Cartilage and Bone - The Facts Quiz

Answer: Head, neck and trunk

The rest of the skeleton is made up of the "appendicular skeleton" - this consists of the bones of both upper and lower limbs, including the shoulder (scapula) and pelvis.

Answer: Humerus

There is a medullary cavity (marrow) inside long bones where a process called hematopioesis takes place - this is the production of new blood cells.

Answer: Collagen secreted by chondrocytes

Chondrocytes are matured chondroblasts but the terms are often interchangeable. Fibroblasts are cells found in connective tissue and secrete collagen along with other proteins. Astrocytes are a type of neuroglia cell that support the neurons of the nervous system.

Answer: Bone growth within an area of hyaline cartilage

Ossification is simply the making of bone. When bones grow without a cartilage model or precursor, they grow by intramembranous ossification. This happens when short bones (e.g. the ones in your wrists and ankles) grow and when any bone thickens laterally (to the side). Endochondral ossification occurs at the primary centre of ossification - the diaphysis (shaft) of long bones.

The secondary centre of ossification is at the epiphyses (ends) of the bone.

Answer: Supports soft tissue

Cartilage has many functions - as well as supporting soft tissues, it acts as a shock absorber for joints, bears mechanical stresses without being distorted permanently, is essential for endochondral ossification and provides a sliding area for the articulating surfaces of joints.

Answer: Appositional growth involves growth from the surface of the cartilage only, whereas interstitial growth occurs from inside it

Neither of these processes are confined to a certain region of the body as implied by one of the above answers. Interstitial growth is only involved in the early development of cartilage formation and occurs by mitotic division of pre-existing chondrocytes. Appositional growth is the more important process where the cartilage can grow in girth by cells differentiating from fibroblasts in the perichondrium (a dense layer of connective tissue surrounding areas of cartilage), becoming chondrocytes.

Answer: Foramen

Foramina provide a route for blood vessels, nerves etc. The large hole in a human vertebrae is for the spinal cord. Note that the foramen in lower vertebrae (e.g. at T12) is smaller than when compared to one higher up (e.g. at C5) because the nervous tissue inside it (spinal cord) has less of the body left to supply when it has travelled down a larger distance.

Answer: All of them

Joints are classified into cartilaginous, fibrous and synovial denominations. Synovial joints are the most common and important for movement. They are divided into many types by the way the 2 or more bones articulate with each other. They are uni- or bi- or multiaxial depending on how many planes of movement there are.

Answer: Through diffusion of the nutrients into the ground substance surrounding the cells making up the cartilage

Cartilage is completely avascular. There are blood vessels that supply the perichondrium around the cartilage, and nutrients can diffuse from here, or from the synovial fluid found in joint cavities. Articular cartilage (that covers uniting bones) is without a perichondrium and therefore gains oxygen and nutrients purely from diffusion from the synovial fluid.

Answer: Lacunae

All of the incorrect answers in this question are not real things! Each lacuna houses only one osteocyte in bone but can house more than one chondrocyte in cartilage. Osteocytes and chondrocytes are differentiated osteoblasts and chondroblasts respectively.