Which type of simple epithelial tissue primarily lines most of the digestive tract (stomach to rectum)?

• A. Simple squamous epithelium
• B. Simple columnar epithelium
• C. Stratified squamous epithelium
• D. Simple cuboidal epithelium

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the function of the digestive tract lining. The lining must facilitate absorption and secretion, which requires cells that are tall enough to house organelles for these processes.
2. Step 2: Review the characteristics of simple epithelial tissues. Simple epithelium consists of a single layer of cells, which allows for efficient diffusion, absorption, or secretion.
3. Step 3: Compare the types of simple epithelium: simple squamous epithelium is thin and flat, ideal for diffusion (e.g., lungs); simple cuboidal epithelium is cube-shaped, often involved in secretion and absorption in glands and kidney tubules; simple columnar epithelium is tall and column-shaped, specialized for absorption and secretion.
4. Step 4: Consider the digestive tract's needs. From the stomach to the rectum, the lining must absorb nutrients and secrete mucus and enzymes, which is best supported by simple columnar epithelium due to its height and organelle content.
5. Step 5: Conclude that simple columnar epithelium primarily lines most of the digestive tract (stomach to rectum) because it is structurally and functionally suited for absorption and secretion in this region.