Epithelial Histology

Question 1

Microvilli

Answer 1

Cytoplasmic processes with actin core.

Specialize for absorption and increase surface area.

Question 2

Stereocilia/Stereovilli

Answer 2

Microvilli of unusual length.
Long and immotile.
Actin core provides rigitity.
Found only in epididymis and sensory cells of inner ear (hair cells).

Question 3

Cilia Types (3)

Answer 3

Motile: beat in wave-like fashion to propel substances across tissue.
Primary: immotile. Function as chemoreceptors, osmoreceptors and mechanoreceptors.
Nodal: embryonic. Have role in L/R axis determination.

Question 4

Flagella

Answer 4

Modified, motile cilia.

Provides movement for spem.

Question 5

6 Characteristics of Epithelia

Answer 5

Cellularity
Polarity
Attachment
Avascular
Innervation
Regeneration

Question 6

Occludens junctions

Answer 6

Impermeable. Creates barrier.

Ex: occludins, claudins.

Question 7

Anchoring junctions (2)

Answer 7

Zonula adherens: interact w/ actin inside cell.
Macula adherens (desmosome): interacts w/ intermediate filaments.
Ex: cadherins.

Question 8

Gap junctions

Answer 8

Fluid filled channels that connect apposed cells.

Function in communication.

Question 9

Focal adhesions

Answer 9

Anchor actin to BM.

Ex: integrins

Question 10

Hemidesmosomes

Answer 10

Anchor intermediate filaments to BM.

Ex: integrins

Question 11

Simple squamous epithelia

Answer 11

Location: lining of endothelium (blood, lymph), lining of
mesothelium (serous membranes) and alveoli, loop of Henle.
Function: exchange, barrier and lubrication.

Question 12

Simple cuboidal

Answer 12

Location: kidney tubules, glands, ducts, terminal bronchioles, covering of ovary.
Function: absorption, barrier, secretion.

Question 13

Simple columnar

Answer 13

Location:auditory tubes, uterus, oviducts, SI/LI, gallbladder.
Function: absorption and secretion.

Question 14

Pseudostratified columnar ciliated

Answer 14

Location: lining of nasal cavity, trachea, pharynx, bronchi.
Function: absorption, secretion. Debris and particulate movement.

Question 15

Urothelium

Answer 15

Location: bladder, ureter, urethra.
Function: barrier, distensible properties.

Question 16

Keratinized stratified squamous

Answer 16

Location: epidermis.
Function: barrier and protection.
*apical layer does not have nuclei.

Question 17

Nonkeratinized stratified squamous

Answer 17

Location: oral cavity, portions of pharynx, esophagus, anus, vagina, urhethra, cornea.
Function: barrier and protection.
*apical layer retains nuclei.

Question 18

Stratified cuboidal

Answer 18

Location: sweat glands, ducts, ovarian follicles, salivary glands.
Function: barrier and passageway.

Question 19

Endocrine vs Exocrine glands

Answer 19

Exocrine releases into a duct and endocrine release into the bloodstream.

Question 20

Types of exocrine glands (3)

Answer 20

1. Merocrine: secretion is in membrane-bound vesicles to apical surface and undergo exocytosis.
2. Holocrine: secretion accumulates within cell and causes apoptosis and contents are released.
3. Apocrine: apical portion of cell is pinched off and it is released into duct.

Question 21

Unicellular glands

Answer 21

Simplest in structure.
Singe-cell secretory cells.
ex: Goblet cell (secretes mucous).

Question 22

Multicellular glands

Answer 22

Classified by arrangement and shape. Portions of duct and secretory portions found in cell.

Question 23

Acinar and tubular

Answer 23

Acinar: bulb-like.
Tubular: long. Deeper in tissue.