A catheter is a thin, flexible tube used in medicine to help with various health issues. It can be inserted into the body to drain fluids, deliver medications, or perform other medical tasks. For example, a urinary catheter helps people who have difficulty urinating by allowing urine to flow from the bladder into a bag outside the body. There are different types of catheters, such as those used for the heart or blood vessels, known as cardiac catheters. These specialized catheters can help doctors diagnose and treat conditions related to the heart and circulatory system. Overall, catheters play a crucial role in modern medical care.