DONE Connective Tissue

Question 1

Extracellular matrix

Answer 1

Extracellular structural network of ground substance + fibres

Question 2

What are the 3 fibres in CT?

Answer 2

Elastic
Reticular
Collagen

Question 3

Elastic fibres

Answer 3

Stretch + recoil after distension

Made of elastin surrounded by fibrillin

Question 4

Reticular fibres

Answer 4

Supporting framework (NOT IN AREOLAR TISSUE)
Collagen 3

Question 5

Collagen fibres

Answer 5

Flexible, high tensile strength
Type 1 = 90% of all collagen = fibrils, fibres in tendons
Type 2 = fibrils (not fibres) = elastic cartilage
Type 3 = reticulin around muscle/nerve tissue
Type 4 = basal lamina

Question 6

What are the 3 components of CT?

Answer 6

Cells = fibroblasts, adipocytes
Fibres = collagen, elastin, reticular fibres
Ground substance = GAGs, protein

Question 7

Function of CT

Answer 7

Binding + supporting
Protection (fat as shock absorber)
Insulate
Transport (blood)

Question 8

Ground substance

Answer 8

Proteoglycans bonded to GAGs (hydrated gel = allows rapid diffusion + resists compression)

Question 9

Fibroblasts

Answer 9

Syn. + secrete fibres that lie in ground substance (scar tissue in wounds)

Question 10

Macrophages

Answer 10

From monocytes, are phagocytes + APCs to T cells

Question 11

Mast cells

Answer 11

Contain granules of histamine (increase blood vessel wall permeability), heparin (anticoagulant), cytokines (attract eosinophils + neutrophils)
Near blood vessels, ABSENT from CNS

Question 12

Adipocytes

Answer 12

From MSCs
Brown = nucleus in centre, multilocular (many small lipid droplets), more mitochondria, lots in neonates, insulation + energy reserve
White = nucleus @ 1 side, unilocular (1 large lipid droplet), lots in adults

Question 13

Fascia

Answer 13

Type of fibrous CT with 3 forms = superficial, deep, visceral
Has parallel collagen fibres
Flexible

Question 14

How are collagen fibrils produced?

Answer 14

Fibroblasts secrete procollagen
Converted to collagen OUTSIDE cell
Aggregates to form collagen fibrils
Fibrils group to form fibres

Question 15

What vitamin is needed for intracellular procollagen formation?

Answer 15

Vitamin C (need 600 mg/day)

Question 16

What is scurvy?

Answer 16

Vit. C deficiency 
Disrupted collagen formation
Gum disease
Skin bruising
Bleeding 
Poor wound healing

Question 17

Marfan’s syndrome

Answer 17

Autosomal dominant
Abnormal elastic tissue
Fibrillin 1 gene mutation
Symptoms = abnormally tall (span > height), arachnodactly, joint dislocation, aortic rupture (difficult to recoil), flat feet, scoliosis, glaucoma

Question 18

Dense CT vs. Loose

Answer 18

Fewer cells
Less ground substance 
More collagen 
Hard
Parallel collagen fibres (1D)

Question 19

What are the 6 types of specialised CT?

Answer 19

Blood, bone, cartilage, adipose, fibrous (dense), loose (areolar), haemopoeitic

Question 20

Loose CT (areolar)

Answer 20

Formed by differentiation of MSCs (blood, adipose, colon submucosa)
Beneath epithelia, surrounds basal lamina
STRUCTURE = multiple cells, 2 fibres (collagen + elastin), ground substance, collagen = straight/long/wavy fibres
FUNCTION = packaging around organs, holds vessels, permit cell migration

Question 21

Regular dense CT (fibrous/collagenous)

Answer 21

Contain fibroblasts
Parallel collagen 1 fibres
Resist stress in 1D
E.g. tendons/ligaments

Question 22

Dense irregular CT

Answer 22

Collagen 1 fibres/resist stress in ALL directions

E.g. deep layer of dermis, intestine submucosa

Question 23

Mucinous CT

Answer 23

Wharton’s jelly in umbilical cord (type 1 + 3 collagen fibres)