Epithelium

Question 1

4 tissue types

Answer 1

• Epithelium
• Muscle
• Nerve
• Connective tissue

Question 2

epithelium

Answer 2

A sheet of cells that line all body surfaces, cavities and tubular organs

Question 3

How do epithelial layers get nutrients

Answer 3

Through diffusion, because they are avascular

Question 4

Where does epithelium come from

Answer 4

Arises from all 3 embryonic germ layers (ectoderm, endoderm, and mesoderm)

Question 5

5 Characteristics of epithelium

Answer 5

• Arises from embryonic germ layers
• Comprised of tightly packed cells
• Avascular
• All require renewal and are capable of regeneration and repair
• Epithelial sheets are polarized

Question 6

Epithelial apical surface

Answer 6

exposed to the external environment

Question 7

Epithelial basal surface

Answer 7

Lies on a supporting connective tissue which is separated from the epithelium by a basement membrane.

Question 8

Basement membrane

Answer 8

Consists of specialized collagenous fibers (basal lamina) and other adhesive molecules (laminin).
-Visible under light microscopy

Question 9

Basal lamina

Answer 9

Anchors the epithelial sheet to the underlying tissue. Only visible with electron microscopy

Question 10

Epithelial cell types

Answer 10

• Simple (single layer of cells)

- Stratified (Comprised of 2 or more layers of cells. Top layer defines epithelium)

Question 11

Simple cells

Answer 11

• Simple Squamous
• Simple cuboidal
• Simple columnar
• Pseudostratified columnar

Question 12

Simple squamous

Answer 12

Cells are flat. Gases and liquids can diffuse easily. Line most internal surfaces

Question 13

3 types of simple squamous

Answer 13

• Endothelium (line blood vessels, lymphatics, and the heart
• Mesothelium (Line serous body cavities and outer tubular organs in the abdomen)
• Epithelium-no special name (Line small tubules in the kidney

Question 14

Simple cuboidal

Answer 14

Width and height of cells are equal. Line small ducts

Question 15

Simple columnar

Answer 15

Height of cells is greater than width. Line much of the GI tract and have secretory and absorptive capability

Question 16

Pseudostratified columnar

Answer 16

Cells are columnar.

• All cells touch the basal lamina, but not all cells reach the lumen
• Found where particulate matter is moved (reproductive and respiratory tracts) usually have cilia

Question 17

Stratified epithelium

Answer 17

Comprised of 2 or more layers of cells. Top layer defines the epithelium

Question 18

3 types of stratified epithelium

Answer 18

• Stratified squamous
• Stratified cuboidal and columnar
• Transitional

Question 19

Stratified squamous

Answer 19

Surface cells are squamous, cells of other layers are polyhedral (usually serves a protective role).

Question 20

2 Types of stratified squamous

Answer 20

• Keritinized (dry, cornified); Surface cells synthesize keratin; a cytoplasmic protein that is abrasion resistant (skin)
• Non-keratinized (wet); Surface cells are viable (esophagus)

Question 21

Stratified cuboidal and columnar

Answer 21

Surface layer defined as cuboidal or columnar. Other cells vary in shape. Line large ducts

Question 22

Transitional

Answer 22

Layered epithelium that changes appearance (between cuboidal and columnar) depending upon its state of distension. Cells appear (poofy when relaxed. Usually just found in the bladder

Question 23

7 functions of the epitheilium

Answer 23

• Protection (Skin)
• Secretion (exocrine glands)
• Absorption (intestines)
• Excretion (kidney tubules)
• Sensation (taste buds)
• Transportation (trachea)
• Reproduction (testes)

Question 24

4 types of connective tissues

Answer 24

• Blood
• Supportive Connective Tissue (cartilage and bone)
• Adipose Tissue
• Connective tissue proper