Natural oils contain hundreds of organic constituents such as hormones, vitamins and other natural elements that are beneficial to the skin. Natural oils fall into two general categories: essential oils and carrier or base oils. Essential oils are volatile compounds found in plants. They give fruits, flowers, herbs and spices their fragrance and flavor. Obtained by distillation or expression, essential oils are highly concentrated and used at a very low concentration. Carrier oils, such as almond, sunflower, olive, walnut and other oils exist in higher concentration in cosmetics and when applied directly to the skin nourish, soften and protect it. Diluting essential oils makes them good bases. Oils are highly penetrating. They easily enter through a cell wall delivering essential vitamins, oxygen and nutrients. This helps stimulate cell metabolism and the regeneration process. The ability of oils to penetrate and carry nutrients through the cell wall to the cell nucleus can prevent cell deterioration, which can lead to infections and diseases.

Effects of Steroids

The kind of binding the steroids have to hormones determines the immediate effects of steroids in the brain. Androgen (male sex hormone) and estrogen (female sex hormone) receptors on the surface of a cell attract steroids. The steroid–receptor complex affects the cell nucleus and can influence patterns of gene expression. Because of this, the acute effects of steroids in the brain are substantially different from those of other drugs. Steroids are not euphorigenic, and do not trigger rapid increases in the neurotransmitter dopamine, which is responsible for the high that often drives substance abuse behaviors. However, long term steroid use eventually influences the same brain pathways and affects chemicals such as dopamine, serotonin and opioid systems. Considering the combined effect of their complex direct and indirect actions, it is not surprising that Steroids can affect mood and behavior in significant ways.

Internal Medicine

Doctors of internal medicine focus on adult medicine and have had special study and training focusing on the prevention and treatment of adult diseases. At least three of their seven or more years of medical school and postgraduate training are to learning how to prevent, diagnose, and treat diseases that affect adults. Internists are sometimes known as the doctor's doctor, because they act as consultants to other physicians to help solve puzzling diagnostic problems. Internists can choose to focus their practice on general internal medicine, or may take additional training to sub-specialize in one of 13 areas of internal medicine. Cardiologists, for example, are doctors of internal medicine who sub-specialize in diseases of the heart. The training an internist receives to sub-specialize in a particular medical area is both broad and deep. Subspecialty training usually requires an additional one to three years beyond the standard three-year general internal medicine residency. Internal medicine is the medical specialty dealing with the prevention, diagnosis, and treatment of adult diseases. Doctors of internal medicine, also known as internists, are sometimes the doctor's doctor, because other physicians consult them to help solve puzzling diagnostic problems. They are especially skilled in the management of patients who have undifferentiated or multi-system disease processes. An internist cares for hospitalized and ambulatory patients and may play a major role in teaching or research. Internal medicine is also a type of veterinary specialty. The term internal medicine comes from the German term "Innere Medizin," popularized in Germany in the late 19th century to describe physicians who combined the science of the laboratory with the care of patients. Many early-20th-century American doctors studied medicine in Germany and brought this medical field to the United States. Specialists in internal medicine are internists in the United States. In modern practice, most internists are subspecialists; that is, in general, they limit their medical practice to problems of one organ system or to one particular area of medical knowledge. For example, gastroenterologists and nephrologists specialize in diseases of the gut and the kidneys, respectively.