Connective tissue is the most abundant tissue in the body and performs many essential functions. It consists of cells and an extracellular matrix of fibers and ground substance. There are several types of connective tissue including loose connective tissue found in skin and around organs, dense connective tissue in tendons and ligaments, cartilage, bone, and blood. The main cell types are fibroblasts, macrophages, mast cells, adipocytes, and leukocytes. Connective tissue disorders are often autoimmune in nature and involve inflammation of connective tissues and blood vessels.

1. Connective
tissue

2.  Introduction
 Functions
 Composition
 Types of fibers
 Connective tissue cells
 Classification of connective tissue
 Membranes
 Connective tissue framework
 Connective tissue disorders
 References

3.  Most abundant basic tissue.
 Derived from somites during prenatal
development.
Functions
 Establishing a structural framework
 Transporting fluids and dissolved materials
 Protecting delicate organs
 Supporting, surrounding and interconnecting
tissues
 Storing energy reserves
 Defending the body from microorganisms

4.  Cells
Fixed
Mobile
 Fibers
Collagen fibers -large
Reticular fibers-thin
Elastic fibers- very fine
 Ground substance

5. 1) PROTEOGLYCANS
Glycosaminoglycans.( GAG) 80-90%
Protein Core. 10-20%
2) GLYCOPROTEINS
Fibronectin
Laminin
Chondronectin

6.  Linear chains of repeating disaccharides
units.
 One of the disaccharides is glucosamine or
galactosamine.
 The other is glucuronic acid or iduronic acid
or galactose.

7. (1) keratin sulfate
Galactose-Glucosamine
Bone and Cornea
(2) Chondroitin sulfate
Glucuronic acid-Galactosamine
cartilage, skin , basal lamina.
(3) Dermatan sulfate
Iduronic acid-Galactosamine
tendon , skin

8. (4) Heparin sulfate
iduronic acid-glucosamine
basal lamina, nerve tissue.
(5) Hyaluronic acid
glucuronic acid-glucosamine
cartilage , synovial fluid
LARGEST , no protein core

9.  Glycosaminoglycans
usually attached to a
protein core and called as
proteoglycan exception is
hyaluronate.
o GAGs are linked to
protein core like bristles
on a hair brush.

10.  Anchor cells to proteoglycans in matrix
and to fibers.
 Fibronectin – general connective tissue.
 Laminin – mainly basement membrane.

11.  Facilitate cell migration.
 May be important for
determining cell shape.
 May play a role in blood
clotting.

12.  Laminin found in
basement
membrane.
 Binds to
collagen type 4
heparin sulfate
Integrin receptor

13. (1)Collagen
(2)Reticular formed from collagen
proteins.
(3)Elastic – formed from the protein
elastin.

14.  Collagen is tough protein
 30% of human body by dry weight.
 Relatively long (300 nm) and narrow(1.5 nm)
 3 polypeptide chain wound together in form
of triple helix.( alpha chains)
 Made up of repetitive sequences of 3 amino
acids.
 25 forms of alpha chains.
 12 types of collagen are known.
 Lots of hydroxyprolines and hydroxylysines.

16. Formation of mRNA for each type of a
chain
Sythesis of alpha chains of procollagen
with peptides.
Hydroxylation of specific prolyl & lysl
residues in rER.( vit C dependent)
Attachment of soluble glucose &
galacotose.
Assembling of procollagen to golgi
complex via transport vescicles.
Packing of procollagen in secretory
vescicles .
Secretory vescicles transported to cell
surface via microfilaments &
microtubules
Discharge of procollegen molecule to
extracellular space.

18.  Randomly oriented and unbranched in loose
areolar CT.
 Collagen fibers consist of closely packed
orderly fibrils and when seen in bundles (as in
tendons, aponeuroses) appear white. In
histological preparations after regular
staining they are acidophilic. Collagen fibers
are flexible, but very inelastic with extremely
high tensile strength.

21. Collagen type Pricipal tissue distribution cells of origin
1 Loose & dense CT,
fibrocartilage,bone,
dentin.
Fibroblasts &
reticular cells
,osetoblast,
ondotoblasts
2 Hyaline & elastic
cartilage, viterous body
of eye.
Chondrocytes and
retinal cells.
3 Loose CT, reticular fibres,
blood vessels
Fibroblasts &
reticular cells,
endothelial cells
4 Basement membranes fibroblasts
5 Fetal
membranes,placenta
membranes,bone
Fibroblasts.

22.  Abundant in lympoid tissue.
 Reticular fibers are very thin (diameters
between 0.5 - 2m m) and are not visible in
normal histological preparations after
regular staining (H & E), however they can be
visualized and stained black after
impregnation with silver salts. This affinity
for silver is called argyrophilia.
 Reticular fibers are also stainedwith the PAS
reaction due to the high content of
glycoproteins It is now recognized that
reticular fibers are a special form of collagen
(Type III).

24.  Oxytylan fibres: glycoprotein containing
microfibirils or microfilaments, 6-10 microm
diameter.
 Elaunin fibres: gradual deposition of elastin
on microfilaments.
 Elastic fibres: heavy deposition of elastin

25.  Comparitively thin
{1 microm}
 Less wavy
 Occurence:
large artries.
loose connective
tissue.
elastic cartilage

26. Fibrillin
 Microfilament glycoprotein important in
elastic fibres.
 Marfan’s syndrome- defect in fibrillin
syntehesis and elastic fibres.
 Connective tissue disorder affecting skeleton,
elastic blood vessels and eye.
 Severe- cardiovascular problems-arteries
cannot stretch.

27.  All connective tissue cells are derived from
two types of stem cells
Hematopoetic stem cells.
Mesenchymal cells

30.  Fibroblast
 Macrophages
 Mast cells
 Plasma cells
 Adipose cells
 Leukocytes
Lymphocytes
Monocytes Mononuclear,agranulocytes
Netrophils
Eosonophil
Basophil
polymorphonuclear,granulocytes

32.  Most common cell type in connective tissue.
 Synthesize collagen , reticular and elastic
fibres.
 Sythesize glycosaminoglycans and
glycoproteins.

34.  10 – 30 mirom in diameter
 Shape can very trmendously
 Phagocytosis and digestion of
bacteria
foreign bodies
blood cells
dead cells
o Oppsonization

36.  Secretes important enzymes –collagenase,
elastase
 Produce cytokines such as:
Tumour necrosis factor
Interlekuins
GM-CSF(granulocyte macrophage – colony
stimulating factor)

37.  Round , oval , 20 – 30 microm
 Basophilic granules in cytoplasm.
 Metachromasia- mast cells stain purple with
methylene blue. Due to heparin content in the
cell.

39.  Heparin- anticoagulant
 Histamine – increases capilliary permeability
primary mediator of acute
inflammatory reaction.
o Eosinophil chemotactic factor
ECF- A
o Slow reacting substance of anaphylaxis
SRS-A
leukotrines.

41.  Can occur within seconds.
 Massive release of histamine from mast cells
 Reduces mean arterial blood pressure –
blood enters peripheral capillaries
 Caused by IgE secretion from plasma cells.
 Epinephrine can reverse HIS by causing
vasoconstriction.

43.  Eccentric nucleus
 Dark staining
cytoplasm , lots of
RER
 10 – 20 micrm
 Don’t leave the
connective tissue
 Produce
antibodies.

45. 1. Loose Connective Tissue:
a. Areolar tissue
Widely distributed under epithelia
b. Adipose tissue
Hypodermis, within abdomen, breasts
c. Reticular connective tissue
Lymphoid organs such as lymph nodes

46. 1. Areolar CT
◦ consists of all 3 types of
fibers, several types of cells,
and semi-fluid ground
substance
◦ found in subcutaneous layer
and mucous membranes, and
around blood vessels, nerves
and organs
◦ function = strength, support
and elasticity

48. 2. Adipose tissue
◦ consists of adipocytes; "signet
ring" appearing fat cells. They
store energy in the form of
triglycerides (lipids).
◦ found in subcutaneous layer,
around organs and in the
yellow marrow of long bones
◦ function = supports, protects
and insulates, and serves as an
energy reserve

50. 3. Reticular CT
◦ Consists of fine interlacing
reticular fibers and reticular
cells
◦ Found in liver, spleen and
lymph nodes
◦ Function = forms the
framework (stroma) of
organs and binds together
smooth muscle tissue cells

51. 2. Dense Connective Tissue:
a. Dense regular connective tissue
Tendons and ligaments
b. Dense irregular connective tissue
Dermis of skin, submucosa of digestive tract
 contains more numerous and thicker fibers and far fewer cells
than loose CT

52. 1. Dense regular
Connective Tissue
• consists of primarily
parallel bundles of collagen
fibers and fibroblasts
• forms tendons, ligaments
and aponeuroses
• Function = provide strong
attachment between
various structures

54. . Dense Irregular CT
◦ consists of randomly-
arranged collagen fibers
and a few fibroblasts
◦ Found in fasciae, dermis
of skin, joint capsules, and
heart valves
◦ Function = provide
strength

56. Supportive Connective
Tissue

57. o Firm, non calcified tissue.
o Serves as skeleton tissue in the body.
o Avascular
 HISTOLOGY OF CARTILAGE
 Cells and matrix
 Cells: chondroblast
chondrocytes

58. ◦ Jelly-like matrix (chondroitin sulfate) containing
collagen and elastic fibers and chondrocytes
surrounded by a membrane called the
perichondrium.
◦ Unlike other CT, cartilage has NO blood vessels or
nerves except in the perichondrium.
◦ The strength of cartilage is due to collagen fibers
and the resilience is due to the presence of
chondroitin sulfate.
◦ Chondrocytes occur within spaces in the matrix
called lacunae.

59. 1. Hyaline cartilage
2. Fibrocartilage
3. Elastic cartilage

60.  Hyaline Cartilage (most
abundant type)
 fine collagen fibers
embedded in a gel-type
matrix. Occasional
chondrocytes inside
lacunae.
 Found in embryonic
skeleton, at the ends of
long bones, in the nose
and in respiratory
structures.
 Function= flexible,
provides support, allows
movement at joints

62. 2. Fibrocartilage
 contains bundles of
collagen in the matrix that
are usually more visible
under microscopy.
 Found in the pubic
symphysis, intervertebral
discs, and menisci of the
knee.
 Function = support and
fusion, and absorbs
shocks.

64. 3. Elastic Cartilage
 threadlike network of
elastic fibers within the
matrix.
 found in external ear,
auditory tubes, epiglottis.
 function = gives support,
maintains shape, allows
flexibility

66. Has osteocytes
◦ Depend on diffusion through canaliculi for
nutrients
 Little ground substance
 Dense mineralized matrix
 Surrounded by periosteum
 Function
◦ Supports and protects organs
◦ Provides levers and attachment site for muscles
◦ Stores calcium and other minerals
◦ Stores fat
◦ Marrow is site for blood cell formation
 Location
◦ Bones

68.  Description
◦ red and white blood cells
in a fluid matrix
 Function
◦ transport of respiratory
gases, nutrients, and wastes
 Location
◦ within blood vessels
 Characteristics
◦ An atypical connective tissue
◦ Consists of cells surrounded by fluid matrix

70. Membranes
Form a barrier
Composed of epithelium and
connective tissue
Four types
Cutaneous
Synovial
Serous
Mucous

72. 1. Mucous membrane = mucosa; it lines cavities
that open to the exterior, such as the GI tract.
◦ The epithelial layer of the mucous membrane
acts as a barrier to disease organisms.
◦ The connective tissue layer of the mucous
membrane is called the lamina propria.
◦ Found as the lining of the mouth, vagina, and
nasal passage.

73. 2. Serous membrane = serosa, membrane
lines a body cavity that does NOT open to
the exterior and it covers the organs that lie
within the cavity.
a. pleura = lungs
b. pericardium = heart
c. peritoneum = abdomen
◦ The serous membrane has two portions:
1. parietal portion = lining outside the
cavity.
2. visceral portion = covers the organ.

76.  Organs and systems are interconnected
 Network of connective tissue proper
consisting of
◦ Superficial fascia
◦ Deep fascia
◦ Subserous fascia

78. Connective tissue disorders

79.  Perivascular collagen deposition=Collagen
Vascular Diseases
 Autoimmune diseases-not the primary cause
 Exact cause remains obscure
 Different diseases associated with specific
autoantibodies

80. Diseases Antibody
 Systemic lupous
erythematosous
 Rhemutoid arthriris
 Sjogren syndrome
 Systemic sclerosis
 Polymyositis/dermato
myositis
 Mixed connective
tissue deseases
 Anti – dsDNA, Anti-SM
 RF, Anti-RA33
 Anti RO(SS-A),AntLa(SSB)
 Anti-Scl-70,anti cetromere
 Anti-Jo-1,
 Anti-U1-RNP

81.  Histopathology: Connective tissue and blood
vessel inflammation and abundant fibrinoid
deposits
 Varying tissue distribution and pattern of
organ involvement
 Symptoms nonspecific and overlapping
 Difficult to diagnose

82.  General
◦ autoimmune multisystem disease
◦ Malar rash first sign in 50%
◦ Erythematous maculopapular eruption after sun exposure
◦ Oral ulceration
◦ 3-5% nasal septum perforation
◦ Acute parotid enlargement 10%
◦ Xerostomia 15%
◦ Larynx and trachea involvement uncommon

84.  Discoid Lupus: Cutaneous manifestations
 Scar upon healing

85.  Inflammation of the
synovial tissue
(lymphocytic) with
synovial proliferation
 Symmetric involvement
of peripheral joints,
hands, feet and wrists
 Occasional systemic
effects: vasculitis,
visceral nodules, Sjogren
syndrome, pulmonary
fibrosis

86.  Rheumatoid Arthritis may involve the TMJ.

87.  Chronic disorder characterized by immune-
mediated destruction of exocrine glands
 Sicca complex accompanying any of the
connective tissue diseases (xerophthalmia,
keratoconjuntivitis, xerostomia with/without
salivary gland enlargement)

88.  Also known as systemic
sclerosis
 Sclerotic skin changes
often accompanied by
multisystem disease.
 Progressive fibrosis from
increased collagen
deposition in intersitium
and intima of small
arteries and connective
tissues
 May be benign cutaneous
involvement or
aggressive systemic
disease.

89. Presentation
Raynaud’s
phenomenon
edema fingers and
hands
skin thickening
visceral manifestations
GI tract, lung, heart,
kidneys, thyroid
arthralgias and muscle
weakness often

90.  Proximal muscle
weakness
 Elevated serum
creatinine kinase
 Myopathic changes
on electromyography
 Muscle biopsy with
evidence of
lymphocytic
inflammation
Rash accompanies
these in
dermatomyositis

91.  Ham’s histology
 Fawcets
 Dental embryology, Histology,and
Anatomy;second edition;Mary Bath
Balgoh,Margaret j Fehrenbach;chapter8 ;basic
tissues.
 Ten cate’s Oral histology;chapter 4 ;
cytoskeleton,junction,fibroblast.
 Textbook of oral pathology;Shafer, Hine,Levy,

92. o Burket’s Oral Medicine;diagnosis and
treatment planning;Greenberg,gGick;tenth
edition
o Epidemiology of connective tissue disorders
M. Gaubitz, rheumatology.oxfordjournals.org,
(2006) 45 (suppl 3)
o Mutations in the human gene for fibrillin-1
(FBN1) in the Marfan syndrome and related
disorders.
o Raynaud’s phenomenon, A.D.A.M. Medical
Encyclopedia.

93. Thank you