Improve this page Learn More. Skip to main content. Module Animal Diversity. Search for:. Epithelial Tissues Learning Outcomes Describe epithelial tissues. Simple columnar epithelial cells line the tissue of the lung. Simple cuboidal epithelial cells are involved in the filtering of blood in the kidney. Pseudostratisfied columnar epithilia occur in a single layer, but the arrangement of nuclei makes it appear that more than one layer is present.
Transitional epithelia change in thickness depending on how full the bladder is. Show Answer Statement a is false. Click through the interactive review to learn more about epithelial tissues. Try It. Did you have an idea for improving this content?
Licenses and Attributions. The important functions of the simple cuboidal epithelium are secretion and absorption. This epithelial type is found in the small collecting ducts of the kidneys, pancreas, and salivary glands. Simple columnar epithelium is a single row of tall, closely packed cells, aligned in a row.
These cells are found in areas with high secretory function such as the wall of the stomach , or absorptive areas as in small intestine. They possess cellular extensions e. These are simple columnar epithelial cells whose nuclei appear at different heights, giving the misleading hence pseudo impression that the epithelium is stratified when the cells are viewed in cross section.
Pseudostratified epithelium can also possess fine hair-like extensions of their apical luminal membrane called cilia. In this case, the epithelium is described as ciliated pseudostratified epithelium. Ciliated epithelium is found in the airways nose, bronchi , but is also found in the uterus and fallopian tubes of females, where the cilia propel the ovum to the uterus.
Stratified epithelium differs from simple epithelium by being multilayered. It is therefore found where body linings have to withstand mechanical or chemical insults. Stratified epithelia are more durable and protection is one their major functions. Since stratified epithelium consists of two or more layers, the basal cells divide and push towards the apex, and in the process flatten the apical cells. Stratified epithelia can be columnar, cuboidal, or squamous type.
However, it can also have the following specializations:. Since stratified epithelium consists of two or more layers, the basal cells divide and push towards the apex, and in the process flatten the apical cells.
Stratified epithelia can be columnar, cuboidal, or squamous type. However, it can also have the following specializations:. In keratinized epithelia, the most apical layers exterior of cells are dead and lose their nucleus and cytoplasm.
They contain a tough, resistant protein called keratin. This specialization makes the epithelium waterproof, and it is abundant in mammalian skin. The lining of the esophagus is an example of a non-keratinized or moist stratified epithelium.
Transitional epithelia are found in tissues that stretch and it can appear to be stratified cuboidal when the tissue is not stretched, or stratified squamous when the organ is distended and the tissue stretches. It is sometimes called the urothelium since it is almost exclusively found in the bladder, ureters, and urethra.
Privacy Policy. Skip to main content. Organization at the Tissue Level. Search for:. Epithelial Tissue. Characteristics of Epithelial Tissue The human body consists of four types of tissue: epithelial, connective, muscular, and nervous.
Learning Objectives Describe the primary functions and characteristics of epithelial tissue. Key Takeaways Key Points Epithelial tissue is composed of cells laid together in sheets with the cells tightly connected to one another. Epithelial layers are avascular, but innervated.
Epithelial cells have two surfaces that differ in both structure and function. Glands, such as exocrine and endocrine, are composed of epithelial tissue and classified based on how their secretions are released. Key Terms epithelium : A membranous tissue composed of one or more layers of cells that form the covering of most internal and external surfaces of the body and its organs.
Types of Epithelial Tissue Epithelial tissue is classified by cell shape and the number of cell layers. Learning Objectives Classify epithelial tissue by cell shape and layers. Correct answer: Stratified squamous epithelial cells. Explanation : Keratinized stratified squamous epithelium makes up the outer layer of skin. Example Question 4 : Epithelium And Endothelium. Possible Answers: Transitional epithelium. Correct answer: Simple epithelium.
Explanation : Since capillaries are the site of diffusion of substances oxygen and carbon dioxide, for example , they need to have extremely thin walls.
Example Question 5 : Epithelium And Endothelium. Where would one expect to find simple columnar epithelium with microvilli? Possible Answers: Thyroid gland. Correct answer: Small intestine. Explanation : Since we are looking for a single layer of cells, we must rule out any area of the body that is subject to lots of friction. Example Question 6 : Epithelium And Endothelium. Where would one expect to find stratified squamous epithelium?
Possible Answers: Skin. Correct answer: All of these. Explanation : All of these areas of the body are subject to lots of friction. Copyright Notice. View Tutors. Jordan Certified Tutor. University of Alabama at Birmingham, Bachelor of Sc Cherub Certified Tutor. Rachel Certified Tutor. University of Colorado Denver, Masters, Social Report an issue with this question If you've found an issue with this question, please let us know. Do not fill in this field.
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