Lecture 1 Flashcards
OF BONES PRESENT AT BIRTH
270
OF BONES PRESENT AT ADULTHOOD
206 (W/VARIATION)** SESMOID BONES, WORMIAN BONES, SACRAL BONES
WHERE ARE RBCs MADE IN ADULTS VS. INFANTS?
ADULTS = BONE MARROW INFANTS = LIVER
HISTOLOGICAL CLASSIFICATION OF BONE
COMPACT (CORTICAL) BONE VS. SPONGY (CANCELLOUS) BONE
COMPACT (CORTICAL) BONE
HARD, DENSE CORTEX
~80% OF ALL BONES IN THE BODY
FORMED BY ENDOCHONDRAL OSSIFICATION
FUNCTIONAL UNIT = OSTEON
FUNCTIONAL UNIT OF COMPACT BONE
OSTEON (FORMED BY LAMELLA) (SPACE IN BETWEEN LAMELLA = LACUNA)
SPONGY (CANCELLOUS) BONE
FORMED BY INTRAMEMBRANOUS OSSIFICATION
HIGH SURFACE AREA TO MASS RATIO
FUNCTIONAL UNIT = TRABECULA
FUNCTIONAL UNIT OF SPONGY BONE
TRABECULA (SPACE IN BETWEEN TRABECULA = RED BONE MARROW)
CONTAINS OSTEOBLASTS AND OSTEOCLASTS
SHAPE CLASSIFICATION OF BONE
- ) LONG BONE
- ) SHORT BONE
- ) FLAT BONE
- ) SESAMOID BONE
- ) IRREGULAR BONE
LONG BONE
LONGER THAN THEY ARE WIDE
CONTAIN EPIPHYSES (ENDS) AND DIAPHYSES (SHAFT)
PRIMARILY COMPACT BONE
EX. HUMERUS, FEMUR, TARSALS, METACARPALS
SHORT BONE
WIDER THAN THEY ARE LONG
PRIMARILY CANCELLOUS BONE SURROUNDED BY A THIN LAYER OF COMPACT BONE (LARGE AMOUNT OF BONE MARROW)
NO EPIPHYSES/DIAPHYSES
EX. CARPALS
FLAT BONE
SERVE AS MUSCLE ATTACHMENT SITES AND PROTECT VITAL ORGANS
STRONG CURVED PLATES OF BONE
FORM THE HIGHEST CONCENTRATION OF RBCS
EX. SCAPULA, STERNUM, CRANIUM
IRREGULAR BONES
DON’T FIT INTO ANY OTHER CATEGORY
EX. VERTEBRAE, MANDIBLE, SACRAM
SESAMOID BONES
DERIVED W/IN TENDONS
EX. PATELLA, PISIFORM
PERIOSTEUM
ATTACHED TO BONE VIA SHARPEY’S FIBERS
CONTAINS OSTEOBLASTS
ENDOSTEUM
LINES MEDULLARY CAVITY AND VASCULATURE
CONTAINS OSTEOCLASTS
OSTEOBLASTS
FORM BONE BY SECRETING CA2+
OSTEOCLASTS
BREAK DOWN BONE BY SECRETING COLLAGENASE AND CREATING A LOCALIZED ACIDIC ENVIRONMENT
DEVELOPMENTAL CLASSIFICATION OF BONES
- ) ENDOCHONDRAL BONE - FORMS MOSTLY COMPACT BONE (I.E. BONES BELOW THE NECK) BY CHONDROCYTES THAT PROGRESS THROUGH A CARTILAGE PHASE
- ) INTRAMEMBRANOUS BONE - FORMS MOSTLY SPONGY BONE (I.E. BONES THAT SKIP CARTILAGENOUS PHASE OF DEVELOPMENT)
DIVISION OF SKELETON
- ) AXIAL - SPINAL CORD, CEREBRAL CORTEX, THORACIC CAGE
2. ) APPENDICULAR - LIMBS, PELVIC AND PECTORAL GIRDLES, AND BONES RELATED TO LIMBS
SURFACE FEATURES OF BONE
- ) ARTICULATING (I.E. BONE TO BONE) - HEAD, CONDYLE, FACET
- ) NON-ARTICULATING (I.E. BONE TO TENDON/MUSCLE) - TUBERCLE, TUBEROSITY, TROCHANTER, EPICONDYLE, PROCESS, SPINE, CREST
- ) DEPRESSIONS AND OPENINGS (I.E. ALLOW PASSAGE OF NERVES, BLOOD VESSELS) - FORAMEN, FOSSA, FOVEA, MEATUS, SINUS, SULCUS, ALVEOLUS
MEDULLARY CAVITY
CARRIES FAT AFTER BIRTH
ALL BONE FORMS FROM…
FIBROUS MEMBRANE (INTRAMEMBRANOUS OSSIFICATION) OR HYALIN CARTILAGE (ENDOCHONDRAL OSSIFICATION)
INTRAMEMBRANOUS OSSIFICATION
- ) OSSIFICATION CENTER APPEARS AFTER CONDENSATION OF MESENCHYME CELLS AND DIFFERENTIATION INTO OSTEOBLASTS
- ) OSTEOBLASTS SECRETE OSTEOID AND ANY TRAPPED OSTEOBLASTS W/IN CONDENSED RING DIFFERENTIATE INTO OSTEOCYTES
- ) OSTEOID SECRETION STIMULATES CALCIFICATION AND DEMINERALIZATION
- ) WOVEN BONE BEGINS TO FORM AROUND VASCULATURE AND TRABECULA
- ) AT THE OUTER EDGES, CANCELLOUS BONE IS REPLACED BY LAMELLAR BONE
- ) BONE COLLAR OF COMPACT BONE FORMS AND RED MARROW APPEARS
* *FORMS FLAT BONES (I.E. CRANIAL BONES, CLAVICLE)
ENDOCHONDRAL OSSIFICATION
- ) PERICHONDRIUM ALLOWS PASSAGE OF VASCULATURE AND NUTRIENTS ARE DELIVERED TO THE HYALIN CARTILAGE
- ) STIMULATION BY NUTRIENTS CAUSES MESENCHYME CELLS TO CONDENSE AND THEY DIFFERENTIATE INTO CHONDROCYTES.
- ) CHONDROCYTES UNDERGO HYPERTROPHY AND THIS CUTS OFF NUTRIENT SUPPLY AND THEY GO INTO A PROGRESSIVE APOPTOSIS STATE FROM 1˚ OSSIFICATION CENTER TO EPIPHYSEAL PLATES.
- ) CENTRAL MEDULLARY CAVITY FORMS AND PERIOSTEAL BUD INVADES CAVITY DIRECTING THE REST OF BONE FORMATION AND BRINGING OSTEOBLASTS AND OSTEOCLASTS W/ IT
- ) OSTEOBLASTS MOVE DIRECTLY TO PERIOSTEUM AND OSTEOCLASTS STAY IN ENDOSTEUM
- ) CARTILAGENOUS GROWTH OCCURS ONLY AT EPIPHYSES AND ONLY REMAINING HYALIN CARTILAGE BY THE END OF BONE REMODELING = ARTICULAR CARTILAGE AND EPIPHYSEAL PLATES
