1
Q
osteology
A
study of bone structure and treatment of bone disorders
2
Q
-blast
A
germ, to form, immature
ex. ostoblast
3
Q
chondro-
A
cartilage
ex. perichondrium
4
Q
-clast
A
to break
ex. osteoclast
5
Q
dia-
A
through
ex. diaphysis
6
Q
endo-
A
within
ex. endosteum
7
Q
epi-
A
over
ex. epiphysis
8
Q
meta-
A
after- beyond
ex. metaphysis
9
Q
myelo-
A
marrow
ex. osteomyelitis
10
Q
os-, osteo-
A
bone
ex. ossification, osteocyte
11
Q
peri-
A
around
ex. periosteum
12
Q
-physis
A
growing
ex. diaphysis
13
Q
Six functions of bone
A
1) support
2) protection
3) assist in movement
4) mineral homeostasis, e.g calcium and phosphorus
5) site of blood cell production:
red bone marrow, erythrocytes, leukocytes, and thrombocytes
6) storage of triglycerides for energy
14
Q
Seven features of a long bone
A
1) diaphysis
2) epiphysis
3) metaphysis
4) articular cartilage
5) periosteum
6) medullary cavity
7) endosteum
15
Q
diaphysis
A
shaft of long bone
16
Q
epiphyses
A
distal and proximal end of long bones
17
Q
metaphysis
A
point of union for diaphysis and epiphysis
epiphyseal plate
18
Q
articular cartilage
A
thin layer of hyaline cartilage covering epiphysis; found ta articular (joint) surface and provide a smooth gliding surface
19
Q
periosteum
A
membrane around outer surface of bone not covered by articular cartilage
Has two layers: fibrous, and osteogenic layers
20
Q
what are the functions of the periosteum?
A
- protects underlying bone (fibrous layer)
- essential for bone growth in thickness, but not length
- fracture repair
- supply nutrients to bone
- attachment point for ligaments and tendons
- attached to underlying bone matrix by perforating fibers of collagen
21
Q
fibrous layer of periosteum
A
- outer layer
- dense, irregular connective tissue
- contains blood vessels, lymphatic vessels and nerves that all serve the bone
22
Q
osteogenic layer of periosteum
A
- inner layer
- contains elastic fibers, blood vessels, and osteogenic cells (stem cells)
23
Q
medullar cavity
A
- space inside diaphysis
- contains osteogenic cells and osteoclasts
24
Q
bone has an abundant ____ surrounding widely separated cells
A
matrix
25
matrix is __% water, __% protein fibers, and ___% mineral salts (hydroxyapatite)
25% water
25% protein fibers
50% mineral salts
26
Four types of bone cells
1) osteogenic cells
2) osteoblasts
3) osteocytes
4) osteoclasts
27
osteogenic cells
- unspecialized cells derived from embryonic tissue
- CAN UNDERGO MITOSIS and become osteoblasts
28
where can you find osteogenic cells?
found in:
- inner portion of the periosteum
- endosteum
-canals in bone that contain blood vessels
29
what are osteoblast
- cells that form bone
- CANNOT divide by mitosis
- secrete matrix around themselves (collagen, other organic compounds and minerals)
30
what are osteocytes?
- principal cell of bone tissue
- mature osteoblasts trapped in the matrix
- CANNOT divide by mitosis
- do not secrete matrix materials
- maintain bone tissue via exchange of nutrients, gases and wastes
31
what are osteoclats?
- huge cells derived from the fusion of as many as 50 monocytes (a blood cell)
- located in the endosteum which lines the medullary cavity
- involved in bone reabsorption (destruction of matrix)
- important in bone development, growth, maintenance, repair and release of calcium ions into blood to maintain blood calcium level balance
32
the _____ border of osteoclasts is the site of ______ of lysosomal enzymes that digest bone
ruffled, exocytosis
33
what substance is pumped under the ruffle border of osteoclasts to dissolve calcium salts?
protons (hydrogen ions or acid)
34
the bone matrix is made up primarily of these salts:
1) hydroxyapatite
2) calcium carbonate
35
mineral salts provide___ to the matrix
hardness
36
the matrix framework is formed by _____ fibers
collagen
37
what is calcification/ mineralization?
when salts crystalize between collagen fibers and the tissue hardens
38
collagen fibers in the bone matrix provide _____ and _____ strength or resistance to stretch or tearing
flexibility, tensile
39
what are the two types of bone tissue?
1) compact: cortical or dense bone
2) spongy: trabecular/ cancellous bone
40
___% of boe tissue is compact and ___% is spongy
80, 20
41
what is compact bone?
aka dense bone
- forms external layer of all bones of the body and the bulk of the diaphysis of long bones
- provide support and protection
- resist loading stresses
42
what are the structures that make up compact bone?
1) central canal
2) concentric lamellae
3) osteons (harversian system): contain lacunae and canaliculi
4) interstitial lamellae
5) circumferential lamellae
43
central canals
aka Haversian canals
- run longitudinally
- carry vessels and nerves
44
concentric lamellae
- rings of hard calcified matrix found around central canals
- forms osteons
45
osteons
aka Haversian system
basic structural unit of compact bone
46
lacunae
small spaces between the lamellae which contain osteocytes
47
canaliculi
- tiny canals that radiate in all directions from the lacunae, filled with interstitial fluid and fingerlike projections from osteocytes
- connect different lacunae together and lacunae to the central canals
- permits diffusion of nutrients and oxygen to osteocytes and removal of wastes
48
interstitial lamellae
- found between osteons
- fragments of older osteons that have been partially destroyed during growth and remodelling
49
circumferential lamellae
encircle cortical region beneath the periosteum and encircle medullary cavity
50
what is spongy bone?
aka cancellous bone
- no true osteons
- make sup most of the bone tissue of short, flat, and irregular bone
- lamellae found in irregular framework called trabeculae
51
trabeculae
thin plates
space between them contain red marrow
contain lacunae, which contain osteocytes
52
____ radiate from lacunae in spongy bone
canaliculi
53
bone tissue is ____
vascular
54
blood vessels enter bones from the ____
periosteum
55
the nutrient _____ enters bone shaft through nutrient ___
artery, foramen
56
periosteum is rich with ____ nerves, therefore anything pressing upon it (teras, tumours etc.) can cause severe pain
sensory
57
what is ossification?
bone formation
begins 6th to 7th week of embryonic life
two types:
1) intramembranous
2) endochondral
58
intramembranous ossification
- bone between sheets of loose fibrous connective tissue
(mesenchyme)
- occurs with flat bones like skull, ribs, pelvis, scapula
59
endochondral ossification
- bone replaces a cartilaginous template
- occurs with most bones but especially long bones of children
60
bones can grow in ___ and ___
length, width
61
interstitial growth
bone growth in length
- occurs by endochondral ossification
- occurs only in cartilaginous regions of bones
- condrocytes divided mitotically laying down more cartilage lengthwise
62
the ______ growth plate permits growth of the diaphysis of long bones
epphyseal
63
bone tissue itself cannot _____ __ ____
grow in length
64
____ hormone is indirectly responsible for lengthening of bone at growth plate before adulthood
growth
65
what hormones can cause sudden growth spurts during adolescence?
estrogen and testosterone
66
when does the epiphyseal line form?
end of puberty
adult levels of sex hormones shut down growth at epiphyseal
plates, they become the epiphyseal line as osteoblasts replace the chondrocytes and the
tissue is ossified
67
bone is a ___ tissue; it is never metabolically at rest
dynamic
68
bone remodelling
ongoing removal of old bone and addition of new bone
consist of:
bone resorption and deposition
69
bone resorption
removal of minerals and collagen by osteoclasts
70
bone deposition
addition of minerals and collagen by osteoclasts
71
bone remodelling often take place along lines of ___
stress
72
hormones ____ remodelling
regulate
73
bone growth requires stimulation of ____
osteoblasts
74
bone repair requires ______ to clean up debris and osteoblast to lay down new bone
osteoclast
75
Three factors that influence bone growth, repair, and remodelling
1) minerals
2) vitamis (C and D)
3) Hormones
76
minerals that influence bone growth, repair, and remodelling
1) hydroxyapatite: principle salt in bone that gives it "hardness:. composed of calcium and phosphorus
2) magnesium; needed for osteoblast activity
77
vitamins that that influence bone growth, repair, and remodelling
- vitamin C:
promotes collagen synthesis. Scurvy= vitamin C deficiency
- vitamin D:
increase absorption of calcium from intestines to blood
decrease loss of calcium in urine
78
rickets and osteomalacia
vitamic D deficiency in children, leads to soft bones
vitamic D deficiency in adults, leads to soft bones
79
hormones that influence bone growth, repair, and remodelling
1) parathyroid hormone (PTH)
2) sex hormones in adulthood
3) calcitonin (CT)
80
parathyroid hormone (PTH)
increases blood calcium levels, promotes bone reabsorption by increasing the number and activity of osteoclasts
81
sex hormones in adulthood
estrogens and testosterone promote deposition of new bone by stimulating
osteoblast activity
estrogen slows resorption of old bone (encourages apoptosis of osteoclasts)
82
calcitonin (CT)
decreases blood calcium levels, promotes bone formation by increasing activity of osteoblasts and inhibiting activity of osteoclasts
83
disorders of bone and contraindications
- fractures
- osteoporosis
osteoarthritis
- osteomyelitis
- rickets and osteomalacia
- osteogenesis imperfecta
