D. Interstitial part.
The organ shown in the photograph represents Fallopian tube.
Mucosa of fallopian tube is folded to form numerous longitudinal folds which project into the lumen. Maximum numbers of these folds are present in the ampulla.
- The mucosa is covered by simple columnar epithelium.
- The epithelium has two types of cells :‑
- Ciliated cells
- Non-ciliated secretory cells (peg cells)
- Secretion of peg cells provides nutrition to ovum.