Mokrzan Study Guide (exam 3, pt 1 = ECM)

Question 1

The ECM is a complex network of _______ in the extracellular space

Answer 1

The ECM is a complex network of MACROMOLECULES in the extracellular space

Question 2

The ECM is secreted by ________

Answer 2

The ECM is secreted by THE CELLS THAT INHABIT IT

Question 3

The ECM gives ____ and ____ support to tissues

Answer 3

The ECM gives STRUCTURAL and ORGANIZATIONAL support to tissues

Question 4

T/F: The ECM only makes up a small part of the tissue volume

Answer 4

FALSE!! The ECM makes up a SUBSTANTIAL part of the tissue volume

Question 5

Collage accounts for _____% of total body protein

Answer 5

Collagen accounts for 30% of total body protein

Question 6

_____% of collagen is Type 1

Answer 6

90% of collagen is type 1

Question 7

What is type I collagen?

Answer 7

Type I collagen is a FIBRILLAR class, with distributions to SKIN, TENDON, TEETH, and BONES

Question 8

What are the 4 main families of molecules that comprise the ECM?

Answer 8

4 main families comprising the ECM include…

1. Collagens
2. Elastins
3. Glycoproteins
4. Proteoglycans

Question 9

There are Fibrillar and non-fibrillar collagens. Type IV is a non-fibrillar (network, to be specific) class which is found in ________.

Answer 9

There are Fibrillar and non-fibrillar collagens. Type IV is a non-fibrillar (network, to be specific) class which is found in BASEMENT MEMBRANES, KIDNEYS, and VASCULAR WALLS, and the GLOMERULUS

Question 10

T/F: The collagen composition is highly consistant in different tissues

Answer 10

FALSE!! • Different types and combinations of collagen molecules predominate in different tissues

Question 11

Collagen is frequently remodeled, and synthesis is affected by physiologic conditions such as
______ and _______

Answer 11

Collagen is frequently remodeled, and synthesis is affected by physiologic conditions such as
DIET and MECHANICAL STRESS
note: half life of collagen in relevant tissues incl:
-Perio ligament = 2 days
-Gingiva = 5 days
-Alveolar bone = 6 bays
-Skin = 15 days

Question 12

Osteogenesis/dentogenesis imperfecta is the result of a genetic mutation that causes ___________ to be replaced by another amino acid

Answer 12

Osteogenesis/dentogenesis imperfecta is the result of a genetic mutation that causes THE GLYCINE IN TYPE I COLLAGEN to be replaced by another amino acid

Question 13

______% of TOTAL BODY PROTEIN is TYPE I collagen

Answer 13

27% of TOTAL BODY PROTEIN is TYPE I collagen (90% of all collagen is type 1, and collagen is 30% of total body protein)

Question 14

How are intra- and inter- chain helices stabilized?

Answer 14

H-bonding stabilizes the helices of collagen

Question 15

Elastin provides ______ and _____ to the ECM

Answer 15

Elastin provides FLEXIBILITY and RESILIENCE to the ECM

Question 16

Elastin is the predominant ECM molecule in _________

Answer 16

Elastin is the predominant ECM molecule in BLOOD VESSELS (note: also abundant in skin, lungs, and intestines)

Question 17

Elastin is found in tissues that require ______

Answer 17

Elastin is found in tissues that require ELASTICITY

Question 18

Elastin is stabilized by _______

Answer 18

Elastin is stabilized by TWO-WAY CROSSLINKS

Question 19

Elastin crosslinks contain ________

Answer 19

Elastin crosslinks contain DESMOSINE

Question 20

________ is not synthesized after adolescence

Answer 20

ELASTIN is not synthesized after adolescence

Question 21

What are the 2 types of Glycoproteins found in the ECM

Answer 21

FIBRONECTIN and LAMININ are are two types of glycoproteins found in the ECM

Question 22

Fibronectin facilitates communication between ________ and ________ compartments

Answer 22

Fibronectin facilitates communication between INTRACELLULAR and EXTRACELLULAR compartments

Question 23

___________ of the ECM binds to membrane-spanning receptor proteins called integrins

Answer 23

FIBRONECTIN of the ECM binds to membrane-spanning receptor-proteins called integrins

Question 24

Fibronectin binds with _______ such as collagen and fibrin

Answer 24

Fibronectin binds to OTHER ECM MOLECULES such as collagen and fibrin

Question 25

All 20 known types of fibronectin (both soluble and insoluble) are produced by _________

Answer 25

All 20 known types of fibronectin (both soluble and insoluble) are produced by ALTERNATIVE SPLICING OF A SINGLE PRECURSOR mRNA

Question 26

What are the 6 major/general roles of Fibronectin?

Answer 26

Fibronectin plays a major role in... 1. Cell adhesion 2. Growth 3. Differentiation 4. Embryogenesis 5. Migration 6. Wound healing

Question 27

How does Fibronectin help with wound healing?

Answer 27

Along with fibrin,plasma fibronectin is deposited at the site of injury, forming a blood clot that stops bleeding and protects the underlying tissue

Question 28

There are both ____ and ______ forms of fibronectin

Answer 28

There are both SOLUBLE and INSOLUBLE forms of fibronectin

Question 29

________ prevents S. mutans, P. gingivalis, and other oral pathogens from binding to the oral cavity

Answer 29

SOLUBLE FIBRONECTIN IN SALIVA prevents S. mutans, P. gingivalis, and other oral pathogens from binding to the oral cavity

Question 30

Alternative splicing is controlled by what 4 factors/processes?

Answer 30

Alternative splicing is controlled by.... 1. Tissue or cell of origin 2. Embryogenesis 3. Wound healing 4. Oncogenesis

Question 31

_______ is found primarily in the basal lamina

Answer 31

LAMININ is found primarily in the basal lamina

Question 32

Laminin gives structural support to ______

Answer 32

Laminin gives structural support to THE ECM (intergral part of ECM "scaffolding")

Question 33

Laminin is a component of basement membranes in _____ and _____ tissues

Answer 33

Laminin is a component of basement membrane is EPITHELIAL and MUSCLE tissues

Question 34

Laminin binds to cells, often through the ______

Answer 34

Laminin binds to cells, often through the INTEGRIN FAMILY OF PROTEINS

Question 35

Defective laminin cause what 3 diseases?

Answer 35

Defective laminin causes.... 1. Muscular dystrophy 2. Lethal skin blistering disease (epidermolysis bullosa) 3. Defects of kidney filter

Question 36

Proteogylcans are the ______ of the ECM

Answer 36

Proteogylcans are the GEL-FORMERS of the ECM

Question 37

Describe the structure of proteoglycans

Answer 37

Amino acids (proteins) are linked to a chain of GlcNAc/N-acetylglucosamine, Galactose, and Glucuronic acid by a Xylose.

Question 38

Describe the diversity of proteoglycans

Answer 38

Proteoglycans can vary in structure and distribution. Specifically, various proteoglycans will have different characteristic disaccharides, sulfide sources (sulfation), and tissue location (joint, bone, cells, cornea, etc)

Question 39

Proteoglycans have _______ charges, which attract cations and water. The result is ______ of the ECM, which provides rigidity and ______.

Answer 39

Proteoglycans have MANY NEGATIVE charges, which attract cations and water. The result is HYDRATION of the ECM, which provides rigidity and DURABILITY (withstands compressional forces!!)

Question 40

| Proteoglycans are ____% of ECM protein, but because of their hydrophilicity, _____ chains fill most of the EC space

Answer 40

| Proteoglycans are <10% of ECM protein, but because of their hydrophilicity, GAG chains fill most of the EC space

Question 41

Describe Aggrecans

Answer 41

Aggrecan are a type of proteoglycan that is found alongside collagen as the main components of cartilage. The negative charges on the repeating GAG units of aggrecan attract water absorption. As a result, aggrecan acts as a cushion for impact retention by absorbing and desorbing water. This role is particularly important in between joints that sustain high amounts of impact in mammalian bodies, such as the knees.

Question 42

What are the tissue-specific functions of proteoglycans?

Answer 42

Tissue-specific functions of proteoglycans include.... 1. Bind Growth Factors 2. Regulate enzyme activity of secreted proteins 3. Act as co-receptors

Question 43

Describe Mucopolysaccharidoses

Answer 43

Mucopolysaccharidoses, are a group of genetic diseases related to proteoglycans and lysosomal storage problems. The inactivity of specific lysosomal enzymes that normally degrade GAGs leads to the accumulation of proteoglycans within cells. This leads to a variety of disease symptoms.

Question 44

The ECM regulates ______

Answer 44

The ECM regulates CELLULAR PROCESSES

Question 45

Collagen provides ______ and _____ to the ECM

Answer 45

Collagen provides STRENGTH AND STRUCTURE to the ECM

Question 46

Glycoproteins provide ______ and ______ to the ECM

Answer 46

Glycoproteins provide STRUCTURE and CELL ADHESION to the ECM

Question 47

Alterations in ECM characteristics can lead to ____________

Answer 47

Alterations in ECM characteristics can lead to CHRONIC DISEASES