Principles of Skeletal System Flashcards
Which two structures is your skeletal system divided into?
Axial + Appendicular
What does the axial structure contain?
Skull + vertebrae + ribs
What does the appendicular structure contain?
limbs and pelvis
When does bone development begin and end?
8 weeks ends at 20 years
Bone comes from which germ cells? and more specifically….
mesoderm
The paraxial and lateral plate
What does paraxial mesoderm form, and using what?
axial skeleton
somites
What does the lateral plate mesoderm form?
limbs (appendicular structure)
Ossification can occur in which two ways?
Intramembranous
Endochondral
What is mesenchyme?
mainly mesodermal embryonic tissue
What is intramembranous ossification?
direct mineralisation of the connective tissue.
process of bone development from fibrous membrane
Where does intramembranous ossification occur ?
In the skull, mandible and clavicle (FLAT BONES)
How do bones in the skill grow?
around the direct mineralisation or arterial/capillary network
The starting point of bone growth is known as the?
primary ossification centre
What direction does intramembranous ossification grow in?
Radially
What happens to the connective tissue which formed a guide for the bone growth and is penetrated by blood cells?
bone marrow
What is Endochondral Ossification?
The process of bone development from cartilage which comes from the mesenchyme
What happens to the cartilage in Endochondral ossification?
it gets replaced by bone - OSTEOGENESIS
What is the first thing cartilage makes in endochondral ossification?
A bone collar which then surrounds the diaphysis
What does diaphysis mean?
shaft or main body of bone
What 2 types of bone are made in endochondral ossification?
compact bone
Spongy bone
A secondary centre for bone growth appears where?
The epiphysis
What type of bone does the secondary centre make?
spongy
What is a growth plate?
The epiphyseal plate is the area of growing tissue in long bone (near edge)
How does bone growth work?
Associated with partial reabsorption of previously laid down down
At what gestation does bone get penetrated with blood vessels?
week 9
What would you not be able to see in a mature bone ?
The epiphyseal plate
What minerals and vitamins are needed for bone maintenance?
Vit A, C, D
Calcium
Phosphorus
What is Vitamin A important for?
Bone remodelling
What is Vitamin C important for?
Connective tissue
What is Vitamin D essential for?
Calcium absorption
Bone development is controlled by what?
hormones
Which hormones control bone development?
Parathyroid hormone
Growth Hormone
What does parathyroid hormone do in bone development?
Increases the reabsorption of bone –> Creates an increase in amount of calcium circulating in blood
What does growth hormone do for bone development?
if you have a lack of growth hormone –> dwarfism
Or an increase in amount after puberty –> acromegaly
What produce growth hormone?
pituitary gland
What is cartilage?
a form of connective tissue
Does cartilage have vascularity ?
no
What does bone form from?
connective tissue
What is the periosteum?
covering of a bone
What is the perichondrium?
the connective tissue surrounding cartilage
What 4 cell types make up bone?
Osteoprogenitor cells
Osteoblasts
Osteocytes
Osteoclasts
what are osteoprogenitor cells?
stem cells of bone which form osteoblasts
What are osteoblasts?
build new bone, occur on the outside of bone.
Lay down organic matrix
What are osteocytes?
osteoblasts stuck in the matrix they make
What are osteoclasts?
eaters of bone
What hormone stimulated all 4 cells?
parathyroid hormone
What is compact bone covered in?
periosteum
Describe the structure of compact bone?
concentric layers of inorganic matrix - lamella
What is the Haversian canal?
Verticle channel which runs through the lamella to hold the blood and nerve supply
Each osteocyte occupies….
its own llamella
What do nutrients travel in to the osteocyte
the canaliculi
What is spongy bone known as?
cancellous bone
What is its structure?
irregular lamellae
What surrounds spongy bone and makes it a distinctive colour?
bone marrow surrounds so makes it red (highly vascularised)
What are long bones?
shaft with two ends
What are flat bones?
cranium, ribs , sternum
What are irregular bones?
vertebrae
What are short bones?
carpal, tarsus,
What are sesamoid bones?
bone embedded in a bone or tendon
patella, big toe, thumb
What is a facet?
articulation process
What is a crest?
Ridge
What is a spine?
pointy bit
What is trochlea?
pulley
What is a groove?
shallow hollow
What is a foramen?
hole
What is a condyle?
rounded edge
What is a epicondyle?
above the condyle (rounded edge)
What is a tuberosity?
raised prominence
What is a trochanter?
bigger
What is head?
head of something
What is Protuberance?
sticking out bits
What is a synovial joint?
joint capsule and synovial cavity. Allow movement
What is a fibrous joint?
connected by collagen, don’t want movement ie. skull
What are cartilaginous joints?
connected by cartilage to allow for some movement
