| Term | Definition | | | | |
| Hyaline cartilage | provides support, flexibility, and resilience | Most abundant type; costal, laryngeal, articular, and nasal | | | |
| Elastic cartilage | contains elastic fibers | external ear and epiglottis | | | |
| Fibrocartilage | collagen fibers have great tensile strength; shock absorber | intervertebral discs and knee menisci | | | |
| ligaments | holds bones together | | | | |
| Appositional | cells secrete matrix on outside of existing cartilage | | | | |
| Interstitial | chondrocytes divide and secrete new matrix, expanding cartilage from within | | | | |
| Calcification of cartilage occurs during | normal bone growth | old age | | | |
| Axial skeleton | bones of head, neck, and trunk | | | | |
| Appendicular skeletal | bones of extremities and girdles which attach them to trunk | | | | |
| Functions of bones | Support: framework for the body | Protects brain, spinal cord, and vital organs | levers for muscle actions | Storage of calcium, phosphorous, and triglyceride | Blood cell formation occurring in red bone marrow |
| Compact bone | dense outer layer | | | | |
| Spongy bone | cancellous | less dense inner layer | honeycomb of trabeculae | filled with bone marrow | located between layers of compact bone |
| Long bones | longer than they are wide | femur | | | |
| Short bones | cube shaped | wrist and ankle | sesamoid bones within tendons & patella | | |
| Flat bones | thin, flat, slightly curved | ribs, scapula, some skull bones | | | |
| Irregular bones | complicated shapes | vertebrae, sphenoid, ethmoid | | | |
| Diaphysis | shaft | compact bone collar surrounds medullary cavity | | | |
| Medullary cavity | within diaphysis | contains yellow marrow in adults | | | |
| Sesamoid bones | tendons, patella | | | | |
| Epiphysis | expanded ends contain spongy bone | red bone marrow | lined with hyaline cartilage at joint surfaces | | |
| Epiphyseal line | remnant of growth plate | | | | |
| Periosteum | outer connective tissue membrane on bone | contains nerve fibers and blood vessels which enter the bone via nutrient foramina | secured to underlying bone by Sharpey's fibers | covers compact bone on the outside | |
| Osteoblasts | bone forming cells | | | | |
| Osteoclasts | bone destroying cells | becomes an osteocyte | cells that resorb bone matrix | come from blood stem cells | |
| Osteogenic cells | stem cells | become osteoblasts | in periosteum and endosteum | | |
| Endosteum | membrane that lines inner surfaces of bone | covers spongy bone within | contains osteoblasts, osteoclasts, and stem cells | | |
| Hematopoietic Tissue | red marrow | red blood cells produced | within proximal epiphysis of femur and humerus | within spongy bone of irregular and flat bones | in infants, found within medullary cavities and all spaces in spongy bone |
| Osteocytes | mature bone cells | each in a lacuna | | | |
| Osteon | Haverisan system | structural unit of compact bone | | | |
| Lamellae | rings of mineralized matrix | | | | |
| Central canal | Haversian canal | contains blood vessels and nerves | | | |
| Perforating canal | Volkmann's canal | at right angles to the central canal | connects blood vessels and nerves of the periosteum and central canal | | |
| Lacunae | small cavities that contain osteocytes | hollowed out space | | | |
| Canaliculi | hair-like canals that connect lacunae to each other and to the central canal | osteocyte projections project through | allows all osteocytes to be connected to nutrient supply of blood | | |
| Trabeculae | blood vessels go through | align along lines of stress | no osteons | contain irregularly arranged lamellae, osteocytes, and canaliculi | capillaries in endosteum supply nutrients |
| Osteoid | organic bone matrix secreted by osteoblasts | ground substance (proteoglycans, glycoproteins) | Collagen fibers (protein) | provide tensile strength and flexibility | |
| Hydroxyapatites | inorganic | mineral salts | 65% of bone mass | mainly calcium phosphate crystals | responsible for hardness and resistance to compression |
| Osteogenesis | ossification | bone tissue formation | bone formation begins in the embryo | bone growth continues until early childhood | bone remodeling and repair occur lifelong |
| Intramembranous ossification | bone develops from embryonic fibrous membrane | forms flat bones, like clavicles, and cranial bones | | | |
| Endochondral ossification | bones form by replacing hyaline cartilage | forms most of the rest of the skeleton | | | |
| Interstitial growth | increases the length of bones | | | | |
| Appositional growth | increases the thickness of bones | remodeling of all bones by osteoblasts and osteoclasts on bone surfaces | | | |
| Epiphyseal plate | growth in length of long bones | | | | |
| Proliferation zone | growth zone | growth of cartilage on the end of bone side of plate | cartilage cells undergo mitosis | | |
| Hypertrophic zone | cartilage cells enlarge | | | | |
| Calcification zone | cartilage cells die, matrix is calcified | | | | |
| Ossification zone | osteogenic | new bone formed on diaphysis side of plate | | | |
| Growth hormone | stimulates growth in the epiphyseal plate | | | | |
| Thyroid hormone | necessary to make growth hormone work | | | | |
| Testosterone and Estrogens | promote adolescent growth spurts | end growth by inducing epiphyseal plate | | | |
| Bone deposit | occurs where bone is injured or remodeled due to increased mechanical stress on bone | requires vitamins C, D, and A | requires calcium, phosphorous, magnesium, and manganese | | |
| Bone resorption | Osteoclasts secrete lysosomal enzymes (digest organic matrix) | hydrochloric acid converts calcium salts into soluble form | dissolved matrix including Ca++ can enter the blood | | |
| Remodeling | hormonal mechanisms maintain calcium levels in the blood | mechanical and gravitational forces stimulated | in response to mechanical stressors over several months | final structure resembles original | |
| Calcium is necessary for | transmission of nerve impulses | muscle contractions | heart contractions | blood clotting | cell division |
| PTH | parathyroid hormone | released during low blood Ca++ levels | stimulates osteoclasts to degrade bone matrix and release Ca++ | blood Ca++ levels increase | |
| Calcitonin | causes osteoblasts to deposit calcium salts in bone | lowers blood Ca++ levels | release by thyroid | | |
| Wolff's law | a bone grows or remodels in response to forces or demands placed on upon it | Handedness results in bone of one upper limb being thicker and stronger | curved bones are thickest where they are most likely to buckle | trabeculae form along lines of stress | large, bony projections occur where heavy, active muscles attach |
| Non-displaced fracture | bone ends retain normal position | | | | |
| Displaced fracture | bone ends out of normal alignment | | | | |
| Complete fracture | broken all the way through | | | | |
| Incomplete fracture | not broken all the way through | | | | |
| Linear fracture | fracture is parallel to long axis of the bone | | | | |
| Transverse fracture | fracture is perpendicular to long axis of bone | | | | |
| Compound fracture | Open fracture | bone ends penetrate skin | | | |
| Simple fracture | Closed fracture | bone ends do not penetrate skin | | | |
| Hematoma | torn blood vessels hemorrhage | clot forms | site becomes swollen, painful, and inflamed | | |
| Fibrocartilagious callus | phagocytic cells clear debris | osteoblasts begin forming spongy bone within 1 week | fibroblasts secrete collagen fibers to connect bone ends | | |
| Bony callus | new trabeculae form a hard callus | formation continues until firm union is formed in 2 months | | | |
| Osteomalacia | soft bones | calcium salts not deposited | caused by vitamin D deficiency or insufficient dietary calcium | Same as Rickets in children | |
| Rickets | osteomalacia in children | legs are bowed and deformed | | | |
| Osteoporosis | loss of bone mass because bone resorption outpaces deposit | spongy bone of vertebrae and neck of femur most susceptible to fracture | Caused by lack of estrogen, calcium, or vitamin D; petite body form; immobility; low TSH; diabetes | Treatment includes calcium and vitamin D; hormone replacement therapy to slow bone loss | Prevention includes weight-bearing exercise throughout life |
| tuberosity | large rounded projection | | | | |
| trochanter | large, blunt, irregular surface | | | | |
| tubercle | small rounded projection | | | | |
| epicondyle | raised area above a condyle | | | | |
| spine | sharp, slender projection | | | | |
| process | any bony prominence | | | | |
| head | rounded bony articular end of a bone | | | | |
| facet | smooth, nearly flat articular surface | | | | |
| condyle | rounded articular projection | | | | |
| meatus | canal-like passageway | | | | |
| sinus | cavity within a bone | | | | |
| fossa | shallow, basin-like depression | | | | |
| fissure | narrow, slit-like opening | | | | |
| foramen | round, or oval, opening through a bone | | | | |
| Cartilage | contains no blood vessels or nerves | | | | |
| Perichondrium | dense connective tissue that surrounds cartilage | contains blood vessels for nutrient delivery to cartilage | | | |
| Chondrocytes | living cells of cartilage | | | | |
