Connective Tissue
COnnective Tissue
Connective Characteristics
· bind, support, protect, fill spaces, store fat,
produce blood cells
· widely distributed throughout body
· most have a good blood supply
· cells are farther apart than in epithelium
· plenty of extracellular matrix
fibers and a ground substances (solid to semisolid)
· fixed cells
Major Cell Types
fibroblasts (fiber builders) - most common; large, star
shaped; produce fibers
mast cells - large; located near blood vessel; release
heparin (prevents blood clotting) and
histamine (inflammation and allergies)
· wandering cells
macrophages (large eater) - carry on phagocytosis
Connective Tissue Fibers
· fibroblasts produce 3 typed of fibers
collagenous, elastic, and reticular
collagenous and elastic most abundant
· collagenous fibers - great tensile strength (resist
pulling force)
tendons (muscle to bone) and ligaments (bone to bone)
found in dense connective tissues
a.k.a. white fibers because they appear white when
grouped together
· elastic fibers - stretch easily
thin fibers that branch
not as strong as collagenous, but return to original shape
after stretching
a.k.a. yellow fibers
· reticular fibers - delicate support
thin collagenous fibers
highly branched
2 Types of Connective Tissue
· connective tissue proper
loose connective tissue, adipose tissue, and dense
connective tissue
· specialized connective tissue
cartilage, bone, blood
Connective Tissue
Loose Connectie Tissue
a.k.a. areolar tissue
bind organs together and holds tissue fluid
main cell type - fibroblast
extracellular matrix - gel-like with many
collagenous and elastic fibers
· beneath skin, between muscles, beneath
epithelial tissues
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Dense COnnective Tissue
· binds organs together
· cells - few fibroblasts
· extracellular matrix - closely packed, thick
collagenous fibers and a network of elastic fibers
· poor blood supply (heals slowly)
· tendons, ligaments, deeper layer of skin
Cartilage - 3 Types
· 3 types based on extracellular matrix
hyaline, elastic, fibrocartilage
· hyaline
fine collagenous fibers
supports, protects, provides framework
nose, ends of bones, rings in the walls of respiratory passages
· elastic
dense elastic fibers
support, protects, provides flexible framework
pinna (external ear) and parts of larynx (voice box)
· fibrocartilage
tough tissue, many collagenous fibers
support, protects, absorbs shock
between vertebra, knee, pelvic girdle
Adipose Tissue
· a.k.a. fat
· protects, insulates, and stores fat
· specialized loose connective tissue
adipocytes (fat cells) store fat droplets with their
cytoplasm and enlarge
· beneath skin, around kidneys, behind eyeballs,
surface of the heart
Cartilage
· cells - chondrocytes
· extracellular matrix - abundant, gel-like with
collagenous fibers
· chondrocytes group together in lacunae
· perichondrium (around the cartilage) surrounds
cartilaginous structures
blood supply to cartilage
· torn cartilage heals slowly
Bone
· cells - osteocytes (bone cells)
· extracellular matrix - rigid, full of collagenous fibers,
mineral salts provide hardness
· matrix forms concentric circles
· good blood supply (heals quickly)
· supports, protects, provides framework, produces
blood cells
· bones of skeleton
Connective Tissue
Blood
· blood - formed elements + plasma
cells (formed elements) - WBC, RBC, platelets
matrix - plasma (watery)
· transports substances, helps maintain homeostasis
· throughout body with a closed system of blood
vessels and heart chambers