Tissues & Cancer Connective Tissue

Connective tissue Many functions include: Bind structures Provide support, protection, and framework Fill space Store fat Make red blood cells (RBCs) Fight infection Repair damage

Connective tissue Not as tightly spaced as epithelial cells Separated by extracellular matrix (ECM) Most can divide Have good blood supply Cell types: Fixed cells Wandering cells

Fibroblasts Most common fixed cell Large & star-shaped Make fibers by secreting proteins into ECM

Fibroblasts make 3 types of fibers Collangenous fibers Elastic fibers Reticular fibers

Collagenous fibers Made up of collagen holds structures together with great tensile strength Grouped in long, parallel bundles Found in ligaments & tendons

Elastic fibers Stretch easily Made of the protein elastin Thin fibers branch to form a complex network Common in body parts that are frequently stretched, like your vocal cords

Reticular fibers Very thin collagenous fibers that lend delicate support Highly branched Found in the spleen, as well as other tissues

Macrophages A type of white blood cell Scavenger & defense cells that clean up foreign substances from tissues through phagocytosis https://www.youtube.com/watch?v=BDr44vLNnPY

Mast Cells Have allergies? Thank your mast cells! Large cells near blood vessels that secrete heparin and histamine Heparin- prevents blood clotting Histamine- dilation of blood vessels & increased mucous production Allergic Response! Some foods have histamine! http://www.michiganallergy.com/food_and_histamine.sht ml

Loose connective tissue Less packed and separated by ECM Areolar tissue, adipose tissue, and reticular connective tissue Areolar tissue- forms delicate thin membranes, binding skin to underlying organs Adipose tissue- cells that store fat droplets in their cytoplasm & enlarge (insulates, cushions, & serves as energy)

Dense connective tissue Closely packed thick collagenous fibers and a fine network of elastic fibers Very strong Tendons and ligaments

Cartilage Provides support and can protect underlying tissue Forms structural models for bones Chondrocytes are the cartilage cells Cartilage is covered in the perichondrium, which contains the blood vessels that supply nutrients to the chondrocytes Do not heal easily because they don’t have a direct blood supply

3 types of cartilage Hyaline cartilage- ends of bones in many joints & end of nose Important in the development and growth of bones Looks like white glass of fine collagenous fibers Elastic cartilage- ears and larynx Dense network of flexible elastic fibers Fibrocartilage- disks in the spinal column Tough collagenous fibers that act as shock absorber In knees too

bone Most rigid connective tissues due to mineral salts (Calcium phosphate) between cells Supports body structures and protects vital organs Contains red marrow to form blood cells Osteocytes are bone cells

bone Form in thin layers called lamellae which form circles around central canals = osteon Osteons cemented together form bone

bone Each central canal contains a blood vessel as a nutrient supply Thus bones heal quicker than cartilage due to the access of a blood supply

blood Functions in transporting nutrients, CO2 and O2, and materials Composed of red & white blood cells and platelets suspended in a fluid ECM called blood plasma Red and white blood cells form in the bone marrow of long bones