Question

Brush border of small intestine cells are formed of
A. Microvilli
B. Cilia
C. Villi
D. Circular folds

Answer 1

Hint: The small intestine is an organ that is situated between the stomach and the large intestine in the gastrointestinal tract. Functionally, the small intestine is primarily involved in food digestion and absorption. Via the hepatopancreatic duct, it receives pancreatic secretions and bile that helps with its functions.

Complete Answer:
The small intestine's histological composition is identical to that of other organs in the digestive tract. Four key layers exist:
1. Mucosa (Innermost layer): Contains the epithelium, lamina propria and muscularis mucosae.
2. Submucosa: A layer of connective tissue comprising blood vessels, lymphatics, and the submucosal plexus.
3. Muscularis externa is composed of two layers of smooth muscle; the longitudinal outer layer and the circular inner layer. Among them lies the myenteric plexus.
4. Adventitia (Outermost layer)-Consisting of poorly arranged fibroblasts and collagen, moving through the vessels and nerves. The bulk of the adventitia of the small intestine is covered by mesothelium and is generally referred to as serosa.

The small intestine is the gastrointestinal tract 's main absorptive site and thus has a variety of modifications to assist its work. Large numbers of folds (or plicas) arranged in a circular fashion in the lumen (hence called plicae circulares) form the mucosa and submucosa. In addition, to further increase the surface area, the plicas contain microvilli, which enhances absorption.

The mucosa is the innermost layer lining the lumen of the alimentary canal. In the stomach, this layer forms irregular folds (rugae) and in the small intestine, small finger-like folds called villi.

Numerous microscopic projections called microvilli are produced by the cells lining the villi, giving a brush border appearance found on some epithelial cells' apical surface. In the plasma membrane enclosing cytoplasm and microfilaments, microvilli are covered. While these are cell extensions, the microvilli are present with little to no cellular organelles. Therefore, microvilli are produced from the brush border of small intestine cells.

The correct Answer is option (A) Microvilli

Note: Coeliac disease is a disorder that causes the small intestine to become inflamed. It is autoimmune in aetiology, affecting approximately 1 in 100 individuals. Immune-mediated disruption to the tiny intestine is secondary to exposure to gluten. Serology and biopsy are the two principal trials of coeliac disease. It is possible to find antibodies to gliadin and its other products in plasma.