Connective Tissue

Question 1

what are the functions of extracellular matrix

Answer 1

provides strength, holds cells in place, directs cells to proper positions, regulates cell development

Question 2

what is the ECM made of

Answer 2

ground substance and protein fibres

Question 3

what macromolecules may be found in the ECM

Answer 3

Glycosaminoglycans (GAGs), Proteoglycans and Cell-adhesive glycoproteins (CAGs)

Question 4

write a note on glycosaminoglycans

Answer 4

these are polysaccharides which are negatively charged, ,long, unflexible, unbranched and have repeating disaccharide units

these attract cations for example sodium and as water follows salt, may result in the attraction of extracellular fluid which helps resist compression

have a slippy texture as neg charges repel each other (synovial fluid)

can be linked covalently to proteins to form proteoglycans

Question 5

write a note on proteoglycans

Answer 5

bind to GAGs. these make the ECM firmer and more solid. they bind water giving the matrix a jelly texture. they resist movement of microorganisms and metastatic cells. also help form molecular filters alongside the basal lamina

Question 6

what is the only non sulfated GAG

Answer 6

hyaluronic acid

Question 7

what are cell adhesive glycoproteins

Answer 7

made of diff types of glycoproteins and their main function is to hold everything in place - adhere cells to cells and surroundings

Question 8

what makes up the fibrous component of ECM

Answer 8

collagen and elastin

Question 9

write a note to generally describe collagen

Answer 9

• is the most abundant protein
• main function is to provide tensile strength
• consists of long straight unbranched fibres

Question 10

from where does connective tissue arise?

Answer 10

secreted into the ECM by connective tissue cells i.e fibroblasts

Question 11

function of type 1 collagen

Answer 11

fibrous supporting tissue, skin, tendons, ligaments ad bone. this is the main structural collagen

Question 12

function of type 2 collagen

Answer 12

hyaline cartilage- fibrils in cartilage ground substance

Question 13

function of type 3 collagen

Answer 13

found in liver, bone marrow + lymphoid organs. this type is delicate and branched

Question 14

function of type 4 collagen

Answer 14

constituent of basement membrane- in a mesh form

Question 15

function of type 7 collagen

Answer 15

anchoring fibrils which link extracellular matrix to the basement membrane

Question 16

function of remaining collagen types

Answer 16

present in specialised situations

Question 17

how is elastin arranged in ECM

Answer 17

fibres

Question 18

what is the function of elastin

Answer 18

stretching and elastic recoil

Question 19

what precursor material do fibroblasts synthesise

Answer 19

tropoelastin

Question 20

what polymerises tropoelastin

Answer 20

lysyl oxidase which requires templates for assembly: glycoprotien fibrillin and other associated glycoprotein

Question 21

where is elastin found

Answer 21

lungs, skin, bladder and blood vessels