731 Tissue Properties

extracellular matrix

composed of a ground substance and fibrous proteins

fibrous proteins

collagen and elastin

collagen

amino acids forming a structure called tropocollagen forming fibrils. 2 types of collagen

1. Thick fibers that are stiff and strong. Ideal for binding and supporting the articulations between bones

2. Thinner and less tensile strength than type 1 collagen. Provides general framework for maintaining shape and structure

Elastin

less stiff than collagen but highly elastic (stretchy). High proportion of elastin readily return to their original shape after being deformed

glycosaminoglycans (GAGs)

polysaccharide molecules that group together t form proteoglycan complexes; very hydrophilic; important to the material properties of articular cartilage

fibroblasts

general connective tissue cells

chondrocytes

cartilage cells

osteoblasts/osteocytes

bone cells

Describe the general histology of connective tissue, including cellular and extracellular components.

Connective tissue can be found in bone, fat, blood, tendon, ligaments, joint capsules, articular cartilage, and fibrocartilage. All of these items have vascular supply EXCEPT for cartilage. The foundation of these structures are built with the extracellular matrix and cells and the ECM is composed of ground substance and fibrous proteins. ECM has two main fibrous proteins: collagen and elastin. Collagen is very stiff and type 1 can be found in the articulation between bones and type 2 is less stiff and can be found as a general framework. Elastin is more stretchy and can be found throughout skin, lungs, tendons, cartilage, etc.

Relate features of connective tissue histology to material properties of tissues and the types of loads tissues experience within the human movement system.

Tendons are aligned and have the strongest in collagen strength. They have strong tensile forces but forces applied in any other way may result in deformation. Ligaments are the second strongest with collagen fibers i alignment but some are out alignment allowing for forces to be absorbed from different directions. Skin is the weakest but has fibers in many different alignments all over the place to give the same resistance no matter where forces are applied.

Explain how tissue properties may be affected by factors such as age, genetics, pathology, and nutrition.

Age—> as we get older our collagen naturally declines and we lose elascticity

Genetics—> Ehler-Danlos Syndrome

Pathology—> osteopenia or osteoporosis

Nutrition—> amino acids/protien, hydration for proteoglycans, milk for bones