Musculoskeletal System Flashcards
Epiphyses
- contains spongy bone
- filled with yellow or red marrow
Diaphyses
- contains yellow bone marrow within medullary cavity
- endosteum within medullary cavity
Periosteum
- Fibrous membrane covering bone
- contains small BV and osteoblasts → forms inner layer of growing bones
- periosteal fibres penetrate underlying bone → weld structures tgt
- BUT periosteum not firmly attached to underlying bone in kids
location of the types of bone in long bones
external compact
internal spongy
features of short/fat/irregular bones
- periosteum covers compact bone
- endosteum covers spongy bone inside
- bone marrow b/w trabeculae
what consist of the bone tissues
consist of cells, fibres, extracellular matrix
bone cells
osteoblasts: builds
osteoclasts: destroy
osteocytes: large inactive mature cells
calcification of inorganic extracellular bone matrix
ca, mg, po4 crystals
- contributes to bone hardening/calcification
- effective at resisting stress and mechanical deformation
calcification of organic extracellular bone matrix
collagen, mixture of protein/sugar (ground substance)
- adhesion b/w cellular and fibrous components → inc str and resilience of bone
microscopic structure of bones
compact bone = 80% mass
- structural units = osteons
- cells cemented → allows delivery of nutrients AND imprisonment of bone cells
spongy bone = 20%
- no haversian system
- but has trabeculae network → inc tensile str
- orientation of network differs according to load and str
what structures penetrate through periosteum to bone?
BV and N from periosteum penetrate to bone via Volkmann’s canal → connect with Haversian canal
vascularity of cartilage
avascular
- chondrocytes receive nutrients & o2 via diffusion
types of cartilage
hyaline: cover articular surfaces
fibrous: greatest # of collagen fibres → greatest tensile str (IV discs)
elastic: elastic and firm (external ear)
step 1 bone formation
ossification centre appears in fibrous connective tissue membrane
- mesenchymal cells dev into osteoblasts
step 2 bone formation
Bone matrix (osteoid) secreted within fibrous membrane - Oblasts → secrete osteoid → mineralised → trapped Oblasts become osteocytes
step 3 bone formation
Woven bone and periosteum forms
- Osteoid accumulate b/w embryonic BV → form network of trabeculae
- Vascularised mesenchyme → condense external of network → becomes periosteum
step 4 bone formation
Bone collar of compact bone forms + red marrow appears
- Trabeculae deep to periosteum thickens → forms woven bone collar later replaced with mature lamellar bone
- Spongy bone persist internally
- Vascular tissues → become red marrow
bone growth
1) Formation of bone collar around hyaline
- With 1o ossification
2) Cavitation of hyaline cartilage (from 1o ossification
3) Invasion of periosteal bud (containing BV…) + spongy bone
4) Medullary cavity formed, 2o oss center appears in epiphysis (childhood)
5) Ossification of epiphyses
bone remodelling with osteoclast and blast
- Oclast → enlarge diameter of medullary
- Oblast → Produce new bone around outside of bone
fibrous articulations
- fibrous tissue
- no/little movement
- cranium sutures
cartilaginous articulation
- hyaline
- slightly movable
- pubic symphysis/iv discs
synovial articulation
- has joint capsule, synovial membrane, articular cartilage (hyaline), menisci, ligaments, bursae
- mobile
bone and ageing
childhood + adolescence → osteogen > bone reabs (clast BD bones)
young adult → osteogen = bone reabs
what 3 structures form the thin filament
actin + troponin + tropomyosin
what form of energy is used for contraction
ATP - aerobic/anaerobic
muscle fibres breaking down creatine phosphate
length of electrical impulse of cardiac muscle
longer than skeletal muscle
- does not run low on ATP and does not fatigue
EC coupling of SM
Ca from outside cell (no sarcomere and SR)
- binds calmodulin → contraction
2 types of SM
multiunit
- many independent single cell units → fine control of contraction (i.e. resp airway, arteries)
single unit
- large continuous sheet
- peristalsis
- i.e. GIT walls
