2.1: Intro to the Skeletal System Flashcards
chemical level
atom and molecular level
cellular level
smallest living unit of the body
tissue level
group of cells and the materials surrounding them that work together on one task
organ level
grouping of two or more tissue types into a recognizable structure with a specific function
organ system level
collection of related with a common function (sometimes an organ is part of more than one system)
organismal level
a living individual
skeletal system includes
bones, cartilage, and ligaments
skeletal system major functions
support, protection, movement, storage mineral (calcium bank), blood cell production (makes all sorts of blood cells), fat storage (bones are full of fat, yellow marrow=fat)
each bone is an organ
contains bone connective tissue, blood vessels nerves, lymph vessels, cartilage, connective tissue covering
skeletal system - cartilage
- precursor to bone, protect while more flexible than bone
- hyaline: ex-articular, costal, respiratory, nasal
–> cushion for bones, so not bone on bone - elastic: ex-external ear and epiglottis
–> always flexibility
-fibrocartilage: ex-meniscus, between vertebrae
–>found where you need a lot of cushioning
axial skeleton
- creates the longitudinal (long) axis of the body
- houses vital organs
- 80 bones:
skull (22), vertebral column (26), hyoid (1), thoracic cage (25), and auditory ossicles (6)
appendicular skeleton
- appendages (arms & legs) + girdles (shoulders & hips)
- connects to axial
- much greater mobility
- 126 bones:
pectoral girdle (4), pelvic girdle (2), upper limbs (60), and lower limbs (60)
long
longer than wide
ex: humerus, femur, toes
short
roughly cube shaped
ex: most wrist and ankle bones
flat
thin, flattened, curved
ex: ribs, sternum, cranial bones
irregular
complex shapes
ex: vertebrae, hyoid
Sesamoid
shape like a sesame seed
form at points of high friction
ex: patella, hands, feet
Sutural
formed between cranial bones vary between individuals
compact bone
AKA dense bone
forms outer layer of most bones
-provides most structures/support, heavier
spongy bone
AKA trabecular bone
surrounds inner cavity (medullary cavity)
-lighter still provides support and resisting mechanical stress
short, irregular, and flat bone
- sandwich of compact bone –> spongy bone –> compact bone
- diploe: layer of spongy bone in cranial bones
gross anatomy - long bones
- epiphysis: end
- diaphysis: middle
- metaphysis: connects epiphyses to diaphysis epiphyseal line/plate
gross anatomy - long bones layers from superficial to deep
- periosteum: not bone, connective tissue wrapping, nervous/blood vessels come/leave
- compact bone
- spongy bone
- endosteum: inside
- medullary cavity: marrow-found in the hole
connective tissue - periosteum
- covers outer surface of living bone
- functions: *isolates and protects bone
*support blood vessels and nerves
*connects to other tissues: fibrous layer- interwoven collagen fibers with either deep fascia or bone (perforating fibers)
*growth and repair: osteogenic layer - contains osteogenic cells (bone stem cells)
connective tissue - endosteum
- reticular connective tissue
- lines medullary cavity and covers spongy bone surface
- contains osteogenic (osteoprogenitor) cells
(important for bone growth and remodeling)
skeletal blood supply
very vascular tissue
- extensive network of blood vessels:
*run through periosteum and enter diaphysis via nutrient foramina
*nutrient artery and vein -medullary cavity
*metaphyseal vessels
*epiphyseal vessels
*periosteal vessels
skeletal innervation
- sensory neurons throughout periosteum
- enter cortex through nutrient foramen to innervate: endosteum, medullary cavity, epiphyses
