Fill in the Blank QuestionFill in the blank question.A capillary's wall is made of a single layer of cells.

What are capillary walls composed of?Multiple choice question.simple squamous epitheliumareolar connective tissuesmooth musclestratified squamous epithelium

Explain why capillaries have a very small lumen and walls that are only one cell thick.

What is the structure of a capillary?

Name the substances that can pass through the walls of the capillary via facilitated diffusion.

Describe the structural changes from arteries to arterioles, capillaries,venules and then to veins. Why are the walls of capillaries so thin?