The Skeletal system Flashcards
The skeletal system
Consists of bobes(skeleton), cartilage, ligaments( binds bones together) and other connective tissues
Orthopaedics and physiatry: The medical specialties for the diagnosis and treatment of the musculoskeletal system
What are the functions of the skeletal system
Support: framework that gives shape to the body.
• Protection: lungs, heart, brain, and other organs.
• Anchorage: serves as lever for movement.
• Site of hematopoiesis: blood cell formation within the red bone marrow.
• Mineral storage: mostly for calcium and phosphate.
• Fat storage: within the yellow bone marrow.
Based on shape, bones are classified as
- long bones
- short bones
- flat bones
- sesamoid(round) bones
- irregular bones
Long bone
Description: Long bones are longer than they are wide.
Examples:
• collar bone, bones in the limbs, hands, feet and fingers
• femur (thigh bone) is the longest bone in the body
Short bone
Description: Short bones are as long as they are wide.
- squarish in size
Examples:
• most bones in the wrists and ankles
Flat bones
Description: Flat bones are thin, curved and contain flat surfaces that are used for muscle anchorage or for protection.
Examples:
• breastbone, ribs, some bones of the skull and shoulder blades
Sesamoid Bones
Description: resembles a sesame seed and are embedded in tendons
Examples:
- knee caps and 1 type of writ bones called the pisiform found in the wrist
Other bones may may be found in the tendons near the joints of carpals and tarpals
Irregular Bones
Description: have complex and varying shapes and does not fit into any other category
- there like interlocking bones like Lego
Description:
- vertebral column, hip bones, some bones of the skull(jaw bones), bones in the ear
Bones: Based os structure, they’re classified as
Compact(cortical) and Spongy(trabecular or cancellous)
Compact bones
- are strong and dense
- form the outer layer of the bone which is the thicker layer
- composed of units called osteons
Osteon
- are circular tubes of bone matrix made up of collagen fibres
- separately they are called a lamella
Within an osteon
Central canal: contains the blood vessels and nerve that serve each osteon
Lacunae: the space found between adjacent lamella that contain osteocytes
- Canaliculu: forms Casals that connect lacunae together and to the central canal
Spongy bones
Are found on the inside of the bone
- contain a honeycomb structure called a trabeculae which are irregularly aligned lamellae
The long bone consists of
The Diaphysis and the Epiphysis
Diaphysis
- the shaft(length) of the long bone
Has compact bone surrounding a medullary cavity filled with fatty tissue and yellow bone marrow
Epiphysis
- the 2 end of the long bone
- the distal, side further from the attachment site and proximal side, side closer to the attachment site
- filled with red bone marrow for blood synthesis
- joint surfaces are covered by articulating hyaline cartilage that protect it from movement
Metaphysics
The region between the diaphysis and epiphysis
- also know as the epiphyseal line in adults or the epiphyseal(growth) plate during bone growth period
Bone surfaces are covered by 2 membranes
- periosteum
- endosteum
Periosteum(outside of bone)
Covers the external bone surfaces except the joints
- like a plastic wrap
Had 2 layers
Outer fibrous layer: made up of dense irregular connective tissue
Inner osteogenic layer: contains blood cells for bone growth and maintenance
Has holes called foremen in the diaphysis
Which is a bone marking that means opening
This is to allow nutrient artery and vein serve the bone marrow and spongy bone
Endosteum(inner bone)
Covers the internal bone surfaces( trabeculae of sponges bones and central canals of compact bones
- contains 1 layer that has bone cells for growth and maintenance
Endosteum(inner bone)
Covers the internal bone surfaces( trabeculae of sponges bones and central canals of compact bones
- contains 1 layer that has bone cells for growth and maintenance
In short, irregular and flat bones
- compact bones outside sandwich the sponges bones inside
- periosteum covers the external surfaces
- endosteum covers the interior surfaces
Where does hematopoiesis occur in adults? [Multi-select]
A. Medullary cavities of long bones (*in infants).
B. Proximal heads of some long bones
C. Diploë of some cranial bones
D. Epiphyseal plate
B and C
Osseous Tissue
Are the type of connective tissue bones are
- it is composed of bone cells and a solid extracellular matrix
Bone cells
Make up only 2% of the bone’s mass
Osteoblasts
Are bone building cells that produce the organic bone matrix called osteoid
- produces collagen and calcium binding proteins
Where are they found?
In the osteogenic layer of periosteum and in the endosteum
Osteocytes
Are bone maintaining cells that develop from osteocytes and no longer divide
- matured bone cells
- regulates bone mass and mineral storage
Where are they found?
In the lacunae and canaliculi
Osteoclasts
Are bone chipping(crushibf) cells that remove matured bone bone matrix(osteolysis) that may be damaged
- Multinucleated due to the fusion of multiple stem cells
- secretes causes to remove the inorganic matrix and protein digesting enzymes to remove the organic ones
Where are they found?
In the osteogenic layer of the periosteum and in the endosteum
Extracellular Matrix
Contains 2 major components:
Organic: osteoid framework
Inorganic: mineral salts
Mineral salts called
Hydroxyapatite are deposited around the organic framework and crystallize through calcification
What would happen to a bone if we soaked it in vinegar for several days?
- vinegar dissolves mineral salt inside a bone, which takes away the hardness. -Only organic framenark left
• bone becomes rubbery and flexible
What would happen to a bone if we baked it for several hours at high temperature (250°F)?
- high temperature breaks down collagen and other proteins, which takes away the tensile strength and flexibility of a bone
• bone becomes brittle
