Final answer:
The small intestine is lined with a simple columnar epithelium and features villi and microvilli to enhance nutrient absorption. The cells here are rapidly dividing, which makes them susceptible to chemotherapy. MALT in the lamina propria contributes to immune function but bile production and detoxification are liver functions.
Step-by-step explanation:
The physiology of the small intestine is complex, with several key functions related to digestion and absorption of nutrients. The epithelium of the small intestine is primarily simple columnar epithelium, not stratified squamous epithelium. This epithelium has adaptations, such as villi and microvilli, which greatly increase the surface area for absorption. These structures are crucial for the digestion and absorption of nutrients as they move from the luminal side into the bloodstream through various cellular mechanisms. The cells of the epithelium are enterocytes, which have a high turnover rate and are often affected by chemotherapy due to rapid cell division, leading to side effects like nausea and vomiting.
The lamina propria of the intestinal mucosa contains mucosa-associated lymphoid tissue (MALT), including Peyer's patches, which play an important role in the immune response to prevent bacteria from entering the bloodstream. The small intestine does not store nutrients, make bile, or detoxify substances; these functions are mainly carried out by the liver. The physiology associated with hiatal hernias, ankyloglossia, and gallstone obstruction (crystallized cholesterol) pertains to other areas of the digestive system and not directly to the small intestine's functions.