Final answer:
B) Laminin 332
In junctional Epidermolysis Bullosa with pyloric stenosis, the defective part of the basement membrane is Laminin 332, which is essential for cell adhesion in the epithelium.
Step-by-step explanation:
The student asked about the part of the basement membrane that is defective in junctional Epidermolysis Bullosa (EBA) with pyloric stenosis. The answer is B) Laminin 332. This protein is a major component of the basement membrane and is essential for proper adhesion between the epithelial cells and underlying tissues. In cases of junctional EBA, mutations affecting Laminin 332 disrupt this adhesion, leading to the clinical manifestations of the disease. It's important to note that collagen types, such as Type IV collagen and Type VII collagen, as well as fibronectin, also play key roles in the structure and function of the basement membrane, but in the specific context of junctional EBA with pyloric stenosis, the defective component is Laminin 332.