Chapter 7; Bone TIssue Flashcards
osteology
the study of bone
skeletal system
composed of bone, cartilages, and ligaments joined tightly to form a strong, flexible framework for the body
osseous tissue
connective tissue in which the matrix is hardened by the deposition of calcium phosphate and other minerals
mineralization (calcification)
the hardening process of bone
flat bones
thin curved bones
long bones
most important bones for movement
short bones
various bones that do not fit the flat or long bone groups
irregular bones
bones of odd shape such as vertebrae and some skull bones
compact (dense) bone
outer shell of dense white osseous tissue
medullary cavity (marrow cavity)
space that contains bone marrow
spongy (cancellous) bone
at the ends of the bones, the central space is occupied by a more loosely organized form of osseous tissue
diaphysis
shaft of a bone
epiphysis
expanded head at each end of a bone
epiphyseal line
slightly denser spongy bone between the epiphysis and diaphysis
epiphyseal plate
remnant of a childhood growth zone
articular cartilage
the joint surface where one bone meets another is covered with a layer of hyaline cartilage
nutrient foramina
blood vessels penetrate into the bone through minute holes
periosteum
sheath covering over a bone
fibrous layer
tough, outer layer of collagen and an inner osteogenic layer of bone-forming cells
perforating fibers
some collagen fibers of the outer layer are continuous with the tendons that bind muscle to bone, and some penetrate into the bone matrix
endosteum
a thin layer of reticular connective tissue that lines the internal marrow cavity, covers all the honeycombed surfaces of spongy bone, and lines a canal system found throughout the compact bone
diploe
spongy layer in the cranium
osteogenic cells
stem cells that develop from embryonic mesenchyme and then give rise to most other bone cell types
osteoblasts
bone-forming cells
osteocytes
former osteoblasts that have become trapped in the matrix they deposited
lacunae
tiny cavities
canaliculi
slender channels
osteoclasts
bone-dissolving cells
ruffled border
the side of the osteoclast facing the bone surface that has many deep infoldings of the plasma membrane
resorption bays
pits that have etched into the bone surface
hydrocyapatite
a crystallized calcium phosphate salt
composite
a combination of two basic structural materials
osteogenesis imperfecta (brittle bone disease)
bone that is excessively brittle
sacrificial bonds
collagen molecules that break under stress, protecting a bone from fracture by dissipating some of the shock
concentric lamellae
layers of matrix concentrically around a central (haversian) canal and connected with each other by canaliculi
osteon (haversian system)
the basic structural unit of compact bone
perforating canals
central canals are joined by transverse or diagonal passages
circumferential lamellae
boundaries that run parallel to the bone surface
interstitial lamellae
the remains of old osteons that broke down as the bone grew and remodeled itself
spicules
rods or spines
trabeculae
thin plates
bone marrow
general term for soft tissue that occupies the marrow cavity of a long bone, the spaces amid the trabeculae of spongy bone, and the larger central canals
red bone marrow (myeloid tissue)
the marrow cavity of nearly every bone
hemopoietic tissue
tissue that produces blood cells
yellow bone marrow
no longer produces blood, although in the event of severe or chronic anemia, it can transform back into red bone marrow and resume its hemopoietic function
ossification (osteogenesis)
formation of bone
intramembranous ossification
produces the flat bones of the skull and most of the clavicle
endochondrial ossification
a process in which a bone develops from a preexisting model composed of hyaline cartilage
primary ossification center
near the middle of the cartilage where chondrocytes begin to inflate and die, while the thin walls between them calcify
primary marrow cavity
osteoclasts arrive in the blood and digest calcified tissue in the shaft
metaphysis
the region of transition from cartilage to bone at each end of the primary marrow cavity
secondary ossification center
chondrocyte enlargement and death occur in the epiphysis of the model
secondary marrow cavity
expands outward from the center in all directions
epiphyseal plate
a thin wall of cartilage separating the primary and secondary marrow cavities at one or both ends of the bone
zone of reserve cartilage
consists of typical hyaline cartilage with resting chondrocytes, not yet showing signs of transformation into bone
zone of cell proliferation
chondrocytes multiply and arrange themselves into longitudinal columns of flattened lacunae
zone of cell hypertrophy
chondrocytes cease to multiply and begin to hypertrophy
zone of calcification
minerals are deposited in the matrix between the columns of lacunae and calcify the cartilage
zone of bone deposition
within each column, the walls between the lacunae break down and the chondrocytes die
interstitial growth
cartilage growth from within, by the multiplication of chondrocytes and deposition of new matrix in the interior
appositional growth
the deposition of new tissue at the surface
wolff’s law of bone
states that the architecture of a bone is determined by the mechanical stresses placed upon it
mineral deposition (mineralization)
crystallization process in which calcium, phosphate and other ions are taken from the blood plasma and deposited in bone tissue
solubility product
critical value of hydroxyapatite crystals formed
ectopic ossification
abnormal calcification of tissues
calculus
a calcified mass in an otherwise soft organ
mineral resorption
the process of dissolving bone
hypocalcemia
calcium deficiency
tetany
the inability of the muscle to relax
trousseau sign
strong spasmodic flexion of the wrist and thumb and extension of the other fingers
laryngospasm
muscles of the larynx contract tightly
hypercalcemia
blood calcium excess
calcitriol
a form of vitamin D produced by the sequential action of the skin, liver, and kidneys
cholecalciferol
vitamin D3
rickets (osteomalacia in adults)
softness of bone
calcitonin
produced by C cells (clear cells) of the thyroid gland
osteoclast inhibition
calcitonin reduces osteoclast activity by as much as 70%
osteoblast stimulation
within an hour, calcitonin increases the number and activity of osteoblast, which deposit calcium into the skeleton
parathyroid hormone
secreted by the parathyroid glands, which adhere to the posterior surface of the thyroid gland
cortisol
inhibits osteoclast activity
estrogen
stimulates osteoblasts and adolescent growth
growth hormone
stimulates bone elongation and cartilage proliferation at epiphyseal plate
insulin
stimulates bone formation
parathyroid hormone
indirectly activates osteoclasts
testosterone
stimulate osteoblasts and promotes protein synthesis
thyroid hormone
essential to bone growth
vitamin A
promotes glycosaminoglycan (chondroitin sulfate) synthesis
vitamin C
required for collagen synthesis, bone growth, and fracture repair
vitamin D
normally functions as a hormone
orthopedics
branch of medicine for bones
stress fracture
a break caused by abnormal trauma to a bone
pathological fracture
a break in a bone weakened by some other disease
nondisplaced fracture
one in which the bone pieces remain in proper anatomical alignment
displaced fracture
one in which at least one piece is shifted out of alignment with the other
comminuted fracture
a bone is broken into three or more pieces
greenstick fracture
bone is incompletely broken on one side but merely bent on the opposite side
fracture hematoma
blood clot in a bone
granulation tissue
soft fibrous mass
soft callus
patches of fibrocartilage
hard callus
bony collar
closed reduction
a procedure in which the bone fragments are manipulated into their normal positions without surgery
open reduction
involved the surgical exposure of the bone and the use of plates, screws, or pins to realign the fragments
osteoporosis
severe loss of bone density
osteitis demorans (pagat’s disease)
excessive proliferation of osteoclasts and resorption of excess bone with osteoblasts attempting to compensate by depositing extra bone
osteomyelitis
inflammation of osseous tissue and bone marrow as a result of bacterial infection
osteosarcoma
most common type of cancer of bone
