Bones, Cartilage. and Joints Flashcards
It is a dynamic organ that functions to provide support, protection, and also act as a reservoir of mineral salts and growth factors.
Bone
Why bones are dynamic?
because its shape adjusts to accommodate stresses
Bone tissue also known as …
osseous tissue
It is hard and many of its functions depend on that characteristic of hardness.
Bone
A thin layer of cartilage covering an epiphysis; reduces friction and acts as a shock absorber
articular cartilage
where two bone surfaces meet
articulation
Channels within the bone matrix that house one of an osteocyte’s many cytoplasmic extensions that it uses to communicate and receive nutrients
canaliculi (singular = canaliculus)
longitudinal channel in the center of each osteon; contains blood vessels, nerves, and lymphatic vessels; also known as the Haversian canal
central canal
dense bone that forms the cortical region of bone
Compact bone
tubular shaft that runs between the proximal and distal ends of a long bone
diaphysis
layer of spongy bone, that is sandwiched between two the layers of compact bone found in flat bones
diploe
delicate membranous lining of a bone’s medullary cavity
endosteum
(also, growth plate) sheet of hyaline cartilage in the metaphysis of an immature bone; replaced by bone tissue as the organ grows in length
epiphyseal plate
wide section at each end of a long bone; filled with spongy bone and red marrow
epiphysis
opening or depression in a bone
hole
spaces in a bone that house an osteocyte
lacunae
(singular = lacuna)
hollow region of the diaphysis; filled with yellow marrow
medullary cavity
small opening in the middle of the external surface of the diaphysis, through which an artery enters the bone to provide nourishment
nutrient foramen
Is is the process of bone formation in which a cartilage model becomes
almost entirely replaced by bone preceding the formation of the actual bone
Endochondral ossification
microscopically dense parallel array of bone
Lamellar bone
This is the process of bone formation in which bones are directly laid in opposition on top of the bone that has just formed.
Membranous ossification
It is the process that is responsible for changing the size and shape of bony tissue.
Modelling
Mesenchymal cells that contribute to bone production and can be seen lining bone surfaces.
Osteoblasts
Smaller elongated cells contained within small cavities in bone called lacunae
Osteocytes
Hematopoietic derived, multinucleated cells that resorb bone.
Osteoclasts
A tubular functional unit of lamellar cortical bone.
Osteons
The process that is responsible for bony tissue maintenance.
Remodeling
Bone that forms multi-directional, anastomosing struts within the marrow cavity.
Trabecular bone
Rapidly deposited randomly arranged arrays of bone.
Woven bone
6 Functions of bones
- Support
- Protection
- Assisting movement.
- Mineral homeostasis
- Blood cell production
- The different constituents of bone function together to facilitate normal growth, adapt to changing stress, repair micro injury, regulate mineral homeostasis, and respond to injury.
It takes place in the bone marrow.
Blood cell production
Composition of bones:
- made up of Cells (osteoblasts and osteocytes) other cell types: osteoprogenitor cells and osteoclasts
- Extracellular matrix
Types of cells found in bones
Cells that are involved in growing bone:
Osteoprogenitor cells (osteogenic cells)
Osteoblasts
Osteocytes
These are the ‘stem’ cells of bone, and are the source of new osteoblasts.
Osteoprogenitor cells (osteogenic cells)
These are undifferentiated and develop into osteoblasts.
Osteogenic cells
Lining the surface of bone, secrete collagen and the organic matrix of
bone (osteoid), which becomes calcified soon after it has been deposited. As they become trapped in the organic matrix, they become osteocytes.
Osteoblasts
It maintain bone tissue. Fine processes from these cells ramify through bone, and form gap junctions with other osteocytes.
Osteocytes
Function of osteocytes
Maintains bone tissue
Function of osteoblast
Forms bone matrix
Osteogenic cells
Stem cells
Osteoclast
Resorbs bone
Osteocytes sit in the calcified matrix, in small spaces called ________.
lacunae
Long processes from the osteocyte lie in small channels called __________.
canaliculi (small canals).
These are channels for the transport for nutrients and waste.
Canaliculi
It is develop from monocytes and macrophages and differ in appearance from other bone cells.
Osteoclasts
It is a bone cell responsible for forming new bone and is found in the growing portions of bone, including the periosteum and endosteum.
osteoblast
Osteoblast is found in what location?
growing portions of bone, including the periosteum and endosteum.
It do not divide but it synthesize and secrete the collagen matrix and calcium salts.
Osteoblasts
As the secreted matrix surrounding the osteoblast calcifies, the osteoblast become trapped within it; as a result, it changes in structure and becomes an ________.
osteocyte
It is the primary cell of mature bone and the most common type of bone cell.
osteocyte
These are undifferentiated cells with high mitotic activity and they are the only bone cells that divide.
osteogenic cells
Immature osteogenic cells are found in what locations?
deep layers of the periosteum
marrow
They differentiate and develop into osteoblasts.
Osteogenic cells
The cell responsible for bone resorption, or breakdown.
osteoclast
They are found on bone surfaces, are multinucleated, and originate from monocytes and macrophages, two types of white blood cells, not from osteogenic cells.
Osteoclast
Osteoclasts are continually breaking down what kind of bone?
Old bone
Osteoblasts are continually forming what kind of bone?
new bone
Osteoblast and osteoclast are responsible in _________.
Reshaping of bones
Cartilage and Bone: 2 Types of mature bone
Compact Bone
Cancellous Bone / Spongy Bone
It is the basic unit of compact bone.
osteon (Haversian system)
The osteocytes are arranged in concentric rings of bone matrix called _________ and their processes run in interconnecting canaliculi.
lamellae (little plates)
Canals thay contain blood vessels and nerves from the periosteum.
Central Haversian canal and horizontal canals
It has large open spaces (marrow spaces) and plates of bone called trabeculae.
Cancellous Bone
plates of bone is called _______
trabeculae
Cells that are involved in remodeling bone
Osteoclasts
These are secretory, and have prominent Golgi apparatus, and vesicles.
Osteoclast
They secrete enzymes such as carbonic anhydrase which acidifies the matrix, and causes it to decalcify, and hydrolyses, which break down the matrix once it is decalcified. Other cell types help to phagocytose and get rid of the debris.
Osteoclast
What is the enzymes secretes by osteoclast?
carbonic anhydrase
These are large multinucleated cells, with a ‘ruffled border’ that resorb bone matrix, as shown in the diagram above.
Osteoclasts
They are important for remodelling, growth and repair of bone.
Osteoclast
clast means…
to break
These are not derived from osteoprogenitor cells. They are derived from blood monocytes/macrophages which are derived from haemopeoitic cells in the bone marrow.
Osteoclasts
Osteoclasts are derived from…
blood monocytes/macrophages which are derived from haemopeoitic cells in the bone marrow
Bone re-modelling is necessary for?
growth
It is necessary for growth
Bone re-modeling
Mechanical stresses on the skeleton cause release of ________, that stimulate bone-remodelling.
calcium
It also control bone re-modelling. Parathyroid hormone stimulates bone resorption and calcitonin inhibits resorption.
Hormones
It stimulates bone resorption and calcitonin inhibits resorption.
Parathyroid hormone
Bone re-modelling is necessary for growth:
- Mechanical stresses on the bone
- Hormones
Types of bone
Compact Bone
Cancellous / Spongy Bone
It is found in the shafts of long bones (in the diaphyses)
Compact Bone
Compact bone of found where?
Diaphysis or long bones
This makes up 80% of all bone.
Compact bone
It is the denser, stronger, It can be found under the periosteum and in the diaphyses of long bones, where it provides support and protection.
Compact bone
It is the microscopic structural unit of compact bone.
osteon, or Haversian system
It is a concentric rings of calcified matrix
lamellae
Running down the center of each osteon is the _______.
central canal or Haversian canal
Central canal / Haversian canal contains what?
blood vessels, nerves, and lymphatic vessels
It is found at the ends of long bones (in the epiphysis).
Spongy (cancellous) bone
This makes up 20% of all bone. This type of bone contains red bone marrow and a network of bony trabeculae.
Spongy (cancellous bone)
They are not arranged in concentric circles.
Spongy bone
The lacunae and osteocytes are found in a lattice-like network of matrix spikes called _________.
trabeculae
It is composed of trabeculae that contain the osteocytes.
Spongy Bones
It fills the spaces in some bones.
Red marrow
It is found on the outside of bone. This is a dense fibrous layer, where muscles insert. It contains bone forming cells. It is not found in the regions of bone covered by articular cartilage.
periosteum
It is the name given to the tissue that lines the inner surfaces of bones.
endosteum
The first bone formed at any site is _______ bone
woven (or primary) bone
The first bone formed at any site is woven (or primary) bone, but this is soon replaced by what bone?
lamellar bone
In this bone, the collagen fibres are random.
woven bone
In this bone, the collagen fibres have become re-modelled to become more parallel - in layers.
lamellar bone
Bone cells
Osteogenic cells
Osteoblasts
Osteocytes
Osteoclasts
Function of osteogenic cells
Develop into osteoblasts
Location of osteogenic
Deep layers of the periosteum and the marrow
Function of osteoblasts
Bone formation
Location of osteoblasts
Growing portions of bone, including periosteum and endosteum
Function of osteocytes
Maintain mineral concentration of matrix
Location pf osteocytes
Entrapped in matrix
Function of osteoclasts
Bone resorption
Location of osteoclasts
Bone surfaces and at sites of old, injured, or unneeded bone
has a very good blood supply
bone
It is riddled with blood capillaries
Bone
The central cavity contains ___________ and is a storage for __________.
blood vessels
bone marrow
All of the osteocytes in bone are within ___________ of a capillary.
0.2mm
Two ways in which bone can grow:
Endochondral
Intramembranous
Formation of bone onto a temporary cartilage model or scaffold.
Endochondral
A cartilage model that becomes almost entirely replaced by bone precedes the formation of the actual bone. Increases in bone length are primarily the result of endochondral ossification, as the cartilage model can grow interstitially (from within the matrix).
Endochondral
Formation of bone directly onto fibrous connective tissue. There is no intermediate cartilage stage.
Intramembranous
Intramembranous occurs in a few specialised places such as the
flat bones of skull (i.e. parietal bone), mandible,
maxilla,
clavicles
_____________ differentiate into __________, then into ____________, which secrete the bone matrix.
Mesenchyme cells
osteoprogenitor cells
osteoblasts
Once the osteoblasts are embedded in the bone matrix, they are known as __________.
osteocytes
The arteries enter through the nutrient _______, small openings in the diaphysis
foramen
Blood vessels and nerves enter the bone through the ________.
nutrient foramen
It is a resilient and smooth elastic tissue, a rubber-like padding that covers and protects the ends of long bones at the joints, and is a structural component of the rib cage, the ear, the nose, the bronchial tubes, the intervertebral discs, and many other body components.
Cartilage
Cartilage is a structural component of the following:
rib cage, the ear, the nose, the bronchial tubes, the intervertebral discs
Lining the innermost aspect of the joint capsule is lined by _________.
synovium
It is thought to contain three distinct cell populations: phagocytic macrophages, antigen presenting cells, and fibrobroblast like cells that produce glycosaminoglycans.
Synovium
3 distinct populations
phagocytic macrophages
antigen presenting cells
fibrobroblast like cells of synovium
It is a filtrate of plasma enriched with proteoglycans.
Synovial fluid
It is the outermost layer and is composed of dense collagen.
Joint capsule
It looks histologically similar and are also composed of very dense collagen.
Tendons and ligaments
Joint capsule is made of…
Dense collagen
The collagenous fibers in tendons insert directly into bone, and these are called ___________.
Sharpey’s fibers
This type of bone is dense and arranged in parallel arrays. This type of bone that forms the normal adult skeletal structures.
Lamellar bone
This type of bone is rapidly produced and is more cellular with less organization than lamellar bone.
Woven bone
This type of bone is seen in animals that are growing or in a bone that is in reparative phase after an injury (like a fracture).
Woven bone
Cells that line a bone surface and responsible for producing to the bone matrix.
Osteoblast
Cells that reside within bone matrix.
Osteocytes
The spaces that encloses osteocyte
Lacunae
