Lecture 4 - Cartilage & Bone Flashcards
What makes up the skeletal system
- > bones - > cartilage - > ligaments - > other supporting connective tissues
What are the main functions of cartilage?
- > support soft tissues (keeps airway open)
- > Articulations (joints; keeps bones from rubbing)
- > Precursor model for bone growth (fetal skeleton stars off as cartilage)
Properties of cartilage
they’re semi-rigid connective tissue
- > avascular
- > flexible/resistant
What kinds of cells make up cartilage? Where do they live?
Chondroblasts - > young cells which produce matrix (brats = hyperactive)
Chondrocytes - > older cells that still produce matrix but are more concerned with matrix mantenace *Both cells live in small spaces called lacunae*
List all types of cartilage
- > hyaline cartilage - > fibrocartilage - > elastic cartilage
Properties of hyaline cartilage
- > lacks significant collagen (present but in small quantity)
- > located in fetal skeleton, ends of bones, trachea, nose
- > weakest of the three
Properties of elastic cartilage
- > made of up elastic fibres
- > position/form able to be influenced; snaps back to original shape
- > found in epiglottis (swallow flap) and external ear
Properties of fibrocartilage
- > densely interwoven collagen fibres which contribute to durability
- > Acts as shock absorbers
- > resists tension in one direction
- > can be found in intervertebral discs and meniscus
Functions of bones
- > support - > protection - > anchors for movement (muscles) - > Hematopoiesis (blood cell production) - > Storage
Properties of Bone
- > primarily connective tissue - > extracellular matrix is sturdy and rigid - > strengthened by calcification (minerals deposited in matrix)
Types of bones
- > long - > short - > irregular - > flat
Properties of long bones
- > have both compact and spongy bone - > longer than wide - > most common bone in body
Properties of short bones
- > Have spongy and compact bone - > roughly as long as it is wide - > ie. patella
Properties of flat bones
- > have compact and spongy bones - > protect underlying structures (ie. cranium protects brain) - > provide muscle attachment sides
Properties of irregular bones
- > odd shapes; can’t fit into any other category - > ie vertebrae, hip bones
Identify A (upper and lower), B and whats in between the two, C, D, G, H and J
A (upper) -> proximal epiphysis
A (lower) -> Distal epiphysis
B -> Diaphysis
In between the epiphysis and diaphysis is the Metaphysis
C - > articular cartilage
D - > periosteum
G - > medullary/ marrow cavity
H - > Endosteum
J - > Epiphyseal (growth) plate
What is the epiphysis and what does it do?
- > the knobby, elongated regions at the ends of a long bone
- > strengthens joints
- > is the attachment cite for tendons/ligaments
What is the metaphysis
- > The section of bone in between the epiphysis and diaphysis.
- > contains epithysial (growth) plate
Functions of articular cartilage
allows bones to glide over one another with very little friction
Articular cartilage also comes together to form joints
What are the different types of bone coverings
- > Periosteum
- > Endosteum
Periosteum
- > covers the external surfaces of bone
- > does not cover articular cartilage (if it did, it would cause friction)
- > acts as anchor for blood vessels and nerves
- > anchored by perforating Sharpey fibres embeded in bone matrix
Endosteum
covers most internal surfaces of bone
Describe each type of bone cell
Osteogenitors: stem cells found in endosteum & periosteum that either produce more stem cells or convert into osteoblasts
Osteoblasts: young cells, form matrix, very mitotic
Osteocytes: maintain the matrix and communicate with osteoblasts to cause further deposit of bone matrix; they’re found in lacunae as they trap themselve in a layer of their own matrix
Osteoclasts: large, multicellular; break down bone & cartilage
What makes up the bone matrix
1/3 organic componants(osteoid) : flexible, resist breaking
- > cells, collagen fibres and ground substance
2/3 inorganic componants: hardness
- > mineral salts of inorganic hydroxyappetite, calcium phosphate and calcium phosphate
Compact vs. Spongy Bone
Compact (aka. cortical)
- > solid and relatively dense
- > makes up internal surfaces of long and flat bone
Spongy (aka. Cancellous or trabecular)
- > makes up internal surfaces of bone
What are osteons
also know as the HAVERSIAN SYSTEM, osteons are cylindrical structures parellel to the shaft of the bone that is made up of concentric lamellae (layers) which surround the central canal
Types of lamellae
Concentric: rings of bone around central canal
Circumferential: along outter edge of periosteum
Interstitial: fills remaining space between osteons (if you draw a lot of circles there’s spaces in between)
Types of canals
Central (havesian): carries blood vessels and nerves
Perforating (volkmanns) cannals: perpendicular connections to central canals
What are lacunae
small spaces between lamellae that house blastocytes
what are canaliciuli
tiny channels between lacunae
what are the two general patterns of ossification
Intramembranous
Endochondral
Explain the process of intramembranous ossification
- > mesenchymal (mesenchyme) cells come together and multiply, and eventually evolve into osteoblast
- > osteoblasts then begin creating bone matrix
- > results in the formation of flat bones
Explain the process of endochondral ossification
- > everyone is born with a fetal skeleton made out of hyaline cartilage.
- > this cartilage is eventually eaten away by osteoclasts and replaced with hard bone by osteoblasts
What are the two types of bone growth
- > Appositional growth
- > Interstitial growth
What is appositional growth
growth in diameter/thicccness
What is interstitial growth
- > increase in length by gradual remodelling at the articular cartilages and epiphyseal plate
Epiphyseal plate vs epiphyseal line
Epiphyseal plate
- > Cartilage still growing
epiphyseal line
- > ossified bone (18-21)
Steps of bone fracture repair
- Hematoma forms
- fibrocartilaginous (soft) callusis formed
- a hard (bony) callus is forms
- the bone is remodelled
explain bone aging
as we age, our bones…
- > lose ability to produce organic matrix (mainly collagen)
- > loses Ca and other salts
what is osteoporosis
disease characterized by low bone mass and deterioration of bone tissue
lacunae
The lacunae are situated between the lamellae, and consist of a number of long spaces
calcification
Calcification is the accumulation of calcium salts in a body tissue/bone ect.
which part of the bone contains bone marrow
the medulary/ marrow cavity usually contains yellow marrow
Identify this type of cartilage
fibrocartilage
Identify this type of cartilage
Hyaline
Identify this cartilage
elastic
