CONNECTIVE TISSUES THEY HAVE A STRUCTURAL AND SUPPORTING ROLE TOWARD THE OTHER TISSUE OF THE BODY. COMPOSED OF CELLS DISPERSED IN AN EXTRACELLULAR MATRIX. ARE HIGHELY VASCULARIZED TISSUES WITH THE ONLY EXCEPTION OF CARTILAGE.

CONNECTIVE TISSUE FUNCTIONS SUPPORT OF TISSUES AND ORGANS 2. DEFENSE 3. NUTRITION OF OTHER TISSUES (EPITHELIA) 4. PARTECIPATE TO EMBRYO AND FOETAL DEVELOPMENT

CLASSIFICATION OF CONNECTIVE TISSUES 1. GENERAL CONNECTIVE TISSUES: LOOSE FIBRILLAR DENSE FIBRILLAR ELASTIC RETICULAR ADIPOSE 2. SUPPORTING: CARTILAGE BONE 3. TROPHIC: and defense BLOOD LYMPH

GENERAL CONNECTIVE TISSUES COMPONENTS OF THE EXTRACELLULAR MATRIX: FIBERS (COLLAGEN, ELASTIC, RETICULAR) AMORPHOUS COMPONENTS -PROTEOGLYCANS = PROTEIN CORE AND GLYCOSAMINOGLYCANS ATTACHED (ACIDIC SUGARS); -GLYCOPROTEINS CELLS: FIBROBLASTS, MACROPHAGES, MASTOCYTES, PLASMA CELLS, FAT CELLS, LYMPHOCYTES, GRANULOCYTES

CONNECTIVE TISSUE FIBERS COLLAGEN FIBERS: RESISTENT TO TRACTION, A POLYMER OF THE PROTEIN COLLAGEN. ELASTIC FIBERS: HIGHELY ELASTIC, FORMED BY POLYMERS OF THE PROTEINS ELASTIN AND FIBRILLIN RETICULAR FIBERS: THIN POLYMERS OF COLLAGEN PROTEIN

CONNECTIVE TISSUE FIBERS Collagene Fibers

CONNECTIVE TISSUE FIBERS Elastic Fibre

EXTRACELLULAR MATRIX

CELLS OF THE GENERAL, LOOSE, CONNECTIVE TISSUE: (Fibroblasts, Macrophages, Mastocytes, Lymphocytes, Plasma Cells, Granulocytes, Fat Cells)

FIBROBLAST Electron micrograph of a fibroblast in human connective tissue, surrounded by bundles of finely banded collagen fibrils which they secrete.

MASTOCYTES

MASTOCYTES

GRANULOCYTES

LINFOCYTES AND PLASMACELLS

LINFOCYTES AND PLASMACELLS

MACROFAGES

MACROFAGES Macrophages in chronically inflamed human connective tissue, showing prominent eosinophic cytoplasmic granules. Also seen are plasma cells, small lymphocytes and fibroblasts, and the endothelial lining of small vessels.

Loose connective tissue General loose connective tissue (human), with bundles of collagen fi bres within an amorphous ground substance, penetrated by blood vessels, lymphatics and nerves. A small autonomic ganglion is arrowed.

Loose connective tissue

Loose connective tissue

Reticular connective tissue Reticular fibres (type III collagen; reticulin) in the human liver, forming a delicate meshwork within the space of Disse, between hepatocytes plasma membranes and the sinusoidal endothelia.

Elastic connective tissue Elastic fibres, seen as fine, dark, relatively straight fibres in a whole-mount preparation of mesentery, stained for elastin. The wavy pink bands are collagen bundles and oval grey nuclei are mainly of fibroblasts.

Dense connective tissue

Dense regular connective Dense regular connective tissue in a tendon. Thick parallel bundles of type 1 collagen (stained pink) give tendon its white colour in life. The elongated nuclei of inactive fibroblasts (tenocytes) are visible between collagen bundles.

Dense regular connective

ADIPOSE OR FAT TISSUE UNIVACUOLAR WHITE FAT: FAT CELLS ARE COMMONLY PRESENT IN LOOSE FIBRILLAR CONNECTIVE TISSUE ADIPOSE TISSUE IS A CONCENTRATION OF FAT CELLS. UNIVACUOLAR WHITE FAT: -SCARSE EXTRACELLULAR MATRIX WITH RETICULAR FIBERS -ENERGY DEPOSIT (1Kg = 7000 Cal) -MECHANICAL SHOCK ABSORBER (KIDNEY FAT PAD) -THERMIC INSULATOR -HORMONE PRODUCTION (leptin) -INVOLVED IN THE INSURGENCE OF HYPERTENSION, ATHEROSCLEROSIS, TYPE II DIABETES)

Adipose tissue (human) Adipose tissue (human). Adipocytes are distended polygonal cells filled with lipid, which has been extracted by the tissue processing. This leaves only the plasma membranes with scant cytoplasm and nuclei, occasionally visible compressed against the cell periphery. Small blood vessels penetrate the adipose tissue.

ADIPOSE OR FAT TISSUE MULTIVACUOLAR BROWN FAT: -COLOR DUE TO THE ABUNDANCE OF MITOCHONDRIA -SCARSE EXTRACELLULAR MATRIX WITH RETICULAR FIBERS -ABUNDANT IN RODENTS, HIBERNANT ANIMALS, IN THE HUMAN FETOUS. - SENSITIVE TO ADRENERGIC STIMULATION -THERMOGENIC