LECTURE 1 bone (connective tissue type) Flashcards Preview

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Flashcards in LECTURE 1 bone (connective tissue type) Deck (24):
1

functions of bone tissue (5)

support, protect, mineral storage, movement, blood-cell formation

2

bone tissue componants

well vascularized, collagen fibers, periosteum, endosteum, formed from cartilage (through endochondralossification)

3

bone tissue cells (3)

osteoblasts, osteocytes, osteoclasts

4

osteoblasts

secrete organic part of bone matrix

5

osteocytes

mature bone cells (in lacunae) that maintain bone matrix

6

osteoclasts

degrade and reabsorb bone (release into blood stream)

7

periosteum

external layer of CT that surrounds bone, outer is dense irregular CT, inner is osteoblasts and osteoclasts, maintains and repairs but can also break down bone

8

endosteum

internal layer of CT that lines cavities and covers trabeculae, contains osteoblasts and osteoclasts, never in cartilage

9

types of bone tissue (2)

compact bone, spongy bone (two organizations of bone tissue made up of same materials - matrix, cells, fibers)

10

compact bone

dense, thick, strong, hard; external, superficial layer; functions: protection and weight bearing; osteon/Haversian system

11

osteon/Haversian system

parallel to the long axis of the bone; groups of concentric tubules; lamella: layer of bone matrix where all fibers run in same direction; adjacent lamella fibers run in opposite directions; Haversian (central) canal runs through center of osteon, contains blood vessels and nerves, connected to each other by perforating (Volkman) canals; interstitial lamellae fills spaces and forms periphery (outside osteon, inside bone)

12

spongy bone

aka cancellous bone; internal/deep layer; function: holding bone marrow, less weight bearing; trabeculae

13

trabeculae

small, needle-like pieces of bone form honeycomb (aka spicuoles); each made of several layers of lamellae and osteocytes; covered by endosteum; no canal for vessels (no need with open space); spaces filled with bone marrow

14

shapes of bones (4)

flat (skull, sternum, clavicle), irregular (pelvis, vertebrae), short (carpals, patella), long (femur, phalanges, metacarpals, humerus)

15

anatomy of a long bone

diaphysis, 2 epiphyses, periosteum, endosteum

16

diaphysis of long bone

centrally elongated, medullary cavity (holds yellow bone marrow), nutrient artery and vein

17

2 epiphyses of long bone

on each end, epiphyseal plates/lines (for growth) made of hyaline carilage, epiphyseal artery and vein

18

periosteum of long bone

does not cover epiphyses

19

endosteum of long bone

covers trabeculae of spongy bone, lines medullary cavity of long bones

20

types of bone formation (2)

intramembranous ossification, endochondral ossification

21

intramembranous ossification

osteoblasts in membrane secrete osteoid that mineralizes

22

endochondral ossification

begins with a cartilage model, cartilage calcifies, medullary cavity is formed by action of osteoclasts, epiphyses grow and eventually calcify (epiphyseal plates remain cartilage for up to 20 years), when cartilage cells die they all become bone and become epiphyseal line (no more growth)

23

growth of bones

lengthening of bones: epiphyseal plates enlarge by chondroblasts, matrix calcifies, bone tissue replaces cartilage on diaphysis side; appositional growth: widening of bone, bone tissue added on surface by osteoblasts of periosteum, medullary cavity maintained by osteoclasts

24

remodeling of bones

due to mechanical stress on bones their tissue needs to be replaced, ideally osteoclasts (breakdown bone) and osteoblasts (create new bone) work at same rate