A peptic ulcer is erosion in the lining of the stomach or the first part of the small intestine, an area called the duodenum. If the peptic ulcer is located in the stomach it is called a gastric ulcer.

Morphology refers to the shape and structure of the sperm. A normal-looking sperm has an oval head and a tail seven to 15 times longer than the head. On a semen analysis, in which we look at sperm under the microscope, we can identify defective sperm by their large heads or strange tails -- kinked, doubled, or coiled.

Masturbation is a process where a person derives sexual pleasure by stroking his genitals by his hands. It is usually performed by singletons but married person also perform this activity highly to reach orgasm level.

Osteosarcoma is the most common primary malignant bone cancer. It most commonly affects younger males between 10 and 25 years old, but can less commonly affect older adults. It often occurs in the long bones of the arms and legs at areas of rapid growth around the knees and shoulders of children. This type of cancer is often very aggressive with risk of spread to the lungs. The five-year survival rate is about 65%. It starts in immature bone cells that normally form new bone tissue.

Stress is caused by the body's instinct to defend itself. This instinct is good in emergencies, such as getting out of the way of a speeding car. But it can cause physical symptoms if it goes on for too long, such as in response to life's daily challenges and changes.