Small intestine and intestinal villi
Small intestine and intestinal villi

Digested food is able to pass into the blood vessels in the wall of the small intestine through a process called diffusion. The inner wall (called mucosa) of the small intestine is covered with folds called plicae circulares that project finger-like projections of tissue called villi. Celiac disease damages these villi.

Anatomy of intestinal villi
Anatomy of intestinal villi

Intestinal villi (singular- villus) are small, finger-like projections that extend into the lumen of the small intestine. Each villus is about 0.5–1.5 mm in length.

Gluten-free and gluten-containing foods
Gluten-free and gluten-containing foods

For people with celiac disease, gluten disrupt the lining of the small intestine and triggers an immune response that attracts inflammatory cells and causes inflammation. Such people must avoid gluten-containing foods.

Normal long villi (above) vs celiac disease (below) with blunted villi
Normal long villi (above) vs celiac disease (below) with blunted

Villi are small, finger-like projections in the small intestines that help absorb the nutrients. The blunting or flattening of the villi can be caused by the damage done by the immune system due to celiac disease after ingesting gluten-containing foods. 

Microscopic view of small intestine with normal elongated villi
Microscopic view of small intestine with normal elongated villi

The picture shows a microscopic view of small intestine with normal elongated villi. The elongated villi increases the surface area for absorption of nutrients. If you have celiac disease, the villi are flat, which causes diarrhea.

Damaged intestinal lining due to celiac disease
Damaged intestinal lining due to celiac disease

A horrible truth of celiac disease is that though the damage it causes affects the gut, only 40% of children and 60% of adults report digestion-related symptoms.

Celiac disease signs and symptoms
Celiac disease signs and symptoms

The most common symptoms of celiac disease are diarrhea, bloating, gas (flatulence, farting), swollen ankles, anemia, fatigue, vitamin K deficiency, bruising and bleeding.

Celiac disease
Celiac disease

Celiac disease is a problem that results in the damage of the lining of the small intestine when foods with gluten are eaten. The tiny, finger-like projections which line the bowel (villi) become inflamed when food with gluten is eaten.