Histology Flashcards
Where are the multiple nuclei located in skeletal muscle fibres?
Periphery, just under the cell membrane (sarcolemma)
What are muscle fibres called when they are grouped into bundles?
Fascicles
**The connective tissue that surrounds the whole muscle?
Epimysium
**The connective tissue that surrounds a single fascile?
Perimysium
**The connective tissue that surrounds a single muscle fibre?
Endomysium
What is the term for the space in the ECM which chondrocytes live within?
Lacuna
What makes up the ECM in hyaline cartilage?
Water (75%), Type II colagen, proteoglycan aggregates made up of GAGs
What are the 3 main types of cartilage?
Hyaline, elastic (eg. pinna) and fibrocartilage
True or false: both cortical and cancellous (trabecular) bone are lamellar (made up of layers)
True
What is the name of the canals that lie in the longitudinal plane of bone and supplies vasculature to the bone?
Haversian canals
Cement lines
The lines often visible surround the osteon
Osteoprogenitor cells
located on bone surfaces, for example under the periosteum, these cells serve as a pool of reserve osteoblasts
Osteoblasts
Bone forming cells found on the surface of developing bone.
Osteoclasts
They are found on the surface of bone and are responsible for bone resorption.
Osteocytes
A bone cell trapped within the bone matrix.
Osteon
Functional unit of cortical bone - consists of concentric lamellae of compact bone tissue that surround a central canal, the haversian canal
How is bone remodelled?
A number of osteoclasts will congregate and begin to ‘drill’ into the bone, forming a tunnel. A blood vessel will grow into the tunnel bringing with it osteoblasts which line the tunnel and begin laying down new lamellar bone. This process continues until only the space of a Haversian canal remains.
The osteoblasts secrete collagen, glycosaminoglycans (GAGs), proteoglycans and other organic components of the matrix which is collectively termed osteoid. This then becomes mineralized over time in the extracellular space.
Woven bone
Bone placed down during healing, which has the collagen fibres laid down in a haphazard fashion rather than all in one plane. It is not as strong so is eventually remodelled into lamellar bone.
