Skeletal System Flashcards
Divisions of the skeletal system
- Axial skeleton
- Appendicular skeleton
Axial Skeleton
Bones of:
- Head (cranium/skull)
- Neck (cervical vertebrae)
- Trunk
What does the trunk consist of?
- Ribs
- Sternum
- Vertebrae
- Sacrum
Appendicular Skeleton
- Bones of the limbs
- Includes pectoral and pelvic girdles
Components of the skeletal system
- Cartilage
- Bone
- Joints
Cartilage
Resilient, semirigid, avascular connective tissue
Where in the skeletal system can cartilage be found?
- Where more flexibility is necessary
- Costal cartilages
Articular Cartilage
- Covers articulating surfaces of bones in a synovial joint
- Hyaline cartilage
Function of articular cartilage
Provides smooth, low-friction gliding surface for free movement
Ratio of cartilage:bone as you age
- Young: cartilage > bone
- Older bone > cartilage
Functions of bone
- Protection
- Support
- Movement
- Salt storage (Ca++)
- Blood cell formation
Composition of bone
Collagen fibers in a mineralized extracellular matrix
Characteristics from bone composition
- Provides hardness
- Enhances rigidity
Principle bone cell types
- Osteocytes (nutrition and metabolic exchange)
- Osteoblasts (bone deposition)
- Osteoclasts (bone resorption)
Types of bone
- Woven (newly calcified, growing and healing)
- Lamellar (Compact & Spongy)
Medullary Cavity
Only place where there’s only compact bone
What happens in the medullary cavity?
Blood cells and platelets are formed
Periosteum
Fibrous connective tissue that covers bone
Perichondrium
The tissue that surrounds cartilage, except articular cartilage
Bone Classifications
- Long
- Short
- Flat
- Irregular
- Sesamoid
Long Bone
Tubular structures
Short Bone
- Cuboidal
- Found only in ankle and wrist
Flat Bone
Usually protective (cranium)
Irregular Bone
- Like those in the face
- Various shapes besides short, long, or flat
Sesamoid Bone
- Develops in certain tendons
- Protects tendons from excessive wear
- Changes the angle of the tendons
Condyle
Rounded articular area
Crest
Ridge of bone
Epicondyle
Eminence superior to a condyle
Facet
- Smooth, flat area, usually covered with cartilage
- Where 2 bones articulate
Forament
Passage through a bone
Fossa
Hollow or depressed area
Line (linea)
Linear elevation
Malleolus
Rounded prominence
Notch
Indentation at the edge of a bone
Process
Projecting spine-like part
Protuberance
Projection of bone
Spine
Thorn-like process
Trochanter
Large, blunt elecation
Tubercle
Small, raised eminence
Tuberosity
Large, rounded elevation
What does all bone originate from?
Mesenchyme
Processes for making bone
- Intramembranous ossification
- Endochondral ossification
Intramembranous ossification
Comes directly from mesenchyme
Endochondral ossification
Comes from cartilage derived from mesenchyme
How do long bones grow?
1) Mesenchymal cells –> chondroblasts
2) Chondroblasts form a cartilaginous bone model
3) Cartilage calcifies in the middle
4) Periosteal capillaries grow and form the periosteal bud
5) Capillaries initiate the primary ossification center
6) Diaphysis grows from the primary ossification center
Secondary ossification center
Epiphyses
Epiphyseal arteries
Grow into the developing cavities with associated osteogenic cells
Metaphysis
Flared part of the diaphysis nearest to the epiphysis
Epiphyseal plates
Cartilaginous section between the diaphysis and epiphysis
Epiphyseal line
Seam formed from the fusion of the epiphysis and diaphysis
Arterial supply of bone
- Nutrient arteries
- Periosteal arteries
- Metaphysial arteries
- Epiphysial arteries
Nutrient arteries
- Pass through the bone via nutrient foramina
- Splits in the medullary cavity into longitudinal branches
Periosteal arteries
Supplies most of the compact bone
Metaphysial/Epiphysial arteries
Supplies the ends of bone
Veins in the bone
Accompany arteries through nutrient foramina
Periosteal nerves
- Carries pain fibers
- Especially sensitive to tearing or tension
Vasomotor nerves in bones
Cause constriction or dilation of blood vessels
Joint
An articulation between 2+ rigid components
Types of joints
- Fibrous
- Cartilaginous
- Synovial
Fibrous joints
United by fibrous tissue
Types of fibrous joints
- Suture
- Syndesmosis
Suture Joints
Sutures in the cranium
Syndesmosis joints
Bones joined by an interosseous ligament or a sheet of fibrous tissue
Cartilaginous joints
Hyaline cartilage or fibrocartilage
Types of cartilaginous joints
- Synchondrosis
- Symphysis
Synchondrosis joints
- Primary cartilaginous joints
- Hyaline cartilage
- Allow growth of bone and allow slight bending during early life
Symphysis joints
- Fibrocartilage
- Strong, slightly mobile
- B/t vertebrae
Synovial joints
- Nourish the articular cartilage
- Lubricates articular surfaces
Types of synovial joints
- Plane/Gliding
- Hinge
- Saddle
- Condyloid
- Ball and socket
- Pivot
Types of connective tissue included in the skeletal system
- Dense regular connective tissue
- Cartilage
- Bone
- Adipose
Characteristics of connective tissue proper
- More fibers (type I collagen) than cells (fibroblasts)
- Binds cells and tissues into organs and organ systems
Types of ligaments
- Intrinsic, internal
- Intrinsic, external
- Extrinsic, internal
- Extrinsic, external
Intrinsic, internal ligaments
Thickenings of the joint capsule occurring internal to the capsule
Intrinsic, external ligaments
Sheets of connective tissue external to the capsule
Extrinsic, internal ligaments
Cordlike, separated from the capsule, inside the capsule
Extrinsic, external ligaments
Cordlike, separated from the capsule outside the capsule
Osteons
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