Human digestive system digestive system is subject to a wide range of disorders many of which can be congenital. Mouth diseases can also be caused by pathogenic bacteria, viruses, fungi and as a side effect of some medications. Mouth diseases include tongue diseases and salivary gland diseases. A common gum disease in the mouth is gingivitis which is caused by bacteria in plaque. The most common viral infection of the mouth is gingivostomatitis caused by herpes simplex. A common fungal infection is candidiasis commonly known as "thrush" which affects the mucous membranes of the mouth. There are a number of esophageal diseases such
Nervous system disease Nervous system disease Nervous system diseases, also known as nervous system or neurological disorders, refers to a small class of medical conditions affecting the nervous system. This category encompasses over 600 different conditions, including genetic disorders, infections, cancer, seizure disorders (such as epilepsy), conditions with a cardiovascular origin (such as stroke), congenital and developmental disorders (such as spina bifida), and degenerative disorders (such as multiple sclerosis, Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis). Signs and symptoms can vary depending on the condition. Given the significance of the nervous system in human physiology, symptoms can involve other organ systems and