skeletal system Flashcards
what does the skeletal system consist of?
bones and joints(articulations)
what are its functions?
protects/supports organs
mineral storage calcium and phosphate
blood cell synthesis in red bone marrow
framework for muscle attachment
what tissues does it consist of?
compact/cortical (strong/dense organized into osteons)
cancellous/spongy (network of trabeculae)
cartilage
what are the three types of cartilage?
elastic-forms external ear and epiglottis
fibrous- forms mensici and intervertebral discs
hyaline- forms nasal cartilages, respiratory cartilages, costal cartilages, covers ends of long bones
what are bone cells?
osteocytes
how is compact bone organized?
organized into units called osteons with central canals
containing blood vessels and nerves
osteocytes sit in lucanae within matrix
what is the matrix of bone organized into?
concentric rings (lamellae)
what are the lacunae connected by?
small canals called canaliculi
what is spongy bone?
osteocytes and trabeculae web-like network
light but strong
how many bones in adults vs children?
206 in adults and 300+ in infants before fusion
what are bones considered in the skeletal system?
organs
what are the four classifications of bones?
long bones- femur, humerous, tibia, fibula, ulna, phalanges
short bones- round/square tarsals carpels
flat bones- scapula, sternum, ribs, cranial bones
irregular bones- vertebrae, maxilla, mandible, ossicles
what are bones that form between tendons?
sesamoid bones eg the patella
what are bones between the cranial bones?
sutural/wormian bones
what does spongy bone contain and covered in?
covered in endoosteum and contains red bone marrow
what does red bone marrow do?
site of blood cell synthesis
what is the process describing bone growth?
osteogenisis or ossification
when does bone growth begin?
begins during embryonic development approx 8 weeks gestation
what regulates bone growth?
regulated by the growth horomone GH secreted by the pituitary gland
what are the bones first modelled in before growth?
fibrous membrane or hyaline cartilage
how does growth occur?
mineral matrix is deposited in tissue “calcification”
when does calcification cease?
early adulthood male-22 female-18 when the epiphyseal plates ossify
what are epiphyseal plates?
are regions at the ends of long bones where growth occurs when these plates ossify an epiphyseal line remains (no more growth possible)
what are osteoprogenitors/mesenchymal cells?
stem cells- differentiate into osteoblasts
located in endosteum and periosteum