2. CONNECTIVE TISSUE
Dr Iram Tassaduq

3. INTRODUCTION
‘Connective tissue’ is the term traditionally applied to a basic type of tissue of mesodermal origin which provides structural and metabolic support for other tissues and organs throughout the body, also known as “Supporting tissue”.

4. COMPOSITION
Cells
Fibers
Ground substance

6. FUNCTIONS Establishing a structural framework
Supporting, surrounding and interconnecting tissues
Exchange of nutrients and waste products
Storing energy reserves
Defending the body from microorganisms
Protecting delicate organs

7. CLASSIFICATION
CONNECTIVE TISSUE
Embryonic
Adult

8. EMBRYONIC CONNECTIVE TISSUE
MESENCHYMAL
MUCOUS

9. ADULT CONNECTIVE TISSUE
CONNECTIVETISSUE PROPER
SPECIALIZED CONNECTIVE TISSUE

11. SPECIALIZED CONNECTIVE TISSUE
CARTILAGE
BONE
ELASTIC
FIBRO
CARTILAGE
HYALINE
COMPACT
SPONGY

12. CELLS OF CONNECTIVE TISSUE
RESIDENT CELLS
Fibroblasts
Macrophages
Adipose cells
Mast cell
Plasma cells
WANDERING CELLS
Lymphocytes
Plasma cells
Neutrophils
Eosinophils
Basophils
Monocytes

13. FIBROBLASTS One of the two most numerous cells of C.T.
Large, flat cells with branching processes and appear fusiform in profile.
Young fibroblasts
Mature/inactive fibroblasts

14. FIBROBLASTS Most common cells
Synthesize proteins, such as collagen and elastin that forms collagen, reticular, and elastic fibers
Secrete “Ground Substance”
Involved in production of “Growth Factors”
Wound healing
Section of rat skin. A connective tissue layer (dermis) shows
several fibroblasts, which are the elongated cells. (H&E) stain.

15. Fibroblasts that are actively engaged in synthesis are richer in mitochondria, lipid droplets, Golgi complex, and rough endoplasmic reticulum than are quiescent fibroblasts (fibrocytes).

17. MACROPHAGES (HISTIOCYTES)
Almost as numerous as fibroblasts
Most abundant in richly vascularized areas
Fixed/resting macrophages
Free/wandering macrophages

18. MACROPHAGES
Size µm
Oval or kidney shaped nucleus located eccentrically
Monocytes-Marophages
Kupffer cells-liver, microglial cells-CNS, osteoclasts- bone tissue
Phagocytosis
Have well-developed Golgi complex, many lysosomes, and a prominent rough endoplasmic reticulum
‘Foreignbody giant cell’

19. IN RESTING PHASE
Appear as irregular cells with short and blunt processes but sometimes the processes may be long, slender and branching.
Nucleus is rounder, smaller and more heterochromatic than that of fibroblast.
Cytoplasm stains darkly & may contain few small vacuoles

20. IN ACTIVE STATE
Cell becomes larger with bigger nucleus and prominent nucleolus
Cytoplasm becomes filled with granules and vacuoles, containing ingested material

22. FUNCTIONS OF MACROPHAGES
Important agent of defense and part of Mononuclear phagocyte system.
These are secretory cells that produces several important substances including enzymes and proteins of complement system
They play very important role in immune system and act as antigen presenting cells.
They are capable of motility and when suitably stimulated grouped around a large foreign body to form multinucleated foreign body giant cells

23. ADIPOSE CELLS
The large mesenchymal cells after accumulation of fat droplets in their cytoplasm are called adipocytes
Occur singly or in clumps along small blood vessels

24. ADIPOSE CELLS Also called “Fat Cells” Size 50-150 µm
Cytoplasm is dispalced to periphery by a single large fat droplet
Nucleus is pressed against the cell membrane “Signet ring”
Functions in energy reserves, insulation, protection, and support

25. TYPES OF ADIPOSE TISSUE
White or unilocular
Brown or multilocular

26. UNILOCULAR FAT Also called white fat Widely distributed in body
Main component of adult fat
Single fat droplet in cytoplasm
Cells show signet ring appearance

27. MULTILOCULAR FAT Also called brown fat Mainly found in children
Multiple small fat droplets
Help in heat production
Rich blood supply
Numerous mitochondria

28. MAST CELLS
Mast means well fed. Their cytoplasm is full of coarse granules so this name is given.
Tend to occur in small groups around blood vessels.
Irregularly oval in outline, have short pseudopodia
Nucleus is small being crowded by large number of prominent granules

29. FUNCTIONS OF MAST CELLS
As these granules contain heparin (a powerful anticoagulant) and histamine (a potent vasodilator) so they play very vital role in homeostasis.

30. METACHROMASIA

31. PLASMA CELLS Large, ovoid cells
Nucleus is spherical and eccentrically placed
‘cart-wheel appearance’
Basophilic cytoplasm due to abundant RER
Rare in most connective tissues
Produce antibodies
Average life is short, 10–20 days
Portion of a chronically inflamed intestinal
villus. PT stain