6.6 - The Skeleton & Bone Tissue - Bone and Bone Tissue Structure Flashcards
What are the two types of bone?
- Compact/cortical
- Spongy/trabecular
Where is cortical/compact bone often found within a bone?
On the outer edge (think: cortical -> cortex -> outer)
Which type of bone contains osteons, and which contains trabeculae?
Osteons: Cortical/compact
Trabeculae: Trabecular/Spongy
What are two consequences of the structure of trabecular/spongy bone?
- Can absorb force from multiple directions
- Contains space for red (active) bone marrow
What is a tendon vs ligament?
Ligament: Bone-Bone
Tendon: Muscle-Ligament
What is diaphysis? What is it made of ?
- Shaft
- Made of compact bone
What is epiphysis? What is it made of?
- End of bone
- Made of trabecular/spongy bone
What is metaphysis? What is it made of?
- Between epiphysis and diaphysis
- Made of trabecular/spongy bone
What is another name for epiphyseal plates?
Growth plates
When do we use the term “epiphyseal line” vs “epiphyseal plate”
Plate: Child
Line: Adult
Where is the medullary cavity located within a long bone? What does it contain?
Yellow bone marrow
Where is articular cartilage located on long boens? What type of cartilage is it?
Located on the epiphysis of long bones. Made of hyaline cartilage
What is the periosteum?
Tough outer fibrous membrane covering bone
What is the function of the periosteum? Does the periostuem cover articular cartilage?
Function:
- Protects vessels and nerves that nourish bone
- Anchors muscle to bone
NO. It does not cover articular cartilage
What is the endosteum?
Thin, delicate membrane lining medullary cavity
What is the function of the endosteum?
Maintain cellular composition of bone during remodelling
What tissues comprise bone?
- Bone
- Cartilage
- Blood
- Lymph
- Nerves
- Fat
What are the four kinds of cells present in bone?
- Osteoclasts
- Osteoblasts
- Osteocytes
- Osteoprogenitor
What organic components give bone its strength?
Collagen fibres
What inorganic components give bones its strength?
Mineral salts
Which cells create the organic components of the bone extracellular matrix?
Osteoblasts
How does inorganic matter make bone hard?
Calcium and phoshorous salts are harvested from surrounding blood, and form crystals with collagen fibres, strengthening the bone.
What does “progenitor” mean?
The beginning of something
What type of cells are osteoprogenitor cells?
Stem cells
What three types of cells can osteoprogenitors become before they differentiate into a bone cell? What type of stem cell is this?
- Adipocyte
- Chrondocyte
- Osteocyte
This is a mesenchymal stem cell.
Which are the only kinds of bone cells that can undergo mitosis?
Osteoprogenitor cells
What is the function of osteoblasts?
- Synthesises and deposits the organic bone matrix (collagen fibres)
- Initiates calcification using inorganic substances
Where are osteoblasts located?
Along the surface/edges of the bone (under periosteum and endosteum)
Under what circumstances do osteoblasts become osteocytes?
When they bury themselves in their own bone deposit
What is the name given to the cavity in which the cell body of an osteocyte is present?
Lacunae
What are the canals that osteocyte fingers run through called?
Canaliculi
Which three bone cell types all come from the same lineage (i.e. same original cell)?
Osteocyte, osteoblast, osteoprogenitor cell
Provide a basic description of an osteoclast
An osteoclast is a cell formed by the fusion of multiple macrophages, and has the capacity to produce enzymes that can break down bone.
Why do osteoclasts have a ruffled basal surface?
This provides a suction zone, enabling the cell to deposit lysosomal enzymes into the bone without these enzymes leaking out into the environment.
What pits do osteoclasts create?
Resorption pits
What is the name of the bony struts found in the spongy/trabecular bone?
Trabeculae
What is another name for osteons?
Haversian systems
What is contained within haversian canals?
Blood vessels, nerves etc.
What are concentric lamellae?
‘Layers’ of bone ‘rings’ around the haversian/central canal
What are the four components of an osteon?
- Haversian/central canal
- Concentric lamellae
- Lacunae
- Canaliculi
What are volkmann’s canals? Which type of bone are they found in?
- Horizontal Haversian canals
- Connect adjacent osteons
- Found in compact bone
What are interstitial lamellae?
Old osteons no longer containing a haversian canal.
True of false: there are no interstitial lamellae in spongy/trabecular bone
False. There is only interstitial lamellae.
Why are osteoclasts able to travel through the bloodstream?
They are derived from hematopoietic stem cells; they are made of multiple white blood cells, and are present in peripheral blood.
Why doesn’t trabecular bone need haversian canals?
There is red bone marrow in the trabecular bone; when blood is produced in this bone marrow, it provides all the nutrients required for the cell.
List some functions of cartilage
- Maintaining shape
- Resists compression and stretch; shock absorption
- Smooth surface to minimise friction
What are the two types of cells in cartilage?
- Chondroblast
- Chondrocyte
How are chondral cells similar to bone cells?
Same principle applies when transitioning from blast -> cyte
Why don’t chondrocytes need canaliculi?
Cartilage retains water and nutrients in its rubbery extracellular matrix
What are the main components of the cartilage extracellular matrix?
- Collagen Type 2
- Chondroitin
Is cartilage vascular or avascular?
Avascular
What are the three types of cartilage?
- Hyaline
- Fibrocartilage
- Elastic
Generally speaking, where is fibrocartilage found?
Areas with not a lot of movement, but that require a lot of strength
What type of bundles/fibres can be found in fibrocartilage?
Collagen type 2 bundles/fibres
What type of fibres can be found in elastic collagen?
Elastic fibres
Where could we find elastic cartilage?
Epiglottis, external ear
What is the function of elastic cartilage?
Provides flexible support; maintains shape
