Midterm 2 Flashcards
Osteoblast
Bone building cell
Osteiod
The immature bone that is first formed. It contains the collagen fibers and proteins that promote calcium salt formation onto the collagen.
Osteocytes
Mature Osteoblasts, Bone cells.
Osteoclasts
Breaks down bone.
Lacunae
empty space in bone, where osteocytes are located.
Chondroblasts
Form cartilage
Connective tissue
Bone, Blood, Dense regular connective tissue, areolar CT. Unifying characteristic- all form from mesenchyme.
4 primary tissue types
epithelial, connective, muscle and neural.
3 types of embryological origin
Mesoderm, Ectoderm, Endoderm
Mesoderm
(middle) “everything else” Connective tissue, Wall of digestive and respiratory tracts, heart. ect.
Ectoderm
Epidermis, hair nails and glands of skin. BRAIN and SPINAL CORD
Endoderm
Epithelial lining and glands of the digestive and respiratory tracts.
Fibroblasts
cell type found in tendons (dense regular connective tissues) and they are responsible for producing the collagen fibers.
Fibroblasts
cell type found in tendons (dense regular connective tissues) and they are responsible for producing the collagen fibers.
Osteons
the structural unit of compact bone. They make up the thick walls of long bone diaphyses and the most superficial compact bone collar (cortex) of long bone epiphyses.
Trabeculae
the struts of spongy bone in the epiphyses and adjacent to the medullary cavity. They are more lightweight than dense compact bone (as evidenced by their many open spaces). In the epiphyses they transmit weight to the more dense compact bone of the outer diaphyseal cortex. They remodel very rapidly in response to signals
Articular cartilage
cartilage on the end of long bones
What is the difference between spongy bone and compact bone?
Spongy bone and compact bone are microscopically arranged differently. Spongy bone and compact bone are made of the same matrix material (1/3rd collagen, 2/3rds mineral), contain the same cellular populations (osteoblasts, osteoclasts, osteocytes, osteoprogenitor cells) and are both found in long bones. Microscopically, the matrix arranges itself as osteons in compact bone, but as non-osteon, irregular lamellae of trabeculae in spongy bone.
lamella
a ring of osteoid secreted by osteocytes that eventually mineralizes and traps the osteocytes within pockets (lacunae).
Hyaline cartilage
connective tissue that makes embryonic protoskeletons and articular cartilage.
endosteum
is made of connective tissue cells, that can deposit or reabsorb bone from the internal aspect of the bone. During growth, the endosteum is particularly important to remodel bone from the inside. Without endosteal bone reabsorption, as bones grow wider overall, the bone would become too heavy. In other words, as bones grow wider (due to periosteal bone deposition), they maintain the same cortical bone thickness because of endosteal removal.
periosteum
a double layered structure on the outside of all bones. The outermost layer is a fibrous connective tissue, the innermost layer (adjacent to the cortical bone) is a layer of osteoblasts, osteoclasts and osteogenic/osteoprogenitor cells.
Appositional growth
occurs when the cartilage model also grows in thickness due to the addition of more extracellular matrix on the peripheral cartilage surface, which is accompanied by new chondroblasts that develop from the perichondrium.
Diaphysis
The shaft of long bone.
