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
Interstitial lamellae
Layers of mineralized matrix lying between and around osteons; the remains of partially destroyed osteons
Spongy bone
a. Found in the interior of a bone
b. Lattice/ network of bony bars and struts (i.e. trabeculae), each consisting of just a few concentric layers of bone tissue
- —Site of blood cell manufacture (RBC, WBC, Platelets)
Subchondral bone
a. Very thin layer of modified compact bone, lacking the extensive vascular channels
b. Found underlying articular cartilage, making up the articular/facet surface
Accessory bone
Abnormal bone growth from existing normal bone (e.g. bone spurs)
Heterotrophic bone
Abnormal bone, formed entirely within soft tissue (some types of kidney stones, gall stones, muscle or tendon calcifications)
Diaphysis
Body/shaft of the bone; primary center of ossification
Epiphysis
Often associated with area of articulation with another bone or site of excessive muscle tension
-Secondary center of ossification
Periosteum
Fibrous structure covering outer bone surface, except for articular bone surfaces and where tendons and ligaments attach onto the bone
a. Anchored onto outer bone surface by Sharperys fibers
b. Consists of a cellular and fibrous layer
Fibrous layer of Periosteum
Superficial; sheet of dense irregular connective tissue containing type I collagen fibers, plus fibroblasts, blood vessels and nerve fibers
Cellular layer of Periosteum
Deep; thin layer containing bone cells (primarily osteoprogenitor cells and osteoblasts)
Endosteum
Very thin connective tissue layer covering inner bone surfaces; primarily consists of a single layer of osteoprogenitor cells and osteoblasts
Medullary cavity (marrow cavity)
Cavity at the center of a long bone; in children, additional site of blood cell manufacture (red bone marrow), in adults, site of adipose storage (yellow bone marrow)
Articular cartilage
Covering articular surfaces; composed of hyaline cartilage
Wolff’s Law
A bone remodels its shape according to the way force is transmitted through it
Intramembranous bone (aka dermal)
Bones at the top of the skull- clavicle
Endochondral bone (aka cartilaginous)
Bones at the skull base + all postcranial bones, including part of the clavicle
Ontogenetic process in endochondral bone
a. Cartilaginous model forms (composed of hyaline cartilage)
b. Ossification begins
c. Further growth takes place along two pathways (interstitial and appositional)
Internal Ossification
a. Cartilage disintegrates and excavates interior of the bone
- Blood vessels invade, bringing undifferentiated mesenchymal cells
- -Mesenchymal cells differentiate into osteoprogenitor cells, then osteoblasts, which start forming spongy bone
External Ossification
- Periosteum forms
- -Osteoprogenitor cells within the cellular layer of the periosteum mature into osteoblasts
- –Osteoblasts start forming compact bone
Interstitial growth
- Between diaphysis and epiphysis
- -Blood vessels invade ends of bone as well, which become secondary centers of ossification
- Epiphyseal plate
- —Growth ceases when plate ossifies
Epiphyseal plate
Zone of hyaline cartilage remaining between primary and secondary ossification centers
-Site of active growth
Appositional growth
- Increase in overall size
- -New compact bone deposited by osteoblasts just below the periosteum
- –Osteoclasts at inner bone surface destroy bone tissue and enlarge the medullary cavity; remodel compact bone/spongy bone interface
- —Growth ceases when interstitial growth ceases
Ontogenetic process in intramembranous bone
- Membranous layer forms around blood vessels
- Undifferentiated connective tissue cells around blood vessels differentiate into osteoprogenitor cells, then osteoblasts, which start forming spongy bone
- Periosteum forms; cells within the cellular layer differentiate into osteoprogenitor cells, then osteoblasts, which start forming compact bone below periosteum
- Remaining growth takes place via mechanism similar to appositional growth
- Process ends concurrently with endochondral growth
Vitamin C
-Necessary for proper collagen formation
–Deficiency leads to scurvy
Without this % of fractures increase due to thinning of bone
Vitamin D
Synthesized within the skin of ingested as part of diet
- Facilitates proper bone mineralization by increasing absorption of calcium within the small intestine and reabsorption of calcium in the kidneys
- –Deficiency leads to rickets (in children) and osteomalacia (in adults)
Parathyroid Hormone
- Increases amount of calcium in blood by indirectly stimulating osteoclast activity
a. Binds to receptors on the osteoblasts, which then release osteoprotegerin ligand (OPGL)
b. OPGL activates receptors on preosteoclast cells, which causes them to mature into osteoclasts
c. These osteoclasts start breaking down bone tissue - -Excess amount of this leads to bone thinning (increase likelihood of fractures)
Pituitary growth hormone (GH)
- Excess growth of hormone in children leads to giantism; in adults to acromegaly
- -Deficit of growth hormone in children leads to dwarfism
Acromegaly
- Too much GH in adults
- Leads to increase in the size of the nose and chin
Giantism
-Too much GH in children
-Blood isn’t able to efficiently travel upwards of 7 feet
Increased length of growth period and increase in rate of growth
Osteitis
Inflammation of bone tissue caused by injury or infection
Healing of fracture
- Fracture hematoma formed from ruptured blood vessels
- Soft callus (mixture of spongy bone and fibrocartilage)
- Hard callus forms by mineralization and remodeling of soft callus
- Remodeling of hard callus to mature (compact and spongy) bone—Spongy on inside, compact on outside
- –Will form a permanent scar in the bone where the fracture took place
Greenstick fracture
- Only seen in children
- -Bow and fracture on convex side of bone
- –Bone basically bends and then breaks
Comminuted fracture
- fragmented fracture
- -Complex healing process
Compression fracture
- Collapsed vertebral body
- -Trauma or weakness of bone from specific disease
Periostitis
Inflammation of perisoteum caused by a trauma or infection
–occurs on the exterior of the bone or on the compact bone
Osteomyelitis
Inflammation of bone interior caused by bacteria, usually initially entering the bone via wound or via bloodstream
–Looks like someone drilled a hole into the bone
Tuberculosis
Can spread to the spongy bone (particularly of the vertebral bodies [Pott’s disease]), resulting in bone and joint destruction
Neoplasms
- Benign tumor
- Malignant tumor
Benign tumors
- Osteochondroma
2. Osteoma
Malignant tumors
- Osteogenic sarcoma (osteosarcoma)
2. Multiple myeloma
Aging
- Repair/healing process is slowed
- Osteoporosis occurs
Osteoporosis
- A significant reduction in bone density due to deossification
- –Part of the aging process; also can result from hypothyroidism, hyperparathyroidism, prolonged vitamin C deficiency
- —Most prevalent in older women- women have less bone mass than men
- Women lose bone mass sooner and faster than men
Synarthrosis
Immoveable, None
“Nuns dont syn”
Amphiarthrosis
Slightly Moveable
“Turn that amp down”
Diarthrosis
Freely Moveable
“Live free Die Hard”
Structure of Joint (3 layers)
- Fibrous
- Cartilaginous
- Synovial
Fibrous
-Bones fastened together by thin layers of fibrous (i.e dense) connective tissue 3 types 1. Syndesmosis 2. Suture 3. Gomphosis
Syndesmosis
i. Bones joined by a fibrous band which forms and ‘interosseous ligament’
ii. Movement classification= amphiarthosis
Suture
- Only between some bones of the skull
- Strap of dense regular connective tissue
i. Bones joined by a very short fibrous band which forms a ‘sutural ligament’
ii. Movement classification= Synarthrosis
Gomphosis
i. Articulation between tooth root and alveolus (bony socket) ; consists of a very short fibrous band which forms a ‘periodontal ligament’
ii. Movement: Synarthrosis
