Epithelial and Connective Tissues: Functions and Locations

Epithelial Tissue Types

Simple Squamous Epithelium

Function: Reduces friction; controls vessel permeability; performs absorption and secretion.

Locations: Mesothelia lining pleural, pericardial, and peritoneal cavities; endothelia lining heart and blood vessels; portion of kidney tubules (thin sections of nephron loops); inner lining of cornea; alveoli of lungs.

Stratified Squamous Epithelium

Function: Provides physical protection against abrasion, pathogens, and chemical attack.

Locations: Surface of skin; lining of mouth, throat, tongue, esophagus, rectum, anus, vagina.

Simple Cuboidal Epithelium

Locations: Glands, ducts, portion of kidney tubules, thyroid gland.

Stratified Cuboidal Epithelium

Function: Protection, secretion, absorption.

Locations: Lining of some ducts (rare).

Simple Columnar Epithelium

Function: Protection, secretion, absorption.

Locations: Lining of stomach, intestine, gallbladder, uterine tubes, collecting ducts of kidneys.

Pseudostratified Columnar Epithelium

Function: Protection, secretion, moves mucus with cilia.

Locations: Lining of nasal cavity, trachea, bronchi, portions of the male reproductive tract.

Stratified Columnar Epithelium

Function: Protection.

Locations: Small areas of the pharynx, epiglottis, anus, mammary glands, salivary gland ducts, urethra.

Connective Tissue Types

Loose Connective Tissue Proper

Areolar Connective Tissue

Function: Protects skin and organs. Binds skin and epithelia to deeper tissue. Provides space for blood vessels and nerves.

Locations: Papillary layer of dermis, subcutaneous layer, surrounding organs, nerve cells, muscle cells, component of blood vessel walls.

Adipose Tissue

Function: Stores energy, insulates, cushions, and protects.

Locations: Subcutaneous layer, covers some organs.

Dense Connective Tissue

Dense Regular Connective Tissue

Function: Resists stress applied in a specific direction.

Locations: Tendons and ligaments.

Dense Irregular Connective Tissue

Function: Withstands stress applied in all directions.

Locations: Dermis, epimysium covering skeletal muscle, epineurium covering nerves, periosteum covering bone, perichondrium covering cartilage, organ capsules.

Cartilage

Hyaline Cartilage

Function: Support; forms most of the fetal skeleton.

Locations: Tip of nose, trachea, bronchi, larynx, costal cartilage, epiphyseal plates, articular ends of long bones, fetal skeleton.

Fibrocartilage

Function: Weight-bearing; resists compression; shock absorber.

Locations: Intervertebral discs, pubic symphysis, menisci of the knee.

Elastic Cartilage

Function: Maintains shape while permitting flexibility.

Locations: External ear, epiglottis.