hubs 4 Flashcards
How do bone cells respond to external forces?
Bone remodels and can change shape throughout life to reflect how the skeleton is used. Bone cells also respond to trauma to unite broken parts.
What is the composition of bone tissue?
Bone tissue is a type of connective tissue that supports other tissues/organs, maintains form, and joins structures together.
What are the two extracellular components of bone?
Bone has two extracellular components: organic (proteins) and inorganic (minerals).
What percentage of bone extracellular membrane is organic?
33% of bone extracellular membrane is organic and consists of collagen and ground substance.
What is the function of collagen in bone?
Collagen makes bone flexible, provides long fibers, and resists tension when force is applied.
What is the inorganic component of bone ECM?
67% of bone ECM is inorganic, consisting of hydroxyapatite and other calcium minerals, making bone hard and resistant to compression.
What are the four types of bone cells?
The four types of bone cells are osteogenic cells, osteoblasts, osteocytes, and osteoclasts.
What is the role of osteogenic cells?
Osteogenic cells are stem cells that produce osteoblasts.
What do osteoblasts do?
Osteoblasts are makers that produce new bone matrix.
What is the function of osteocytes?
Osteocytes are maintainers that recycle protein and minerals from the matrix.
What do osteoclasts do?
Osteoclasts are destroyers that remove bone matrix.
What are the two types of bone structure?
Compact and cancellous bone are made of the same components but are structured differently.
What is the structure of compact bone?
Compact bone has an outer dense surface (periosteum) and is made up of circumferential lamellae and units called osteons.
What is an osteon?
An osteon is a longitudinal unit within compact bone that provides a pathway for nutrients to reach cells in the ECM.
What are the components of an osteon?
An osteon consists of a central canal, lamellae, lacunae, and canaliculi.
What is cancellous bone?
Cancellous bone has no central canal and is made up of trabeculae, with marrow filling the cavities between them.
What does trabecular bone do?
The organization of trabeculae resists force from multiple directions and directs force from body weight down the shaft.
What is bone remodeling?
Bone remodeling allows bones to grow through appositional growth, where osteoblasts add bone matrix and osteoclasts remove bone from the medullary cavity.
What is bone homeostasis?
Bone homeostasis is the balance of osteoblast and osteoclast activity, allowing for constant formation and destruction of bone.
What happens when bone homeostasis is not maintained?
An imbalance in osteoblastic and osteoclastic activity can occur without adequate calcium in the diet and moderate exercise.
What is osteoporosis?
Osteoporosis is characterized by the loss of cortical bone and thinning of trabeculae in cancellous bone, leading to compression fractures.
Who is at higher risk for osteoporosis?
Biological females are more at risk due to loss of estrogen post-menopause, along with lifestyle factors like lack of exercise and nutritional deficiencies.
What is peak bone mass?
Peak bone mass is typically reached in your 20s; if this is already low, the likelihood of developing osteoporosis increases.
