Final answer:
A tract between two epithelium-lined surfaces open at both ends is called a fistula. Epithelial membranes, including mucous membranes, line body cavities and passageways exposed to the environment. Epithelium and endothelium cover and line various parts of the body. The correct option is A.
Step-by-step explanation:
The student is asking what a tract between two epithelium-lined surfaces that is open at both ends is called. The correct answer is a) Fistula. A fistula is an abnormal connection between two body parts, which could include organs, blood vessels, or epithelium-lined surfaces. This pathological feature is typically hollow and could allow the content from one part to pass into the other.
Epithelial membranes are composed of epithelium attached to a layer of connective tissue. A mucous membrane, sometimes referred to as mucosae, is a type of epithelial membrane that lines body cavities and hollow passageways which are exposed to the external environment. These include, but are not limited to, the digestive, respiratory, excretory, and reproductive tracts.
The mucous membrane produces mucus that covers the epithelial layer, and its underlying connective tissue known as the lamina propria helps support this epithelial layer.
Most Epithelial Tissues
Most epithelial tissues form large sheets of cells that cover all the surfaces of the body exposed to the outside world and line the outside of organs. These areas include the airways, the digestive tract, and the urinary and reproductive systems, all lined by epithelium. Hollow organs and body cavities that do not open to the exterior are lined by endothelium.