o Length is about = to the width o Examples: wrist and ankle bones Flat bones o Are usually quite large o “Generally broad and thin with a flattened and often curved surface” (1) o Examples: shoulder blades, ribs, and breastbone Irregular bones o “various sizes and shapes” (1) o Examples: spine and facial bones o Sesamoid- kneecap/patella 2) Structure of Long Bone o Diaphyis- shaft, cylinder shape, provides support o Epiphyses- top and bottom, bulbous shape, mainly spongy bone o Articular cartilage- covers joint surfaces o Periostereum- “dense, white fibrous membrane that covers bone except at joint surfaces” (1) o Medullary- hollow tube space, in the diaphysis, necessary for survival of the bone o Endosteum- lines the medullary cavity, epithelial membrane o (1) 3) Bone Tissue-“Consists of cells, fibers, and extracellular material, or matrix” (1)
the fracture, can Remodeling generally be seen makes bones in X-rays just a stronger and few weeks after more compact the bone fracture and blood occurs.” (4) circulation in the bone improves.” (4)“When a patient breaks a bone, doctors take measures to encourage strong, quick repair. Thesemeasures include: Setting and immobilizing the break. If necessary, a physician will move bone segments back into place before immobilizing the fracture using a cast or brace. Surgery. Some patients may need surgery to set and stabilize a fracture — a process that can involve metal plates, screws or nails. If fractures do not show signs of healing, additional intervention is necessary. Some doctors choose to perform additional surgeries; others turn to devices like EXOGEN. Bone growth stimulation. To help heal fractures, many doctors prescribe a device like EXOGEN — the only stimulator that uses ultrasound waves to stimulate the body’s natural healing process, helping boost bone growth. Therapy. If a patient is in a cast for a long period of time, he or she may benefit from physical therapy to regain full use of stiff or weak muscles.” (4) Compare the basic structural units of bone andcartilage. 1.Cartilage: Collagenous fibers embedded in a rubbery ground-substance calledChondrin, which is a protein-carbohydrate complex. The chondron is secreted by chondrocytes.2.Bone: mineralized connective tissue. Cells called osteocytes deposit a matrix of collagen andcalcium-phosphate which harden to form crystals of a substance called hydroxyapatite.Mammalian bone is constructed from repeated units called HaversianUnits.The process ofmaking new bone is called ossification.
Identify the three specialized types of cartilage, giveexamples of each, andsummarize the structuralandfunctional differences among them. Cartilage is a specialized form of connective tissue containing chondrocytes whichsecrete, and are surrounded by, an extensive intercellular matrix. Chondrocytes occur singly or inisogenous groups, composed of 2-8 cells derived by mitosis from a single chondrocyte. Thecells are in the lacunae (cavities) within the matrix. Matrix stains more intensely immediatelyadjacent to the lacunae and the dark staining zone is called the capsule. The strength anddurability of cartilage are properties of the matrix, which is an interlaced network of collagenousand/or elastic fibers in a ground substance, a gel of complex proteoglycans. The collagen ismostly Type II. How does this differ from dense C.T.?There are three types of cartilage characterized by the composition of the intercellular matrix.(1) hyaline, (2) elastic and (3) fibrocartilage. Hyaline cartilage is found lining articular surfaces, and in the nasal septum, tracheal rings, costal cartilages, and the epiphyseal cartilage of growing bone. Study the trachea on slide #72 (trachea). Even numbered boxes usually contain slides stained for elastic tissues, odd numbered boxes have slides stained with hematoxylin and eosin. The former will have a brown coloration, the latter, the pink and blue you are familiar with. In this slide considerable fading has occurred, and the normal basophilia of freshly stained cartilage is almost absent. The trachea is a large open tube, with cartilage constituting the principal component of its wall. Using the scanning lens, locate the cartilage rings. At higher power, identify single chondrocytes and locate isogenous groups. There are clear areas between many of the chondrocytes and the walls of their lacunae because of shrinkage of the cells brought about by fixation, and because some chondrocytes had lipid droplets which dissolved during histological preparation.Identify the perichondrium. Note the gradation of cell shape changes from fibroblast-like in theouter layer to the round cell shape within the cartilage. The perichondrium is acidophilic due tothe preponderance of collagen fibers. At the interface between perichondrium and cartilage,transitional cells can be seen which are still elongated but are beginning to be surrounded bymatrix.
cartilage that bone tissue later replaces.Cartilage Growth- cartilage is formed from condensed mesenchyme tissue, whichdifferentiates into chondrocytes and begins secreting the molecules that form the extracellularmatrix· Ball-&-socket joint: allows freedom to rotate in a back-and-forth movement· Condyloid joint:this allows the bones to move in any direction, but they cannotrotate· Plane joint:this allows them to move in all directions and rotate.· Hinge joint: allows back and forth movement. (no twisting or side to side. For exampleyour elbow)· Pivot joint: this allows one bone to spin around another· Saddle joint: both of the bones that meet have odd shapes, but they are totallycomplementary to one another.