Ch5,6,7,8 Flashcards
Functions of the skeletal system
Support Storage of minerals and lipids Blood cell production (yellow or red bone marrow) Protection Leverage
Outer lining
Periosteum
Endosteum
Inner lining
Sutural bones
Bones that form within a suture
Sesamoid bones
Bones that form in places of stress
Bone structure
Two types of bone
- Compact bone (dense)
- Spongy bone (cancellous) hard and rigid different structure ``1
A typical long bone includes
-Diaphysis
-Epiphyses
-Metaphysis
-Articular cartilage
-Marrow cavity
Filled with red or yellow marrow
Epiphyses
Epi= means on top of
Located at the top ends of long bones (both top and bottom)
Epiphyses. X————————————-X Epiphyses
Metaphyses
These are located directly under epiphyses on the top and bottom ends of the long bone
Epiphyses (metaphyses) X—————————X Epiphyses (metaphyses)
Marrow cavity
Located in the shaft middle area of long bones
Yellow marrow= fats and lipids
Red marrow=RBC
Articular
Joint
Articular cartilage
Thin cartilage found on the Epiphyses of bones
Prevents rubbing of bones
Osseous Tissue
Supporting tissue with a solid matrix
-Crystals of hydroxyapatite (calcium salt)
Minerals deposited in lamellae (layers of matrix)
-covered by periosteum (thin membranous sheet cove
Matrix of bones (ground substance and fibers/ what cells are suspended in)
Calcium (extremely brittle)
Collagen (very elastic and rubbery)
Combination very strong compared to concrete
Central canal
Area in bone where artery and vein are that are going to nourish the bone
Osteocyte
-mature bone cell Accounts for the majority of bone cells DO NOT DIVIDE -maintain the protein and mineral content of the matrix (KEEPS bone strong firm and rigid ) Lives in a house lacuna
Lacunae
Means little house
Pocket in the bone matrix where osteocytes reside
Canaliculi
Canals or highways that lead from one osteocyte to another
Cytoplasmic extension of osteocytes (like tentacles) that attach them to each other and to the central canal
Lamellae
Osteocytes form ring like patterns in the matrix
These rings are called lamellae (layers of matrix)
Osteon
Unit of compact bone that includes Osteocyte Lacunae Canaliculi Lamellae Central canal Matrix
Compact bone
Made up of osteons (basic unit)
- osteocytes are arranged around a central canal (where central artery and vein located)
- perforating canals extend between adjacent osteons
- compact bone located where stresses are limited in direction (on the outside, really great at handling weight)
Osteocytes
Mature bone cells in lacunae
Connected by canaliculi
Osteoblasts
Synthesize new matrix
- Osteogensis (process of creating new bone or matrix) or heal fracture
- immature bone cell
Osteoclasts
Dissolve bone matrix
-osteolysis
This is very important
Osteoprogenitor cells
Differentiate into osteoblasts
Important in bone repair
Spongy bone
On interior of bone
- spongy bone located where stresses are weaker or multidirectional (really tough, can take weight and stress) so porous makes bone light ( so we dont have to carry a ton of weight around)
- Contains trabeculae ( looks like coral reef or branches of tree or sponge)
Bones are
Covered by periosteum (thin membranous sheet)
-lined by enosteum (incomplete lining inside the marrow cavity)
Ossification
Converting other tissues into bone
Two types
1.intra-membranous (inter-utero fetal development, dermal bones, bones of skull)
2.endochondral ossification
Calcification
Depositing calcium salts within the tissues
Endochondral ossification
-cartilage model gradually replaced by bone at metaphysis (right under ephysis end of bone so its the middle)
-increasing bone length
-timing of epiphyseal closure differs
-appositional growth increases bone diameter
Production of the rest of the skeleton
Starts with hyline cartilage
Epiphyseal cartilage
GROWTH PLATE
Timing of closure or completely ossifies growth ends
Bone is continually changing
-remodeling
-exercise (increases bone mass)
-hormone levels (also increase bone mass)
Growth hormone and thyroxine bone mass
-calcitonin (lowers blood Calcium) and PTH (parathyroid calcium increases calcium) control blood calcium levels
The skeleton in a calcium reserve
- 99%of the bodys calcium is in the skeleton
- Calcium ion concentration maintained by the bones, GI tract, and kidneys (if too low gi tract will absorb more instead of letting it go, kidneys will hold on instead of urinating it out, bones will disolve releasing it into the blood.) if too high the bones with store excess.
- Calcitonin and PTH regulate blood calcium levels
- PTH increases blood calcium levels
Bone fracture repair 3 step process
- Fracture hematoma = (extensive bleeding occurs, large blood clot forms and fracture hematoma develops)
- Internal callus : an internal callus forms as a network of spongy bone unites the inner surfaces, and an external callus of cartilage and bone stabilizes the outer edges.
- External callus: the cartilage of the external callus has been replaced by bone, and struts of spongy bone now unite the broken ends. Fragments of dead bine and the areas closest to the break have been removed and replaced.
- Remodeling occurs
Bone markings
Are characteristics for each bone and each individual Markings include -elevations -projections -depressions (valleys) -grooves and tunnels
Osteopenia
Is inadequate ossefaction or reduction in bone mass because osteoblasts activity declines
Osteoporosis
Loss of spongy bone mass
Over the age of 49, 25% of women will be diagnosed
Axial skeleton (axis =center or core)
SKULL
Auditory ossicles and hyoid bone
Vertebral column
Thoracic cage (rib cage)
Appendicular skeleton (appendages)
Pectoral and pelvic girdles
Upper and lower limbs
Skull
Frontal paritial occipital temporal ethmoid nasal lacrimal zygomatic maxillary vomer
Vertebral column
Vertebrae, sacrum, coccyx
- 7cervical vertebrae
- 12 thoracic vertebrae
- 5 lumbar vertebrae
- sacrum and coccyx are fused vertebrae
Four spinal curves
Primary (accommodation) curves= thoracic and sacral ; late in fetal development
Secondary (compensation) curves= lumbar and cervical ;appear several months after birth
Kyphosis
Hunch back
Abnormal curvature at the top of the thoracic spine
Normally in elderly osteoporosis loss of spongy bone mass , sometimes in children
Lordosis
Abnormal curvature of lower (lumbar) spine.
Caused in differences in thickness of intervertebral disc spacing, pregnancy, excessive weight gain
Scoliosis
Sway back like an S in the spine, exaggerated lateral curvature. Higher rates in women.
Sacrum
Protects reproductive, digestive and urinary organs
Articulates with pelvic girdle and fused elements of coccyx
Appendicular skeleton
- upper and lower limbs
- pectoral and pelvic girdle
Pectoral girdle (shoulder girdle)
- articulates (joins where two bones join) the upper limbs with the trunk
- consists of clavicle and scapula
Clavicle and scapula
- position shoulder joint
- help move upper limb
- provide a base for muscle attachment (back of scapula is flat and allows for attachment)
Humerous
-articulates with the radius and ulna
Forms elbow joint
Carpal bones and hand
-carpus forms wrist
-two rows of short bones
-distal row articulates with metacarpals
-pollex (thumb) has two
#ed from 1-5, 1 will always be the thumb and 5 will always be the pinky
Pelvic girdle and lower limbs
- more massive than the pectoral girdle
- consists of two os coxae
- fusion of ilium, ischium, and pubis
Ilium
Largest hip bone
- within acetabulum, fused to the ischium (posteriorly) and the pubis (anteriorly)
- pubic symphysis limits left to right
The lower limbs
-femur longest bone in the body
-articulates with tibia at the knee
Patella is a large sesamoid bone
-fibula parallels tibia laterally
TARSUS (FOOT)
- 7 tarsal bones
- pattern of metatarsal bones and phalanges parallels that of the hand
- all toes have three phalanges except the hallux (two phalanges)
Ankle and arches
- when standing, most of the weight of the body is transferred from the talus to the calcaneous
- rest os passed onto the metatarsals
- weight transfer occurs along longitudinal arch
- transverse arch