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Flashcards in 1a1-chapter 7 bone tissue Deck (91):
1

osteology

the study of bone

2

skeletal system

composed of bones, cartilages, and ligaments

3

ligaments

hold bones together at the joints

4

tendons

attach muscle to bone

5

Functions of the Skeleton

support
protection
movement
electrolyte balance
acid-base balance
blood formation

6

bone

bone(osseous tissue) -connective tissue with the matrix hardened by calcium phosphate and other minerals

7

mineralization

calcification–the hardening process of bone

8

long bones

–longer than wide
–rigid levers acted upon by muscles

9

short bones

–equal in length and width
–glide across one another in multiple directions

10

flat bones

–protect soft organs
–curved but wide & thin

11

irregular bones

–elaborate shapes that don’t fit into the other categories

12

compact (dense) bone

outer shell of long bone

13

diaphysis

(shaft) -cylinder of compact bone to provide leverage

14

medullary cavity

(marrow cavity) -space in the diaphysis of a long bone that contains bone marrow

15

epiphyses

enlarged ends of a long bone
–enlarged to strengthen joint and attach ligaments and tendons

16

spongy (cancellous) bone

covered by more durable compact bone
–skeleton about three-fourths compact and one-fourth spongy bone by weight
–spongy bone found in ends of long bones, and the middle of nearly all others

17

articular cartilage

a layer of hyaline cartilage that covers the joint surface where one bone meets another
–allows joint to move more freely and relatively friction free

18

nutrient foramina

minute holes in the bone surface that allows blood vessels to penetrate

19

periosteum

external sheath that covers bone except where there is articular cartilage
-outer fibrous layer of collagen
-inner osteogenic layerof bone forming cells

20

perforating (Sharpey’s) fibers

periosteum
–other outer fibers that penetrate into the bone matrix

21

endosteum

thin layer of reticular connective tissue lining marrow cavity
–has cells that dissolve osseous tissue and others that deposit it

22

epiphyseal plate (growth plate)

area of hyaline cartilage that separates the marrow spaces of the epiphysis and diaphysis
–enables growth in length

23

epiphyseal line

in adults, a bony scar that marks where growth plate used to be

24

Structure of a Flat Bone

•sandwich-like construction
•two layers of compact bone enclosing a middle layer of spongy bone
–both surfaces of flat bone covered with periosteum

25

diploe

spongy layer in the cranium
–absorbs shock
–marrow spaces lined with endosteum

26

bone

connective tissue that consists of cells, fibers and ground substance

27

four principal types of bone cells

–osteogenic (osteoprogenator) cells
–osteoblasts
–osteocytes
–osteoclasts

28

osteogenic (osteoprogenator) cells

stem cells found in endosteum, periosteum, and in central canals
–arise from embryonic mesenchymal cells
–multiply continuously to produce new osteoblasts

29

osteoblasts

bone forming cells

30

osteocytes

former osteoblasts that have become trapped in the matrix they have deposited

31

lacunae

tiny cavities where osteocytes reside

32

canaliculi

little channels that connect lacunae

33

cytoplasmic processes

reach into canaliculi

34

osteoclasts

bone-dissolving cells found on the bone surface
ruffled border –side facing bone surface

35

resorption bays

(Howship lacunae) –pits on surface of bone where osteoclasts reside

36

remodeling

results from combined action of the bone-dissolving osteoclasts and the bone-depositing osteoblasts

37

bone is a composite

combination of two basic structural materials, a ceramic and a polymer

38

matrix of osseous tissue

bone combines the polymer, collagen, with the ceramic, hydroxyapatite and other minerals

39

hydroxyapatite

(crystallized calcium phosphate salt)

40

rickets

soft bones due to deficiency of calcium salts

41

osteogenesis imperfecta

or brittle bone disease –excessively brittle bones due to lack of protein, collagen

42

osteon

(haversian system) –the basic structural unit of compact bone
–formed by a central canal and its concentric lamella connected to each other by canaliculi

43

perforating (Volkmann) canals

are transverse or diagonal passages along the length of the osteon

44

nutrient foramina

on the surface of bone tissue that allow blood vessels and nerves to enter the bone

45

circumferential lamellae

inner and outer boundaries of dense bone
•–run parallel to bone surface

46

interstitial lamellae

remains of old osteons that broke down as bone grew and remodeled itself

47

Spongy Bone consists of

–slivers of bone called spicules
–thin plates of bone called trabeculae
–spaces filled with red bone marrow

48

spongy bone has

few osteons and no central canals
–all osteocytes close to bone marrow
•provides strength with minimal weight
–trabeculae develop along bone’s lines of stress

49

bone marrow

general term for soft tissue that occupies the marrow cavity of a long bone and small spaces amid the trabeculae of spongy bone

50

red marrow(myeloid tissue)

–in nearly every bone in a child
–in adults, found in skull, vertebrae, ribs, sternum, part of pelvic girdle, and proximal heads of humerus and femur

51

hemopoietic tissue

produces blood cells and is composed of multiple tissues in a delicate, but intricate arrangement that is an organ to itself

52

yellow marrow

found in adults
–most red marrow turns into fatty yellow marrow
–no longer produces blood

53

ossification or osteogenesis

the formation of bone

54

in the human fetus and infant, bone develops by two methods:

–intramembranous ossification
–endochondral ossification

55

intramembranous ossification

produce the flat bones of the skull and most of the clavicle (collar bone)
these bones develop within a fibrous sheet

56

mesenchyme develops into

embryonic connective tissue condenses into a layer of soft tissue with dense supply of blood capillaries

57

endochondral ossification

process in which bone develops from pre-existing cartilage model
–most bones develop by this process

58

mesenchyme develops into

a body of hyaline cartilage in location of future bone

59

primary ossification center

chondrocytes in the middle of the model enlarge

60

primary marrow cavity

forms from blood and stem cells filling hollow cavity

61

metaphysis

region of transition from cartilage to bone at each end of primary marrow cavity
zone of transition facing the marrow cavity

62

secondary ossification center

created by chondrocyte enlargement and death in the epiphyses

63

secondary marrow cavity

in epiphyses
•cavity expands outward from the center in all directions

64

epiphyseal plate

epiphyseal plate –a region of transition from cartilage to bone
•functions as growth zone where the bones elongate
•consists of typical hyaline cartilage in the middle
•with a transition zone on each side where cartilage is being replaced by bone

65

bones grow in two directions

length and width

66

bone elongation

interstitial growth -bones increase in length
–bone elongation is really a result of cartilage growth within epiphyseal plate
–epiphyses close when cartilage is gone –epiphyseal line

67

Zones of the Metaphysis

–zone of reserve cartilage
–zone of proliferation
–zone of hypertrophy
•chondrocyte enlargement
–zone of calcification
-zone of bone deposition

68

growth in width

appositional growth -bones increase in width throughout life
–the deposition of new bone at the surface

69

bone remodeling

occurs throughout life -10% per year
–repairs microfractures, releases minerals into blood, reshapes bones in response to use and disuse

70

Wolff’s law of bone

architecture of bone determined by mechanical stresses placed on it and bones adapt to withstand those stresses

71

Dwarfism

achondroplastic dwarfism
–long bones stop growing in childhood
pituitary dwarfism
–lack of growth hormone

72

mineral deposition

(mineralization) -a crystallization process in which calcium phosphate, and other ions are taken from the blood plasma and deposited in bone tissue

73

abnormal calcification

(ectopic ossification)
–may occur in lungs, brain, eyes, muscles, tendons or arteries (arteriosclerosis)

74

calculus

calcified mass in an otherwise soft organ such as the lung

75

mineral resorption

the process of dissolving bone and releasing minerals into the blood
–performed by osteoclasts at the “ruffled border”

76

Calcium Homeostasis

depends on a balance between dietary intake, urinary and fecal losses, and exchanges between osseous tissue

77

hypocalcemia

blood calcium deficiency
hypercalcemiais rare
–vitamin D deficiency
–diarrhea

78

hypercalcemia

blood calcium excess

79

calcium homeostasis is regulated by three hormones:

calcitriol, calcitonin, and parathyroid hormone

80

calcitriol

a form of vitamin D produced by the sequential action of the skin, liver, and kidneys
behaves as a hormone that raises blood calcium concentration

81

parathyroid hormone

(PTH) –secreted by the parathyroid glands which adhere to the posterior surface of thyroid gland
PTH raises calcium blood level

82

calcitonin

secreted by C cells (clear cells) of the thyroid gland when calcium concentration rises too high
•lowers blood calcium concentration

83

Phosphate Homeostasis controlled by

calcitriol promotes its absorption by small intestine
PTH lowers blood phosphate

84

stress fracture

break caused by abnormal trauma to a bone

85

pathological fracture

break in a bone weakened by some other disease

86

fractures classified by structural characteristics

–direction of fracture line
–break in the skin
–multiple pieces

87

Healing of Fractures

–fracture hematoma and granulation tissue
–soft callus formation
–conversion to hard callus
–remodeling

88

closed reduction

procedure in which the bone fragments are manipulated into their normal positions without surgery

89

open reduction

involves surgical exposure of the bone and the use of plates, screws, or pins to realign the fragments

90

orthopedics

the branch of medicine that deals with prevention and correction of injuries and disorders of the bones, joints, and muscles

91

osteoporosis

the most common bone disease
–severe loss of bone density
•bones lose mass and become brittle due to loss of organic matrix and minerals