Connective Tissue

Question 1

What are the main components of connective tissue?

Answer 1

Extracellular matrix (fibres embedded in ground substance) and cells

Question 2

What are the three types of fibre in connective tissue?

Answer 2

Collagen, elastin, reticulin

Question 3

What is the structure of collagen?

Answer 3

3 polypeptide chains in an alpha helix

Question 4

How many types of collagen are there?

Answer 4

27

Question 5

Where do you find type I collagen fibre?

Answer 5

connective tissue proper, bone, tendon, ligaments

Question 6

Where do you find type II collagen fibre?

Answer 6

cartilage, intervertebral discs

Question 7

Where do you find type III collagen fibre?

Answer 7

reticular fibres (reticulin)

Question 8

Where do you find type IV collagen fibre?

Answer 8

basement membranes

Question 9

Where do you find type VII collagen fibres?

Answer 9

Linking basement membranes to underlying fibres

Question 10

What is reticulin?

Answer 10

Reticulin is a special type of collagen. It is much thinner than other collagen and requires a special stain to see it. It makes up a framework to support cells like hepatocytes and bone marrow.

Question 11

What is elastin?

Answer 11

Elastin is another type of connective tissue. It is thinner than collagen. It is made up of a central core of elastin surrounded by fibril in microfibrils. Its function is for recoil so it is found in tissues that require recoil such as the aorta, the lung and skin.

Question 12

What are the properties of ground substance?

Answer 12

Ground substance is viscous, clear and has a high water content. It makes up 4/5ths of the extracellular fluid in the body.

Question 13

What are the components of ground substance?

Answer 13

Glycosoaminoglycans (GAGs) and glycoproteins

Question 14

What is the main type of GAG in loose connective tissue?

Answer 14

Hyaluronic acid

Question 15

What are the properties of GAGs

Answer 15

GAGs are negatively charged, this means that Na+ is attracted to them and water will follow the Na+ ions. Also GAGs are often linked to proteins.

Question 16

What is the function of the extracellular matrix (fibres and ground substance)?

Answer 16

The extracellular matrix fills in spaces between cells, but it also has a metabolic regulatory role, provides mechanical and structural support, supports organs and nerves, can store growth factors, can provide scaffolding for cellular proliferation and more.

Question 17

What are the cells present in connective tissue?

Answer 17

Fibroblasts, myofibroblasts, macrophages, mast cells, mesenchymal stem cells, adipocytes and other cells of specific connective tissues.

Question 18

What cells are responsible for the synthesis of the extracellular matrix?

Answer 18

Fibroblasts

Question 19

What is the basement membrane?

Answer 19

The basement membrane is a specialised layer of connective tissue which is the interface between support tissues and parenchymal cells.

Question 20

What are the components of the basement membrane?

Answer 20

Collagen IV, heparan sulphate and glycoproteins laminins and fibronectin

Question 21

What are the functions of the basement membrane?

Answer 21

structural support, control of epithelial growth, links epithelium to underlying tissue, selective barrier to nutrients