Ch. 6: Bones & Skeletal Tissues Flashcards
What are the functions of bones?
- Support - for body & soft organs
- Protection - protects brain, spinal cord, & vital organs
- Movement - levers for muscle action
- Mineral & growth factor storage - calcium & phosphorus & growth factors reservoir
- Blood Cell Formation - Hematopoiesis occurs in red marrow cavities of certain bones
- Triglyceride (fat) storage - fat, used for an energy source, is stored in bone cavities
How many bones are in the human skeleton?
206 bones
Describe the Axial Skeleton
- Long axis of body
- Skull, vertebral column, rib cage
Describe the Appendicular Skeleton
- Bones of upper & lower limbs
- Girdles attaching limbs to axial skeleton
What are the classification of bones?
- Long bones - longer than wide, limb bones
- Short bones - cube shaped (wrist & ankle), sesamoid bones form within tendons (ex. patella), vary in size & number in different individuals
- Flat bones - thin, flat, slightly curved, sternum, scapulae, ribs, most skull bones
- Irregular bones - complicated shapes, vertebrae & hip bones
Why are bones organs?
They contain different types of tissues
What types of tissue are present in bone?
Bone (osseous), nervous, cartilage, fibrous connective, muscle cells, epithelial cells (in blood vessels)
What are the 3 levels of structure?
- Gross
- Microscopic
- Chemical
Describe Compact Bone
Dense outer layer on every bone that appears smooth & solid
Describe Spongy Bone
Made up of a honeycomb of small, needle-like or flat pieces of bone (trabeculae)
What are the open spaces of spongy bone (trabeculae) filled with?
Red or yellow bone marrow
Describe the structure of short, irregular, & flat bones
- Consist of thin plates of spongy bone (dipole) covered by compact bone
- Compact bone between connective tissue membranes
- Bone marrow scattered throughout spongy bone (no defined marrow cavity)
Describe Periosteum
Covers outside of compact bone
Describe Endosteum
Covers inside portion of compact
Describe the parts of a long bone
- Diaphysis
- Epiphyses
- Metaphyses
- Articular cartilage
- Periosteum
- Medullary cavity
- Endosteum
What is the Diaphysis?
Bone shaft
What are the 2 Epiphyes?
Both ends of the bone at the joints
What are the 2 metaphyses?
Region between diaphysis & epiphysis
What is Articular Cartilage?
Covering both epiphyses
What is Periosteum?
Connective tissue surrounding the diaphysis
- White, double-layered membrane that covers external surfaces except joints
What is Medullary Cavity?
Hollow space within diaphysis
What is Endosteum?
Thin membrane lining the medullary cavity
- Delicate connective tissue membrane covering internal bone surface
- Covers trabeculae of spongy bone
- Lines canals that pass through compact bone
Where is Hematopoietic Tissue (red marrow) found in bones?
- Trabecular cavities of spongy bone
- Diploe of flat bones
- In newborns: medullary cavities & all spongy bone
- In adults: in heads of femur & humerus, active areas are flat bone diploe & some irregular bones
- Yellow marrow can convert to red if person is anemic
Define Tuberosity (site of muscle/ligament attachment)
Large rounded projection; may be roughened
Define Crest (site of muscle/ligament attachment)
Narrow ridge of bone; usually prominent
Define Trochanter (site of muscle/ligament attachment)
Very large, blunt, irregularly shaped process (on femur)
Define Line (site of muscle/ligament attachment)
Narrow ridge of bone; less prominent than a crest
Define Tubercle (site of muscle/ligament attachment)
Small rounded projection or process
Define Epicondyle (site of muscle/ligament attachment)
Raised area on or above a condyle
Define Spine (site of muscle/ligament attachment)
Sharp, slender, often pointed projection
Define Process (site of muscle/ligament attachment)
Any bony prominence
What are surfaces that help to form joints?
- Head: bony expansion carried on a narrow neck
- Facet: smooth, nearly flat articular (joint) surface
- Condyle: rounded articular projection; often articulates with a corresponding fossa
List the depressions & openings
- Groove: furrow
- Fissure: narrow, slitlike opening
- Foramen: round or oval opening through a bone
- Notch: indentation at the edge of a structure
- Meatus: canal-like passageway
- Sinus: cavity within a bone, filled with air & lined with mucous membrane
- Fossa: shallow, basin like depression in a bone, often serving as an articular surface
What does Microscopic Anatomy of Bones look at?
Cells of bone tissue
Define Osteogenic cells (osteoprogenitor cells)
Mitotically active stem cells in periosteum & endosteum
(from bone cell lineage)
Define Osteoblasts
Bone forming cells that secrete unmineralized bone matrix called osteoid
(from bone cell lineage)
Define Osteocytes
Mature bone cells in lacunae that no longer divide, maintain bone matrix and act as stress or strain sensors
(from bone cell lineage)
Define Osteoclasts
Derived from sane hematopoietic stem cells that become macrophages, giant multinucleate cells function in bone resorption (breakdown of bone)
(from bone WBC lineage)
Describe an Osteon (Haversian system)
- Osteon is the structural unit of compact bone
- Consists of an elongated cylinder that runs parallel to long axis of bone
- An osteon cylinder consists of several rings of bone matrix called lamellae
Describe Lamellae
- Contains collagen fibers that run in different directions in adjacent rings
- Withstands stress and resist twisting
- Bone salts are found between collagen fibers
What are the structures in osteon?
- Central (Haversian) canal: runs through core of osteon (contains blood vessels & nerve fibers)
- Perforating (Volkmann’s) canals: canals lined with endosteum that occur at right angles to central canal (connect blood vessels & nerves of periosteum, medullary cavity, and central canal)
- Lacunae: small cavities that contain osteocytes
- Canaliculi: hairlike canals that connect lacunae to each other & to central canal
Describe the microscopic anatomy of spongy bone?
- Appears poorly organized but is actually organized along lines of stress to help bone resist any stress
- Trabeculae: cables on a suspension bridge, confer strength to bone
- No osteons present, contains irregularly arranged lamellae & osteocytes interconnected by canaliculi
- Capillaries in endosteum supply nutrients
What are the organic components of bone?
- Osteogenic cells, osteoblasts, osteocytes, osteoclasts, & osteoid, sacrificial bond in/between collagen molecules
Describe an Osteoid
Makes up 1/3 of organic bone matrix; consists of ground substance & collagen fibers, which contribute to Hugh tensile strength & flexibility of bone
What causes Bone Resilience?
Sacrificial bonds in or between collagen muscles that stretch & break to dissipate energy and prevent fractures
What are the inorganic components of bone?
- Hydroxyapatites (mineral salts)
- Make up 65%-75% of bone by mass
- Consist mainly tiny calcium phosphate crystals in & around collagen fibers
- Responsible for hardness & resistance to compression
