L4 Bones Tissue & Its microscopic structure Flashcards
What are the two main components of bone tissue?
Organic (collagen & ground substance) and inorganic (hydroxyapatite & calcium minerals).
What percentage of bone extracellular matrix (ECM) is organic?
33%.
What percentage of bone ECM is inorganic?
67%.
What makes bone hard and resistant to compression?
The inorganic component (hydroxyapatite & mineral salts).
What are the four types of bone cells?
Osteogenic cells, osteoblasts, osteocytes, osteoclasts.
What is the function of osteoblasts?
They build new bone matrix.
What is the function of osteocytes?
They maintain bone by recycling protein and minerals from the matrix.
What is the function of osteoclasts?
They break down bone matrix.
What are the two types of bone tissue?
Compact bone and cancellous bone.
What is an osteon?
A longitudinal structural unit in compact bone that provides a pathway for nutrients.
What is the function of the central canal in an osteon?
It contains blood vessels and nerves.
What are lacunae?
Small spaces where osteocytes reside.
What are canaliculi?
Channels that transport nutrients to osteocytes.
What is the difference between compact and cancellous bone?
Compact bone is dense and strong, while cancellous bone has trabeculae that resist forces from multiple directions.
How do bones grow in width (appositional growth)?
Osteoblasts add bone to the outer surface, while osteoclasts remove bone from the medullary cavity.
What is bone homeostasis?
The balance of osteoblast and osteoclast activity, ensuring bone mass remains constant.
What happens if bone homeostasis is not maintained?
It can lead to conditions like osteoporosis.
What is osteoporosis?
A condition where osteoclast activity exceeds osteoblast activity, leading to weak bones.
What are some risk factors for osteoporosis?
Post-menopause (due to estrogen loss), lack of exercise, poor nutrition, and low peak bone mass.
Why do trabeculae become thinner in osteoporosis?
Due to an imbalance in bone formation and destruction.
