Cartilage, Bone and Bone Development.

Question 1

Cartilage

One of the supporting connective tissues.

____ support in adult. Pinna of ear, epiglottis

Minimizes ____

____ surfaces in joints.

____ support

• During ____ development.
• During ____ of bony tissue e.g. fractures.

Answer 1

One of the supporting connective tissues. Flexible support in adult. Pinna of ear, epiglottis Minimizes abrasion. Articular surfaces in joints. Temporary support During embryonic development. During healing of bony tissue e.g. fractures.

Question 2

Cartilage Composition.

Cells in cartilage are ____s

. Chondroblasts are on the ____

Extracellular matrix

• ____
• ___ ___

____ and receives nutrition by diffusion Nutrients diffuse from the capillaries in ___ or from the ___ ___. No ___ ___ or ___

Answer 2

Cells in cartilage are chondrocytes. Chondroblasts are on the surface. Extracellular matrix fibers “ground substance”. Avascular and receives nutrition by diffusion Nutrients diffuse from the capillaries in perichondrium or from the synovial fluid No lymphatic vessels or nerves!

Question 3

Cartilage Cells.

Chondrocytes. Lie within the ____ they have synthesized.

Chondroblasts. Located in _____

Perichondrium. A __ ____ connective tissue divided into the__ ___ ___ and the ___ __ ___

Answer 3

Chondrocytes. Lie within the matrix they have synthesized. Chondroblasts. Located in perichondrium Perichondrium. A dense irregular connective tissue divided into the outer fibrous layer and the inner chondrogenic layer.

Question 4

Chondrocytes.

Lie within spaces known as ____ in the ECM.

May continue to synthesize material around them by ___ ___.

Capable of cell division: Clusters of 2, 4 or 8 cells___ __ ___

Answer 4

Lie within spaces known as lacunae in the ECM. May continue to synthesize material around them by interstitial growth. Capable of cell division: Clusters of 2, 4 or 8 cells Isogenic cell nests.

Question 5

Chondroblasts.

Located in the ____ on surface of the cartilage.

___ to ___ cells that may resemble ____.

Easily differentiate into ____

Answer 5

Located in the perichondrium on surface of the cartilage. Flattened to oval cells that may resemble fibroblasts. Easily differentiate into chondrocytes.

Question 6

The Three Types of Cartilage Hyaline Elastic Fibrocartilage

Answer 6

Hyaline Elastic Fibrocartilage

Question 7

Hyaline Cartilage.

____ plus____ flexibility.

Where: ___ , ___ ___

Fibers:. Type ___ collagen only.

Perichondrium?

Answer 7

Strength plus limited flexibility. Ribs, articular surfaces. Type II collagen only. Perichondrium.

Question 8

Elastic Cartilage.

___ strength but___ flexibility.

Collagen type ___ plus ____ fibers.

Where: ___ of ___ , ____

Perichondrium?

Elastic fibers stained with Weigert’s stain.

Answer 8

Some strength but great flexibility. Collagen type II plus elastic fibers. Pinna of ear, epiglottis. Perichondrium. Elastic fibers stained with Weigert’s stain.

Question 9

Fibrocartilage.

Resistance to __ ___

Where: ____ ___ of ___, ___ ___.

Thick bundles of type ___ collagen plus fine fibers of type ___ collagen.

____ chondrocytes or____ c groups arranged in long or short ___.

Perichondrium?

Answer 9

Resistance to mechanical stress Intervertebral disc of vertebrae. Pubic symphysis. Thick bundles of type I collagen plus fine fibers of type II collagen. Single chondrocytes or isogenic groups arranged in long or short rows. No perichondrium.

Question 10

Extracellular Matrix Fibers All cartilage types contain Collagen type II. Collagen type II fibers are generally __ ___to see at the light microscope level. Elastic cartilage also contains elastic fibers. Fibrocartilage also contains numerous large bundles of type I collagen.

Answer 10

Fibers All cartilage types contain Collagen type II. Collagen type II fibers are generally too small to see at the light microscope level. Elastic cartilage also contains elastic fibers. Fibrocartilage also contains numerous large bundles of type I collagen.

Question 11

Extracellular Matrix Ground substance components include:

_____: Chondroitin – 4 sulfate. Chondroitin – 6 sulfate. Keratan sulfate. Core proteins. ____

___ and ___

Answer 11

Ground substance components include: Proteoglycans. Chondroitin – 4 sulfate. Chondroitin – 6 sulfate. Keratan sulfate. Core proteins. Chondronectin. Water and ions.

Question 12

Extracellular Matrix.

____ matrix: ECM immediately surrounding the____. ___in glycosaminoglycans- ___ in collagen. ___ basophilic.

____ matrix. Remaining ECM

Answer 12

Territorial matrix: ECM immediately surrounding the lacunae. Rich in glycosaminoglycans- poor in collagen More basophilic. Interterritorial matrix. Remaining ECM

Question 13

Bone. A supporting connective tissue in which the extracellular matrix is __ ___

Answer 13

A supporting connective tissue in which the extracellular matrix is highly mineralized.

Question 14

Osteo- , ossi from the Greek osteon meaning ___: Osteoblasts, Osteocytes. Osteoarthritis. Osteoporosis etc.

Answer 14

Osteo- , ossi from the Greek osteon meaning bone: Osteoblasts, Osteocytes. Osteoarthritis. Osteoporosis etc.

Question 15

Bone. Major Functions:

___ and ___ internal organs.

____ site for muscle leverage.

Site for homeostatis of various___s

. Site for ____s (bone marrow).

Answer 15

Major Functions: Supports and protects internal organs. Attachment site for muscle leverage. Site for homeostatis of various ions. Site for hematopoiesis (bone marrow).

Question 16

Bone - General Structure.

Cells: Osteo___. Osteo___. Osteo___

Extracellular matrix: ___, __ ___, ____

Answer 16

Cells: Osteocytes. Osteoblasts. Osteoclasts. Extracellular matrix: Fibers. Ground substance. Mineral.

Question 17

General Structure.

Cells in ___, surrounded by ____.

Matrix is infiltrated with ____ salts for a rigid, inflexible mass.

Periosteum or endosteum –cells on____

____ vascular.

Constant ___ in response to physical stresses of body and mineral needs.

Answer 17

Cells in lacunae, surrounded by matrix. Matrix is infiltrated with inorganic salts for a rigid, inflexible mass. Periosteum or endosteum –cells on surface. Highly vascular. Constant remodeling in response to physical stresses of body and mineral needs.

Question 18

General structure of bone

Bone Marrow Cavity: Red: Hematopoietic Yellow: Fat

Spongy (Cancellous) Bone: Trabeculae with ___

Compact Bone Almost exclusively __ ___

Answer 18

Bone Marrow Cavity: Red: Hematopoietic Yellow: Fat Spongy (Cancellous) Bone: Trabeculae with spaces Compact Bone Almost exclusively bone substance.

Question 19

Components. By volume: Water ~ 10% Organic components ~ 35- 45% Inorganic ~ 50% By weight: Water ~ 10% Organic components ~ 33% Inorganic ~ 60 -65%

Answer 19

By volume: Water ~ 10% Organic components ~ 35- 45% Inorganic ~ 50% By weight: Water ~ 10% Organic components ~ 33% Inorganic ~ 60 -65%

Question 20

Inorganic. A mixture of calcium phosphate, carbonate, potassium, magnesium, sulfate, fluoride and traces of other metals.____is the most common: Ca10(PO4)6OH2

Answer 20

A mixture of calcium phosphate, carbonate, potassium, magnesium, sulfate, fluoride and traces of other metals. Hydroxyapatite is the most common: Ca10(PO4)6OH2

Question 21

Organic Collagen type ___ major organic ~ 90%.

Proteoglycan aggregates, specific structural glycoproteins, non-collagenous proteins ~ 10%.

Answer 21

Collagen type I major organic ~ 90%. Proteoglycan aggregates, specific structural glycoproteins, non-collagenous proteins ~ 10%.

Question 22

Non Collagenous Proteins.

Include:

Osteocalcin – involved in ___ ___

Osteonectin - important in ___ ___

Osteopontin - ____ ____

Bone sialoprotein - ___ ___

Bone morphogenic protein - may be a ____ factor.

Note that many of these are found in various tissues.

Answer 22

Include: Osteocalcin – involved in bone mineralization. Osteonectin - important in bone formation. Osteopontin - osteoblast attachment. Bone sialoprotein - osteoblast adhesion. Bone morphogenic protein - may be a differentiation factor. Note that many of these are found in various tissues.

Question 23

Other Components. Chondroitin -_–sulfate. Chondroitin -_ – sulfate. ____ sulfate.

Answer 23

Chondroitin -6 –sulfate. Chondroitin -4 – sulfate. Keratan sulfate.

Question 24

Bone Cells and Functions. There is always a __ ___r of cells on bone surface. Osteocytes - cells ___ in bone ECM. ____ bone.

Osteoblasts - on the ___e of bone. ____bone. Bone lining cells - ___ ___

Osteoclasts - on the ____of bone. ____ bone.

Answer 24

There is always a continuous layer of cells on bone surface. Osteocytes - cells embedded in bone ECM. Maintain bone. Osteoblasts - on the surface of bone. Form bone. Bone lining cells - resting osteoblasts. Osteoclasts - on the surface of bone. Resorb bone.

Question 25

Osteoid. Bone is formed by first synthesizing a ___ ___d bone matrix know as osteoid and then ____this matrix.

While the osteoid is being mineralized __ ___ is being formed

The surface of bone therefore always contains a ___ of__ ___ ___

Answer 25

Bone is formed by first synthesizing a non mineralized bone matrix know as osteoid and then mineralizing this matrix. While the osteoid is being mineralized new osteoid is being formed The surface of bone therefore always contains a layer of non mineralized osteoid.

Question 26

Osteocytes. Lie within spaces (____) in the bone ECM

Communicate with other osteocytes and with osteoblasts on the surface by means of ___ ___ in bone known as ____.

Osteocytes are able to aid in homeostasis via metabolism of ions that are then transferred to cells on the surface.

Answer 26

Lie within spaces (lacunae) in the bone ECM Communicate with other osteocytes and with osteoblasts on the surface by means of small channels in bone known as canaliculi. Osteocytes are able to aid in homeostasis via metabolism of ions that are then transferred to cells on the surface.

Question 27

Osteoblasts.

Cells on the surface of bone that form the bone ECM and then ____e it.

Cuboidal cells with basophilic cytoplasm.

When surrounded by ECM they produce they become ____.

Answer 27

Cells on the surface of bone that form the bone ECM and then mineralize it. Cuboidal cells with basophilic cytoplasm. When surrounded by ECM they produce they become osteocytes.

Question 28

Bone Lining Cells. In essence “resting osteoblast”.

____cells on surface of bone. Able to again become____ osteoblasts if required.

Answer 28

In essence “resting osteoblast”. Flattened cells on surface of bone. Able to again become active osteoblasts if required.

Question 29

Periosteum and Endosteum.

Periosteum: A __ ___ connective tissue of ___layers on the___l surfaces of bone. Endosteum A ___ layer of cells on all ____ surfaces of bone.

Answer 29

Periosteum: A dense irregular connective tissue of 3-4 layers on the external surfaces of bone. Endosteum A single layer of cells on all inner surfaces of bone.

Question 30

Osteoclasts.

Large ____ cells on the surface of bone.

Pink to red in H and E due to large number of ____.

Resorb both the___ and ___ components of bone.

Form hollowed spaces known as ____ ____

Answer 30

Large multinucleate cells on the surface of bone. Pink to red in H and E due to large number of mitochondria. Resorb both the organic and inorganic components of bone. Form hollowed spaces known as Howship’s lacunae.

Question 31

Bone Cells.

Bone cells are coordinated in their ___ and have various ___.

Osteoclast and osteoblast differentiation and functions are controlled by a variety of ___ and ___ factors.

Answer 31

Bone cells are coordinated in their functions and have various receptors. Osteoclast and osteoblast differentiation and functions are controlled by a variety of transcription and signaling factors.

Question 32

Classifications of Bone.

Development – time of formation ___, ___

Function:___, ____.

Method of formation: _____, ____

Answer 32

Development – time of formation Mature, immature. Function: Spongy. Compact. Method of formation: Intramembranous. Endochondral.

Question 33

Immature Bone. Various names. Immature bone. ___, ____

Answer 33

Various names. Immature bone. Primary bone. Woven bone.

Question 34

Immature Bone. This is laid down ____ without time for the regular ____ seen in adult bones. Cells and fibers ___ oriented. Bone is___ as ____as mature bone.

Immature bone is a ____ bone.

____

____ of fractures

Answer 34

This is laid down rapidly without time for the regular organization seen in adult bones. Cells and fibers randomly oriented. Bone is not as strong as mature bone. Immature bone is a temporary bone. Development Healing of fractures

Question 35

Mature Bone. Also known as ____ bone or___ bone.

Bone composed of layers or ____.

Alternate lamellae have ____ fibers oriented in ____directions to increase overall ____.

Mature bone is an adult bone that includes both __- and ____ bone

Answer 35

Also known as lamellar bone or secondary bone. Bone composed of layers or lamellae. Alternate lamellae have collagen fibers oriented in different directions to increase overall strength. Mature bone is an adult bone that includes both spongy and compact bone.

Question 36

Spongy Bone.

Various names:

Spongy bone – ___ like appearance.

____bone – as it is made of plates known as ____

___bone – because of the presence of ____ between bone plates.

This is a type of mature bone and is always formed of lamellae.

Answer 36

Various names: Spongy bone – sponge like appearance. Trabecular bone – as it is made of plates known as trabeculae. Cancellous bone – because of the presence of spaces between bone plates. This is a type of mature bone and is always formed of lamellae.

Question 37

Spongy Bone. Forms a network from individual ____ of bone known as trabeculae.

____ but supportive.

A very ___ surface area available for metabolism. Is a type of lamellar bone.

Answer 37

Forms a network from individual spicules of bone known as trabeculae. Lightweight but supportive. A very large surface area available for metabolism. Is a type of lamellar bone.

Question 38

Compact Bone. Various names:

Compact bone -__ ___ except for lacunae.

___ bone –___and able to withstand ___.

___ bone – composed of units known as___ or ___ ___

Answer 38

Various names: Compact bone - few spaces except for lacunae. Dense bone – tough and able to withstand trauma. Haversian bone – composed of units known as osteons or Haversian Systems.

Question 39

Compact Bone. A type of lamellar bone in which between 4 and 20 lamellae are arranged around the ____ in a___ ___ ___.

Composed of units known as osteons or Haversian systems.

Compact bone is ___, ___ _flexible, resists abrasion and trauma

____ of long bones. ____ of mandible and maxilla.

Answer 39

A type of lamellar bone in which between 4 and 20 lamellae are arranged around the vasculature in a central Haversian canal. Composed of units known as osteons or Haversian systems. Compact bone is hard, relatively inflexible, resists abrasion and trauma Shafts of long bones. Surfaces of mandible and maxilla.

Question 40

Bone Formation. Bone is a dynamic tissue that is constantly being remodeled. Provides source of ___ and other ions. Changes with the changing physical demands of muscle etc.

Answer 40

Bone is a dynamic tissue that is constantly being remodeled. Provides source of calcium and other ions. Changes with the changing physical demands of muscle etc.

Question 41

Methods of Formation. ____(=membranous) de novo formation.____Requires a cartilage template.

Answer 41

Intramembraneous (=membranous) de novo formation. Endochondral Requires a cartilage template.

Question 42

Intramembranous Bone Formation. This is the __ ____ type of bone formation and can occur ____ in connective tissue with the appropriate ___. The bone that is formed can be remodeled to form either __ or __ bone or both.

Answer 42

This is the most common type of bone formation and can occur anywhere in connective tissue with the appropriate signal. The bone that is formed can be remodeled to form either spongy or compact bone or both.

Question 43

Intramembranous Bone Formation.

Sequence:

Undifferentiated mesenchymal cells aggregate.

Differentiate into ____

. Osteoblasts lay down bone matrix – ____.

Osteoid becomes ____.

More bone ____ laid down etc.

Osteoblasts become incorporated as ____

Answer 43

Sequence: Undifferentiated mesenchymal cells aggregate. Differentiate into osteoblasts. Osteoblasts lay down bone matrix – osteoid. Osteoid becomes mineralized. More bone ECM laid down etc. Osteoblasts become incorporated as osteocytes.

Question 44

Endochondral Bone Formation.

This involves the formation of a ___ ___.

This template increases in ___ and ____.

____replaces some of the outer cartilage as a collar of bone (future shaft).

Increase in the size of __ ___ Cavity.

There is growth in ___ of long bone.

Temporary support is bY ____/___ columns.

Answer 44

This involves the formation of a cartilage template. This template increases in diameter and length. Bone replaces some of the outer cartilage as a collar of bone (future shaft). Increase in the size of bone marrow cavity. There is growth in length of long bone. Temporary support is by cartilage/bone columns.

Question 45

Endochondral Bone Formation

The bone marrow cavity increases due to ____ activity so that the columns of mineralized matrix are _____.

Some bone spicules remain to form _____ bone within the marrow cavity.

Answer 45

The bone marrow cavity increases due to osteoclast activity so that the columns of mineralized matrix are temporary. Some bone spicules remain to form spongy bone within the marrow cavity.

Question 46

Endochondral Bone Formation.

Cartilage cells formed at the ends (epiphyseal plate) go through different ____s as columns of cells due to influence of __ ___ (somatotrophin).

____
____
____

Answer 46

Cartilage cells formed at the ends (epiphyseal plate) go through different stages as columns of cells due to influence of growth hormone (somatotrophin). Proliferation Hypertrophy Apoptosis

Question 47

5 zones of endochondral bone formation.

____ zone

Zone of____n

Zone of ___y

Zone of ___ ____.

Zone of ____

Answer 47

Resting zone Zone of proliferation Zone of hypertrophy Zone of cartilage mineralization. Zone of ossification.

Question 48

Endochondral Bone Formation.

Apoptotic cells break down and their space is occupied by ___ ___cells.

Cartilage between the cells remains as columns

Columns ____ to strengthen them.

____ is then laid down on the ____ of these calcified cartilage columns.

Answer 48

Apoptotic cells break down and their space is occupied by bone marrow cells. Cartilage between the cells remains as columns Columns calcify to strengthen them. Bone is then laid down on the surface of these calcified cartilage columns.

Question 49

Summary. Intramembranous:

Converts ____ to bone in ___- and _____ period (____ ossification centers)

Endochondral Bone Formation: Coverts ___ to ___ in pre- and perinatal period (____ ossification centers)

Endochondral bone growth: Occurs after ___, ____ of long bones, requiring cartilaginous ___ ___, ceasing at adulthood

Answer 49

Intramembranous: Converts mesenchyme to bone in pre- and perinatal period (primary ossification centers) Endochondral Bone Formation: Coverts cartilage to bone in pre- and perinatal period (secondary ossification centers) Endochondral bone growth: Occurs after birth, lengthening of long bones, requiring cartilaginous epiphyseal plate, ceasing at adulthood

Question 50

Bone remodeling

Bone growth is associated with___ ____ of pre-formed tissue.

Shape of the bone is _____while it grows.

Very ___ in children, in adults occurs simultaneously in many areas in the skeleton.

Answer 50

Bone growth is associated with partial resorption of pre-formed tissue. Shape of the bone is maintained while it grows. Very common in children, in adults occurs simultaneously in many areas in the skeleton.

Question 51

Calcium mobilization Factors

Parathyroid hormone – bone____

Calcitonin – ____ deposition.

Somatotropin – see endochondral bone growth.

Cytokines.

Vitamin D. Vitamin A. Vitamin C.

Rapid

Hydroxyapatite to blood

Spongy bone

Slow

Actions of hormones

Answer 51

Factors Parathyroid hormone – bone resorption. Calcitonin – calcium deposition. Somatotropin – see endochondral bone growth. Cytokines. Vitamin D. Vitamin A. Vitamin C. Rapid Hydroxyapatite to blood Spongy bone Slow Actions of hormones

Question 52

Bone Repair – Sequence.

A ___ ___ forms in damaged area.

Cells in the Periosteum and endosteum _____.

A ____ s often formed by ___ ___.

Endosteal ____ of these cartilage fragments occurs.

____ bone formation occurs.

Callus and granulation tissue.

Answer 52

A blood clot forms in damaged area. Cells in the Periosteum and endosteum proliferate. A callus is often formed by cartilage fragments. Endosteal ossification of these cartilage fragments occurs. Membranous bone formation occurs. Callus and granulation tissue.

Question 53

Jaw Fractures The clues to diagnose a broken jaw: facial tenderness, swelling, a change in symmetry of the face, pain on moving the jaw, inability to speak and open or close the jaw. The possibility of other damage, e.g., to the zygomatic arch, the orbit and eye must also be carefully considered (second illustration).

Answer 53

The clues to diagnose a broken jaw: facial tenderness, swelling, a change in symmetry of the face, pain on moving the jaw, inability to speak and open or close the jaw. The possibility of other damage, e.g., to the zygomatic arch, the orbit and eye must also be carefully considered (second illustration).

Question 54

Bone Healing.

Bony defects often heal slowly.

To allow the bone time to heal and soft tissue to attach and heal, sometimes materials are used in the defect to act as a ____ to allow cell migration .

Materials may be natural biodegradable such as ____, ____ , or ____

. Plastics such as poly propylene fumarate show a ____nflammatory response and allow surrounding tissue to grow into the plastic.

Answer 54

Bony defects often heal slowly. To allow the bone time to heal and soft tissue to attach and heal, sometimes materials are used in the defect to act as a scaffold to allow cell migration . Materials may be natural biodegradable such as collagen, fibrin or plastics. Plastics such as poly propylene fumarate show a low inflammatory response and allow surrounding tissue to grow into the plastic.

Question 55

Bone Formation and Maintenance

Materials needed for collagen metabolism and mineralization.

Protein 22% of bone mass - 0.5 gms per pound body weight. Potassium. Vitamin C. Vitamin K – protein synthesis Vitamin B12 – controls amount of homocysteine. Magnesium – make up 1% of minerals in bone, aid in preventing crystals from becoming too large.

Answer 55

Materials needed for collagen metabolism and mineralization. Protein 22% of bone mass - 0.5 gms per pound body weight. Potassium. Vitamin C. Vitamin K – protein synthesis Vitamin B12 – controls amount of homocysteine. Magnesium – make up 1% of minerals in bone, aid in preventing crystals from becoming too large.

Question 56

Some Bone Pathologies.

____

____
____
____
____ disease

Answer 56

Osteoporosis Osteopetrosis Rickets. Osteomalacia. Paget’s Disease.

Question 57

Osteoporosis. A generic term covering a group of disorders in which there is ___ bone mass and deterioration of the bone mass and bone architecture.

Answer 57

A generic term covering a group of disorders in which there is low bone mass and deterioration of the bone mass and bone architecture.