2. Stomach 3.Ulcers 4.Duodenum 5.Mucosa 6.Submucosa 7.Muscle

When peptic ulcers occur, they can be found in either the lining of the stomach, the lining of the duodenum, or in both. Peptic ulcers can be minor (they only go through the first or the second layers of the stomach), or can be considered a medical emergency (they go through every layer of the stomach or duodenum lining)
A peptic ulcer is a defect that occurs in the first part of the small intestine or in the lining of the stomach. Gastric ulcers occur in the stomach whereas duodenal ulcers occur in the intestine. Small ulcers may not be noticeable, whereas large ulcers are painful and are considered medical emergencies. Abdominal pain is a common symptom seen with multiple types of ulcers. Common causes of ulcers can be: bacterial infections in the stomach or duodenum, a weakening of the stomach lining caused by a continuous use of an anti inflammatory, or, there is a common belief that ulcers are caused by stress.