principles of the skeletal system Flashcards
What is the function of the skeletal system?
- protection of organs
- supports the body
- movement
- metabolic reservoir
- production of new red blood cells
What are the two divisons of the skeletal system?
axial and appendicular
What is part of the axial division of the skeletal system?
- cranium
- thoracic cage
- spine
- sacrum
What is part of the appendicular division of the skeletal system?
- shoulders
- hips
- limbs
What are the 3 layers of the embryonic disc?
- ectoderm
- mesoderm
- endoderm
What are the two types of tissues in the skeletal system?
cartilage and bone
Describe the cartilage
- forms skeleton in parts where flexibility is required
- avascular
- connective tissue
What are the two types of bone?
compact and spongy
Describe bone
- hard form of connective tissue
- provides rigid framework
- vascular
What is ossification?
the process by which bone is formed
What is the process by which bone is formed called?
ossification
What are the two methods through which ossification can occur?
- intramembranous
- endochondral
What is mesenchyme?
embryonic connective tissue
Describe the steps of intramembranous ossification?
- mineralisation of mesenchyme
- cells divide and condense around capillary network (grows radially, fusing together and replacing connective tissue)
What is the starting point in intramembranous ossification called?
primary ossification centre
What does undifferentiated mesenchyme become in intramembranous ossification?
bone marrow
Give examples of bones arising from intramembranous ossification
- skull
- mandible
- clavicle
What is endochondral ossification?
where a cartilaginous template made from the mesenchyme is replaced by bone
What 2 cells is the bone made up of?
- osteoprogenitor cells
- osteoclasts
What 2 cells types can osteoprogenitor cells become?
osteoblasts and osteocytes