SI Sessions Unit 2 Flashcards
Bones
20% of total body weight
Usually 206 bones (in adults)
Functions of bone
Support
Protect
Movement
Mineral and fat storage
Hematopoiesis
Hormone production
Respiration
Hearing
Compact bone vs. spongy bone
Compact - dense, strong bone that looks solid to the make eye
Spongy - more porous and lightweight than compact bone
Diaphysis
Epiphysis
Growth plate
Metaphysis
Diaphysis - shaft
Epiphysis - where the bone ends
Growth plate - space between the epiphysis and Metaphysis
Metaphysis - where the bone gets wider
Medullary cavity
(an open space filled with fat) is inside the diaphysis
Periosteum
A double-layered membrane covering the external surface of bones (except joints)
- cling tightly to the surface
Endosteum
Membrane lining internal structures of the bone
- contain stem cell -> bone cells
- among the trabeculae
Bone composition
35% organic
65% inorganic
Hydroxyapatite gives what?
The structure
Calcium homeostasis
- is a negative feedback loop
- balance between calcium and no production on what the body needs
- parathyroid: stimulates osteoclasts
- calcitonin: weakly inhibits calcium activity
Osteon
Central canal
Lacunae
Canliculi
Lamellae
Perforating (Volkmann’s) canal
Osteon - function unit of compact bone
Central canal - contain blood vessels and nerve fibers (in the middle)
Lacunae - open spaces (rings) that osteocytes occupy
Canaliculi - tiny canals that connect osteocytes together
Lamellae - concentric rings/ layers within the osteon
Perforating (Volkmann’s) canal - run perpendicular to central canals
Endochondral
Think hyaline cartilage first then turn into bone
Epiphyseal growth plate
- the main site of longitudinal growth of the long bones
- contains cartilage growth plates, which we need to grow these bones.
Appositional bone growth
- when the medullary cavity grows while the outside is also forming
- osteoblasts at the bone surface secrete bone matrix, and osteoclasts on the inner surface break down bone
