Ch.4 Epithelial Tissue (4.4)

Question 1

Epithelia Tissue or epithelium

Answer 1

consists of cells arranged in sheets in either single of multiple layers

Question 2

ET may be classified in 2 general types:

Answer 2

1. Surface Epithelium (covering and lining epithelium) - forms the outer covering of the skin; some internal organs; the inner lining of structures (such as blood vessels, ducts, body cavities) and the lining of the respiratory, digestive, urinary, and genital systems.
2. Glandular Epithelium - makes up the secreting portion of glands (such as the thyroid gland, suprarenal (adrenal) glands, sweat glands, and digestive glands

Question 3

Functional ET:

Answer 3

Protects, secretes (mucus, hormones, enzymes), absorbs (nutrients in the digestive canal), and excretes (various substances in the urinary tract)

Question 4

An epithelial cell has an Apical surface

Answer 4

most superficial layer; a tubular duct that receives cell secretions; may contain cilia or microvilli

Question 5

An epithelial cell has a Basal surface

Answer 5

deepest layer; adhere to extracellular material such as the basement membrane; hemidesmosomes are on this layer

Question 6

A epithelia cell has a Lateral surface

Answer 6

may contain tight junctions, adhering junctions, desmosomes, and/or gap junctions

Question 7

Basement membrane

Answer 7

a thin extracellular layer that consists of 2 layers: basal lamina and reticular lamina

• they have a role in kidney failure and blindness due to thickened blood capillaries

Question 8

Basement membrane (basal lamina)

Answer 8

(top) closest to and secreted by the epithelial cells; contains the proteins lamina and collagen and glycoproteins and proteoglycans

Question 9

Basement membrane (reticular lamina)

Answer 9

(bottom) closer to the underlying CT; contains collagen produced by CT cells fibroblasts

Question 10

ET has its own nerve supply, but is avascular

Answer 10

it relies on the blood vessels of CT; the exchange of materials between the epithelium and adjacent CT is done by diffusion

Question 11

ET has a high capacity for renewal due to high rates of mitosis. This is because:

Answer 11

ET is repeatedly exposed to physical stress and injury

Question 12

Classification of Surface Epithelium (Layers)

Answer 12

1. Simple epithelium (one layer)
2. Pseudostratified epithelium (one layer that appears as several)
3. Stratified epithelium (several layers)

Question 13

Classification of Surface Epithelium (Cell Shapes)

Answer 13

1. Squamous cells (thin, wide, flat)
2. Cuboidal cells (cube-like)
3. Columnar (rectangular)
4. Transitional cells (change shape; variable)

Question 14

Different types of ET

Answer 14

Simple Epithelium 
A. Simple squamous epithelium 
  1. Endothelium 
 2. Mesothelium 
B. Simple cuboidal epithelium 
C. Simple columnar epithelium 
  1.Ciliated 
 2. Nonciliated 
D. Pseudostratified columnar epithelium 
  1. Ciliated
 2. Nonciliated 

Stratified Epithelium 
A. Stratified squamous epithelium 
  1. Keratinized 
 2. Nonkeratinized 
B. Stratified cuboidal epithelium 
C. Stratified columnar epithelium 
D. Transitional or urothelium epithelium (lines most of the urinary tract)