Chitin is a primary component in the exoskeletons of arthropods and crustaceans and is also found in the cell walls of fungi. It's a polysaccharide, and it's excreted by the epidermal cells in arthropods.
Definition & Facts. Hemorrhoids, also called piles, are swollen and inflamed veins around your anus or in your lower rectum. External hemorrhoids form under the skin around the anus. Internal hemorrhoids form in the lining of the anus and lower rectum.
What are external hemorrhoids? Hemorrhoids occur when the veins of the rectum or anus become dilated or enlarged. Depending on where your hemorrhoids are located, they are considered âinternalâ or âexternal.â External hemorrhoids are usually found beneath the skin that surrounds the anus.