Lecture 6: Bone Tissue - Microscopic Structure Flashcards
What does ossify mean?
To develop into bone or bony tissue (eg. from cartilage).
Bone grows, can repair itself and ________.
Bone grows, can repair itself and REMODELS.
What type of tissue is bone>
Connective tissue.
What twoi components make up bone?
Organic and inorganic.
How much of the bone matrix is organic?
33%
How much of the bone matrix is inorganic?
67%
What is the primary function of the organic component in bone?
To resist tension.
What is the primary function of the inorganic component in bone?
To resist compression.
The inorganic bone component is mostly made up of ________?
Hydroxyapatite (mineral salts)
The organic bone component is mostly made up of ________ and __________?
Collagen (protein) and ground substance (proteoglycans).
If the collagen is removed from a bone, what is the effect on its structure?
It will become very brittle and break easily.
If the minerals (inorganic) are removed from a bone, what is the effect on its structure?
It will become very flexible and bend easily.
What do osteoblasts do?
They build ECM
What is an osteocyte?
A mature bone cell.
What do osteoclasts do?
They break down ECM.
What are foramina?
Small holes on the surface of compact bone,
What is an osteon?
A longitudinal (lengthwise) unit within compact bone, consisting of lamellae, lacunae, canaliculi and the central canal.
What are lamalla/e?
Tubes of ECM with collagen fibres aligned to resist forces. Series of concentric lammellae running longitudinally dow the shaft make up the osteon unit.
What is the function of an osteon?
To maintain osteocytes by providing nutrients.
What does the central canal consist of?
A blood vessel and nerves.
What are laccunae?
“Lakes” for osteocytes. Small cavity in the bone.
What are canaliculi?
Channels through the ECM for osteocytes.
What is the periosteum?
A dense layer of vascular connective tissue enveloping the bones except at the surfaces of the joints.
What is the subperiosteal surface of the bone?
The surface of the actual bone, beneath the periosteum.
What are trabeculae?
Struts of lamella bone.
What fills the cavities in cancellous bone?
Marrow
Where are osteocytes housed in cancellous bone?
In the lacunae on the surfaces of the trabeculae.
Trabeculae struts are arranged to follow the _____ __ _____.
Trabeculae struts are arranged to follow the LINES OF STRESS.
What percentage of bone is living cells?
3%
