Lecture 1

Question 1

OF BONES PRESENT AT BIRTH

Answer 1

270

Question 2

OF BONES PRESENT AT ADULTHOOD

Answer 2

206 (W/VARIATION)** SESMOID BONES, WORMIAN BONES, SACRAL BONES

Question 3

WHERE ARE RBCs MADE IN ADULTS VS. INFANTS?

Answer 3

ADULTS = BONE MARROW
INFANTS = LIVER

Question 4

HISTOLOGICAL CLASSIFICATION OF BONE

Answer 4

COMPACT (CORTICAL) BONE VS. SPONGY (CANCELLOUS) BONE

Question 5

COMPACT (CORTICAL) BONE

Answer 5

HARD, DENSE CORTEX
~80% OF ALL BONES IN THE BODY
FORMED BY ENDOCHONDRAL OSSIFICATION
FUNCTIONAL UNIT = OSTEON

Question 6

FUNCTIONAL UNIT OF COMPACT BONE

Answer 6

OSTEON (FORMED BY LAMELLA) (SPACE IN BETWEEN LAMELLA = LACUNA)

Question 7

SPONGY (CANCELLOUS) BONE

Answer 7

FORMED BY INTRAMEMBRANOUS OSSIFICATION
HIGH SURFACE AREA TO MASS RATIO
FUNCTIONAL UNIT = TRABECULA

Question 8

FUNCTIONAL UNIT OF SPONGY BONE

Answer 8

TRABECULA (SPACE IN BETWEEN TRABECULA = RED BONE MARROW)

CONTAINS OSTEOBLASTS AND OSTEOCLASTS

Question 9

SHAPE CLASSIFICATION OF BONE

Answer 9

1. ) LONG BONE
2. ) SHORT BONE
3. ) FLAT BONE
4. ) SESAMOID BONE
5. ) IRREGULAR BONE

Question 10

LONG BONE

Answer 10

LONGER THAN THEY ARE WIDE
CONTAIN EPIPHYSES (ENDS) AND DIAPHYSES (SHAFT)
PRIMARILY COMPACT BONE
EX. HUMERUS, FEMUR, TARSALS, METACARPALS

Question 11

SHORT BONE

Answer 11

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

Question 12

FLAT BONE

Answer 12

SERVE AS MUSCLE ATTACHMENT SITES AND PROTECT VITAL ORGANS
STRONG CURVED PLATES OF BONE
FORM THE HIGHEST CONCENTRATION OF RBCS
EX. SCAPULA, STERNUM, CRANIUM

Question 13

IRREGULAR BONES

Answer 13

DON’T FIT INTO ANY OTHER CATEGORY

EX. VERTEBRAE, MANDIBLE, SACRAM

Question 14

SESAMOID BONES

Answer 14

DERIVED W/IN TENDONS

EX. PATELLA, PISIFORM

Question 15

PERIOSTEUM

Answer 15

ATTACHED TO BONE VIA SHARPEY’S FIBERS

CONTAINS OSTEOBLASTS

Question 16

ENDOSTEUM

Answer 16

LINES MEDULLARY CAVITY AND VASCULATURE

CONTAINS OSTEOCLASTS

Question 17

OSTEOBLASTS

Answer 17

FORM BONE BY SECRETING CA2+

Question 18

OSTEOCLASTS

Answer 18

BREAK DOWN BONE BY SECRETING COLLAGENASE AND CREATING A LOCALIZED ACIDIC ENVIRONMENT

Question 19

DEVELOPMENTAL CLASSIFICATION OF BONES

Answer 19

1. ) ENDOCHONDRAL BONE - FORMS MOSTLY COMPACT BONE (I.E. BONES BELOW THE NECK) BY CHONDROCYTES THAT PROGRESS THROUGH A CARTILAGE PHASE
2. ) INTRAMEMBRANOUS BONE - FORMS MOSTLY SPONGY BONE (I.E. BONES THAT SKIP CARTILAGENOUS PHASE OF DEVELOPMENT)

Question 20

DIVISION OF SKELETON

Answer 20

1. ) AXIAL - SPINAL CORD, CEREBRAL CORTEX, THORACIC CAGE

2. ) APPENDICULAR - LIMBS, PELVIC AND PECTORAL GIRDLES, AND BONES RELATED TO LIMBS

Question 21

SURFACE FEATURES OF BONE

Answer 21

1. ) ARTICULATING (I.E. BONE TO BONE) - HEAD, CONDYLE, FACET
2. ) NON-ARTICULATING (I.E. BONE TO TENDON/MUSCLE) - TUBERCLE, TUBEROSITY, TROCHANTER, EPICONDYLE, PROCESS, SPINE, CREST
3. ) DEPRESSIONS AND OPENINGS (I.E. ALLOW PASSAGE OF NERVES, BLOOD VESSELS) - FORAMEN, FOSSA, FOVEA, MEATUS, SINUS, SULCUS, ALVEOLUS

Question 22

MEDULLARY CAVITY

Answer 22

CARRIES FAT AFTER BIRTH

Question 23

ALL BONE FORMS FROM…

Answer 23

FIBROUS MEMBRANE (INTRAMEMBRANOUS OSSIFICATION) OR HYALIN CARTILAGE (ENDOCHONDRAL OSSIFICATION)

Question 24

INTRAMEMBRANOUS OSSIFICATION

Answer 24

1. ) OSSIFICATION CENTER APPEARS AFTER CONDENSATION OF MESENCHYME CELLS AND DIFFERENTIATION INTO OSTEOBLASTS
2. ) OSTEOBLASTS SECRETE OSTEOID AND ANY TRAPPED OSTEOBLASTS W/IN CONDENSED RING DIFFERENTIATE INTO OSTEOCYTES
3. ) OSTEOID SECRETION STIMULATES CALCIFICATION AND DEMINERALIZATION
4. ) WOVEN BONE BEGINS TO FORM AROUND VASCULATURE AND TRABECULA
5. ) AT THE OUTER EDGES, CANCELLOUS BONE IS REPLACED BY LAMELLAR BONE
6. ) BONE COLLAR OF COMPACT BONE FORMS AND RED MARROW APPEARS
   * *FORMS FLAT BONES (I.E. CRANIAL BONES, CLAVICLE)

Question 25

ENDOCHONDRAL OSSIFICATION

Answer 25

1. ) PERICHONDRIUM ALLOWS PASSAGE OF VASCULATURE AND NUTRIENTS ARE DELIVERED TO THE HYALIN CARTILAGE
2. ) STIMULATION BY NUTRIENTS CAUSES MESENCHYME CELLS TO CONDENSE AND THEY DIFFERENTIATE INTO CHONDROCYTES.
3. ) CHONDROCYTES UNDERGO HYPERTROPHY AND THIS CUTS OFF NUTRIENT SUPPLY AND THEY GO INTO A PROGRESSIVE APOPTOSIS STATE FROM 1˚ OSSIFICATION CENTER TO EPIPHYSEAL PLATES.
4. ) CENTRAL MEDULLARY CAVITY FORMS AND PERIOSTEAL BUD INVADES CAVITY DIRECTING THE REST OF BONE FORMATION AND BRINGING OSTEOBLASTS AND OSTEOCLASTS W/ IT
5. ) OSTEOBLASTS MOVE DIRECTLY TO PERIOSTEUM AND OSTEOCLASTS STAY IN ENDOSTEUM
6. ) CARTILAGENOUS GROWTH OCCURS ONLY AT EPIPHYSES AND ONLY REMAINING HYALIN CARTILAGE BY THE END OF BONE REMODELING = ARTICULAR CARTILAGE AND EPIPHYSEAL PLATES