Phys Exam 2 Flashcards
Function of Skeletal muscle
a. Provides structure, support, and protection
b. Essential for locomotion and movement
c. Site of blood cell formation
d. Storehouse for some inorganic minerals, especially calcium
e. Indicator of sex, age, height, weight, racial background, and sometimes medical history
Long bones
a. Longer than wide, cylindrical with a medullary cavity
b. Main components of limbs
- Humerus, radius, ulna, femur, tibia, fibula, metacarpals, metatarsals, phalanges)
Short bones
a. Roughly cubical (carpals and tarsals)
b. Found where mobility is needed, but space is limited
Flat bones
a. Relatively thin bones (very thin on the inside)
b. Provide broad surfaces for muscle attachment and/or protection of underlying organs
- Ribs, frontal, parietal, innominate, scapula
c. Main site of blood cell formation in adults
Irregular bones
a. Irregular shape with numerous projections
- Vertebrae, some bones of the skull (sphenoid, ethmoid, scapula)
Pneumatic bones
a. Containing sizable air spaces; only found in some bones of the skull (e.g. frontal, maxilla, sphenoid, ethmoid, temporal (mastoid process))
b. Reduces weight of the skull, thus reducing the need for large neck muscles
Sesamoid bones
a. Small round bones embedded within a tendon (e.g., patella and sesamoids of the hands and feet)
b. Alter the angle of a muscle attachment to increase mechanical leverage
- Facilitates easier movement of the knee
Axial skeleton
Bones of the skull, hyoid, vertebral column, and rib cage
Appendicular skeleton
Bones of the limbs and their attachment onto the axial skeleton (i.e. pectoral and pelvic girdles (excluding the sacrum))
Cranial skeleton
Bones of the skull
Post-cranial skeleton
Bones of the vertebral column, hyoid, rib cage, limbs, pectoral girdle, and pelvic girdle
What are the two parts of the bone tissue matrix?
- Fibers
2. Ground substance
Fibers of Bone tissue
-Primarily made up of type I collagen fibers, which provide strength to resist tensile forces
What are the two parts of the ground substance in bone tissue?
- Organic Component
- Inorganic component
Organic component of ground substance of bone tissue
-Composed of proteogylcans (chondroitin sulfate, keratan sulfate, and hyaluronic acid) and Glycoproteins (especially osteonectin and osteocalcin)
Inorganic component of ground substance of bone tissue
-Hydroxyapatite, a calcium mineral composite, which provides strength to resist compressive forces (not very good at twisting resistance)
What are the types of bone cells?
a. Osteoprogenitor cells
b. Osteoblasts
c. Osteocytes
d. Osteoclasts
Osteoprogenitor cells
- Give rise to osteoblasts
- Located within the central and perforating canals of osteons and within the periosteum (cellular layer) and endosteum
Osteoblasts
- Lay down the new bone tissue
- -Located within the central and perforating canals of osteons and within the periosteum (cellular layer) and endosteum
- –Originate from osteoprogenitor cells
Osteocytes
- Former osteoblasts, located within the lacunae of the osteons of compact bone and bony struts of spongy bone
- -Maintain surrounding bone tissue and regulate mineral content
- –Never make brain tissue
Osteoclasts
- Bone destroying cells
- -Cells are large and multinucleated, originating from the fusion of several monocytes
- –Located wherever they are needed
- —Have different origins and functions
Primary bone tissue
a. Develops first, during fetal development
b. Also associated with repair of fractures
c. Collagen fibers are more randomly arranged; mineral content is lower; contains more osteocytes than found in mature/secondary bone tissue
–Immature and tend to have lower mineral content
aka Woven bone
Secondary bone tissue
a. Compact (cortical) bone
b. Spongy bone
c. Subchondral bone
Compact bone (cortical)
-Outer layer of densely packed bone tissue, composed of osteons (Haversian systems), circumferential lamellae, and interstitial lamellae
Contents of Osteons
a. Lamellae
b. Central canal (Osteonic or Haversian)
c. Lacunae
d. Canaliculi
e. Perforating canals (Communicating or Volkmanns)
Lamellae
Concentric layers of bone tissue; within each layer, the collagen fibers are oriented at right angles in the adjacent layers
Central (osteonic or Haversian) canal
Contains vascular structures and nerves; lined by osteoprogenitor cells and osteoblasts
Lacunae
Holes found between lamellae
-osteocytes located inside of these spaces
Canaliculi
Passageways connecting lacunae to each other and to the central and perforating canals
Perforating (communicating or Volkmann’s) canals
Connecting central canals to each other; lined by osteoprogenitor cells and osteoblasts
Circumferential lamellae
Multiple layers of mineralized matrix made up of internal and external parts
External circumferential lamellae
Located immediately deep to the periosteum
Inner circumferential lamaellae
Located at the perimeter of the medullary cavity