Download B. Connective Tissues

B. Connective Tissues
• Made up of:
– Cells, which are further apart than epithelial cells
– Fibers
– Matrix: intercellular material
• Major cell types:
1. Fibroblasts – large, fixed, star-shaped cell that
secretes fibers
2. Macrophages – wandering scavenger cells that
defend against infection
3. Mast cells – large cells, located near blood
vessels, that secrete heparin and histamine
Connective Tissues (cont.)
• Connective tissue fibers:
1. Strong, collagenous fiber (white fiber), made of
the protein collagen; adds strength
2. Stretchy, elastic fiber (yellow fiber), made of
the protein elastin; adds ____________.
3. Reticular fibers – thin collagenous fibers that
form supportive networks in tissue
Connective Tissues (cont.)
1. Loose Connective Tissue (“areolar tissue”)
– Cells are some distance apart; separated by gellike matrix
– Forms delicate, thin membranes
– Binds skin to underlying organs, fills space
between muscles
Connective Tissues (cont.)
2. Adipose Tissue – fat
– Large fat droplets in cells push nuclei close to the
cell membranes.
– Beneath the skin, between muscles, around
kidneys, behind eyeballs, on heart, around joints
Connective Tissues (cont.)
3. Dense Connective Tissue – closely packed,
thick collagenous fibers + elastic fibers
– Strong!
– Binds organs together
– Found in tendons, ligaments, deep skin layers
Connective Tissues (cont.)
4. Cartilage – a rigid connective tissue
– Chondrocyte: cartilage cell
– Perichondrium: around cartilage; membrane
surrounding cartilage; contains blood vessels to
supply nutrients
– Three types of cartilage, distinguished by
intercellular (???) matrix:
a) Hyaline cartilage
b) Elastic cartilage
c) Fibrocartilage
Connective Tissue (cont.)
a) Hyaline cartilage
– Very fine collagenous fibers in matrix
– White glass appearance
– Ends of bones in joints, soft part of nose
b) Elastic Cartilage
– Dense network of elastic fibers = more flexible
– Framework for external ears and parts of larynx
c) Fibrocartilage
– Very tough; many collagenous fibers
– Forms intervertebral discs and pads between
bones in knees and pelvic girdle
Connective Tissue (cont.)
5. Bone – the most rigid connective tissue
– Matrix made of mineral salts and collagen fibers
– Osteocyte: bone cell
6. Blood
• See Table 5.4, p.105!!!