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73 Cards in this Set
- Front
- Back
6 functions of bone tissue and skeletal system
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Support
Protection Assistance in movement Mineral homeostasis Blood cell production Triglyceride storage |
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In certain bones, a connective tissue called ____________ produces red blood cells, white blood cells, and platelets, a process called _________
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Red bone marrow
hemopoiesis |
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Triglycerides stored in adipose tissue of ___________ is an important chemical energy reserve.
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Yellow bone marrow
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In the newborn, all bone marrow is ______ and involved in ________
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red
hemopoiesis |
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bone shaft or body. Long, cylindrical main portion of bone
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diaphysis
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distal and proximal ends of bone
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epiphyses
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regions in a mature bone where diaphysis joins the epiphysis.
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metaphysis
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In growing bone, each metaphysis includes an ____________, a layer of hyaline cartilage that allows the diaphysis of the bone to grow in length
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epiphyseal plate
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When bone growth in length stops, the cartilage in epiphyseal plate is replaced by bone a becomes the ____________
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epiphyseal line
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thin layer of hyaline cartilage covering epiphysis where bone forms articulation with another bone
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articular cartilage
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tough sheath of dense regular connective tissue that surrounds bone surface when it is not covered by articular cartilage
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periosteum
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space within the diaphysis that contains fatty yellow bone marrow in adults.
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medullary OR marrow cavity
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thin membrane that lines medullary cavity. Contains single layer of bone forming cells and small amount of connective tissue
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endosteum
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Bone matrix is about 25%_____, 25%_____, and 50% ________
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25% water
25% collagen fibers 50% crystallized mineral salts |
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process of mineral salts being deposited in framework formed by collagen fibers of the matrix
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calcification
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The combination of _________ and ____________ is responsible for the hardness of bone
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crystallized salts
collagen fibers |
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A bones hardness depends on ____________, a bone's flexibility depends on _____________
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crystallized inorganic mineral salts
collagen fibers |
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4 types of cells in bone tissue
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osteogenic
osteocytes osteoblasts osteoclasts |
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unspecialized stem cells derived from mesenchyme, only bone cells to undergo cell division
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osteogenic cells
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After cell division, daughter cells of osteogenic cells develop into
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osteoblasts
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synthesize and secrete collagen fibers and other organic components needed to build the matrix of bone tissue, and they initiate calcification.
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osteoblasts
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As osteoblasts surround themselves with matrix, they get trapped in their secretions and become _______
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osteocytes
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main cells of bone tissue and maitain it's daily metabolism, such as exchange of nutrients and waste with the blood. Do Not undergo cell division
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osteocytes
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derived from fusion of as many as 50 monocytes, concentrated in endosteum, plasma membrane that faces the bone surface is folded into a ruffled border, release powerful lysosomal enzymes and acids that break down bone
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osteoclasts
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The breakdown of bone matrix by osteoclasts is called _____
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resorption
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About 80% of skeleton is ____ bone and 20% is ____ bone
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compact
spongy |
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forms external layer of all bones and bulk of diaphysis of long bones, arranged in units called osteons or Haversian systems
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compact bone tissue
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blood vessels, lymphatic vessels, and nerves from the periosteum penetrate the compact bone through transverse _________
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perforating (Volkmann's) canals
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concentric rings of hard, calcified matrix found in compact bone, surround the central (Haversian) canals
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concentric lamellae
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between the lamellae are small spaces called _______, which contain osteocytes
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lacunae (little lakes)
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Radiating in all directions from the lacunae are tiny _________, which are filled with ECF.
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Canaliculi (small channels)
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Inside the canaliculi are slender fingerlike processes of _________. Neighboring osteocytes communicate via ___________
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osteocytes
gap junctions |
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Osteons in compact bone tissue are aligned in the same direction along __________
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lines of stress
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Lines of stress in bone are not _______. They change over time in response to _________
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static
physical stress |
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The areas between osteons contain _________, which also have lacunae with osteocytes and canaliculi
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interstitial lamellae
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Lamellae that encircle the bone just beneath the periosteum are called _______, and lamellae that encircle the medullary cavity are ______
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outer circumferential lamellae
inner circumferential lamellae |
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bone that does not contain osteons, consist of irregular latticework of thin columns of bone called _______
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spongy bone
trabeculae |
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______ bone tissue makes up most of the bone tissue of short, flat, and irregularly shaped bones.
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Spongy
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The spongy bone tissue of hip bones, ribs, breastbone, backbones, and the ends of long bones is the only site of ________ in adults
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hemopoiesis
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Near center of the epiphysis, a large nutrient artery passes through a hole in compact bone called the _____________
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nutrient foramen
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One or two _______ accompany nutrient artery in diaphysis, numerous ______ and ______ exit with their respective arteries in the epiphysis, and many small _____ exit with arteries in the periosteum
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nutrient veins
epiphyseal and metaphyseal periosteal |
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The process by which a bone forms is called ______ or ______
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ossification OR osteogenesis
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2 methods of bone formation
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endochondral ossification
intramembranous ossification |
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method of bone formation that occurs directly on or within loose fibrous connective tissue membranes
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Intramembranous ossification
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Replacement of cartilage by bone
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endochondral ossification
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4 phases of intramembranous ossification
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Development of center of ossification- osteoblast secrete matrix
Calcification of the matrix Formation of trabeculae Development of the periosteum |
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Connective tissue that is associated with the blood vessels in trabeculae differentiates into ____
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red bone marrow
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Bones that develop by intramembranous ossification
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flat bones of skull, mandibles, soft spots
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5 stages of endochondral ossification
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Development of cartilage model- chondroblasts produce hyaline cartilage model
growth of cartilage model- chondrocytes hypertrophy, burst, increase of pH triggers calcification Development of primary ossification center Development of secondary ossification center Formation of articular cartilage and epiphyseal plate |
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Interstitial growth results in _____ of bone, whereas ______ results in increase of thickness
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lengthening
appositional growth |
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Once perichondrium starts to form bone it is called ____
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periosteum
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_____ is a layer of hyaline cartilage in the metaphysis of a growing bone
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epiphyseal plate
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4 zones of epiphyseal plate that increases bone length
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Zone of resting cartilage- cells anchor epiphyseal plate to epiphysis
Zone of proliferating cartilage- chondrocytes divide to replace. Zone of hypertrophic cartilage- lengthening results from cell divisions in proliferating zone and maturation of cells in hypertrophic zone Zone of calcified cartilage- calcified cartilage is replaced by bone |
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The diaphysis of a bone increases in length bc of activity of the _____
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epiphyseal plate
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The epiphyseal plates close at around ___ - ___ years of age
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18-25
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When the epiphyseal plate fades, it leaves a bony structure known as ____
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epiphyseal line
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Bone grows in thickness due to addition of new bone tissue by _____ around the outer surface of a bone. Known as ____ growth
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periosteal osteoblasts
appostional growth |
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Sex steroids, especially ______ shut down growth at the epiphyseal plates
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estrogens
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During childhood, the most important hormones that stimulate bone growth are ____ and ____
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IGF- insulinlike growth factor
hGH- human growth hormone |
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ongoing process where osteoclasts carve out tunnels in old bone and osteoblasts rebuild it. Can take only 2 to 3 months, or last much longer
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bone remodeling
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The breakdown of matrix by osteoclasts is
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bone resorption
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One way that estrogens slow resorption of bone is by promoting ______ of osteoclasts
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apoptosis (programmed death)
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series of microscopic fissures in bone that forms without any evidence of injury to other tissues. Standard x-rays normally fail to reveal, but show clearly in bone scan
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stress Fx.
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5 steps of repair of a bone Fx
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Formation of Fx hematoma- blood clots, blood capillaries grow, phagocytosis cleans up debris
Fibrocartilaginous callus formation- repair tissue that bridges the broken ends of the bone. Takes about 3 weeks Bony callus formation- osteogenic cells develop into osteoblasts. Fibrocartilage converted into spongy bone Bone remodeling- dead portions of bone are resorbed by osteoclasts. Compact bone replaces spongy bone |
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For bones to unite, the ends of the Fx bone must be brought into alignment, a process known as _____
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reduction
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Bone id body's major calcium reservoir, storing ___% of body calcium
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99%
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The most important hormone that regulates calcium exchange between bone and blood is ____, secreted by ______
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PTH (parathyroid hormone)
parathyroid gland |
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If blood Ca decreases, parathyroid gland cells detect the change and increase production of _______. The gene for PTH in _________ cell detects increased production of _____, resulting in increased _____ being released into the blood. The presence of more ____ increases number and activity of ______, which liberates Ca to move into blood and increase levels to normal.
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cAMP (cyclic adenosine monophosphate)
parathyroid gland cell cAMP PTH PTH osteoclasts |
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_____ acts on the kidneys to decrease loss of Ca in urine, and stimulates formation of ______, a hormone that promotes absorption of Ca from GI tract.
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PTH (parathyroid hormone)
calcitriol |
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When blood Ca rises above normal, parafollicular cells in thyroid gland secrete _____.
_____ inhibits activity of osteoclasts, speeds up Ca uptake by bones, and accelerates Ca deposition into bones |
calcitonin (CT)
(CT) |
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During middle of fourth week of development upper limbs appear as small elevations called ______. End of fourth week _______ appear. The ______ consist of masses of general mesoderm covered by ________.
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upper limb buds
lower limb buds limb buds ectoderm |
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About 22 to 24 days after fertilization, mesodermal cells form a solid cylinder of cells called the ______, which plays a critical role in inducing, through chemical signals, __________ cells to develop into specialized tissues and organs.
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notochord
unspecialized embryonic cells |
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loss of calcium and other minerals from bone matrix
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demineralization
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