UNIT II : SKELETAL BIOLOGY Flashcards
the strongest, least flexible connective tissue less than 20%of body weight
bone
one of the strongest biological materials in the human body, it is the main supporting tissue of the body
bone
a composite material made up of protein (collagen) and mineral (hydroxyapatite) making it lightweight
bone
functions of bone
support
protection (skull, pelvis, rib cage)
movement
site of blood cell formation (within the marrow cavities of the bone)
mineral storage
triglyceride storage
a large structure large enough to be viewed with the naked eye
MACROSTRUCTURE (GROSS ANATOMY)
– the end of a bone; a secondary center of ossification
Epiphysis
– the shaft or primary center of ossification
Diaphysis
the area of epiphysis-diaphysis union or fusion
Metaphysis
the marrow cavity within the shaft of a long bone
Medullary cavity
– holes in bone for passage of blood vessels
Nutrient canals
a structure that cannot be seen without magnification
MICROSTRUCTURE (MICROSCOPIC ANATOMY)
dense bone; it forms the bone cortex
the structural component is the osteon or Haversian system
COMPACT BONE
a cylinder-shaped structure oriented parallel to the long axis of the bone and the main compression stresses
made up of concentric lamella.
osteon or Haversian system
spongy bone or trabecular bone and contains the marrow
CANCELLOUS BONE
bone with tubular lamellae
LAMELLAR BONE
fibrous, nonlamellar, primitive, embryonic, or healing bone;
the matrix is irregular
WOVEN BONE
contains few spaces and is the strongest form of bone tissue
found beneath the periosteum of all bones and makes up the bulk of the diaphysis of long bones
Compact Bone / Cortical Bone
provides protection and support and resists the stresses produced by weight and movement
Compact Bone / Cortical Bone
nourished by self-contained blood vessels that travel within the central canals of the osteon and interconnect by perforating or Volkmann’s canals
Compact Bone / Cortical Bone
connects muscles to the bone
tendon
the largest tendon in the body
muscle to heels
Achilles tendon
inner lining of the bone
endosteum
outer lining of the bone
periosteum
connects one haversian to another haversian
transmit blood vessels from the periosteum into the bone
Volkmann canal
much less complex in the organization than the compact bone
made up of TRABECULAE, each of which has a few layers of lamellae, but lacks osteons and self-contained blood vessels
Spongy Bone / Cancellous Bone
nourished by diffusion from capillaries in the surrounding endosteum
makes up most of the bone tissue of short, flat, and irregularly shaped bones
Spongy Bone / Cancellous Bone
forms most of the epiphyses of long bones and a narrow rim around the medullary cavity of the diaphysis of long bones
has a more spongy, porous, lightweight, honeycomb structure
Spongy Bone / Cancellous Bone
limb bones and many of the hand and foot bones that are tubular in shape and have expanded ends
long bones
include bones of the cranial vault, shoulder, pelvis, and rib cage
Flat Bones
include bones of the ankle, wrist, and spine
Irregular Bones
the process of laying down new bone material by cells
called osteoblasts.
It is synonymous with bone tissue formation
OSSIFICATION
are the cells that form new bones. They also come from the bone marrow and are related to structural cells
They have only one nucleus.
OSTEOBLASTS
They produce new bone called “osteoid” which is made of bone
collagen and other protein. Then they control calcium and mineral
deposition. They are found on the surface of the new bone.
OSTEOBLASTS
large cells that dissolve the bone
come from the bone marrow and are related to white blood cells
usually have more than one nucleus
found on the surface of the bone mineral next to the dissolving bone
OSTEOCLASTS
cells inside the bone
also come from osteoblasts
sense pressures or cracks in the bone and help to direct where osteoclasts will dissolve the bone
OSTEOCYTES
elastic tissue - bone - one & stability
thighbone to the shinbone, stabilizing the knee joint
ligament
soft, gel-like padding between bones that protect joints and facilitates movement
cartilage
most common type of cartilage in your body
lines your joints and caps the ends of your bones
hyaline cartilage
tough cartilage made of thick fibers
strongest and least flexible
fibrocartilage
cartilage found at the end of bones that form joints, between ribs, in nasal passage
hyaline cartilage
cartilage found at the meniscus in your knee, disks between the vertebrae in your spine, supporting muscles, tendons, and ligaments
fibrocartilage
most flexible cartilage
supports parts of the body that need to bend and move to function
elastic cartilage
cartilage found at the external ears, eustachian tubes, larynx
elastic cartilage
LCL
lateral collateral ligament
MCL
medial collateral ligament
ACL
anterior cruciate ligament
PCL
posterior cruciate ligament
major
embryonic
process of
bone
formation
Endochondral
Ossification
This is a
process that
uses hyaline
cartilage as
the model for
long bone
formation.
Endochondral
Ossification
Results in trabecular or cancellous bone formation
Produces somewhat haphazard cancellous structure found in internal aspect of some bone
Endochondral
Ossification
a cartilaginous secondary center of ossification
- a tissue layer responsible for bone formation, it “grows away” from the shaft center
GROWTH PLATE / EPIPHYSEAL GROWTH PLATE
As the individual grows, the epiphyseal plate is pushed further from the primary growth center of the bone (shaft), thus lengthening the bone
true
Ossification and bone growth come to a halt when cells at the growth plate stops dividing, and the epiphysis fuses with the metaphysis of the shaft. Because the ends of the long bone flare, substantial remodeling occurs as the bone
lengthens during this process
trur
the process of bone development from fibrous membranes.
. Intramembranous Ossification
It is involved in the formation of the flat bones of the skull, the mandible, and the clavicles. Ossification begins as mesenchymal cells forma
template of the future bone. They then differentiate into osteoblasts at theossification center
. Intramembranous Ossification
Osteoblasts secrete the extracellular matrix and deposit calcium, which hardens the matrix. The non-mineralized portion of the bone or osteoid continues to form around blood vessels, forming spongy bone. Connective tissue in the matrix differentiates into red bone marrow in the fetus. The spongy bone is remodeled into a thin layer of compact bone on the surface of the spongy bone
. Intramembranous Ossification
This ossification forms the compact, regularly organized bone that is
exposed on the external surface
. Intramembranous Ossification
flat bones
cranial bones
sternum
scapulae
ribs
irregular bones
hip bones (2)
cervical (7)
thoracic (12)
lumbar (5)
sacrum (1)
coccyx (1)
hyoid bone (1)
temporal bone (2)
ethmoid (1)
sphenoid (1)
zygomatic (2)
maxilla (2)
mandible (1)
inferior nasal concha (2)
palatine (2)
malleus (2)
incus (2)
stapes (2)
- Formation of bone collar around hyaline cartilage model.
- Cavitation of the hyaline cartilage within the cartilage model.
- Invasion of internal cavities by the periosteal bud and spongy bone formation.
- Formation of the medullary cavity as ossification continues, appearance of secondary ossification centers in the epiphyses in preparation for stage 5.
- Ossification of the epiphyses; when completed, hyaline cartilage remains only in the epiphyseal plates and articular cartilages
Endochondral
Ossification
- Development of ossification center:
osteoblasts secrete organic extracellular matrix - Calcification; calcium and other mineral salts are deposited and the extracellular matrix calcifies (hardens)
- Formation of trabeculae: extracellular matrix develops into trabeculae that fuse to form spongy bone
- Development of the periosteum mesenchyme at the periphery of the bone develops into the periosteum
intramembranous ossification
