1. Vinnytsya National Pirogov Memorial University Histology Department CONNECTIVE TISSUE
as. Hrytsenko A.S.

2. Connective tissues
is a complex of mesenchyme derivatives, consisting of cells diferons and big quantity of extracellular matrix (fibers and ground substance);
comprises more than 50% of human body mass;
It participates in formation of organs, layers between other tissues, derma of a skin, skeleton.

3. functions of connective tissue
1. Support:
formation of stroma of inner organs;
separation of structural-functional units of other tissues and organs;
maintenance and coordination of all body functions.
2. Defense:
physical - the viscosity of the extracellular matrix slows the spread of many bacteria and foreign particles; sheets of tightly packed collagen fibers, as in organ capsules, help to confine local infections;
immunologic - cells of connective tissue activate local immune responses (inflammation).
3. Repair: injury stimulates proliferation of fibroblasts, which rapidly form collagenous matrices that close wounds and form scars.
4. Storage: reserves of water and electrolytes, especially sodium; energy reserves in the form of lipids are stored in adipocytes.
5. Most blood and lymphatic vessels and peripheral nerves are surrounded by loose connective tissue.

4. CLASSIFICATION OF inner tissues:
Blood and lymph
Sceletal tissue:
Bone
Cartilage
Connective tissue proper:
loose connective tissue
dense connective tissue:
dense irregular connective tissue
dense regular connective tissue
Connective tissue with special properties:
Reticular
Mucoid
Pigmented
Adipose:
White adipose
Brown adipose

5. LOOSE CONNECTIVE TISSUE
Consists of:
Cells;
Extracellular matrix:
Fibers;
Ground substance.

6. CELLS OF CONNECTIVE TISSUE
Fixed (permanent resident) cells are native to the tissue in which they are found:
Fibroblasts
Myofibroblasts
Fibroclast
Macrophages
Monocyte-derived phagocytes
Mast cells
Adipose cells
Pericytes
Wandering (transient) cells are immigrant cells, usually from blood or bone marrow:
Plasma cells
Lymphocytes
Monocytes
Neutrophils
Eosinophils
Basophils

7. FIBROBLASTS Structure: size of the cell is 40-50 mcm;
is stellate shape;
has long cytoplasmic processes;
has large, ovoid, pale-staining nucleus with 1-2 big nucleolus;
contains rough endoplasmic reticulum and Golgi complex;
Function;
synthesize, secrete, and maintain all major extracellular matrix components:
synthesis GAG (glycosaminoglycan) of the intercellular ground substance;
synthesis procolagen and elastin
FIBROBLASTS
Fibroblast differon:
stem cell→unmature fibroblast →mature (active) fibroblast →myofibroblast, fibroclast and fibrocyte;
are the principal and most common cells in connective tissue;
are mitotically active;
There are two types of these cells:
Active (fibroblast);
Quiescent (fibrocyte)

8. FIBROCYTES spindly shaped; has an acidophilic cytoplasm ;
contein small amount of rough endoplasmic reticulum;
contein small amount of other organelles;
synthetic processes are decreased;
may revert to the fibroblast state and participate in tissue repair.

9. Unmature fibroblast is mitotically active cell;
size of the cell is mcm;
cytoplasm is slightly basophilic;
cytoplasm is rich in RNA molecules;
has short processes and round or oval-shaped nucleus;
rouph endoplasmic reticulum and Golgi complexes are undeveloped;
production of collagen and other matrix components very poor.

10. Myofibroblast
displays properties of both fibroblast and smooth muscle cell;
have the morphologic characteristics of fibroblasts but contain increased amounts of actin and myosin microfilaments;
is responsible for wound closure and contraction;
is found in the periodontal ligament, where it probably assist in tooth eruption.

11. Fibroclast
has high phagocytic and hydrolytic activity, share in resorption of extracellular matrix in an involution of organs;
combine features of mature fibroblast and lysosomes with hydrolases.

12. macrophages
Is derived from monocytes that infiltrate connective tissue and develop into phagocytes;
large, stellate cells;
contain a large Golgi, rough and smooth endoplasmic reticulum, mitochondria, secretory vesicles and lysosomes;
Functions:
phagocytosis;
presenting lymphocytes with concentrated antigens;
removing foreign substances and cell debris.

13. Mast cell derive from bone marrow precursors;
large (20 to 30 mcm) cells;
has electron-dense basophilic granules;
have many small plasma membrane folds;
well-developed Golgi complex;
small central nucleus;
have surface receptors for the IgE antibodies that trigger degranulation, the exocytosis of the granule;
Granules contain :
heparin;
histamine;
eosinophilic chemotactic factor of anaphylaxis (ECF- A);
neutral proteases;
neutrophil chemotactic factor (NCF);
arachidonic acid precursors: leukotrienes (LTD4, LTE4 and LTC4), thromboxanes (TXA2 and TXB2), and prostaglandins (PGDg);
cytokines: platelet-activating factor (PAF), bradykinins, interleukins (IL-4, IL-5, IL-6), and tumor necrosis factor-alpha (tnf)

14. Adipose cell Brown adipose tissue: mesenchymal derivatives;
specialized for lipid storage;
smaller than white adipocytes;
has many small droplets;
contain many mitochondria.
White adipose tissue:
mesenchymal derivatives;
specialized for lipid storage;
diameter varies from 50 to 150 nm;
contains a single large lipid droplet;
displaces the nucleus;
cytoplasm to the cell periphery;
near the nucleus contains a Golgi complex, mitochondria, a small amount of rouph endoplasmic reticulum, and free ribosomes;
in the thin rim contains smooth endoplasmic reticulum and pinocytotic vesicles.

15. PERICYTES is developed from undifferentiated mesenchymal cells;
partly surround the endothelial cells;
is surrounded by their own basal lamina;
combine characteristics of smooth muscle cells and endothelial cells;
under certain conditions, they may differentiate into other cells.

16. PLASMA CELL differentiate from antigen-stimulated В lymphocytes;
producers of circulating antibodies;
large and ovoid;
eccentric nucleus and abundant rouph endoplasmic reticulum;
containing a well-developed Golgi complex and centrioles;
characteristic "clock face" nucleus results from a large, central nucleolus and large heterochromatin clumps regularly spaced around the nuclear envelope's inner surface envelope.

17. Components of extracellular matrix
Fibers:
collagen;
reticular;
elastic;
Ground substance:
proteoglycans - consist of a core protein to which glycosaminoglycans (GAGs) are attached;
glycosaminoglycans (GAGs) - are much smaller than proteoglycans; are straight-chain polymers of repeating amino-glucose heterodimers made up of a hexosamine (glucosamine or galactosamine) and a uronic acid (glucuronic or iduronic acid).

18. Dense regular connective tissue
The fibers are tightly packed into parallel bundles;
Between the bundles are a few fibroblasts;
Small amount of ground substance;
Function:
transmits the force of muscle contraction, attaches bones, and protects other tissues and organs;
Localization:
Tendons, ligaments, periosteum, perichondrium, deep fascia, and organ capsules.

19. Dense irregular connective tissue
Seems poorly organized than dense regular;
Function:
Covers tissues and organs, protecting them from multidirectional mechanical stresses;
Localization:
reticular layer of the dermis and in most organ capsules.

20. Adipose tissue Brown adipose tissue:
White adipose tissue:
is present in most of the fatty tissue of the body;
is characterized by containing unilocular adipose cells;
Functions:
energy storage, insulation of heat, supportive pads of fat for other organs and gives the body its characteristic contour .
Brown adipose tissue:
is present in few sites in the body: mediastinum, perinephric fat and around the aorta;
contains multilocular adipose cells;
Functions:
thermoregulation.

21. Mucoid connective tissue
mucoid amorphous component of the intercellular substance is dominating, with mucoid cells and some few collagenous fibers;
Localization:
Wharton’s jelly of the umbilical cord, and bulb of the tooth.

22. Pigmented connective tissue
pigment cells are dominating;
Localization:
It can be seen in the uveal tract of the eye ball (the choroid, the ciliary body and iris).