A&P 6: Bones & Skeletal Tissue Flashcards

1
Q

Skeletal cartilage

A

made of some variety of cartilage tissue molded to fit its body location and function

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2
Q

Hyaline cartilages

A

provide support with flexibility and resistance; most abundant skeletal cartilages; chondrocytes are spherical; only fiber type in matrix is fine collagen (undetectable microscopically); includes articular, costal, respiratory, and nasal cartilages

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3
Q

Elastic cartilages

A

more stretch elastic than hyaline cartilages and so are better able to stand up to repeated bending; found in only 2 skeletal locations - the external ear and the epiglottis

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4
Q

Fibrocartilages

A

highly compressible with great tensile strength; consist of roughly parallel rows of chondrocytes alternating with thick collagen fibers; occur in sites subjected to both pressure and stretch (padlike cartilages (menisci) of knee and the discs between vertebrae)

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5
Q

Appositional growth

A

“growth from outside”; cartilage-forming cells in the surrounding perichondrium secrete new matrix against the external face of the existing cartilage tissue

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6
Q

Interstitial growth

A

“growth from inside”; the lacunae-bound chondrocytes divide and secrete new matrix, expanding the cartilage from within

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7
Q

Axial skeleton

A

forms the long axis of the body; includes the bones of the skull, vertebral column, and rib cage; protect, support, or carry other body parts

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8
Q

Appendicular skeleton

A

consists of the bones of the upper and lower limbs and the girdles (shoulder bones and hip bones) that attache the limbs to the axial skeleton

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9
Q

Long bones

A

bones that are considerably longer than they are wide; has a shaft plus 2 ends which are often expanded; all limb bones except the patella, wrist, and ankle bones are this type

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10
Q

Short bones

A

bones that are roughly cube shaped; example: bones of the wrist/ankles

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11
Q

Sesamoid bones

A

“shaped like a sesame seed”; special type of bone that form in a tendon (ex. patella); vary in size and number in different individuals; some act to alter the direction of pull of a tendon

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12
Q

Flat bones

A

bones that are thin, flattened, usually a bit curved; ex: sternum, scapulae, ribs, and most skull bones

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13
Q

Irregular bones

A

bones with complicated shapes that fit no class; ex. vertebrae, hip bones

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14
Q

Hematopoiesis

A

blood cell formation; mostly occurs in the red marrow cavities of certain bones

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15
Q

Compact bone

A

external layer of bone; dense, looks smooth, solid

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16
Q

Spongy bone

A

AKA trabecular bone; internal to compact bone, a honeycomb of small needle-like or flat pieces (trabeculae)

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17
Q

Trabeculae

A

“little beams”; small needle-like or flat pieces in spongy bone

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18
Q

Diploe

A

in flat bones, the spongy bone is called this, which means “folded”

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19
Q

Diaphysis

A

tubular shaft that forms the long axis of a typical long bone

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20
Q

Medullary cavity

A

diaphysis is constructed of a relatively thick collar of compact bone that surrounds a central _________ ______; in adults, it contains fat (yellow marrow)

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21
Q

Yellow marrow cavity

A

in adults, the medullary cavity contains fat and is called this

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22
Q

Epiphyses

A

ends of long bones; in many cases, are broader than the diaphysis

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23
Q

Epiphyseal line

A

between the diaphysis and each epiphysis of an adult long bone is this, a remant of the epiphyseal plate

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24
Q

Epiphyseal plate

A

disc of hyaline cartilage that grows during childhood to lengthen the bone

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25
Q

Periosteum

A

glistening, white double-layered membrane that covers the external surface of the entire bone except the joint surfaces; outer fibrous layer, osteogenic layer

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26
Q

Nutrient foramina

A

periosteum is richly supplied with nerve fibers and blood vessels which pass through the shaft to enter the marrow cavity via these “openings”; perforating (Sharpey’s) fibers secure the periosteum to the underlying bone

27
Q

Endosteum

A

“within the bone”; delicate, connective tissue membrane which covers internal bone surfaces

28
Q

Red marrow

A

hematopoietic tissue, typically found within the trabecular cavities of spongy bone of long bones and in the diploe of flat bones

29
Q

Red marrow cavities

A

trabecular & diploe cavities often called this

30
Q

Bone markings

A

serve as sites of muscle, ligament, and tendon attachment, as joint surfaces, or as conduits for blood vessels and nerves; those that are depressions and openings include fossae, sinuses, foramina (sing = foramen), and grooves - allow nerves/blood vessels to pass; projections (project outward) = heads, trochanters, spines, etc)

31
Q

Osteogenic (osteoprogenitor) cells

A

mitotically active stem cells found in the membranous periosteum and endosteum; in growing bones = flattened/squamous cells; when stimulated, differentiate into osteoblasts or bone lining cells, while others persist as is

32
Q

Osteoblasts

A

bone-forming cells that secrete the bone matrix; actively mitotic; unmineralized bone matrix they secrete includes collagen (90% of bone protein) and calcium-binding proteins that make up the initial unmineralized bone (osteoid); also play a role in matrix calcification

33
Q

Osteocytes

A

spidery, mature bone cells that occupy spaces (lacunae) that conform to their shape; monitor and maintain the bone matrix; act as stress/strain sensors and respond to mechanical stimuli (bone loading, bone deformation, weightlessness)

34
Q

Bone lining cells

A

flat cells found on bone surfaces where bone remodeling is not going on; thought to help maintain the matrix; on the external bone surface, AKA periosteal cells; those lining internal surfaces AKA endosteal cells

35
Q

Osteoclasts

A

derived from the same hematopoietic stem cells that differentiate into macrophages; giant multi-nucleate cells located at sites of bone resorption; rest in a shallow depressions called a resorption bay when actively breaking down (resorbing) bone; exhibit a distinctly ruffled border which directly contacts the bone (increase surface area for enzymatically degrading the bones and seal off that area from the surrounding matrix)

36
Q

Osteon (Haversian system)

A

structural unit of compact bone; each = elongated cylinder oriented parallel to the long axis of the bone; tiny, weight-bearing pillars

37
Q

Lamella

A

“little plate”; a layer, such as of bone matrix in an osteon of compact bone

38
Q

Lamellar bone

A

AKA compact bone

39
Q

Central (Haversian) Canal

A

running through the core of each osteon is this canal, containing small blood vessels and nerve fibers that serve the osteon’s cells

40
Q

Perforatin (Volkmann’s) Canals

A

canals that lie at right angles to the long axis of the bone and connect the blood and nerve supply of the periosteum to those in the central canals and the medullary cavity

41
Q

Lacunae

A

spider-shaped osteocytes occupy these at the junctions of the lamellae

42
Q

Interstitial lamellae

A

lying between intact osteons are incomplete lamellae; either fill the gaps between forming osteons or are remnants of osteons that have been cut through by bone remodeling

43
Q

Circumferential lamellae

A

located just deep to the periosteum, just superficial to the endosteum; extend around the entire circumference of the diaphysis, effectively resist twisting of the long bone

44
Q

Osteoid

A

organic part of bone matrix; makes up 1/3 of the matrix, includes ground substance (composed of proteoglycans and glycoproteins) and collagen fibers, both of which are made and secreted by osteoblasts; contribute to a bone’s structure and to the flexibility and tensile strength that allow it to resist stretch and twisting

45
Q

Ossification

A

AKA osteogenesis; process of bone formation

46
Q

Cartilage (endochondral) bone

A

bone developed by replacing hyaline cartilage (via endochondral ossification)

47
Q

Membrane bone

A

in intramembranous ossification, a bone develops from a fibrous membrane

48
Q

Endochondral ossification

A

essentially all bones below the base of the skull (except the clavicle) form by this process

49
Q

Primary Ossification Center

A

formation of a long bone typically begins in the center of the hyaline cartilage shaft at a region called this

50
Q

Periosteal bud

A

collection of elements which contain a nutrient artery and vein, nerve fibers, red marrow elements, osteogenic cells, and osteoclasts; invades the forming cavities to form spongy bone

51
Q

Secondary ossification centers

A

shortly before or after birth, these appear in one or both epiphyses, and the epiphyses gain bony tissue

52
Q

Intramembranous ossification

A

forms the cranial bones of the skull (frontal, parietal, occipital, and temporal bones) and the clavicles; most bones formed by this process are flat bones

53
Q

Bone remodeling

A

bone deposit & bone resorption

54
Q

Parathyroid hormone (PTH)

A

hormonal control of remodeling; produced by the parathyroid glands

55
Q

Calcitonin

A

produced by parafollicular cells (C cells) of the thyroid gland, may be involved in hormonal control of remodeling, though to a lesser extend than PTH

56
Q

Fractures

A

breaks in bones

57
Q

Hematoma

A

mass of clotted blood; forms at the fracture site in bones

58
Q

Fibrocartilaginous callus

A

entire mass of repair tissue that splints the broken bone

59
Q

Bony (hard) callus

A

new bone trabeculae appear in the fibrocartilaginous callus and gradually convert it to this; formation continues until a firm union forms about 2 months later

60
Q

Osteomalacia

A

“soft bones”; includes a number of disorders in which the bones are poorly mineralized; osteoid is produced, but calcium salts are not adequately deposited, so bones are soft and weak; main symptom is pain

61
Q

Rickets

A

like osteomalacia, but in children and much more severe; bowed legs, deformities of the pelvis, skull, and rib cage are common; epiphyseal plates cannot calcify (so continue to widen) and the ends of long bones become visibly enlarged and abnormally long

62
Q

Osteoporosis

A

refers to a group of diseases in which bone resorption outpaces bone deposit; bones become fragile, have tendency to break much more easily than normal; composition of the matrix remains normal, but bone mass declines, and the bones become porous and light

63
Q

Paget’s disease

A

characterized by excessive and haphazard bone deposit and resorption; has an abnormally high ratio of spongy bone to compact bone