Cell Adhesion Molecules

Question 1

Structure/junction of tight junction

Answer 1

Physical barrier at apical border
Junction: cell-cell

Question 2

Function of tight junction

Answer 2

Blood-brain barrier
Integrity of epithelial cell layer

Question 3

Structure/junction of adherens junction

Answer 3

• located in apical region of cells just below the tight junctions, allowing neural tube development
• junction: cell-cell

Question 4

Function of adherens junction

Answer 4

• cytoskeleton: contractile actin network
• linker glycoprotein: cadherins
  Note: in absence of Ca, junction opens and causes dysfunctions such as leaky gut

Question 5

Desmosome structure/junction

Answer 5

Spot junction: cell-cell junction

Question 6

Function of desmosome

Answer 6

• maintains epithelial integrity
• cytoskeleton: intermediate filaments

Question 7

Gap junction is also known as ____

Answer 7

Communicating junction

Question 8

Function of gap junction

Answer 8

Transfer chemical or electrical signals between neighbouring cells

Question 9

Hemidesmosome structure/junction

Answer 9

• connects cells to basal lamina
• junction: cell-matrix

Question 10

Function of hemidesmosome

Answer 10

Cytoskeleton: intermediate filaments

Question 11

Extracellular matrix structure

Answer 11

Main component of CT:
1. Glycosaminoglycans
2. Fibrous proteins
3. Adhesive proteins

Question 12

Structure of glycosaminoglycans

Answer 12

• highly negatively charged sulfates
• especially important in joints
• with protein called proteoglycans —> bottle brush appearance

Question 13

Function of glycosaminoglycans

Answer 13

• attract Na+
• water drawn in
• results in swelling or turgor
• turgor resists tissue compression

Question 14

Fibrous proteins are made by ____

Answer 14

Fibroblasts

Question 15

Collagen and elastin are ____

Answer 15

Fibrous proteins

Question 16

Structure of collagen

Answer 16

• organized into fibrils
• can be bundled into fibers

Question 17

Function of collagen

Answer 17

Resist shearing forces

Question 18

Structure/function of elastin

Answer 18

• found in tissues able to stretch & recoil (BVs, skin, lungs)
• in Extracellular space cross-linked

Question 19

Adhesive glycoproteins contain domains that…

Answer 19

1. Bind to cell surfaces
2. Interact with collagen
3. Bind to proteoglycans

Question 20

Function of adhesive glycoproteins

Answer 20

Act as Extracellular glue