Bone Tissue And Its Microscopic Structure Flashcards
What are the 2 cellular components of bones and their functions
- organic material (made of collagen and proteoglycans) which resists tension and gives flexibility
- inorganic material (made of hydroxyapatite and other Ca minerals) which makes bones hard and resists compression
the 4 types of cells of bones (and function)
- osteogenic: stem cells that produce osteoblasts
- osteoblasts: produce new bone matrix
- osteocytes: recycle protein and minerals from the matrix
- osteoclasts: remove bone matrix (maintain healthy bones
the structures of 2 bone tissue types
- compact bone: osteon structure
- cancellous: trabecular structure
explain the structure of compact bones
periosteum- the outer surfaces seem dense and impenetrable
foramina- for blood vessels to supply nutrients
made of circumferential lamellae and units called osteons
what are osteons (and function)
Osteons are longitudinal units within compact bone the provide a pathway for nutrients to cells in the extracellular matrix
what are the 4 components of osteons (and functions)
- central canal: contains blood vessels and nerves
- lamellae: a series of cylinders formed of ECM around the central canal
-forms the shape of osteons and the collagen fibers within lamellae resist force - lacune: lakes for osteocytes
- recycle area for proteins and minerals from matrix - canaliculi: channels for nutrients to travel to osteocytes through ECM
explain the structure of cancellous bones
- consists of trabeculae (struts of lamella bone) and bone marrow fill the cavities in between
- osteocytes are housed in lacuna between lamellae
why do cancellous bones not have a central canal
osteocytes are housed in lacuna between the lamellae which is close to the surface - therefore it is close to the surface and nutrients can be directly diffused from marrow into the cells.
how do bones grow in width
Osteoblasts add new bone tissue on the outer surface (periosteum) and osteoclasts remove older bone from the medullary cavity therefore bone mass won’t increase significantly
what is osteoporosis
When osteoclastic activity is much larger than osteoblastic activity therefore trabeculae structure becomes thinner.
3 factors that influence osteoporosis (and explain)
- biological female: due to loss of estrogen post menopause
- lifestyle choices: lack of exercise, smoking/drinking, lots of salt or not enough calcium intake
- depends on start point: peak bone mass is in your 20’s, if it is already low then you are more likely to get osteoporosis
