What are the 4 principle tissue types?
What are the 4 bone classes and give an example of each.
- Long - femur, humerus
- Short - carpals
- Flat - sternum, ribs
- Irregular - vertabrae
What are the 2 principle types of connective tissue?
Describe structure and function of compact bone.
- Dense bone
- Function as levers
Overview the structure and function of cancellous bone.
- Constructed of traberculae
- Function - weight bearing and shock absorbtion
Describe the structure function of inorganic component in bone matrix.
- Hydroxyapatite (mineral salts)
- Resists compression
- Adds hardness
Describe the structure and function of organic component in bone matrix.
- Ground substance (proteoglycans)
- Resists tension (adds "spring" to bones)
List the 3 principle cell types in bone
- Perform endochondral ossification
- The bone builders
- Involved in remodelling
- Breakdown bone matrix
- Found in lacunae
- Mature osteoblasts (about 20%)
- Cytoplasmic processes link to other osteoclasts in bone matrix
Describe an osteon and it's parts
- Functional unit of compact bone responsible for maintenance
- Consists of blood vessel in central canal surrounded by concentric bone layers called lamallae
- Blood vessels feed osteocytes in lacunae via their cytoplasmic processes running through canaliculi.
Name two sites of bone growth
- Diaphysis - primary centre
- Epiphysis - secondary centre
Describe how bones grow in length.
- Bone grows for the diaphysis against the growth plate, an area of inactive cartilage between the diaphysis and epiphyses. This allows bone to grow in length at end of diaphysis without reaching the epiphyses and joining it.
- Joining of the epiphyses and diaphysis only occurs when bone has reached it's full size
Describe how bones grow in width.
- Osteoblasts in the sub-periosteal layer ossify bone, building outwards.
- Osteoclasts remodel the bone on the inside, maintaining bone thickness and the medullary cavity.
Describe how the structure of cancellous bone relates to its function.
Cancellous bone consists of highly ordered traberculae which are arranged to best cope with stresses on the bone through weight and activity
List the 5 functions of the skeletal system.
- RBC formation
How many bones comprise the axial skeleton?
How many bones in the appendicular skeleton?
What are the functions of the appendicular skeleton?
- Allows locomotion
- Protects organs involved in locomotion, excretion, reproduction and digestion
What are the functions of the axial skeleton?
- Protection of organs (ribcage, skull)
- Maintains upright posture, transmit weight down to lower extremities
What 3 bone groups comprise the skull?
What are the divisions of the vertebral column and how many bones in each?
- Cervical (7)
- Thoracic (12)
- Lumbar (5)
Sacrum and coccyx
What are the divisions of the hand and how many bones in each?
- Carpals (8)
- Metacarpals (5)
- Phalanges (3 per finger, 2 for thumb)
What are the divisions of the foot and how many bones in each?
- Tarsals (7)
- Metatarsals (5)
- Phalanges (3 for small toes, 2 for big)
Describe a "greenstick" fracture.
Not broken completely through the bone
Describe a closed/simple fracture
Clean break, 2 parts in alignment
Describe a open/compound fracture.
Out of alignment, skin may be broken.
Outline the 4 stages of fracture healing.
- 1 - Damaged capillaries cause haemotoma
- Phagocytes clean up area
- 2 - Fibroblasts and chondroblasts form procallus
- 3 - Osteoblasts start forming bony callus
- 4 - Remodelling by osteoblasts and osteoclasts