Cytoskeleton, junction, ECM

Question 1

What are the three main cytoskeletal components?

Answer 1

1-Microfilaments
2-Intermediate filaments
3-Microtubules

Question 2

What are microfilaments composed of and what do they do?

Answer 2

composed of actin. act as structural (shape) component of cell (6-8 nm in diameter)

Question 3

What are intermediate filaments made of and what do they do?

Answer 3

• sometimes vimentin (mesenchymal) or cytokeratin (10nm diameter)
• anchors cell (as in desmosomes)
• bundles are called tonofilaments

Question 4

What are microtubules made of and what do they do?

Answer 4

• Made of tubulin in hollow tubes (25nm diameter)

- “monorail system” of the cell via kinesins and dynein

Question 5

What are the 6 cell attachments?

Answer 5

1-Tight Junction
2-Zonula adherens
3-Focal adhesion
4-Desmosomes
5-Hemidesmosomes
6-Gap Junctions

Question 6

Claudin, Occluding, and Jam interact homotypically binding to actin microfilaments by forming what?

Answer 6

Tight junction (maintains cell polarization and controls movement of “stuff”)

Question 7

Caherins (outside) and Catinins (inside) form a band like complex that hold cells together by forming what?

Answer 7

Zona adherens (20 nm gaps)

Question 8

Cadherins are dependent on what cation?

Answer 8

Ca +2

Question 9

What do cinvulin and actinic attach to in zone adherens?

Answer 9

actin filaments

Question 10

Integrins (replace cadherin as a transmembrane component) associating with ECM form what?

Answer 10

Focal Adhesion junctions

Question 11

Vinculin, actinin and talin attach to what in focal adhesion junctions?

Answer 11

actin filaments

Question 12

Cadherins (outside) referred to as desmoglein and desmocollin along with catinins (inside) like the “plaks” interact heterotypically to form lines externally and plaques internally called what?

Answer 12

Desmosomes (Gaps of 25nm)

*resist shear forces

Question 13

What structural component to desmosomes attach to?

Answer 13

intermediate filaments

Question 14

Interns attached to basal lamina by intern-laminin and collagen 7 attach to intermediate filaments to form what?

Answer 14

hemidesmosome

Question 15

Aqueous pores used to pass small ions, molecules and electrical signals are called what?

Answer 15

Gap junctions

*made of 6x connexins called a connexon

Question 16

50-100 nm thick, basal lamina connects what?

Answer 16

epithelium to connective tissue

Question 17

What are the 3 zones of basal lamina?

Answer 17

1-Lamina lucida (Laminin, entactin, integrins)
2-lamina densa (collagen 4/chicken wire)
3-lamina fibroreticularis (usually collagen III, epithelial tissues)

Question 18

What amino acid helps hold the strands of collagen form a triple helical structure and ultimately a fibril?

Answer 18

Proline and lysine

Question 19

What type of collagen is dentin, pulp, and cartilage?

Answer 19

• Dentin: Type I, some Type III
• Pulp: Type I and III
• Cartilage: Type II

Question 20

the overlap of microfibrils align in a parallel, staggered fashion causing what appearance?

Answer 20

banded appearance

*crystals are typically in the gaps

Question 21

Glycoproteins Fibrillin-1 and 2 form scaffold to which what accumulates?

Answer 21

Elastin fibers

*elastin is a fibroblast product and binds growth hormone

Question 22

proteoglycans and glycoproteins make up a gel like, highly hydrated substance called?

Answer 22

Ground substance

Question 23

What main component of ground substance helps sequester water and growth factors?

Answer 23

proteoglycans made up of GAGs and a protein core

Question 24

What helps break down matrix for remodeling?

Answer 24

MMPs