Session 3 - Skeletal System Flashcards
What are the two functional parts of the skeleton?
- Axial skeleton
- Appendicular skeleton
Which tissues make the largest contribution to the skeleton?
- Bone tissue
- Cartilage tissue
What is the name of cells that form bone tissue?
Osteoblasts
Which cells are responsible for the dissolution and absorption of bone?
Osteoclasts
What is the name of the cells that form cartilage?
Chondrocytes
What is the perichondrium?
The layer that covers cartilage. It nourishes and repairs cartilage and serves as site of attachment for tendons and ligaments.
Where is cartilage usually found on the skeleton?
The part of the skeleton where more flexibility is required.
Briefly describe the changes in the proportion of cartilage and bone’s contribution to the skeleton at different ages from embryo to old age.
The younger a person is, the more cartilage they have. Newborns have soft and flexible joints and their skeletons comprise mostly of cartilage.
As people get older, the proportion of bone and cartilage changes and they develop more bone and less cartilage.
List the functions of bone tissue and the skeletal system
- Provides support for the body and vital cavities
- Protects vital structures
- It is the mechanical basis for movement
- Provides storage for salts e.g. calcium
- Provides continuous supply of new blood cells from the bone marrow
What is the periosteum?
The vascular connective tissue membrane that covers the outer surface of the bone.
What are the functions of the periosteum?
- Nourishes and repairs bone tissue
- Serves as site for the attachment of tendons and ligaments
What is the general structure that all bones have?
All bones have a thin layer of compact bone (solid matter) which provides strength for weight bearing, a central mass of spongy bone and a medullary cavity where blood cells and platelets are formed.
What are the types of bones according to shape?
- Long bones - have 2 epiphysis and diaphysis
- Short bones - are cuboidal in shape and found in the wrist (carpals) and ankle (tarsus)
- Flat bones - provide protection
- Irregular bones - have various shapes
- Sesamoid bones - found in tendons and protect from excessive wear and change of angle
Give examples of long bones.
Femur
Humerus
Tibia
Fibula
Give examples of short bones
Carpals of the wrist
Tarsals of the ankle
Gives examples of flat bones
Sternum
Cranium
Give examples of irregular bones
Vertebrae
Face bones
Give an example of a sesamoid bone
Patella
What are the two types of bones according to development?
Intramembranous bone
Endochondral bone
What is mesenchyme?
Embryonic connective tissue with the capacity to for bone
Describe the ossification of intramembranous bone
It ossifies directly from the mesenchyme in the foetal period and forms the flat bones of the skull
Describe the ossification of endochondral bone
- Mesenchymal cells condense and differentiate into chondroblasts thereby forming a cartilaginous bone model.
- In the mid-region of the model, the cartilage calcifies and periosteal capillaries grow into into the calcified cartilage of the bone model and supply its interior. These blood vessels along with associated osteogenic cells, form a periosteal bud.
- The capillaries initiate the primary ossification centre.
What are the six major parts of a typical long bone?
Epiphysis
Epiphysial plate
Diaphysis
Metaphysis
Epiphysial plate
Epiphysis
Where does bone tissue receive nutrients?
Bone tissue receives nutrients via the nutrient arteries which enter the bone at a nutrient foramen
Describe bone growth in response to a fracture
- Reduction of fractions occurs
- New blood vessels develop
- Collagen producing fibroblasts forms a collar of callus to hold the bones together
- Callus calcifies as osteoblasts form insoluble crystals
- The callus is resorbed and replaced by bone matrix
List the types of cartilage.
- Hyaline cartilage
- Elastic cartilage
- Fibrocartilage
List the primary subdivisions of the axial skeleton.
Skull
Vertebrae (including sacrum)
Hyoid bone
Ribs
Sternum
List the primary subdivisions of the appendicular skeleton
Bones of limbs
Shoulder girdle
Pelvic girdle
What is the capitulum?
Small, round articulating head
What is a condyle?
Rounded, knuckle-like articular area, often occurring in pairs.
What is a crest?
Ridge of a bone
What is a facet?
Smooth flat area, usually covered with cartilage, where a bone articulates with another bone.
What is a foramen?
A passage through a bone
What is a fossa?
A hollow or depressed area
What is a groove?
An elongated depression or furrow
What is a notch?
An indentation at the edge of a bone
What is a protuberance?
Projection of bone
What is a tuberosity?
Large rounded elevation
What is a tubercle?
Small raised eminence
What is a trochlea?
Spool-like articular process or a process that acts as a pulley.
What is a trochanter?
Large blunt elevation
What is the diaphysis?
The shaft of the bone that ossified from the primary ossification centre
Name the three fontanelles.
Anterior fontanelle
Posterior fontanelle
Mastoid fontanelle
When does the anterior fontanelle become closed?
By 18 months
When does the posterior fontanelle become closed?
At the end of 1st year
