Medullae may be classified as being:
A) Continuous
B) Fragmented
C) Interrupted or Absent
D) Both A and B
E) All of the above
The correct answer and explanation is:
The correct answer is E) All of the above.
Medullae in hair structure refer to the central core of the hair shaft, which may have varying degrees of continuity or absence. It can be classified in multiple ways, depending on its appearance and composition.
- Continuous: In some hair types, the medulla is continuous, meaning it forms an uninterrupted, solid structure running the length of the hair. This is typically seen in thicker or coarser hair types. The continuous medulla is often visible when hair is examined under a microscope, forming a clear and solid central portion.
- Fragmented: In other cases, the medulla may be fragmented, meaning it appears in broken or discontinuous segments. This type of medulla might have gaps or spaces within it, making it look incomplete. This is commonly seen in finer or softer hair types and can vary from hair to hair.
- Interrupted or Absent: Some hair types might have an interrupted medulla, where it is present only in sections along the hair shaft, or it may be completely absent. Fine, light-colored hair often lacks a medulla altogether. This absence can also be seen in certain individuals where genetic factors prevent its formation.
Hair with a continuous or fragmented medulla is often found in humans, though the presence and characteristics of the medulla can vary among different species. Its presence and form can affect the hair’s strength, appearance, and even its thermal properties. Understanding the classification of the medulla can aid in the identification of hair types and contribute to fields like forensic science, where hair analysis may be crucial.