Nature of connective tissues

Question 1

What are connective tissues?

Answer 1

Biological tissues that supports, separates and connects tissues and organs

Maintains the form of the body and its organs

Question 2

What are types of connective tissues?

Answer 2

Fibrous

Muscle

Bone

Question 3

What are the three main components of connective tissues?

Answer 3

Fibres

Ground substance

Cells

Question 4

What is the ground substance?

Answer 4

Clear colourless solution containing GAGs and proteoglycans

Fix body water and fibers within ECM

Question 5

What makes up the ECM?

Answer 5

Body fluid and ECM

Question 6

Can fibers be non-fibrous?

Answer 6

Yes

Blood and adipose tissue are non-fibrous fibers

Question 7

What are the two types of cells of connective tissues?

Answer 7

Resident

Fluctuating

Question 8

Examples of resident cells in connective tissues

Answer 8

Fibroblasts 
Adipocytes 
Osteoclasts 
Osteoblasts 
Mesenchymal stem cells

Question 9

Examples of fluctuating cells in connective tissues

Answer 9

Macrophages
Lymphocytes
Mase cells

Question 10

What is Mesengenesis?

Answer 10

Genesis of resident mesenchymal cells in bone and cartilage

Question 11

What do mesenchymal stem cells undergo upon activation?

Answer 11

Proliferative and commitment events

Progeny into distinct lineages - bone, cartilage, cardiac

Terminal differentiation into ultimate phenotypes - osteocytes, chondriac, myocytes

Question 12

What is the basement membrane?

Answer 12

Thin sheet-like network

Formed by two layers:

Basal lamina
Reticular connective tissue

Question 13

What are the functions of the basement membrane?

Answer 13

Physical support

Developmental control

Filtering functions

Question 14

What is the ECM?

Answer 14

Highly organised, complex arrangement of molecules filling intracellular spaces

Question 15

What creates the ECM?

Answer 15

Resident local cells

Secrete proteins and assemble outside the cell

Question 16

What determines the shape of the ECM?

Answer 16

Amount of ECM components

Organisation of the ECM components

Question 17

What types of cells make up the ECM?

Answer 17

Structural insoluble proteins - collagen

Hydrostatic soluble fibrillar polymers - GAGs and PGs

Substrate adhesion molecules - laminin, fibronectin

Cytokine and GF binding proteins

Question 18

What is the role of insoluble fibers?

Answer 18

Resist tensile forces

Question 19

What is the role of soluble fibrillar polymers?

Answer 19

Inflate fibrous network and provide resistance to compression

Question 20

What is the role of non-collagenous adhesive glycoproteins?

Answer 20

Bridges between matrix and basement membrane

Question 21

Describe the structure of collagen

Answer 21

Triple helix

Three chain wrap around each other in rope-liek fashion

28 members in a family

Six classes - fibrillar = most abundant

Question 22

What percentage total body collagen does collagen I compose?

Answer 22

90%

Question 23

Structure of GAGs

Answer 23

Oligosaccharides and glycans attached to polypeptide chains

Carbohydrates attached to proteins by glycosylation

Question 24

Examples of common GAGs

Answer 24

Hyaluronic acid

Chondroitin sulphate

Heparan sulphate

Dermatan sulphate

Question 25

GAGs are important components of ground substance TRUE or FALSE

Answer 25

TRUE

Question 26

Role of Hyaluronate

Answer 26

Important GAG Chief component of ECM Important in cell migration/ proliferation Increases viscosity of synovial fluid Important in tissue repair

Question 27

What are substrate adhesion molecules?

Answer 27

Proteins that mediate cell adhesion to ECM Enhance integrin-expressing cell binding Contrcact ECM to allow cells to bind

Question 28

What are integrins?

Answer 28

Transmembrane receptor proteins that bridge cell-cell and cell-ECM interactions

Question 29

What happens when integrins become activated?

Answer 29

Trigger intracellular signal transduction pathways