Tissue organisation, cellular basis

Question 1

Definition of connective tissue

Answer 1

Extracellular matrix and supporting cell population

3 forms, soft, semi hard (cartilage), hard (bone)

Question 2

Definition of soft connective tissue

Answer 2

Cells embedded in ECM, synthesis and secrete ECM

Question 3

Composition of soft connective tissue

Answer 3

Collagen fibres
Macrophages
Capillary
Elastic fibre
Fibroblast
Mast cell
Hyaluronan, proteoglycan and glycoproteins

Question 4

Function of soft connective tissue

Answer 4

Space filler, mechanical support attachment
Protection highway for nutrient storage (fat, calcium)
Site of immunological defense (if tissue tears, pathogens cam enter)

Question 5

Types of connective tissue

Answer 5

Mesenchyme, embryonic
Loose, mesentery, under dermis
Dense, tendon, dermis, capsules
Reticular, bone marrow, lymph nodes
Adipose, fat cells

Question 6

Components of ECM

Answer 6

Proteins, glycoproteins
Glycosaminoglycans
Together they form a large hydrated gel

Question 7

Major proteins of ECM

Answer 7

Synthesized and secreted by fibroblasts
Collagen, tensile strength of matrix
Elastin, elasticity of matrix
Adhesive, adhesion proteins for fibroblasts and other cells

Question 8

Properties of collagen

Answer 8

Tensile strength of matrix tendons, dense CT, ligaments
Not extensible, form fibrils
Shape and size varies according to function

Question 9

Types of collagen

Answer 9

T1 bone, tendon, skin and dermis
T2 cartilage
T3 blood vessels, skin
T4 basement membrane

Question 10

Properties of elastic fibres

Answer 10

Recoils passively after tissue stretched
Energy stored pushes blood through circulation
Network of fibrillar microfibrils embedded in cross linked elastic core
Synthesized by embryonic and juvenile fibroblasts

Question 11

Where is elastic fibres found

Answer 11

In skin, blood vessels, lungs

Question 12

Properties of adhesive proteins

Answer 12

Cross link cells of CT => collagen, bind to transmembrane receptors (integrins)
Fibronectin, abundant in all CT
Tenascin, produced at wounds, function obscure
Laminin, in BM, bind epithelium to BM

Question 13

Function of BM

Answer 13

Separates CT from epithelial layer

Physical barrier to cells, maintains tissue integrity

Question 14

What is a proteoglycan

Answer 14

Heavily glycosylated proteins

Core protein with covalently attached GAG

Question 15

What are glucosaminoglycans

Answer 15

Chains covalently attached to proteoglycans

Have repeating disaccharide arrangement with high density of
-ve charge (SO3-, COO-)

Question 16

Properties of proteoglycans

Answer 16

Too stiff to fold into compact structures
Strongly hydrophilic, water moves into ECM to withstand compressive dories
Adopt highly extended shapes, occupy huge volume
H2O absorbed into matrix by osmotically active ion cloud

Question 17

Cells of connective tissue

Answer 17

Indigenous, ECM synthesis, lipid storage

Immigrant, immune system cells

Question 18

What cells are indigenous

Answer 18

Mesenchymal stem cells, give rise to all inidigenous cells of SCT
Fibroblasts, ECM, collagen, elastic fibre producer
Adipocytes, fat storage, leptin, secretion
Mast cells, histamine secretion

Question 19

What cells are immigrant

Answer 19

Leukocytes
Neutrophils, phagocytic
Monocytes/macrophages, phagocytic
Dendritic cells, immune surveillance
Eosiniphils, parasitic infection
Basophils,  ?
Lymphocytes, antibody production, cell killing