GENERAL HISTOLOGY

Detailed explanation-1: -Histologically, the large intestines can be distinguished from the small intestines by the absence of villi, plicae circularis, and Paneth cells (in adults). Simple columnar epithelium lines its mucosa. The crypts of Lieberkühn are deeper in the colon and goblet cells become more abundant.

Detailed explanation-2: -The mucosa of the small intestine includes circular folds, villi, and microvilli. The wall of the large intestine has a thick mucosal layer, and deeper and more abundant mucus-secreting glands that facilitate the smooth passage of feces.

Detailed explanation-3: -Goblet cells reside throughout the length of the small and large intestine and are responsible for the production and maintenance of the protective mucus blanket by synthesizing and secreting high-molecular-weight glycoproteins known as mucins.

Detailed explanation-4: -In the respiratory tract, besides protecting the epithelial surface, mucus traps harming particles inhaled with air to protect the airway. Goblet cells produce small amounts of mucus continually, which is known as basal (constitutive) secretion.