Bone

Question 1

Bone is a

Answer 1

specialized connective tissue

Question 2

Support cells in bone

Answer 2

osteoblast and osteocytes

Question 3

Bone Remodeling cells

Answer 3

osteoclasts

Question 4

Bone matrix

Answer 4

-non-mineralized organic
-made of collagen and GAGs

OSTEOID

Question 5

What is the inorganic mineral salts within the bone matrix?

Answer 5

hydroxyapatite

Question 6

Function of Bone

Answer 6

-mechanical support
-locomotion
-protection
-metabolic reservoir for mineral salts

Question 7

Diaphysis

Answer 7

-shaft
-contains red marrow

Question 8

What bone is found in the medullary cavity?

Answer 8

cancellous/ trabecular
(spongy)

Question 9

What bone is found in the cortex of the Diaphysis?

Answer 9

compact bone

Question 10

Cortex of the Diaphysis

Answer 10

more dense outer portion

Question 11

medullary cavity of the Diaphysis

Answer 11

-where red or yellow marrow is found
- the inner less dense portion

Question 12

Epiphyses

Answer 12

-end of the bone
-full of spongy bone
-has cap of hyaline cartilage

Question 13

Metaphysis

Answer 13

-between the Epiphyses and the Diaphysis
- where you find growth plate

Question 14

Osteoid

Answer 14

-organic matrix
-collagen type 1 and GAGs

Question 15

What produces osteoids?

Answer 15

osteoblasts

Question 16

What gives bones its characteristic of rigidity and strength?

Answer 16

deposition of mineral salts into the osteoid

Question 17

Woven bone

Answer 17

-random organization of collagen
-“chucking collagen in there
-faster
-weaker

Question 18

Lamellar

Answer 18

-parallel sheets of collagen
-strong

Question 19

Outer bone

Answer 19

-cortex/ cortical bone
-resists deformation

Question 20

Inner Bone

Answer 20

trabecular/cancellous/ spongy

system of internal struts

Question 21

Functional Unit of bone

Answer 21

Osteon (Haversian system)

Question 22

Haversian Canal

Answer 22

-At the center of an osteon
-where blood vessels and nerves come in

Question 23

What do you find in lacunae of bone?

Answer 23

osteocyte

Question 24

Volkmann’s Canal

Answer 24

-horizontal (right angle to haversian canal)
-link osteons

Question 25

Canaliculi

Answer 25

-allows communication between osteocytes -contain cytoplasmic extensions

Question 26

Spongy and woven bone lack

Answer 26

Haversian System

Question 27

What can cause abnormalities in bone architecture?

Answer 27

-breaking a bone -osteoporosis -cancer - congenital disease

Question 28

Endosteum

Answer 28

-inner lining -thinner than periosteum -has osteoprogenitor cells -type 3 collagen

Question 29

Endosteum lines

Answer 29

-bone marrow cavity -haversian canal - all internal cavities

Question 30

Periosteum

Answer 30

-outer covering of the bone -has 2 layers

Question 31

Outer Fiberous Membrane

Answer 31

- irregular, dense connective tissue -more collagenous - fewer cells | periosteum

Question 32

Inner Cellular Layer

Answer 32

-osteoprogenitor cells

Question 33

In the Inner Cellular Layer of adults ________ may be absent

Answer 33

osteoblasts (appear when required)

Question 34

osteoprogenitor cells

Answer 34

-mulitpotent stem cells -precursor to osteoblast -fibrobalst-like -flat

Question 35

Sharpey's Fibers

Answer 35

-parallel bundels of collagen -extend from periosteum -found in periodontal ligament (anchor root of tooth into bone)

Question 36

Osteoblast

Answer 36

-osteoprogenitor cells that are turned on -synthesise and mineralize osteoid (hydroxyapatite) -polygonal

Question 37

Why are Osteoblast very basophilic?

Answer 37

organelles for synthesis of large amounts of proteins and proteoglycans

Question 38

Osteocyte

Answer 38

-osteoblast trapped in the matrix -inactive

Question 39

Osteoclast

Answer 39

-resorb bone to release calcium and phosphate -phagocytic

Question 40

Osteoclast derive from

Answer 40

monocytes

Question 41

What stimulates osteoclast

Answer 41

-Parathyroid Hormone (low serum calcium)

Question 42

Matrix Vesicle

Answer 42

-secreted by osteoblast and calcify the matrix

Question 43

What do Matrix Vesicle contain

Answer 43

alkaline phosphatase (causes precipitation of mineral salts)

Question 44

What portion of the (compact) bone matrix is inorganic salts?

Answer 44

70%

Question 45

What portion of the (compact) bone matrix is organic?

Answer 45

30%

Question 46

What is the organic portion of the matrix mostly made of?

Answer 46

Type 1 collagen (90% of organic)

Question 47

What synthesizes type 1 collagen in the bone matrix?

Answer 47

osteoblast

Question 48

The GAGs of the ground substance of bone mostly consist of

Answer 48

-hyaluronic acid (most) -chondroitin sulfate -keratan sulfate

Question 49

What are the non-collagenous organic molecules of the bone matrix

Answer 49

-osteocalcin -osteonectin -sialoproteins

Question 50

osteocalcin

Answer 50

binds intercellular Ca during mineralization

Question 51

osteonectin

Answer 51

bridge/ binds to collagen and minerals

Question 52

sialoproteins

Answer 52

-rich in sialic acid -concentrated from plasma

Question 53

Mineralized portion of bone

Answer 53

hydroxyapatite (inorganic salts)

Question 54

Bone has an an affinity for

Answer 54

-heavy metals (Pb, Hg) - radioactive isotopes

Question 55

Osteocytes communicate with each other via

Answer 55

gap junctions

Question 56

Where do you find osteoclasts?

Answer 56

on the endosteal/periosteal surface in a depression called - Howship;s Lacunae - or Resorption Bay

Question 57

Osteoclasts produce

Answer 57

organic acids and lysozymes

Question 58

What has a ruffled border?

Answer 58

osteoclast (increases surface area)

Question 59

Blast

Answer 59

build

Question 60

Clast

Answer 60

chew (break down)

Question 61

Parathyroid Hormone (PTH)

Answer 61

secreted by parathyroid gland stimulates osteoCLAST activity

Question 62

Parathyroid Hormone _______ blood Ca levels and _________ renal excretion by kidneys

Answer 62

increases, decreases

Question 63

Calcitonin

Answer 63

secreted by thyroid gland stimulates osteoBLAST, inhibits osteoclast (tone down Ca)

Question 64

Calcitonin _______ blood Ca levels

Answer 64

decrease

Question 65

Somatotropin

Answer 65

stimulates growth (growth plate) decreases blood Ca

Question 66

Oversecretion of what can lead to giantism or acromegaly

Answer 66

Somatotropin

Question 67

Undersecretion of Somatotropin leads to

Answer 67

pituitary dwarfism