Paneth cells contain –
**Core Concept**
Paneth cells are a type of epithelial cell located in the crypts of Lieberkühn in the small intestine. They play a crucial role in maintaining the intestinal microbiome by secreting antimicrobial peptides, such as defensins and lysozyme.
**Why the Correct Answer is Right**
Paneth cells are characterized by their large, eosinophilic granules that contain these antimicrobial peptides. The granules are produced by the cell through a process involving the enzyme protein kinase C (PKC), which activates the transcription factor NF-κB, leading to the expression of genes involved in defensin production. The defensins are then packaged into the granules and secreted into the intestinal lumen, where they help to protect against bacterial overgrowth and infection.
**Why Each Wrong Option is Incorrect**
**Option A:** Paneth cells are not primarily involved in the absorption of nutrients, which is the main function of intestinal epithelial cells.
**Option B:** Paneth cells do not contain lysosomes, which are membrane-bound organelles responsible for cellular digestion and recycling.
**Option C:** Paneth cells are not a type of goblet cell, which are responsible for producing mucin, a key component of mucus.
**Clinical Pearl / High-Yield Fact**
Paneth cells are an important example of the intestinal epithelium's ability to adapt to environmental changes, and their dysfunction has been implicated in various gastrointestinal disorders, including Crohn's disease and ulcerative colitis.
**Correct Answer: C. Paneth cells contain antimicrobial peptides, such as defensins and lysozyme.**