click below
click below
Normal Size Small Size show me how
Bones & Tissues
A&P Ch 6 (set 2)
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 |