Lecture 12 - Musculoskeletal system 2: Bones Flashcards
Bones grow as what occurs to cartilage
It is solidified and calcified into a stronger structure
In what two ways does Bone growth occur
- Appositional (widening)
2. Interstitial (lengthening)
How is appositional growth accomplished
- cells of the perichondrium (chodeoblasts) secrete matrix
- this matrix is deposited on the surface of the cartilage
- cartilage grows from the outside
How does interstitial growth occur
- chondrocytes enclosed in their lacunae ( still chondroblasts) divide and form more matrix.
- cartilage grows from the inside
- principal way used for cartilage being formed but this lengthening stops when become an adult.
What is zone 1 of interstitial growth
Proliferative zone
- chondrocytes divide rapidly which results in:
- epiphyses moving away from each other
- new cells are pushed towards the diaphysis
What is zone 2 of interstitial growth
Hypertrophic zone
- older chondrocytes enlarge and undergo degenerative changes
- surrounding cartilage matrix calcifies
What is zone 3 of interstitial growth
Ossification zone
- remaining calcified cartilage rapidly break down
- produces spongy bone which break down into the medullary cavity
What happens in interstitial growth as we age
- eventually zone 1 slows done chondrocytes replication
- ossification on the diaphysis side catches up to the epiphysis
- bone of the epiphysis fuses with that of the diaphysis
- this results in epiphyseal line
What 3 parts is cartilage made up of
- Chondrocytes (in lacuna)
- Matrix (ground substance)
- Fibers (elastic, reticular, collagen)
What is the surrounding layer of cartilage that sometimes appears
Perichondrium
Cartilage Matrix distribution depends on
The type of cartilage
What type of cartilage has the most matrix
Fibrocartilage
What type of cartilage has the least matrix
Elastic
Cartilage matrix is resistant to
Stretch and compression
The cartilage matrix is composed of
- chondroitin sulfate
- keratin sulfate
- hyaluronic acid
- principally H2O = great elasticity (returns to initial form after being compressed)
What is structure of hyaline cartilage
- spherical chondrocytes
- only collagen fibers
Where do you find hyaline cartilage
- articular cartilage (ends of bones in joint)
- costals ( joins ribs to sternum)
- the larynx (its skeleton and voice box)
- tracheal, bronchial (resp airways)
- cartilage of nose (supports nostrils)
Structure of elastic cartilage
- resemble hyaline cartilage
- except fibers are especially elastic
Where do you find elastic cartilage
Ear (pinna)
Epiglottis
Structure of fibrous cartilage (fibrocartilage)
- alternating rows of chondrocytes
- bundle of thick collagen fibers resisting to compression and stretching
- no perichondrium
Where do you find fibrous cartilage
- intervertebral discs
- knee meniscus
What are the differences in bones of males and females
- skull size: males bigger
- bones : in general lighter and thinner in females
- muscle attachment sites: larger in males
- joint surfaces: smaller in females
- differently shaped pelvis
Fracture repaired is a slow process because (3)
- requires the process ossification
- relies on the production of osteocytes
- following a fx irrigation is low
What is step 1 of simple fx repair
-blood vessels in central canals and periosteum are broken and coagulation forms a HEMATOMA (occurs within a few hours)
What is step 2 of simple fx repair
-capillaries develop around and in hematoma
- phagocytes/osteoblasts ensure breakdown and reabsorption of the damaged area surrounding hematoma (up to a few weeks)
- the hematoma transforms into a SOFT CALLUS
(Temp scar tissue that joins the separated parts of the bone )
What is step 3 of simple fx repair
- osteoblasts continue healing process
- soft callus becomes BONY CALLUS
- end: 2-3 months after accident
What is step 4 of simple fx repair
Phase of REMODELING
- osteoclasts and osteoblasts remodel tissue until the repair is complete
6 types of fractures
Closed Open Comminuted Impacted Spiral Greenstick
What is closed fx
Majority of cases
Does not break skin
What is open fx
More serious than closed
Can have acute infection or osteomyelitis
What is comminuted fx
Breaks in several pieces
Usually cases where bone more brittle like elderly
What is impacted fx
Bone crushes into itself
Common in hip
Or when put arm out to stop fall
What is spiral fx
Bone broken by twisting force
Common for athletes
What is greenstick fx
Common in children
Chunk out of one side
What happens when there is a decrease in estrogen since osteogenic cells stimulate ossification
Progressive decalcification happens
- particularly nearing menopause 30-40
When does decalcification start in males
In their 60’s
What protein synthesis decreases with age
Collagen synthesis
What happens faster with age the loss of collagen or decalcification
Collagen loss is greater
- so gradually the bone contains proportional more calcium salts
What are joint and articulations
Region where 2 or more bones meet
What is classification of 3 types of articulations
- Synarthroses/ fibrous
- Amphiarthroses / cartilaginous
- Diarthroses / synovial
What are suture fibrous articulations
- thin layer ct btw bones of cranium
- become bone with age called synostose
- they are immobile (short fibers)
What are syndesmosis fibrous articulations
- regular dense ct forms: ligament and intraosseous membrane
- semi-mobile (fibers a bit longer)
What is gomphosis fibrous articulations
- roots of teeth with alveoli of the maxilla and mandible, the whole structure is held by a sheet of tiny ligaments, called the periodontal membrane.
- immovable (one bone in another)
What is synchondrosis cartilaginous articulations
- contains hyaline cartilage
- ex. Epiphyseal cartilage (joins epiphysis to diaphysis)
- ex. 1st rib to the sternum
- immovable
What is symphysis cartilaginous articulations
- form a flat disc of fibrocartilage joined to bony surfaces that are covered by hyaline cartilage
- ex. Intervertebral discs
- ex. Public symphysis (btw the 2 coxal bones)
- semi mobile
What is synovial articulations
- lots of mobility
- must utilize all of its parts to function properly without wearing them down
What are the 5 characteristics of synovial articulations
1.contains articular cartilage (hyaline): covers end of bones
2. Joint cavity is formed by articular capsule
3. Articular or joint capsule that join the bones, consist of 2 layers: (external= fibrous capsule, internal= synovial membranes)
4 ligaments: specialized bands adding to solidity of the articulation
5. Synovial liquid: secreted by synovial membrane, they lubricate articulation, get lighter with intensified movement and give nutrients to the cartilage
What is the meniscus
- articulation disc of fibrous cartilage, fixed to fibrous layer
- help to adapt 2 bones of different forms
- maintains contact and absorbs the shock
What are bursa and tendon sheaths (elongated bursa)
- pocket with a synovial membrane filled with synovial liquid
- act like “ball bearing” that decrease friction of the tendons on the bone and other structures of the articulation
What are uniaxial joints
- Hinge joint that allow movement in only one dirext(ex. Elbow
- Pivot joints that allow rotation (ex. Between C1 & C2)
What are biaxial joints
- Saddle joint: only found in carpo-metacarpal joint of the thumb
- Condylar joint: allow movement in 2 planes
- wrist articulation btw the radius and the carpal bones; knuckle joints
What are multiaxial joints
- ball and socket joint: allow greatest mobility, are very solid (femur with coxal bone, humerus with scapula)
- plane joint: allow gliding on various planes( ex. Carpal bone, articular facets of adjacent vertebrae)
ROM; angular movements (4)
- Flexion: decreases the angle btw bones
- Extension: increases angle btw bones; hyperextension goes beyond anatomical position
- Plantar flexion and dorsiflexion: downward/ upward tilt of foot
- abduction and adduction: movement away / towards from the medium plane
ROM: Circular movements (2)
- Rotation : pivot of bone on its axis, circumduction (distal end moves in circle)
- supination and pronation: twisting movement laterally/ medially
ROM: Gliding movements
- articular surface of one bone moving over articular surface of another bone
- no circular or angular movement
- carpals/ tarsals, vertebrae
ROM: Special movements
- inversion & eversion: turning sole of foot inward/outward
- protection & retraction: movement of a part forward/ backward
- elevation & depression: movement of part up and down
What is osteoporosis
- increased bone porosity, reduced density and mineral mass.
- leads to progressive microfractures in trabeculae and eventual collapse
- woman 2x more than men
What is osteomalacia
- loss of mineral from mature bone due to vitamin D deficiency
- comes with increased production of unmineralized matrix
- known as rickets in your kids ( bones are demineralized before hitting maturity and = contouring of legs)
What is osteitis deformans
- increased proliferation of osteoclasts
- leads to osteoblastic activity
- rapid and disorganized bone remodeling
- sometimes asymptomatic
- aka Paget’s disease
What is osteomyelitis
- bacterial infection of bone and marrow tissue
- difficult to treat due to decreased blood supply
- often 2nd to another infection or direct bone contamination
What is Lordosis
Abnormal spinal curvature of lumbar curve
- caused by pregnancy, traumatic injury, degeneration or vertebral bodies
What is kyphosis
Abnormal spinal curvature of thoracic curve
- common in elderly w/ osteoporosis or chronic arthritis
- developing at puberty: Scheuermann disease
What is scoliosis
Abnormal spinal curvature side to side
- typically appears before adolescence
What is a sprain
Elongation of tear of ligaments that reinforce articulations
What is dislocation (luxation)
Displacement of bones from their normal position in the articulation
What is Bursitis
- inflammation of a bursa
- prolonged pressure, excessive exercise, sudden trauma
What is tendonitis
Inflammation of the tendon sheaths
What is arthritis
Genetic term designating many inflammatory or degenerative diseases of the articulations
What is rheumatoid arthritis
Inflammation disorder, chronic, autoimmune
- the body decides to degenerate the articulation
What is gouty arthritis
Uric acid ( waste of the metabolism of nucleic acids) - excess of uric acid can deposit in the soft tissues of the articulations (mobility becomes very restricted)
What are the major bone of the cranium
Occipital Parietal Temporal Frontal Sphenoid Nasal Ethmoid Zygomatic Maxilla Mandible Lacrimal Vomer
