Connective Tissue And Fat Flashcards
Types of Connective Tissues
- Loose irregular
- Dense irregular
- Dense regular
- Adipose tissue
1) Structural found in skeleton (cartilage and bone)
2) blood
Composition of Connective Tissue
- Cells: fibrocytes, fibroblasts, blood cells, adipocytes
- Matrix: PGs, GAGs, glycoproteins, tissue fluid
- Fibers: collagen, reticular, elastic
Function of connective tissues
1) supports and connects cells, tissues, and organs, allows blood vessels and nerves to come in proximity to epithelial
2) provides medium for exchange of gasses, nutrients, and metabolites
3) contains cells of the immune system that protect the organism from invasion of foreign material
4) Fibers provide strength and or flexibility depending on the location and type
Fibroblasts
- active in producing fibers and matrix
- spindle shaped with small, dark staining nucleus
Fibrocytes
-inactive, resting fibroblasts
Adipocytes
1) unilocular- one large lipid droplet found in white fat
2) multilocular - many smaller lipid droplets found in brown fat
3) may occur singly or in groups
Mast cells
- oval cells with many dark staining, basophilic granules
- located close to blood vessels
- leukotrienes released from cell membrane ave vasoactive properties (asthma)
- granules contain histamine, heparin, and chemoattractants
- granules released in response to allergens or irritants
Macrophages (Histiocytes)
- phagocytic cells derived from circulating monocytes
- called histiocytes when resident in the connective tissue
- phagocytize foreign material and stimulate immune responses
Leukocytes
- neutrophils, eosinophils, lymphocytes
- defense against infection
Plasma cells
- activated lymphocytes that produce immunoglobulins
- defense against infection
Matrix Function
- in connective tissue, GAGs hold water to make a gel which provides spaces for cells and capillary beds and a diffusion medium for nutrients
- make tissues able to withstand compression, in dermis makes skin supple, in cartilage makes it strong, flexible plastic-like bearing surfaces for joint
Tissue Fluid
-formed by transcytosis of fluid through capillary endothelial cell
Collagen in connective tissue
Type 1 - primary collagen, high tensile strength, stains pink to orange with H&E
Type 2 - found in hyaline and elastic cartilage and the vitreous of the eye, resists pressure
Type 3 - branching collagen that makes reticular fibers, form fine mesh that hold some tissues together (lymphoid organs)
Type 4 - network forming collagen found in basement membranes
Reticular fibers
- made of type 3 collagen
- forms a mesh of fibers that support lymphoid organs, blood vessels, muscle cells and nerves
- requires special stain
Elastic fibers
- made of elastin
- synthesized by fibroblasts in skin and tendons, chondrocytes in cartilage and by smooth muscle cells in large blood vessels
- found in locations where stretching and recoil is necessary ( bladder, large blood vessels, and lungs)