Chapter 6: Cartilage Flashcards
Chondroblast
The cells that make up the cartilage matrix in our bones
What are the two ways the cartilage grows?
- Interstital growth - grow from within the cartilage itself
- Appositional growth- growth along the cartilage outisde edge
_____________ the main thing that makes up the bone
Bone connective tissue (Osseous connective tissue)
What are the four classes of bone?
- Long bone (most common, is in the upper limbs, lower limbs, feet & toes)
- Short bone
- Flat bone
- Irregular bone
One of the main features of the long bon eis its ___________
Diaphysis (Shaft)
Epiphysis
Knobby region at each of the long bone
Metaphysis
Region of mature bone between the diaphysis & epiphysis
Articular cartilage
Thin layer of hyaline cartilage covering the epiphysis at a joint surface
Medullary cavity
Hollow cylindrical space within the diaphysis
Endosteum
An complete layer of cells that cover all internal surfaces
Periosteum
Covers the outer surfaces of the bone except for the areas covered by articular cartilage
What are the 4 types of cells in the bone connective tissue?
- Osteoprogenitor cell
- Osteoblast
- Osteocyte
- Osteoclast
Osteoprogenitor cell
Stem cells that came from mesechyme
Osteoblast
Are responsible for creating & secreting bone (osteoid) (Also they are single nucleated cubodial ells & line the surface of the bone)
Osteocyte
Maintains bone tissue & mature bone cells that repsonds to stress
Osteoclast
Break down bone through bone resorption (which is a process where bone tissue is broken down & released minerals into the blood)
The main salt crystal in the bone is ____________
Hydroxyapatite- which is made up of calcium phosphate & calcium hydroxide
What is the major structure of compact bones?
Osteons
What are the 4 structures of osteons?
- Central (Haverison) Canal
- Concentric Lamellae
- Osteocytes
- Canaliculi
Central (Haverison) Canal
Is the channel that runs through the center of the osteon (Contains blood vessels & nerves)
Concentric Lamellae
Are rings of connective tissue that surround the central cannel
Osteocytes
Are bone cells found between lamellae
Canaliculi
Are tiny channels that connect lacuna to other lacuna & to the central canal (They transport nutrients, gasses, minerals, & wastes through jap junctions)
What are the additional structure outside the osteon?
- Perforating (Volkamann’s) Canals
- Circumferential Lamella
- Interstitial lamella
Perforating (Volkmann’s) Cannals
Run perpendicular to central canals to connect adjacent osteons
Circumferential lamella
Externally found underneath the periosteum or innerally found around the marrow cavity
Interstitial lamella
Sits between osteons & have no central canal
What are the features in the spongy bone?
- Trabecule
- Parallel Lamellae
Trabecule
Is an opne networks of bone rods & plates
Parallel Lamellae
Composed of bone matrix that run across spongy bone
The spongy bone doesnt contain ________
Osteons
_____________ is the process of destroying the bone matrix
Bone resorption
Endochondral ossification
Hyaline cartilage is created and then invaded by osteoblast that calcifies it (begins with hyaline cartilage and produces most bones in the body (long bones in skeleton)
Intramembranous ossification
Osteoblasts differentiate directly from the mesenchyme and builds bone
What are the phases in stage 1 of Endochondral ossification?
- Zone of resting cartilage
- Zone of proliferating cartilage
- Zone of hypertrophic cartilage
- Zone of calcified cartilage
- Zone of ossification
What are the phases in stage 2(Ossification at the cartilaginous diaphysis) of Endochondral ossification?
- Osteoprogenitor cells in the perichondrium divide to become osteoblasts
- Cartilage calcifies and forms a periosteal bone collar
- Periosteal bud arises from the bone collar
- . Bone is deposited from primary ossification center towards the epiphysis
- Once at the epiphysis, same process is repeated, giving rise to a secondary ossification center.
- Bone growth and remodeling continuous at the epiphyseal plates until early adulthood
Bone remodeling
Is the continual removal of old bone (resorption) and addition of new bone tissue (deposition)
Mechanical stress
Is put on the bone from weight-bearing movements and exercise
How does hormones affect bone remodeling?
- Growth hormones (somatropin) stimulates the growth of cartilage in epiphyseal plate
- Insulin-like growth factor (IGF) stimulates the growth of cartilage in epiphyseal plate
- Thyroid hormones stimulate bone growth by increasing metabolism of bone cells
- Sex hormones (estrogen/testosterone) accelerate bone growth at puberty
- Glucocorticoids (steroid hormones) stimulate bone loss
Stress fracture
Is a thin break due to repetitive stresses from physical activity (Ex: runners)
Fractures
Are breaks in the bone due to unusual stress or a sudden ________________
Pathological fracture
Can occur in diseased bone
Simple fracture
Occurs when the broken bone does not go through the skin
Compound fracture
Occurs when the broken bone does go through the skin
What are the 4 stages how bone fractures are repaired?
- Formation of fracture hematoma (Bleeding from damaged blood vessels, clots)
- Fibrocartilaginous (soft) callus (forms New blood capillaries enter the clot)
- Hard (bony) callus (Osteoprogenitor cells become osteoblasts to produce trabeculae & Trabeculae replaces the soft callus to form the hard callus)
- Bone is remodeled
