Skeletal System Flashcards
how many bones does the adult skeleton have?
206
functions of bones
- support
- protection
- movement
- storage
- blood cell formation
What is stored in the bones
mainly calcium and phosphorous
hematopoiesis
- AKA blood cell formation
- occurs w/ in marrow cavities of certain bones
parts of skeleton
- axial
- appendicular
makes up axial
- skull
- vertebral column
- bony thorax
makes up appendicular
- limbs
- pectoral girdle
- pelvic girdle
types of osseous tissue
- compact
- spongy
compact bone
- dense
- looks smooth and homogeneous
- contains nerves and blood vessels (supply nutrients)
- has osteocytes
- lacunae arranged in lamellae around haversian canal
- contains canaliculi
- contains volkmann’s canals
spongy bone
- small needlelike pieces of bone
- lots of open space
osteocytes
-mature bone cells located inside lacunae
lacunae
-tiny, matrix-filled cavities that hold osteocytes
lamellae
concrete circles that surround a haversian canal
haversian canal
-central canal in the middle of compact bone
osteon
- each central canal and matrix ring
- AKA Haversian system
canaliculi
- tiny canals, connecting all bone cells to nutrient supply through hard bone matrix
- in compact bone
volkmann’s perforating canals
-run into compact bone at right angles to the shaft
Types of bones
- long
- flat
- short
- irregular
long bones
- usually longer than wide
- composed of shaft w/ heads at both ends
- mostly compact
- example: all limbs except wrist and ankle
short bones
- cube-shaped
- mostly spongy bone
- example: wrist and ankle bones, sesamoid bones
sesamoid bones
form with tendons
- example: patella
flat bones
- thin, flattened, usually curved
- made up of 2 thin layers of compact bone w/ layer of spongy bone in between
- example: skull bones, ribs, sternum
irregular bones
- don’t fit other categories
- example: vertebrae, hip bones
long bone structure
- diaphysis makes up most of bone’s length
- covered & protected by periosteum
- epiphyses
- articular cartilage covers external surface of epiphyses
- epiphyseal line (adults)
- yellow marrow makes up cavity of diaphysis
- red marrow in diaphysis of infants