Chapter 6 Flashcards
Skeletal system
°bones
°joints
°supporting tissue
Bones are?
Organs of the skeletal system made of osseous tissue and dense regular & irregular CT, and bone marrow
Functions of the skeletal system
(6 functions)
°Protect
°storage
°red blood cell formation
°fat storage
°movement
°support
Functions of the skeletal system
Protect
To Protect vital organs
Functions of the skeletal system
Storage
Mineral storage and acid base homeostasis
Functions of the skeletal system
Red blood cell production
Produce red-blood cells in the red bone marrow (hemopoiesis)
Functions of the skeletal system
Fat storage
Storeing fat in the yellow bone marrow (medullary cavity)
Functions of the skeletal system
Movement
Muscles attach to bone to create movement
Functions of the skeletal system
Support
Supports the weight of the body and its structural framework
Shapes of bones:
(5 of them)
°long bones
°short bones
°flat bones
°irregular bones
°sesamoid bones
Shapes of bones:
long bones
°long and skinny
°most bones in arms and legs
Shapes of bones:
short bones
°roughly cube shaped
° carpals and tarsals
Shapes of bones:
flat bones
°thin and broad
°ribs, pelvis, sternum, and flat bones of skull
Shapes of bones:
Irregular bones
Vertebrae and certain skull bones
Shapes of bones: sesamoid bones
°located within tendons
°patella (kneecap)
Bone structure of long bone
°Diaphysis (shaft)
°Epiphysis (ends)
°Marrow cavity (contains bone marrow)
Compact bone
°hard, dense outer region
(found in diaphysis)
°allows bones to resist stress (compression and twisting)
Spongy bone
(Cancellous)
°found inside the epiphysis
°resist forces from many directions
°honeycomb like frame work
Epiphyseal lines
° Separates epiphysis from diaphysis
°remnants of epiphyseal plates
Epiphyseal plate
(Growth plates)
Hyaline cartilage found in developing bones of children
Extracellular matrix of the bone is made up of?
Inorganic matrix and organic matrix.
Extracellular Matrix of bone:
Inorganic matrix
65%
Consisting of minerals
(makes bones hard)
Hydroxyapatite salts of Ca & P
Extracellular Matrix of bone:
Organic matrix
35%
Osteoid
Consist of collagen fibers and usually ECM. (Gives flexibility)
Bone cells:
(4 of them)
°osteogenic
(differentiate into osteoblast)
°osteoblast
Bone building
°osteocytes
Mature bone cells in lacunae
°osteoclasts
Bone resorption
Secrete enzymes and acids
Structure of compact bone:
Osteon
(haversian system)
°lamellae (rings)
°central canal
(blood vessels and nerves)
°lacunae (space of osteocytes)
°canaliculi (little canals)
°volkmans canal
(blood vessels and nerves that go perpendicular to central canals)
Structure of spongy bone
°not wt. Bearing
°not organized into osteons
°trabeculae
Ossification (osteogensis)
° Process of bone formation.
° Begins in embryonic period and continues throughout adulthood.
Intramembranous ossificatio
°forms many flat bones
(bones of skull and clavicles)
°formed within a mesenchymal membrane
Spongy bone ossifies before outer compact bone layers
°forms primary ossification center
°Fotanels areas of incomplete Intramembranous ossification
Endochondral ossification
°Bone development for all bones below head except Clavicles
°Many bones complete ossification by age 7
Endochondral ossification
°bones begin within hyaline Cartilage template
°Hyaline cartilage model made of chondrocytes, collagen and ECM surrounded by CT perichondrium
°Cartilage breaks down
°Collar formation (periosteum )
°primary ossification center mid-diaphysis
°secondary ossification centers at epiphy seal ends
°Most bones of skeleton formed this way.
Appositional growth
Bone growth in width
Growth hormone (GH)
°secreted by anterior pituitary gland
°enhances protein synthesis and cell division in most all tissues, including bone
Testosterone
°pronounced effect on bone growth:
- Increases appositional growth in males
- Increases rate of mitosis in epiphyseal plate; leads to “growth spurts “ in teenage
Estrogen also plays a role in bone growth:
⁃ Increases the rate of longitudinal growth and inhibits osteoclasts
°Accelerates closure of epiphyseal plate at a much faster rate than testosterone
> average height differences between genders
Bone remodeling
new bone is formed by bone deposition, and old bone is removed by bone resorption
°Maintenance Replacement of calcium ion homeostasis
°Adaptation to tension and stress
°Adaptation to tension n stress
PTH (parathyroid hormone from parathyroid gland)
°stimulates effects that increase blood Ca+2 levels
° Increases osteoclast activity
○ Increases absorption of calcium from gut
o Inhibits calcium /oss in urine
Calcitonin (from thyroid gland)
°causes decreased blood Ca+2 levels
o Inhibits osteoclasts
○ Increases calcium loss in urine
Fractures:
°Simple
°compound
°spiral
°compression
°comminuted
°avulsion
°greenstick
°epiphyseal plate
Fractures:
Simple
Break inside body
Fractures:
Compound
Bone breaks skin
Fractures:
Spiral
Break in twisting factor
Fractures:
Compression
Force breaks or impact breaks bone
Fractures:
Comminuted
Shattered bone
Fractures:
Avulsion
Piece of bone breaks off the bone
Fractures:
Greenstick
Bone doesn’t break all the way through, most common in children because bones are soft and flexible
Fractures:
Epiphyseal plate
Cartilage breaks (most common in children)
