A&P: Skeletal System - Bone Tissue Flashcards
Functions of Bone
Support (structural / muscle attach)
Protect
Movement Assistance (leverage)
Mineral Homeostasis (esp Ca+2)
Blood Cell Production (@red bone marrow)
Triglyceride Storage (@yellow bone marrow)
Parts of Long Bone
Articular Cartilage
Epiphysis
Epiphyseal Plate
Metaphysis
Diaphysis
Periosteum
Endosteum
Medullary Cavity
Diaphysis
“growing btwn”
main shaft or body of the long bone
Epiphysis
proximal and distal ends of long bone
Metaphysis
region between epiphysis and diaphysis
epiphyseal plate -> epiph line
Articular Cartilage
covers part of epiphysis
f(x) absorb shock and reduce friction @ joints
Periosteum
covers bone
outer layer - dense
inner layer - osteogenic layer
blood supply included
attached to bone by Perforating Fiber (Sharpey’s Fibers)
Perforating Fibers
connects periosteum and bone tissue together
aka Sharpey’s Fibers
Medullary Cavity
hollow cylindrical space; contains marrow (red -> yellow)
lined with endosteum
aka marrow cavity
Endosteum
single layer of osteogenic cells
lines Medullary Cavity
Cell Types of Bone Tissues
osteogenic cells
osteoblasts
osteoclasts
osteocytes
Osteoprogenitor Cells
unspecialized bone stem cells
cell division into osteoblasts
@ periosteum, endosteum, canals within bone
Osteocytes
mature bone cells
tissue metabolism
maintain mineral concentration
turned from osteoblasts
@ lacunae
Osteoblast
bone building cells
forms bone extracellular matrix for calcification turns into osteocyte
@ any growing portions (in&out)
Osteoclast
bone resorption
developed from fusion of monocytes
@ Endosteum
Haversian Canals
longitudinal canals
surrounded by concentric Lamellae
Haversian Systems
arrangements of concentric lamellae
aka Osteons
Lamellae
plates of mineralized extracellular matrix
Lacunae
“lake”
spaces where osteocytes are located
Perforating Canal
transverse canal that connects periosteum level into haversian canal
Periosteal Arteries and nerves
aka Volkmann’s Canal
Trabeculae
irregular lattice pattern
makes it look spongy
Nutrient Canal
Nutrient Arteries at oblique angle
leads from Nutrient Foramen, into Medullary Cavity
Compact Bone
consists of Osteons
over spongy bone
strongest form
Spongy Bone
consists of trabeculae
forms most of short, flat, irregular bone and epiphyses
resistance along the line of stress
Ossification
process of bone tissue forming
aka osteogenesis
2 Types of Embryonic Formation
Endochondral Ossification and Intramembranous Ossification
Endochondral Ossification
bone replaces hyaline cartilage
- cartialge model develops (mesenchymal cells -> chondroblast -> cartilage model)
- cartilage model grows thru cell division @ shaft
- primary ossification center forms @ shaft
- development of medullary cavity by osteoclast
- secondary ossification center forms @ ends of bone
- articular cartilage and epiphyseal plate forms
ex) long bones
Intramembranous Ossification
bone replaces mesenchyme
- osteoblasts secrete organic extracelluar matrix
- calcification (osteoblasts -> osteocyte)
- formation of spongy bone trabeculae (working around blood vessels)
- development of periosteum (mesenchyme at periphery of the bone)
ex) flat bones
Interstitial Growth of Bone
growth in length
epiphyseal plate -> epiphyseal line
Appositional Growth of Bone
growth in thickness
Factors Affecting Bone Growth and Remodeling
minerals, vitamins, hormones, stress endured
Pott’s Fracture
Fx of distal end of fibula w/ serious injury to distal tibial articulation
Colles’ Fracture
Fx of distal end of radius; FOOSH
Bone Repair Process
- Reactive Phase - hematoma formation
- Reparative Phase - fibrocartilaginous callus formation
- Reparative Phase - bony callus formation (spongy bone)
- Bone remodeling - peripheral spongy bone -> compact bone
Roel of Ca2+
blood clotting
nerve/muscle cells function
cofactor for enzymatic processes
When Ca2+ goes down…
- parathyroid gland detects
- cAMP⬆️
- PTH⬆️
- Osteoclasts bone resorption ⬆️
Kidneys loss of Ca2+ ⬇️
Calcitriol (vitamin D) ⬆️
Ca2+⬆️
When Ca2+ goes up…
- thyroid gland detects
- parafollicular cells secrete Calcitonin
- osteoclasts activity ⬇️
osteoblast activity ⬆️
Ca2+ deposition ⬆️
Ca2+ lowers in bloodstream