Epithelial Tissue

Question 1

What are the main characteristics of epithelial tissue?

Answer 1

Cell rich.
On the surface.
Lies on a basement membrane (connects epithelial tissue to connective tissue; provides structural support).

Question 2

Describe simple squamous epithelium.

Answer 2

Found in the air sacs of lungs and vessels of the blood / lymph.
Allows for diffusion and filtration.

Question 3

Describe simple cuboidal epithelium.

Answer 3

Found in the ducts of small ducts and kidney tubules.
Allows for secretion and absorption.

Question 4

Describe simple columnar epithelium.

Answer 4

Found in the bronchi, digestive tract and bladder.
Allows for secretion and absorption.

Question 5

Describe pseudostratified columnar epithelium.

Answer 5

Found in the trachea.
Allows for secretion and movement of mucus; usually has goblet cells present.

Question 6

Describe stratified squamous epithelium.

Answer 6

Found in the mouth, oesophagus and vagina.
Allows for protection.

Question 7

Describe stratified cuboidal epithelium.

Answer 7

Found in sweat glands, salivary glands and mammary glands.
Allows for protection.

Question 8

Describe stratified columnar epithelium.

Answer 8

Found in the male urethra.
Allows for protection and secretion.

Question 9

Describe transitional epithelium.

Answer 9

Found in the bladder and urethra.
Allows for expansion and stretching.

Question 10

What are junctional complexes?

Answer 10

Keeps cells close together.
Stops fluid and molecules getting between cells.
Involved in cell signalling.

Question 11

Describe cilia and microvilli.

Answer 11

Cilia are respiratory and move particles. They are longer and thicker than microvilli.

Microvilli are gastrointestinal and absorb particles. They are non-motile.

Question 12

What is the difference between exocrine and endocrine glands?

Answer 12

Exocrine - remains in contact with the epithelium via ducts; secretes directly into the lumen of tubes; locally acting.

Endocrine - has no contact with the epithelium; secretes into blood vessels; distally acting.

Question 13

What are examples of unicellular and multicellular glands?

Answer 13

Unicellular - goblet cells.
Multicellular - salivary glands.

Question 14

What are examples of simple and compound glands?

Answer 14

Simple tubular - sweat glands.
Simple acinar - gastric glands.
Tubuloacinar - pancreatic glands.

Question 15

Describe mucous secretion.

Answer 15

Rich in proteoglycans.
Pale staining.
Peripherally flattened nuclei.

Question 16

Describe serous secretion.

Answer 16

Watery; has enzymes.
Dark staining.
Rounded, more central nuclei.

Question 17

Describe the mechanisms of exocrine secretion.

Answer 17

Merocrine - vesicles exocytose.
Via sweat glands.

Apocrine - portions of the cell pinch off.
Via mammary glands.

Holocrine - cells die and become the secretory product.
Via sebaceous glands.

Question 18

What are the functions of myoepithelial cells?

Answer 18

Found in glandular epithelium as a thin layer above the basement membrane.
Contractile cells associated with secretory end-pieces.

Question 19

How are endocrine glands structured?

Answer 19

Clusters of epithelial cells that secrete hormones into surrounding blood vessels.

Question 20

What are examples of secretory organs?

Answer 20

Exocrine - pancreas, salivary glands.
Endocrine - thyroid, adrenal glands.
Both - liver.