Video Transcript
Bones in the skeleton form from
cartilage, and cartilage also makes up structures like the external ears and the
nose. Which of the following is a correct
difference between bone and cartilage? (A) Cartilage is a connective
tissue, whereas bone is an epithelial tissue. (B) Cartilage is a hard tissue,
whereas bone is a soft tissue. (C) Cartilage contains a network of
capillaries, whereas bone contains a network of arterioles. Or (D) cartilage does not contain
blood vessels, whereas bone does.
Bone and cartilage are both
connective tissues, meaning they are made up of living cells and fibers suspended in
a nonliving matrix. And they both play a role in the
skeletal system, as mentioned in this question. Since we know that bone and
cartilage are both connective tissues, we can eliminate (A). But what are some differences
between bone and cartilage?
While both bone and cartilage are
strong connective tissues, bone is strong and hard. Cartilage is more flexible and not
quite as strong as bone. The bone in your elbow is certainly
harder, for example, than the flexible cartilage in your ears and nose. Since we know that bone is harder
than cartilage, we can eliminate (B).
One of the key differences between
bone and cartilage is that bone contains blood vessels, and therefore its cells have
a ready blood supply. Cartilage does not contain blood
vessels. In fact, when bone is forming in
areas of cartilage in an immature skeleton, one of the key changes during this
process is that blood vessels grow into the area where bone will form. The lack of blood supply in
cartilage is one reason why if it is damaged it heals very slowly. When a young child whose bones have
not completely formed breaks an arm, it may take longer to heal for this reason. Since we know cartilage does not
contain blood vessels, we can eliminate (C).
The correct answer is (D). A difference between bone and
cartilage is that cartilage does not contain blood vessels, whereas bone does.
