Where is Type 1 collagen NOT primarily found?

Type 1 collagen is a major structural protein that is predominantly found in various tissues throughout the body, particularly in areas that require tensile strength. It is the most abundant collagen type and is primarily associated with bones, tendons, and skin.

In the context of the question, Type 1 collagen is primarily found in bones as it provides strength and support. The corneal stroma is another location where Type 1 collagen plays a significant role, contributing to the structural integrity and transparency of the cornea. The sclera, which is the white outer coating of the eyeball, consists predominantly of Type 1 collagen, giving it the necessary strength to maintain the shape of the eye.

Descemet's membrane, however, is distinct in its composition. While it is located within the cornea, it is primarily made up of Type 4 collagen, which is characteristic of basement membranes. This differentiation is crucial since Type 4 collagen is specifically involved in providing a supporting layer for epithelial cells rather than the tensile strength associated with Type 1. Therefore, indicating that Type 1 collagen is not primarily found in Descemet's membrane is accurate, making this the correct answer.