Adrenaline causes an increase in heart rate, breathing, and blood pressure. This makes the heart work harder to pump blood faster around the body. Nicotine also causes the blood vessels to constrict. This means the heart works harder to pump blood through increasingly narrow vessels. Over time, this can lead to high blood pressure and cardiovascular disease. It also makes it more difficult for oxygen and nutrients to reach the skin, nails, hair, and mouth. As a result, people who use nicotine develop more wrinkles in their skin, brittle nails, thin hair, bad breath, and diseases of the mouth. Gradually, nicotine leads to changes in the walls of blood vessels, causing fatty substances such as cholesterol to build up more easily in the arteries. This disrupts the flow of blood through the body as fatty deposits restrict blood transportation. Over time, this buildup can cause cardiovascular disease, which is the leading cause of death in the US. Respiratory System The respiratory system’s primary function is to enable breathing. Nicotine causes inflammation of the lungs and also reduces the lungs’ ability to protect against foreign particles, which can lead to long-term damage. As a result, people who use nicotine may experience shortness of breath. Nicotine use also increases risk for developing chronic obstructive pulmonary disease (COPD) and cancer, which are also leading causes of death in the US. Nervous System The nervous system consists of the brain, spinal cord, and nerves. Nicotine usually acts as a stimulant, increasing heart rate, blood pressure, and breathing. In large doses, it can also act as a sedative, reducing anger and anxiety. Nicotine causes the release of a chemical called dopamine in the brain. Dopamine leads to a pleasurable sensation, just like when people use heroin or cocaine. People continue to use nicotine because they want this good feeling. Over time, the body develops a tolerance to nicotine, and people need higher levels of nicotine to enjoy the same effects. Using nicotine disrupts the brain’s natural production of dopamine. As a result, people become dependent on nicotine to experience dopamine’s positive sensations. This is why addiction happens so easily. Teens are especially sensitive to the effects of nicotine because their brains are still developing. Using nicotine rewires the brain and makes it easier to develop an addiction to other drugs. Nicotine also makes it harder to concentrate, learn, and control impulses. Digestive System Nicotine has harmful effects on the digestive system. The body is not able to process food as easily. Common conditions such as heartburn, gastroesophageal reflux disease, and ulcers may develop due to nicotine use. Nicotine use also increases the risk of Crohn’s disease (a form of inflammatory bowel disease), as well as pancreatitis and colon polyps. Immune System Using nicotine also leads to a weakened immune system. Your immune system includes organs, tissues, and cells that defend against disease-causing bacteria, parasites, and viruses. People who use nicotine have a greater risk of becoming ill from diseases like the common cold, flu, pneumonia, and meningitis. Copyright Goodheart-Willcox Co., Inc. Chapter 11 Vaping and Tobacco 367