Epithelium

Question 1

What are the four basic types of tissues in the human body?

Answer 1

Epithelial, connective, nervous, and muscle tissues.

Question 2

What is epithelial tissue, and where is it found?

Answer 2

Epithelial tissue consists of closely packed cells forming layers that cover body surfaces, line cavities, and form glands.

Question 3

How is epithelial tissue classified by the number of cell layers?

Answer 3

Simple epithelium (one layer), stratified epithelium (multiple layers), and pseudostratified epithelium (appears layered but is single).

Question 4

What are the shapes of epithelial cells, and where might you find each type?

Answer 4

Squamous: flat, found in lungs.

Cuboidal: cube-shaped, found in kidney tubules.

Columnar: tall, found in the intestines.

Question 5

Describe the function and location of simple squamous epithelium.

Answer 5

It allows diffusion and filtration, found in alveoli and blood vessels.

Question 6

What is the main function of simple cuboidal epithelium, and where is it located?

Answer 6

Its main functions are secretion and absorption, located in glands and kidney tubules.

Question 7

How does simple columnar epithelium appear under a microscope, and what are its functions?

Answer 7

Appears as a single layer of tall cells with nuclei near the base, functions in absorption and secretion, found in the intestines.

Question 8

What are pseudostratified epithelia, and where are they commonly found?

Answer 8

They appear multi-layered but are single-layered; found in the respiratory tract.

Question 9

Differentiate between keratinized and non-keratinized stratified squamous epithelium.

Answer 9

Keratinized: found in the skin, provides protection and water resistance.
Non-keratinized: found in moist areas like the mouth and esophagus, protects against abrasion.

Question 10

Where is stratified cuboidal epithelium typically found, and what is its main function?

Answer 10

Found in ducts of sweat glands and salivary glands, its main function is protection and some excretion.

Question 11

What is the function of transitional epithelium, and where is it located?

Answer 11

Allows for stretching, found in the urinary bladder.

Question 12

Name and describe three surface specializations found in epithelial cells.

Answer 12

Microvilli: increase surface area for absorption, found in intestines.

Cilia: move substances across cell surfaces, found in respiratory tract.

Stereocilia: longer, for absorption, found in epididymis.

Question 13

What are tight junctions, and what role do they play in epithelial cells?

Answer 13

They seal adjacent cells to prevent leakage, found near the apical surface of cells.

Question 14

What are gap junctions, and why are they important?

Answer 14

They allow the transfer of ions and small molecules between cells, enabling communication.

Question 15

How do desmosomes support epithelial tissue?

Answer 15

They provide strong adhesion between cells, helping the tissue withstand mechanical stress.

Question 16

Explain the function of hemidesmosomes in epithelial cells.

Answer 16

Hemidesmosomes anchor epithelial cells to the basement membrane, providing stability.

Question 17

What is the basement membrane, and why is it essential?

Answer 17

A thin layer supporting epithelial cells, anchoring them and regulating molecule movement.

Question 18

Describe the structure and function of ciliated columnar epithelium.

Answer 18

Single layer of columnar cells with cilia, found in the uterine tube, moves mucus or particles.

Question 19

Which epithelial tissue types are most protective, and where are they found?

Answer 19

Stratified squamous (skin, esophagus) and transitional epithelium (urinary tract) are most protective.

Question 20

What are some diseases associated with epithelial cell junctions?

Answer 20

Diseases include psoriasis (skin inflammation) and Darier disease (impaired desmosomes).

Question 21

What are the main types of epithelial tissue?

Answer 21

The main types are simple (single cell layer) and stratified (multiple cell layers) epithelium, each further classified by cell shape as squamous, cuboidal, or columnar.

Question 22

How is epithelial tissue classified by function?

Answer 22

Epithelial tissue is classified as surface epithelium (covering/lining surfaces and cavities) and glandular epithelium (specialized for secretion, found in glands like the thyroid and sebaceous glands).

Question 23

How does the type of epithelium relate to its function?

Answer 23

Simple squamous: diffusion/filtration (e.g., alveoli).

Simple cuboidal: secretion/absorption (e.g., kidney tubules).

Simple columnar: absorption/secretion (e.g., intestines).

Stratified squamous: protection (e.g., skin).

Transitional: allows stretching (e.g., bladder).

Question 24

What are the main epithelial surface specializations, and their functions?

Answer 24

Cilia: movement of substances across the surface (e.g., respiratory tract).

Microvilli: increase surface area for absorption (e.g., intestines).

Stereocilia: long, immotile, for absorption (e.g., epididymis).

Flagella: movement, seen in sperm cells.

Question 25

What are the main types of cell junctions in epithelial tissue?

Answer 25

Tight junctions: seal cells together, control molecule passage.

Adherens junctions: link the cytoskeleton of adjacent cells.

Desmosomes: strong intermediate filament coupling.

Gap junctions: allow exchange of ions and small molecules.

Hemidesmosomes: attach cells to the basal lamina.

Question 26

How do cell junctions impact disease spread?

Answer 26

Tight junctions can be compromised by pathogens like Clostridium perfringens, leading to infections. Inhalation of allergens from dust mites can damage these junctions, causing asthma.