Connective tissue

1. Connective Tissue

2. Objectives
 state the general functions of connective tissue
 Outline the classification of connective tissue
 state the site of each type of connective tissue
 list the different types of cells with functions in
connective tissue

4. Connective tissue – embryological origin
Primitive mesenchyme
irregular cells + slender processes

5. This is a type of supporting tissue which connect
tissues to tissue
tissues to structures
tissues to skeleton
Connective tissue
 Also know as supporting tissue

6.  Supporting framework ; Cartilage and bone
 Metabolic function
storage of fat white adipose tissue
regulate body temperature brown adipose
 Defense mechanisms
 Tissue repair
 Medium of exchange of nutrients and metabolites
Connective tissue - functions

7. Cells
+
Extracellular matrix- EC matrix
Basic components of connective tissue

8. Connective Tissue Cell types
 Fibroblasts- produce and secrete fibrous proteins and
ground substance
 Macrophages- phagocytic cells that engulf and digest
foreign particles
 Plasma Cells- produce antibodies
 Mast Cells- produce histamine, which dilates blood vessels
produce heparin, an anticoagulant
 Adipocytes- store fat
 Leukocytes- white blood cells, several different types,
function in immunity

9. Connective Tissue Cell types
 Erythrocytes- red blood cells, transport oxygen
 Thrombocytes- blood platelets, aid in blood clot
formation
 Chondroblasts- produce and secrete fibers and ground
substance in cartilage
 Chondrocytes- maintains the matrix of cartilage
 Osteoblasts- produce and secrete fibers and ground
substance in bone
 Osteocytes- maintains the extracellular matrix of bone

10. Fibroblasts
Fibroblast

11. Macrophages
Macrophages
• Macrophages are derived from blood monocytes
• pseudopodia - amoeboid moments
• Small , oval shaped accentric nuclei
• Cytoplasm contain numerous lysosomes

12. Mast Cells

13.  Derived from blood basophils
 Locations
 Skin /GIT /Respiratory tract /round blood vessels
 Functions : storage of chemical mediators (histamine) of
the inflammatory response
Mast Cells
Degranulation results in the release of histamine
and other vasoactive substances that induce
hypersensitivity responses (urticaria, allergic
rhinitis, asthma, anaphylactic shock

14. Plasma Cells

15. Leukocytes
Neutrophils
Eosinophils
Lymphocytes
Monocytes
Basophils

16.  Adopted for the storage of fat
 Found in clusters in loose connective tissue
 Main cell type in adipose tissue
 Two main types
White adipose tissue
Brown adipose tissue
Adipocytes

17. Adipocytes
cytoplasm
nucleus
White adipose tissue

18.  Found throughout the body in the deep layers of the skin
 Forms an energy store
 Act as an insulator
 Cushion against mechanical shock
 Fat stored in the form of lipid droplets
 They accumulate and form large droplet in the
cytoplasm
White adipose tissue

19.  cytoplasm is reduced to a thin rim
 nucleus becomes compressed
 EM shows the main droplet with an
irregular outline
 smaller droplets are seen in the periphery
 Mitochondria are found in peripheral
cytoplasm
White adipose tissue

20. White adipose tissue

21. Adipocytes

22. Brown adipose tissue

23.  highly specialized
 found in newborns
 small amounts are found in adults
 plays a part in temperature regulation
 arranged in lobules separated by fibrous septa.
 lipid is stored as minute droplets giving rise to
multilocular appearance
 cytoplasm stains intensely because mitochondria
with numerous closely packed cristae for cytochromes
involved in energy production.
Brown adipose tissue

24. Cells
+
Extracellular matrix- EC matrix
Basic components of connective tissue

25. ground substance
variety of fibres
 nature of the EC matrix decide differences in the
various types of supporting tissue
Extracellular matrix- EC matrix
EC matrix

26. collagen (white) fibres
Reticular fibres
elastic (yellow) fibres
Fibre Types

27.  Thick fibre that found in all types of supporting tissue
 Most abundant protein
 Flexible & high tensile strength
 Collagen is secreted by fibroblasts as tropocollagen
molecules secreted to the extracellular matrix
Collagen (white) fibres

28. Several types - on the basis of its morphology, amino acid composition
and physical properties.
Type 1collagen
found in loose supporting tissue, in the dermis, in tendons and ligaments
and in bone
the arrangement varies depending on the mechanical support required.
collagen fibrils are arranged in bundles
2-10μm in diameter.
Type 2 collagen
found in hyaline cartilage and consists of fine fibrils
Type 3 collagen
the reticular fibres which form a branched network in cellular organs like
the liver and lymphoid tissue.
Type 4 collagen
does not form fibrils. It is an important constituent of the basement
membrane.
Collagen (white) fibres

29. Reticulin fibres

30.  thinner than collagen,
 no banding.
 short branching fibres form an irregular network
Elastic fibres

31. Areolar connective tissue
 Pink large fibres – collagen fibers
 Dark, thin, more tortuous fibers - elastic fibers
 Most of the nuclei are fibroblasts nuclei

32. Cells
+
Extracellular matrix- EC matrix
Basic components of connective tissue
variety of fibres
ground substance

33.  cells and fibres are embedded semifluid gel
 Formed by 3 main classes of components
Glycosaminoglycans (mucopolysaccharides )
Proteoglycans
Multiadesive glycoproteins
Ground substance

34.  ground substance act as mechanical barrier to
prevent bacteria entering the body
 act as a selective barrier containing inorganic ions
and charged molecules
• Ground substance is a medium of nutrients and
gases and metabolites with which exchange of
substance occur between cells and capillaries
Ground substance - functions

35. Connective tissue classification

36. Adipose tissue

37. Connective tissue proper

38.  Locations: :lamina propria, surrounds capillaries
 A meshwork of thin collagen and elastic fibres
 All cells types are found among the fibres
Loose connective tissue (areolar tissue)

39.  Location : dermis, capsules of organs, periosteum.
 A network coarse collagen fibres, few elastic or
reticular fibres
 Fibroblasts are few
Dense irregular connective tissue

40. Collagen fibres are densely packed with a regular
arrangement
 Tendons
 Aponeuroses
 Ligaments
Dense regular connective tissue

41. In tendons-
 collagen fibres arranged as parallel bundles
 only cell type that is fibroblasts
 lie in rows between the bundles.
Aponeuroses-
 collagen fibres arranged as broad sheets
 number of layers
 fibres of one layer running at an angle to the
adjacent layer
In ligaments-
 arrangement of fibres not so regular
 ligamentum nuchae
made of elastic fibres
 ligamentum flava

43. connective tissue with special properties

44. Mucoid tissue
• Location : umbilical cord / vitreous body in eye
 ground substance is mucoid
 scanty meshwork of collagen fibres and few cells
 no mature fibres
 Permits free diffusion of metabolites in the foetus

45. SUMMERY

46. SUMMERY – Connective Tissue
Cells + fibers + ground substance

48. Connective tissue proper
Loose connective
tissue
Dense irregular
connective tissue
Dense regular
connective tissue

49. REFFERENCES
 Burkit, H.G, young, B. (1993). Wheaters
functional histology. 4 th ed.,
london:Churchill livingstone
 Junqueira, L.C., Carneiro (1998). Basic
histology. 9 th ed., stamford: Appleton &
lange