DIfferent types of epithelium and where found

Question 1

Ectoderm

Mesoderm

Endoderm

Answer 1

epithelial of skin and oral mucosa

epithelium of urinary tract/lining blood vessels and body cavities

Epithelium lining respiratory and digestive tracts

Question 2

Basal lamina

Answer 2

Contains laminins: connect to integrins
Type 4 collagen: attaches to laminins network
Entactin and perlecan: attaches laminin network to type 4 collagen

Question 3

Covering/lining Epithelium

Simple/stratified/pseudostratified/Urothelium

Cell shape

Answer 3

i. Simple: single layer
ii. Stratified: two or more layers

iii. Epithelial cells classified by shape: squamous, cuboidal, and columnar (classification based on shape of cells forming the surface layer)

Pseudostratified epithelium: all cells attached to basal lamina but not all reach the surface. Appearance of multiple layers
Urothelium: surface cells change shape as tissue stretches (urinary system)

Question 4

Glandular Epithelium:

Answer 4

Made of secretory cells (unicellular and multicellular)
Develop from lining epithelium; the glands grow into the underlying connective tissue

Types of Epithelium: Exocrine / Endocrine

Question 5

Exocrine:

Answer 5

release products with ducts onto body surfaces (secretory portion + duct)

2. Have many forms: simple (unbranched) and compound (branched), tubular (straight or coiled) or acinar or tubuloacinar

3 modes of secretion: merocrine/holocrine/apocrine

Chemical nature of secretion: serous, mucous

Question 6

Myoepithelial Cells

Answer 6

special contractile cells that move secretions in duct system. Wrapped around secretory portion of gland and duct

type of exocrine gland

Question 7

a. Merocrine

Answer 7

: release of contents of secretory vesicles (most common)

Question 8

b. Holocrine:

Answer 8

entire cell fills with secretion products, dies, and is shed (ex. Sebaceous; disintegrating cells w/ contents becoming secretion)

Question 9

c. Apocrine

Answer 9

lipid droplets surrounded by a little cytoplasm and some plasmalemma are the secretion product (ex. Mammary gland)

Question 10

ii. Endocrine

Answer 10

glands release their products (hormones) into extracellular fluids; NO DUCTS

1. Hormones enter the bloodstream and are carried throughout the body  act upon cells which have receptors for them
2. Paracrine: endocrine secretion acts on the cell in the local environment
3. Autocrine: cell which released the secretion has receptors for the secretion product; self