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.
A hemorrhoid is an enlarged vein in the anus (it's also called a varicose vein). In a healthy person, the tissue around the anus fills with blood to regulate bowel movements. However, when there is constant pressure restricting blood flow, the veins become inflamed. Poor blood flow may cause a blood clot. That results in a painful, swollen, protruding hemorrhoid.