Lecture 4 Flashcards
What is bone described as?
A dynamic connective tissue with both cells and a calcified extracellular matrix (ECM)
Bone constantly remodels in response to external forces and trauma, maintaining structure and function.
What percentage of bone is organic and what does it provide?
33% - Provides flexibility and resists tension
Organic components include collagen (protein) and ground substance (proteoglycans).
What percentage of bone is inorganic and what does it provide?
67% - Provides hardness and resists compression
Inorganic components include hydroxyapatite and other calcium minerals.
What are the types of bone cells?
- Osteogenic cells
- Osteoblasts
- Osteocytes
- Osteoclasts
Osteogenic cells are stem cells producing osteoblasts, osteoblasts build new bone matrix, osteocytes regulate bone homeostasis, and osteoclasts break down bone matrix.
What is the function of osteoblasts?
Build new bone matrix
Osteoblasts are known as the ‘Makers’ of bone.
What is the function of osteocytes?
Regulate bone homeostasis
Osteocytes are referred to as ‘Maintainers’ of bone.
What is the function of osteoclasts?
Break down bone matrix
Osteoclasts are known as the ‘Destroyers’ of bone.
What are the two types of bone structure at the macroscopic level?
- Compact Bone
- Trabecular (Spongy) Bone
Compact bone is dense with foramina for blood supply, while trabecular bone consists of struts of lamellar bone with marrow-filled cavities.
What is an osteon?
Longitudinal unit of compact bone providing a nutrient pathway
Osteons are critical for nutrient supply in bone.
What does the central canal in an osteon contain?
Blood vessels and nerves
Central canals are essential for nutrient and signal transmission.
What are lamellae?
Cylindrical layers of ECM with collagen fibers resisting force
Lamellae are structural components of osteons.
What are lacunae?
Spaces housing osteocytes
Lacunae provide shelter for osteocytes within the bone matrix.
What are canaliculi?
Channels for nutrient transport
Canaliculi connect lacunae and facilitate communication and nutrient exchange.
What is appositional growth?
Osteoblasts add new bone matrix to the surface
Osteoclasts remove bone from the medullary cavity, maintaining balance.
What influences bone remodeling?
- Diet (calcium intake)
- Exercise
These factors are crucial for maintaining bone strength and health.
True or False: Bone remodeling allows bones to adapt and resist strain.
True
Continuous remodeling ensures bone maintains strength and function throughout life.
What can imbalances in bone remodeling lead to?
Bone weakening
Maintaining the balance of bone formation and destruction is vital for bone health.
