Which one of the following pairs of structures is correctly matched with their correct description?
A
Tibia and fibula – Both form parts of knee joint
B
Cartilage and cornea – No blood supply but do require oxygen for respiratory need
C
Shoulder joint and elbow joint – Ball and socket type of joint
D
Premolars and molars – 20 in all and 3-rooted
The answer is B.
Solution
Cartilage and the cornea are both avascular, i.e., they have no blood vessels. Being living tissues, they still need oxygen, which they obtain by diffusion (cartilage from the surrounding perichondrium, the cornea from the air and the aqueous humour). This pair is correctly described. The knee joint is formed between the femur and the tibia (with the patella in front); the fibula does not take part in it. The shoulder joint is a ball and socket joint, but the elbow joint is a hinge joint. An adult has 8 premolars and 12 molars, i.e., 20 in all, but they are not all 3-rooted (premolars are mostly single- or double-rooted, lower molars are 2-rooted). Hence the correctly matched pair is cartilage and cornea.
ConceptAvascular tissues
Skeletal System and Joints in past papers
3 questions from this chapter have appeared across 2 exam years.
