Bones Flashcards
Sub-divisions of the Skeleton
- Axial Skeleton (Skull, Vertebrae, Rib Cage)
- Appendicular Skeleton (Everything that comes off of the Axis)
Functions of Bones
- Support the body
- Protect soft organs
- Allow movement due to attached skeletal muscles
- Store minerals and fats
- Blood cell formation-Hemopoiesis (B12 is a vitamin)
- Found in bone: Calcium and Phosphorus
Bones of the Human Body
- Adult has 206 bones
- Two basic types of bone tissue
- Compact bone
- Homogeneous
- Spongy Bone (cancellous)
- Small needle-like pieces of bone (trabecule)
- Many open spaces
- Compact bone
- Two basic types of bone tissue
Classifications of Bone
- Long bone
- Short bone
- Flat bone
- Irregular bone
Long Bones
-Typically longer than they are wide
-Have a shaft w/ heads on both ends
-Contains mostly compact bone
Ex: Femur, Humerus
Short Bone
- Generally cube-shape
- Contain mostly spongy bone
- Ex: Carpals, Tarsals
Flat Bones
-Thinned, flattened, and usually curved
-Two thin layers of compact bone surround a layer of spongy bone
Ex: Skull, ribs, sternum
Irregular Bones
- Irregular shape
- Do not fit into other bone classification categories
- Ex: Vertebrae, Hip bones
Diaphysis (Anatomy of Long Bone)
- Shaft
- Composed of compact bone (support and protection)
Epiphysis (Anatomy of Long Bone)
- Ends of the bone
- Composed mostly of spongy bone (helps produce blood)
Periosteum
- Outside coving of the diaphysis
- Fibrous connective tissue membrane
Sharpey’s Fibers (Anatomy of Long Bone)
-Secure periosteum to underlying bone
Arteries (Anatomy of a Long Bone)
-Supply bone cells with nutrients
Articular Cartilage (Anatomy of a Long Bone)
- Covers the external surface of the epiphyses
- Made of hyaline cartilage (tough, smooth, shiny)
- Decreases friction at joint surfaces
Epiphyseal Plate (Anatomy of Long Bone)
-Flat plate of hyaline cartilage seen in young, growing bone
Epiphyseal Line (Anatomy of Lone Bone)
- Remnant of the epiphyseal plate
- Seen in adult bone
Medullary Cavity
- Prevents it from being too compact & brittle
- Support and Storage
- Cavity inside the shaft
- Contains yellow marrow (mostly fat) in adults
- Contains red marrow (for blood cell formation) in infants
Endosteum (Anatomy of Long Bone)
-Lining of the Medullary Cavity
Surface Features of Bone
- Sites of attachments for muscles, tendons, and ligaments
- Passages for nerves and blood vessels
Categories of Bone Markings
- Projections or processes– grow out from the bone surface
- Depressions or cavities—- indentations
Osteon (Haversian System)
- Microscopic Anatomy of Bone
- A unit of bone containing central canal and matrix rings
Central (Haversian) Canal
- Microscopic Anatomy of Bone
- Opening in the center of osteon
- Carries blood vessels and nerves
Perforating (Volkman’s) Canal
- Microscopic Anatomy of Bone
- Canal perpendicular to the central canal
- Carries blood vessels and nerves
Lacunae
- Microscopic anatomy of Bone
- Cavities containing bone cells (osteocytes)
- Arranged in concentric rings
Lamellae
- Microscopic Anatomy of Bone
- Rings around the central canal
- Sites of lacunae
Canaliculi
- Microscopic Anatomy of Bone
- Tiny canals
- Radiate from the central canal to lacunae
- Form a transport system connecting all bone cells to a nutrient supply
Formation of Human Skeleton
- In embryos, the skeleton is primarily hyaline cartilage
- During development, much of this cartilage is replaced by bone
- Cartilage remains in isolated areas
- Bridge of the nose
- Parts of ribs
- Joints
Zygote–> Blastola —> Embryo–> Fetus
Bone Growth (Ossification)
- Epiphyseal plates allow for lengthwise growth of long bones during childhood
- New cartilage is continuously formed
- Older cartilage becomes ossified
- Cartilage is broken down
- Enclosed cartilage is digested away, opening up a medullary cavity
- Bone replaces cartilage through the action of osteoblasts
Bones and Growth
- Remodeled and lengthened until growth stops
- Bones are remodeled in response to two factors
- Blood calcium levels
- Pull of gravity and muscles on the skeleton- Bones grow in width (called appositional growth)
Endochondral Ossification vs Intramembranosus Ossification
EO: Replacing cartilage to make bone longer
IO: Filling in a membrane, wider but kept flat (ex top of babies head)
Type of Bone Cells
- Osteocytes- Mature bone cells
- Osteoblasts- Bone forming cells
- Osteoclasts- Bone destroying cells
- Break down bone matrix for remodeling and release of calcium in response to parathyroid hormone
- Bone remodeling is preformed by both osteoblasts and osteoclasts
Joints
- Articulations of bones
- Functions of joints
- Hold bones together
- Allow for mobility
- Ways joints are classified
- Functionally
- Structurally
Functional Classifications of Joints
- Synarthroses
- Immovable- Amphiarthroses
- Slightly movable joints
- Diathroses
- Freely movable joints
- Amphiarthroses
Structural Classifications of Joints
Fibrous joints
-Generally immovable
Cartilaginous joints
-Immovable or slightly movable
Synovial joints
-Freely moveableFibrous Joints
-Bones united by fibrous tissue
Example:
-Sutures - cranium and face bones except mandible
-Syndesmoses
-Allows more movement than sutures
-Example: distal end of tibia and fibula
Cartilaginous Joints
- Bones connected by cartilage
- Example:
- Pubic symphysis
- Intervertebral joints
Synovial Joints
- Articulating bones are separated by a joint cavity
- Synovial fluid is found in the joint cavity - lubrication, shock absorber, transportation, regulate temperature
Features of Synovial Joints
- Articular cartilage (hyaline cartilage) covers the ends of bones
- A fibrous articular capsule encloses joint surfaces
- A joint cavity is filled with synovial fluid
- Ligaments reinforce the joint
Structures associated with Synovial Joints
- Bursae - flattened fibrous sacs
- Lined with synovial membranes
- Filled with synovial fluid
- Not actually part of the joint
- Tendon sheath
- Elongated bursa that wraps about a tendon
Inflammatory Conditions Associated with Joints
-Bursitis - inflammation of a bursa usually caused by a blow or friction
-Tendonitis - inflammation of tendon sheaths
-Arthritis - inflammatory or degenerative diseases of joints
Over 100 different types
-The most widespread crippling disease in the United States
Parts of the Skeletal System
- Bones (skeleton)
- Joints
- Cartilages
- Ligaments (Bone to Bone Joint)
