Question

Each of the following is true about basal lamina except

A) it serves as a structural support.
B) it allows for movement of some small molecules but blocks movement of large molecules.
C) it can influence cell migrations in certain areas of the body.
D) it contains collagen type IV, proteoglycans, laminins, and entactin.
E) it is composed primarily of fibronectin.

Answer 1

The statement 'it is composed primarily of fibronectin' is not true about the basal lamina; it primarily contains collagen type IV, proteoglycans, laminins, and entactin.

Step-by-step explanation:

The main answer to the question, "Which of the following is not true about the basal lamina?" is E) it is composed primarily of fibronectin. The basal lamina contains collagen type IV, proteoglycans, laminins, and entactin, but not primarily fibronectin.

Fibronectin is indeed an important glycoprotein involved in cell adhesion and migration; however, it is not a primary component of the basal lamina. Instead, fibronectin typically links the extracellular matrix components together and to integrins. The basal lamina primarily serves as an attachment site for epithelia, separates them from underlying connective tissues, and plays roles in tissue differentiation, cell migration, and filtration in organs like the kidneys.