Found in the GI tract, stomach, small intestine, and large intestine.

Epithelia: Pseudostratified ciliated columnar

False layers. One layer. Tall cells. Cilia. Nuclei neatly arranged.

Goblet cells secrete mucus.

Found in trachea.

Epithelia: Stratified squamous

Many layers. Nonkeratinized → internal surfaces of the esophagus.

Flat cells.

Protection against abrasion and corrosion.

Keratinized ~ skin

Epithelia: Transitional

Many layers, many shapes. Tall cuboidal. Umbrella cells.

Functions: Stretch/distinction.

Gland

One or more cells that makes and secretes an aqueous or oily fluid. Endocrine - internal secretions. Exocrine - external secretions (digestive secretions)

Ground substance (connective tissue)

Unstructured material that fills the space between cells.

Fibers

Collagen, elastic, or reticular. C

Collagen

Tough, resist longitudinal (pulling) stress.

Elastic

Rubber-band like. Stretch and recoil.

Reticular

Branched collagenous fibers. (trees). Physical support organs, blood vessels.

Connective tissue proper: loose, areolar

Loosely packed fibers. All 3 fiber types. Collagen. Elastic and reticular.

Function: Hydration and cushion.

Found in the skin.

Connective tissue proper: loose, adipose (fat)

1 nucleus per cell.

Function: Insulation and cushions.

Found under the skin.

Connective tissue proper: loose, reticular

Lots of cells (most) immune cells.

Reticular fibers.

Function: physical supports.

Found in lymph organs (nodes)

Connective tissue proper: dense regular

High concentration of fibers. Neatly stacked collagen fibers.

Function: Resist pulling stress in one direction.

Found in tendons and ligaments.

Connective tissue proper: dense irregular

Irregular arrangement of collagen fibers.

Function: Resist pulling stress in multiple directions.

Found in the skin. C

Connective tissue proper: elastic (dense)

Neatly arranged collagen and elastic fibers.

Function: stretch and recoil.

Found in the aorta.

Connective tissue: hyaline cartilage

Inconspicuous fibers. Chondrocytes in lacuna (space). “Jello”.

Function: Resist compression.

Most common in cartilage.

Found in all joints.

Connective tissue: Elastic cartilage

Elastic fibers.

Functions: bendy

Pinna epiglottis

Connective tissue: fibrocartilage cartilage

Collagen fibers.

Function: Increase strength.

Only found in knees, between vertebrae and hips (pubic symphysis)