MCM Epithelium

Question 1

Simple squamous is located _______.

Answer 1

• Blood vessels (endothelium)
• body cavities (mesothelium)
• Bowman’s capsule
• alveoli

Question 2

Simple cuboidal function & location?

Answer 2

• function: protective, secretory, and absorptive
• location: Gland ducts, kidney tubules

Question 3

Simple columnar - long, _____ nucleus. Location?

Answer 3

• ovoid
• Lining of intestine, stomach, female reproductive system, etc

Question 4

• Microvilli has_____ and is located _____.

Answer 4

• glycocalyx
• Striated border = microvilli + glycocalyx

Increases surface area for absorption/secretion

Question 5

Cilia function and location.

Answer 5

• fxn: Transport matter along cell surface
• location: Found on columnar cells

Question 6

Location of nonkeratinized epithelium?

Answer 6

Lining moist cavities (oral cavity, esophagus, vagina, anal canal)

Question 7

Stratified cuboidal is found _____.

Answer 7

sweat glands

Question 8

Stratified columnar

Answer 8

conjunctiva,

lining ducts of large glands

Question 9

Where is Where is transitional epithelium found?

Answer 9

bladder

ureter

urethra

cells are binucleate (unique to this epithelium)

Question 10

Describe the transitional epithelium when the bladder is full vs. empty.

Answer 10

full: apical cells flattened (“shield”)
empty: apical cells rounded & dome-like

Question 11

Pseudostratified columnar epithelium location & specializations?

Answer 11

• respiratory tract & male reproductive system
• stereocilia (surface of epididymal epithelium)

Single layer attached to basal lamina (Nuclei arrangement → appearance of 2-3 cell layers)

Question 12

Location of Glandular epithelium?

Answer 12

penetrate into the underlying connective tissue (exocrine glands)

Question 13

Describe the major components of the epithelial basal lamina.

Answer 13

• Type IV collagen, laminin 5, fibronectin, hemidesmosomes
• Laminin – atta­­­ches BL to the epithelium, has binding sites for integrin/collagen IV

Acellular dense fibrous sheet interposed between the basal epithelial cell layer and the underlying connective tissue

Question 14

What is the importance of the epithelial basal lamina?

Answer 14

• Forms barrier between epithelium and underlying connective tissue.
• Firm, yet flexible support for overlying epithelium.

Question 15

Name the epithelia in the grey box (simple).

Answer 15

• squamous
• cuboidal
• columnar

Question 16

Name the epithelia in the pink box (stratified).

Answer 16

• squamous
• cuboidal
• columnar

(same shapes as simple epithelia)

Question 17

Name the epithelia in the blue box (simple).

Answer 17

• pseudostratified
• transitional

Question 18

Microvilli are Composed of _______.

Answer 18

villin, actin filament, myosin I, terminal web, & intermediate filaments

Question 19

What is the name of microvilli + glycocalyx? Where are they located?

Answer 19

• Brush or striated border.
• Brush: intestine
• Striated: Kidney

Question 20

Function of cilia?

Answer 20

Motile cilia generates fluid flow (lung cilia) and movement with fluid (sperm)

Question 21

Define axoneme & its composition.

Answer 21

the microtubule based cytoskeleton of cilia

contains dynein (cytoskeleton motor protein that “drives the beat” of cilia, transforming the chemical energy of ATP into mechanical work)

Question 22

Define cilia dyskinesia.

Answer 22

Immotile cilia, often leading to chronic respiratory problems & infertility in males

Question 23

Define lateral surface folding.

Answer 23

increasing surface area or cell/tissue attachment

Involved in fluid transport (kidney tubules)

Question 24

Name the three intercellular junctions.

Answer 24

1. Junctional complex
2. Hemidesmosomes
3. Gap junctions

(Junctional complex includes zonula occludens, zonula adherens, macula adherens/spot desmosomes)

Question 25

What is the function of the zona occludens?

Answer 25

* Help tie the cell together via fused plasma membranes * Prevents water-soluble molecules from passing between cells (TEM: quilt-like pattern; AKA "tight junction")

Question 26

What are Zonula adherens (AKA **"belt desmosomes")**? Where are they located?

Answer 26

* Transmembrane linker proteins - E-cadherin, Actin filament, vinculin and caterin * Located basal to the TJ, holding adjacent cells together, completely encircle the cell (NOT to be confused w/**"spot desmosomes"/macula adherens** which are ALSO a component of the junctional complex).

Question 27

Define Macula adherens (AKA "spot desmosomes") function and location.

Answer 27

* Location: Intermediate filaments, desmocollin and desmoglein. Located below belt desmosomes, distributed along **lateral** cell membranes, disk-shaped * Function: Help to distribute shearing force (NOT to be confused with "belt desmosomes"/zonula adherens, which are also part of the junctional complex)

Question 28

Define Hemidesmosomes.

Answer 28

* Extracellular portions of linker proteins * Bind to laminin and collagen IV of basal lamina Do not confuse with "spot desmosomes"/macula adherens or "belt desmosomes"/zonula adherens, both of which are part of the junctional complex)

Question 29

# Define gap junctions.

Answer 29

Six subunits, dumbbell-shaped, 1 connexon consist of 6 connexins. Makes a channel for cells to communicate through. ## Footnote (Also allows movement of molecules like cAMP, ions & hormones.)