#3 Bone Cell Types, Cortical and Trabecular Bones Flashcards
What are osteoblasts responsible for?
Producing collagen fibers and ground substance, leading to bone formation
Osteoblasts are often thought of as ‘building’ bone.
What do osteoclasts do?
Break down bone to release calcium, maintaining calcium homeostasis
Osteoclasts can be thought of as ‘carnivores chewing’.
Where are osteocytes found and what is their function?
Mature resting cells found in lacunae, responsible for monitoring and maintaining bone health
What are osteoprogenitor cells?
Stem cells located in the periosteum and endosteum, capable of developing into osteoblasts
What is cortical (compact) bone?
Dense bone found on the outer surface, composed of repeating units called osteons
Where is trabecular (spongy) bone located?
At the center of bones, characterized by an irregular pattern with spaces for bone marrow
What percentage of bone composition is inorganic material?
65%
Calcium crystals in inorganic material provide strength.
What role do collagen fibers play in bone composition?
Provide flexibility and resistance to stretching and twisting
Lack of collagen results in brittle bones.
What is the balance between osteoblast and osteoclast activity important for?
Maintaining bone mass
What happens when calcium levels are low?
Osteoclasts increase activity, breaking down bone to release calcium
What are osteons?
Circular units in cortical bone, with a central canal for blood vessels
What are trabeculae?
Basic units of trabecular bone, providing strength and space for bone marrow
What is the function of red marrow?
Produces red and white blood cells
What happens to red marrow as we age?
It is replaced by yellow marrow (fat storage)
What is the role of blood vessels in the central canal?
Supply nutrients and oxygen to osteocytes via canaliculi
How do nutrients reach cells farthest from the blood supply?
Through diffusion
How are collagen fibers arranged in bone?
In alternating directions within lamellae, providing strength against various forces
What is the benefit of trabecular bone structure?
Reduces weight while maintaining strength, supporting bone marrow
What condition can lead to fragile bones in older individuals?
Osteoporosis
What can increase bone density and strength?
Regular stress on bones, such as weight-bearing exercises
What is the periosteum?
Outer connective tissue layer of bone
What is the endosteum?
Inner lining of bone, covering trabeculae
What are lacunae?
Spaces housing osteocytes
What are canaliculi?
Tiny channels connecting osteocytes, allowing nutrient and oxygen exchange
