Biol. Sci. 204 Lecture Exam 2 study guide
1.Know the classification of bones based on their shape and function.
• Four categories (Classified based on shape and corresponding function)
– Long bones (smallest phalanges/finger)
*longer than they are wide
*General Features of Bones-primarily in long bones
• Epiphysis
– Ends of the bone
– Composed of cancellous (spongy) bone
*lined by hyaline cart. Where bone connect articulate no friction
*spongy bone on the ends-holes/poresRED BONE MARROW->make
RBC
• Diaphysis
– Shaft of the bone
– Composed of compact bone
*metaphasis- when someone is stil growing…between other 2 abov
•
Medullary cavity- hollow space in diaphysis
-Contains yellow bone marrow (adipose tissue)
-Epiphyiseal plate –
–
Short bones-patella, tall as they are wide found in wrist and ankles
–
Irregular bones- vertebrate,
–
Flat bones-flat *cranial bones, sternum
2. Know the two types of ossification and be able to describe how the processes occur (mainly
endochondral ossification) and know the two types of bone growth.
Ossification or osteogenesis: Formation of bone
-Two methods
– Intramembranous ossification- Produces flat bones of skull and clavicle
• Starts w/ osteoid
• Ends with diploe
•
-Endochondral ossification- Bone develops from a hyaline model *replace hyaline cartilage w/
bone, chondrocytes in matrix-> to maintain matrix
3. Know the types of cells found in bone and their functions. Also know the structures that compose
compact and spongy bone and what the bony matrix is made of.
•
Four main types of bone cells
– Osteogenic (osteoprogenitor) cells
• give rise to osteoblasts, osteocytes
*Pleripotent stems cells-> give rise to osteoblasts
– Osteoblasts (make boney matrix)
• Bone-forming cells
• Found along endosteum (lining compact bone) and periosteum (lining compact
bone)
• Secrete osteocalcin
– Osteocytes
• Former osteoblasts that have been trapped in their lacunae
• Maintain bony matrix
• Strain sensors
– Osteoclasts (break boney matrix)
• Bone-dissolving cells
OTHER STRUCTURES:
• Matrix- composed of inorganic and organic components
• Inorganic component-
–
Hydroxyapatite
• Composed mainly of CaPO4 salt
• Organic components
– Protein and carbohydrate
• Collagen
-Bone is a composite
-Spongy Bone
•
Composed by a network of spicules and trabeculae• Spaces filled with red marrow
• Beams arranged to sustain stress
-Compact Bone:
• Osteon (haversian system)
– Basic structural unit of compact bone **central canal (nerves and blood vessels) Highly
vascular
• Central (haversian) canal surrounded by concentric lamellae (matrix)
• Perforating canals
– Transverse or diagonal passages into the central canal
– Originate at nutrient foramen