Info

Type

Description

Function

Location

Simple squamous epithelium Simple cuboidal epithelium

Single layer, flattened cells Single layer, cube-shaped cells

Filtration, diffusion, osmosis, covers surface Secretion, absorption

Air sacs of lungs, walls of capillaries, linings of blood and lymph vessels Surface of ovaries, linings of kidney tubules, and linings of ducts of certain glands

Linings of uterus, stomach, and intestines

Simple squamous epithelium Simple cuboidal epithelium

Simple columnar epithelium Pseudostratified columnar epithelium Stratified squamous epithelium Stratified cuboidal epithelium

Stratified columnar epithelium

Transitional epithelium

Single layer, flattened cells Single layer, cube-shaped cells

Single layer, elongated cells

Single layer, elongated cells

Many layers, top cells flattened 2-3 layers, cube-shaped cells

Top layer of elongated cells, lower layers of cube-shaped cells Many layers of cube-shaped and elongated cells

Filtration, diffusion, osmosis, covers surface Secretion, absorption

Protection, secretion, absorption

Protection, secretion, movement of mucus and cells Protection

Protection

Protection, secretion

Distensibility, protection

Air sacs of lungs, walls of capillaries, linings of blood and lymph vessels Surface of ovaries, linings of kidney tubules, and linings of ducts of certain glands

Linings of uterus, stomach, and intestines

Linings of respiratory passages

Outer layer of skin, linings of oral cavity, throat, vagina, and anal canal Linings of larger ducts of mammary glands, sweat glands, salivary glands, and the pancreas Vas deferens, part of the male urethra, and parts of the pharynx

Inner lining of urinary bladder and linings of ureters and part of urethra epithelium forms a barrier that helps prevent the contents of the urinary tract from diffusing back into the internal environment. Table 5.2 summarizes the characteristics of the different types of epithelial tissues.

Up to 90% of all human cancers are carcinomas, which are growths that originate in epithelium. Most carcinomas begin on surfaces that contact the external environment, such as skin, linings of the airways in the respiratory tract, or linings of the stomach or intestines in the digestive tract. This observation suggests that the more common cancer-causing agents may not penetrate tissues very deeply.

U List the general characteristics of epithelial tissue.

Explain how epithelial tissues are classified.

Describe the structure of each type of epithelium.

Describe the special functions of each type of epithelium.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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