Bone tissue

Question 1

What is the composition of cartilage?

Answer 1

• avascular, devoid of nerve fibers
• ground substance contains glycosaminoglycans (chondroitin sulfate and hyaluronic acid)
• collagen fibers
• 80% water
• small cavities in matrix

Question 2

What are perichondrium?

Answer 2

layer of dense connective tissue surrounding cartilage like gridle
- in damage areas it causes scar tissue

Question 3

What is the difference between chondroblasts, chondrocytes and lacunae?

Answer 3

CB - immature cartilage cells - actively form cartilage
CC - mature cartilage cells - maintain cartilage
L - localized clusters of chondrocytes in cartilage

Question 4

Why are lacunae in clusters?

Answer 4

could be the way cartilage grows

Question 5

What is elastic cartilage made of, its function and location in the body?

Answer 5

• like hyaline cartilage, but more elastic fibers
• maintain shape, flexibility
• external ear, epiglottis

Question 5

What is hyaline cartilage made of, its function and location in the body?

Answer 5

• collagen, glassy blue-white chondrocytes, lots of ECM
• firm support and pliability
• nose, trachea and larynx

Question 5

How do bones respond to force and what does it respond to calcium?

Answer 5

• when force is applied, bone increases in density (deposition) and roughness or decreasing it (resorption)
• stores calcium - reabsorbed and transferred to bloodstream when needed (forms new blood)

Question 6

What is fibrocartilage made of, its function and location in the body?

Answer 6

• rows of chondrocytes with collagen
• tensile strength
• intervertebral discs, discs of knee joints

Question 7

What are the 7 functions of bones?

Answer 7

1. support
2. protection
3. anchorage and movement (attach to muscles)
4. mineral storage
5. blood cell formation (bone marrow)
6. fat storage (bone marrow)
7. hormone production (bone metabolism)

Question 7

What is the function of bone calcium salts and what does bone hold inside?

Answer 7

• gives hardness and strength for support/ protection of soft tissue
• cavities for fat storage and synthesis of blood cells

Question 8

What is the cell bone tissue from WBC lineage?

Answer 8

osteoclast - bone resorbing cell/ tissue
- breaks down matrix

Question 8

What are the stages of bone cell lineage?

Answer 8

1. osteoprogenitor cell - stem cells
2. osteoblasts - bone growth
3. osteocyte - mature bone cell

Question 9

What are the layers of bone?

Answer 9

periosteum: outer fibrous layer + inner osteogenic layer
endosteum: covers trabeculae of spongy bone and lines canal of compact bone

Question 9

Calcified tissue - what is the difference in compact bone and spongy (trabecular) bone?

Answer 9

CB - dense, outer layer - strength and support
SB - trabeculae - middle region (red marrow in spongy bone)

Question 10

What are the 2 main divisions of the skeleton?

Answer 10

• axial skeleton (central axis)
• appendicular skeleton (limbs)

Question 11

How are bones classified and the types?

Answer 11

by shape
1. long
2. short
3. flat
4. irregular

Question 12

Explain what flat bones shape, composition, location and function?

Answer 12

thin, flattened and sometimes curved
- 2 layers of compact bone with spongy middle
- skull, ribs, sternum
- protection/ muscles attachment

Question 12

Explain what long bones shape, composition, location and function?

Answer 12

longer than wide with 2 ends
- mostly compact bones with marrow cavity
- spongy near joint ends
- weight bearing/ movement

Question 13

Explain what irregular bones shape, composition, location and function?

Answer 13

irregular shape
- mostly spongy bone + thin layer of compact bone
- hip bone, vertebrae
- protection of nervous tissue and movement

Question 13

Explain what short bones shape, composition, location and function?

Answer 13

cube-like shape
- mostly spongy bone + thin compact bone
- wrist, ankle
- range of movement + flexability

Question 14

What is the structural parts of a typical long bone?

Answer 14

• diaphysis (shaft)
• epiphyses (bone ends)
• membrane

Question 15

What is the function of the epiphyses and what is its composition?

Answer 15

• expanded for joining of bones (joints)
• compact and spongy bone with hyaline on the outer surface (reduces friction and increases shock absorption)

Question 15

What does the diaphysis surround and what does it contain?

Answer 15

marrow cavity (medullary cavity)
- contains fat (yellow marrow)

Question 16

Where is the epiphyseal located, where does it come from and what happens to it once you reach adulthood?

Answer 16

• between diaphysis and each epiphysis
• epiphyseal (growth) plate - longitudinal growth
• cartilage turns into bone

Question 17

How is the structure of short, irregular and flat bone similar?

Answer 17

periosteum (attaches to muscle) - covers outside of compact bone endosteum (maintenance and repair) - inside portion medullary cavity

Question 18

What does flat, short and irregular bones lack?

Answer 18

- shaft - marrow cavity - epiphyses

Question 19

What is an osteon, what is it also called and what is its function?

Answer 19

structural unit of compact bone - lamellae - run parallel which act to bear weight

Question 20

What is compact bone also called and what does it consist of?

Answer 20

lamellar bone 1. osteon (haversian system) 2. canals and canaliculi 3. interstitial and circumferential lamellae

Question 21

What are the 3 canals of compact bone?

Answer 21

1. osteons 2. haversian (central) canal 3. Volkmann's (perforating) canal - perpendicular to long axis of bone + Have canal

Question 21

What is the difference between osteocytes and canaliculi?

Answer 21

O - mature bone cells that are in cavity (lacunae) with bony matrix - maintain bone tissue C - small canals that connect lacunas - connected to Have system

Question 22

What is the difference between interstitial lamellae and circumferential lamellae?

Answer 22

IL - fill gaps between forming osteons or are leftovers of osteons that were partially destroyed by bone remodeling CL - sheets of bone located just deep to periosteum and extend around entire shaft

Question 22

What is intramembranous ossification and when does it start?

Answer 22

bone development from fibrous CT membrane containing mesenchymal cells - 8 weeks embryo

Question 23

What is the composition of spongy bone and why does its location served a function?

Answer 23

trabeculae, lamellae, osteocytes and canaliculi - trabeculae runs along stress lines to help bone to resist stress

Question 24

What does spongy bone lack and how does nutrients enter into the bone?

Answer 24

- osteons - thorough canaliculi from marrow space between trabeculae to osteocytes

Question 25

What is ossification and what are the 3 steps?

Answer 25

bone tissue formation 1. formation of bony embryotic skeleton 2. postnatal bone growth during childhood and adolescents 3. bone remodeling and repair throughout life

Question 26

Which bones are affected by intramembranous ossification and what is it also called?

Answer 26

flat bones (cranial and clavicles) - membrane bones

Question 27

What is endochondral ossification and what are its bones called?

Answer 27

development via replacement of hyaline cartilage model - cartilage bones

Question 27

When does endochondral ossification start and what does it form?

Answer 27

2nd month of embryo - forms most skeleton/ all bones below skull (except clavicles)

Question 28

How does the bone grow longer and wider?

Answer 28

longer - by interstitial growth of epiphyseal plates wider - thickness by appositional growth

Question 29

Which bones continue to growth after early adulthood?

Answer 29

some facial bones - nose, lower jaw

Question 30

What are the regions of the epiphyseal plate?

Answer 30

1. resting zone 2. proliferation zone (cartilage cells) 3. hypertrophic zone (older cart. cells enlarge) 4. calcification zone (cartilage dies) 5. ossification zone (new bone development)

Question 31

What is the locational difference between epiphyseal plates and diaphysis?

Answer 31

EP - wider part of bone D - shaft (which grows longer to support EP)

Question 32

What is the role of osteoclasts and osteoblasts in bone growth?

Answer 32

OC - destroy bones OB - lay down cells on inner and outer surface

Question 33

What is unique about the size of the epiphyseal plate throughout childhood and what happens in adulthood - name??

Answer 33

- stays the same size - stops growing (epiphyseal plate closure)

Question 34

What is the function of the primary osteoblast and primary osteoclasts?

Answer 34

OB - on periosteal side secrete bone matrix OC - on endosteal side remove bone

Question 35

What causes osteoporosis, what are the consequences and what are the areas that are most likely affected?

Answer 35

imbalance between bone resorption (more) and formation (less) - bone more porous (more likely to fracture) - spine, neck of femur

Question 35

How does the parathyroid control calcium levels?

Answer 35

if levels fall, para releases PTH which make osteoclasts degrade bone matrix and release Ca2+ into blood

Question 36

What are the 4 major stages of fracture repair?

Answer 36

1. hematoma formation - localized formation of blood outside blood vessels (inflammation) 2. fibrocartilaginous callus formation - macrophages clean area - osteoclasts reabsorb - the blasts lay down collagen and tissue 3. bony callus formation - converted to trabeculae bone 4. bone remodeling - extra bone material is removed - bone regains original shape

Question 37

What are the risk factors of osteoporosis and what are the contributing factors?

Answer 37

- age/ testosterone and estrogen - lack of exercise, diet poor in Ca bad protein/ bad Vit D receptors, smoking

Question 38

What is the importance of bone markings?

Answer 38

- identification of bone - understanding how they join