Bones terminology Flashcards
What is the skeletal system?
the basic framework of the body and the joints between them
What is spongy bone? What does it provide?
a central honeycomb network that provides strength without adding excess weight
What is the layer of denser bone surrounding spongy bone called?
compact bone
What are the units that make up compact bone called?
Osteons
What do osteons consist of?
a central canal surrounded by closely packed layers called lamelle
what do the osteonic canals house?
blood vessels and nerves
What is the periosteum?
a thin membrane that protects the bone and houses the nerves and blood vessels responsible for detecting pain and supplying the bone with nutrients
What is the epiphyses?
The bone heads - distal or proximal ends of the bone
What is the diaphysis?
the bones shaft or midsection
What is the metaphyses?
regions in mature bone where the epiphyses (ends) joins the diaphysis (middle/shaft)
In growing bones, what does the metaphyses include?
an epiphyseal plate - a layer of hyaline cartilage that allows the bone to grow
What is articular cartilage?
a thin layer of hyaline cartilage covering the epiphyses (ends of bone)
What does the periosteum do?
enables the bone to grow in diameter and protects the bone
What is the medullary cavity?
the space that contains fatty yellow bone marrow in adults
What is the endosteum?
a thin membrane that lines the medullary cavity
Are bones living cells?
yes
Why would you consider bone tissue extremely dynamic?
because it undergoes constant structural change
What kind of tissue is bone?
a connective tissue that has been mineralised, mainly by calcium salts
What kind of fibres are bones comprised of? What are the fibres suspended in?
a network of protein fibres (mainly collagen) suspended in inert salts (mainly calcium)
What qualities do collagen fibres give bones?
resilience and elasticity
What qualities do the salts provide bones?
hardness and strength
What are the two forerunners of bone in the embryo?
- cartilage
- membrane of fibrous tissue
What are limb bones formed out of in the embryo?
cartilage
what is the process by which bone forms in the body called?
Ossification
What are the three important periods of bone development?
- the formative period
- the growth period
- the consolidation period
When does the formative period happen in bone formation?
from the 5th - 12th week of intra-uterine life
In which period of bone development do nearly all primary centers of ossification appear?
the formative period
When does the growth period of bone development happen?
from the ?12th week of intrauterine life until pubity
In which period of bone development do all secondary growth centers appear?
the growth period
When does the consolidation period occur in bone formation?
from puberty to the attainment of adult stature 14th - 25th year
What are the two ossification (bone formation) methods?
- intramembranous ossification
- Endochondral ossification
What are the four types of cells present in bone?
- Osteagenic cells
- Osteoblasts
- Osteocytes
- Osteoclasts
What are Osetogenic cells?
Unspecialised stem cells
What are Osteoblasts?
Bone building cells
What are Osteocytes?
Mature bone cells - the main cells in the bone tissue
What are Osetoclasts?
Cells that breakdown the bone matrix
Where do Osteogenic cells derive from?
The tissue from which all connective tissues are formed (mesenchyme)
What do osteoblasts do?
form collagen and deposit calcium to build, maintain and repair bone
What do Osteocytes do?
they maintain the daily metabolism of the bone
What do Osteoclasts do?
breakdown the collagen and release calcium into the blood
What is the breaking down of the bone matrix referred to as?
resorption
What is the purpose of resorption?
to help growth, maintenance and repair of the bone
Are bones completely solid? why?
no they have spaces to provide channels for blood vessels, this makes the bones lighter
What does the architecture of bones indicate?
function
What are the two categories for bone regions?
- spongy/cancellous
- Compact/dense
What does spongy bone tissue provide?
some support and a storage area for marrow
Where in the bone do you find spongy bone tissue arranged?
arranged along lines of force transmission
what does compact bone tissue provide?
protection and a considerable amount of support
Where in the bone do you find dense bone tissue?
most commonly concentrtaed near the middle of the bone shaft and in areas prone to fracture
How many bones are in the human skeleton at birth?
270
How many bones are in the human skeleton in adults?
206
Where do the bones of the skeleton connect?
at the joints