Tissue Types

Simple Cuboidal Epithelium Function

Function- Secretion, absorption, and protection.

Simple Cuboidal Epithelium Structure

Structure- Single layer of cubed/hexagonal-shaped cells

Simple Cuboidal Epithelium Structure

Location- Kidney tubules, secretory portion of the thyroid, salivary glands

Simple Squamous Epithelium Function

Function- Diffusion of gases, nutrients, and waste across a thin membrane.

Simple Squamous Epithelium Structure

Structure- Single layer of flat, thin, and smooth cells closely fitted together.

Simple Squamous Epithelium Location

Location- Air sacs of lungs, capillary walls, interior of heart, lining ventral body cavities.

Simple Columnar Epithelium Function

Function- Secretes enzymes, mucous or other substances; absorption microvilli increases surface area.

Simple Columnar Epithelium Structure

Structure- Single layer of taller than wider cells; may contain mucous secreting glands, microvilli, or cilia.

Simple Columnar Epithelium Location

Location- Digestive tract

Goblet cells

A type of columnar cell that is a unicellular, mucous secreting gland found in the digestive and respiratory tracts

Stratified Squamous Epithelium Function

Function- Found where mechanical stresses are harsh; protection against wear and tear of constant friction.

Stratified Squamous Epithelium Keratinized

Bottom layers of cells are living, completing mitosis, and producing keratin. Top layers are flat dead and full of keratin. Location- Skin

Stratified Squamous Epithelium Non-keratinized

Top layers of cells are living and not keratinized. Location- mouth, tongue, vaginal canal, pharynx, esophagus, anus

Stratified Squamous Epithelium Structure

Structure- Thick membrane with several layers of cells; top layers squamous, bottom layers typically cuboidal or columnar.

Stratified Cuboidal Epithelium Function

Duct lining: secretion, absorption, protection

Stratified Cuboidal Epithelium Structure

Rare tissue, multiple layers of cubed/hexagonal-shaped cells

Stratified Cuboidal Epithelium Location

Sweat glands, mammary glands

Stratified Columnar Epithelium Function

Protection

Stratified Columnar Epithelium Structure

Rare; either two layers or multiple layers

Stratified Columnar Epithelium Location

Conjunctiva covering the eye, salivary ducts, mammary glands, urethra

Pseudo-stratified Columnar Epithelium Function

Protection, secretion, movement of mucous

Pseudo-stratified Columnar Epithelium Structure

Several cell types with varying shapes and functions; appears to be layered because nuclei are seen at diffrent heights but not truly stratified, since every cell comes into contract with the basement membrane; typically possess cilia

Transitional Epithelium Function

Allows for the distension without tearing the membrane

Transitional Epithelium Structure

Modified-stratified epithelium (cells change shape from round to flat)

Transitional Epithelium Location

Urinary bladder

Endocrine Gland Function

Ductless glands that secrete hormones into the extracellular space; secretions absorbed into the blood to be circulated throughout the body

Endocrine Gland Location

Thyroid gland, adrenal gland, pituitary gland, and pancreas

Exocrine Gland Function

Contain ducts or tubes to take the secretion away from the gland to an epithelial surface

Exocrine Gland Location

Salivary glans, sweat glands, gastric glands, pancreas

Types of Exocrine Gland secretions

Serous glands- watery solution with enzymes. Mucous glands- Mucins that hydrate to form mucous. Mixed glands- different types of gland cells secrete different exocrine secretions

Holocrine Secretion

Gland cell bursts when a cell is packed with secretion; stem cells go through cell division to replace lost cells

Merocrine Secretion

Most common; released from secretory vesicles by exocytosis

Apocrine Secretion

Loss of cytoplasm along with the secretion through packed vesicles in the apical portion of the cytoplasm; must rebuild before the next secretion.