UCF Pathophysiology II Exam 4 (Chapters 50 + 51 + 52)

Functions of Skeletal System

Protects internal organs, provies bony attachments for muscles and ligaments, presents rigid lever to allow functional movement of the body and it's separate parts, and stores mineral and marrow elements for forming new blood cells.

Fibroblasts/Fibrocytes

Needed for collagen production.

Osteoblasts

Lay down bone, formed from osteoprogenitor cells.

Osteocytes

Mature bone cells.

Osteoclasts

Responsible for bone resorption.

Collagen Fibers

Compose around 95% of the extracellular matrix. Provide stability, strength, and tensile stiffness; tolerate tension but not compression.

Osteon (Haversian System)

Basic unit of the bone.

Cancellous (Trabecular Bone)

Laid down in response to stress and shape to accommodate loads placed on the bone.

Compact Bone

Resistant to compression and dense in structure.

Functional Properties of Bone

Bone is capable of altering it's shape and density in response to mechanical stress. Absence of bone stress due to immobility or altered weight bearing leads to demineralization.

Endochondral Ossification

Involves cartilage replacement by bone (embryonic development, fracture healing, and some bone tumor growth)

Wolff's Law

Response of bone to stress. Bone is laid down where it is needed and resorbed where it is not needed. With external forces (loads), osteoclast activity is higher than osteoblast activity and bone mass decreases.

5 Stages of Bone Healing

- Hematoma Formation (1-3 Days)

- Fibrocartilage Formation (3 Days-2 Weeks)

- Callus Formation (2-6 Weeks)

- Ossification (3 Weeks - 6 Months)

- Consolidation / Remodeling (6 Weeks - 1 Year)

Joints

A point of contact between bones. Joints permit complex, highly coordinated, and purposeful movements. The more complex the movement, the more complex the joint structure.

Synarthroses (Nonsynovial) Joints

Two Types: Fibrous and Cartilage

Fibrous Joints

Include bones united with fibrous tissue.

Cartilage Joints

Have bony segments connected by fibrocartilage or hyaline growth cartilage.

Suture Joint

Type of fibrous joint. Unites bones with a thin but dense layer of fibrous tissue; found only in skull.

Gomphosis Joint

Type of fibrous joint. Reflected by a peg in a hole; only joint between teeth and mandible.

Syndesmosis Joint:

Type of fibrous joint. Two bones joined by a ligament or interosseous membrane (between tibia and fibula).

Symphysis Joint

Type of cartilage joint. Connect bony segments by a fibrocartilage plate to disk; symphysis pubic joint.

Synchrondrosis Joint

Type of cartilage joint. Involves cartilage connecting bony components; found at growth sites of the body; first sternocostal joint.

Diarthroses (Synovial Joints)

Joints designed to allow mobility.

Proteoglycan Aggregation

Provides structural rigidity and better compression tolerance than collagen fibers.

Ligaments

Connect bone to bone, provide mechanical stability to joints, and guide joint movements.

Tendons

Attach muscle to bone and assist in generation f movement.

Connective Tissue Around Sarcolemma

Endymysium

Connective Tissue Around Fasiculi

Perimysium

Connective tissue Around Entire Muscle

Epimysium

Striation

Organized structure of myofibrils of the contractile apparatus.

Scoliosis

Lateral curvature of the spine resulting in "S" or "C" shaped spinal column. Most cases are idiopathic. Usually congenital, connective tissue, or neuromuscular disorder. Can be nonstructural or structural.

Nonstructural Scoliosis

Resolved when patient bends to affected side. No deformity. Can be related to postural issues or inflammation. Not progressive. Treatment includes bracing, exercise and surgical alignment.

Structural Scoliosis

Fails to correct itself by bending. Involved deformity. Condition is progressive.

Osteoporosis

Most common metabolic bone disorder. Occurs when rate of bone reposition is higher than that of bone formation. Leads to fragile bones and fractures.

Rate can be influenced by age, genetics, estrogen, and risk factors. Tends to demineralize trabecular first.

Treatment includes calcium and vitamin D, exercise, and estrogen replacement therapy.

Estrogen

Prevents loss of osteoblasts and halts osteoclast activity. Loss of estrogen results in osteoblast loss and no control of osteoclasts.

Rickets

Deficits in the mineralization of newly formed bone matrix in the growing skeleton.

Osteomalacia

Deficits in mineralized of newly formed bone matrix in the mature skeleton.

Osteomyelitis

Severe pyogenic infection of bone and local tissue. Infection can enter body through blood stream, adjacent soft tissue, or directly into the bone (through wounds, surgical contamination, etc).

Staphylococcus Aureus is most common.

Multiple Myeloma

Slow growing bone marrow malignancy with neoplastic proliferation of a single cone of plasma cells. Homogenous immunoglobulin is found in urine. Pain is main symptom.

Ligament Injuries

Occurs when loading exceeds physiologic range of motion.

Tendon Injuries

Range from mile to complete tear. Tendonitis can develop infection.

Muscular Dystrophy

A group of genetically determined myopathies characterized by progressive muscle weakness and degeneration.

Duchenne Muscular Dystrophy

Most common and severe type. X linked recessive gene therefor mainly inherited by men. Muscle cells are deficient in dystrophin. Can begin around age 3. Manifest in calf muscle enlargement and distal muscle involvement. Treated through corticosteroids.

Myasthenia Gravis

Chronic autoimmune disease. Affects neuromuscular function of voluntary muscles and characterized by profound muscle weakness and fatiguability.

Treatment is through acytlcholinesterase inhibitors.

Arthritis

Inflammation of one or more joints. Joint pain, stiffness, swelling, etc. Most common disabling musculoskeletal disorder in the untied states. Risk factor is increasing age.

Synovial Fluid Analysis

Noninflammatory: <2000 WBC's

Inflammatory >2000 WBC's

Septic: >100,000 WBC's

Osteoarthritis

Characterized by inflammatory damage or destruction in the synovial membrane or articular cartilage and by systemic signs of inflammation. Includes fever, leukocytosis, malaise, anorexia, etc. Can be infectious or noninfectious.

Treated through acetaminophen, NSAID's, physical therapy, etc.

Rheumatoid Arthritis

Inflammatory joint disease. Systemic autoimmune damage to connective tissue, primarily in the joints. Similar symptoms to osteoarthritis. Presence of rheumatoid factors (RA or RF test). Women 2-3x more likely to develop. Specific cause is unknown.

Pannus

Vascularized tissue made up of lymphocytes, macrophages, histiocytes, fibroblasts, and mast cells. Erode and destroy articular cartilage.

Gout

Heterogenous disorder of uric acid metabolism. Risk increases with age. Most common in middle aged men and post menopausal women. Recurrent attacks of articular and periarticular inflammation, accumulation of tophi, renal impairment, and uric acid calculi.