Chapter 7 Flashcards
What are the functions of the 💀?
- 💉 formation
- acid-base balance
- electrolyte balance
- protection
- movement
- support
What is the💀 system made of?
- 🦴
- cartilage
- ligaments
What are long 🦴?
- most important 🦴 for movement
* rigid levers acted on by 💪🏼 for movement (like crowbars)
What are some examples of long 🦴?
- humerus
- radius
- ulna
- femur
- tibia
- fibula
- metacarpals
- metatarsals
- phalanges
What covers joint surfaces in nature skeleton?
cartilage
What holds bones together?
ligaments
What attaches muscles to bones?
Hint: similar to ligaments
tendons
Where is spongy (cancellous) 🦴 found?
- inside ends of long 🦴
- inside compact 🦴 of long 🦴 shaft
- middle of most flat/irregular/short 🦴
How is the skeleton divided between compact & spongy 🦴?
- 3/4 compact
* 1/4 spongy
What’s the general anatomy of long 🦴?
- outer shell = dense white osseous tissue AKA compact (dense) bone
- shell around medullary cavity AKA marrow cavity
- ends of bone filled w/spongy (cancellous) tissue
- diaphysis = shaft (middle); leverage
- epiphysis = head (ends); strengthens joints & adds room for tendons/ligaments to attach
What is a joint surface?
What’s it covered with?
What’s the purpose of this covering?
- where 🦴 meet
- articular cartilage
- works w/lubricant fluid so joints move easier
Periosteum
- external 🦴 sheath covering
- tough/fibrous collagen layer-outer
- osteogenic bone forming cells layer-inner
- provides strong attachment from 💪🏼 > tendon > 🦴
Endosteum
- thin layer of reticular tissue
- lines internal marrow cavity
- covers spongy 🦴
- lines canal system in compact 🦴
What is the spongy layer of the cranium?
diploe
Flat 🦴
•thin curved plates
Ex: •most cranial 🦴 are flat 🦴 •paired parietal 🦴 (form dome of top of head) •sternum (breastbone) •scapula (shoulder blade) •ribs •hip bones
What tissues make up 🦴?
- osseous
- 💉
- 🦴 marrow
- cartilage
- adipose
- nervous
- fibrous connective
What are the 4 🦴 cells?
Osteogenic cells
- stem cells develop from mesenchyme
- give rise to most bone 🦴 cells
- multiply constantly
- some become osteoblasts
- stimulated by stress/fractures (then multiply faster)
Osteoblasts
- 🦴 forming cells
- cuboidal or angular
- single layer on bone surface under endosteum & periosteum (similar to cuboidal epithelium)
- nonmitotic (don’t recreate except through osteogenic cells)
- synthesize matter in bone matrix which hardens
- stress/fractures stimulate osteogenic cells = more osteoblasts = faster 🦴 repair
Osteocytes
- osteoblasts that get trapped in matrix they made
- stuck in lacunae (cavities)
- lacunae connected by canaliculi
- canaliculi used to send nutrients/chemical signals/pass waste to 💉 cells
- resorb bone matrix/deposit 🦴 matrix
- homeostatic maintenance of 🦴 density & blood concentrations
- strain sensors:
1) pressure/load applied to 🦴
2) lacunae & canaliculi flow through ECF
3) osteocyte cilia stimulated
4) cells secrete signals to regulate 🦴remodeling
Osteoclasts
- 🦴 dissolving cells
- on 🦴 surface
- develop from 🦴 marrow stem cells that give rise to 💉 cells
- fused stem cells = osteoclasts
- 3 or 4 nuclei (up to 50)
- live in resorption bays
What’s the basic structural unit of compact 🦴?
Osteon (haversian system)
What is spongy 🦴 made of?
•lattice of spicules & trabeculae
What is 🦴 marrow?
•soft tissue occupying…
- marrow cavity of long 🦴
- space amid trabeculae of spongy 🦴
- larger central canals
