Fungi. A fungus (singular) is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms (Figure 1). Fungi are classified as a kingdom that is separate from plants, animals, and bacteria.One major difference is that fungal cells have cell walls that contain chitin, unlike the cell walls of plants, which contain cellulose.he discipline of biology devoted to the study of fungi is known as mycology, which is often regarded as a branch of botany, even though genetic studies have shown that fungi are more closely related to animals than to plants. Pathogenic fungi are fungi that cause disease in humans or other organisms.
Erectile Dysfunction Causes and Symptoms. There are many causes of erectile dysfunction (impotence) and some include: 1  blood vessel diseases (such as peripheral vascular disease and others), 2  systemic disease, 3  hormonal imbalance, and. 4  medications (such as blood pressure and heart medications).
1 Erectile dysfunction is defined as persistent difficulty achieving and maintaining an erection sufficient to have sex. 2  Causes are usually medical but can also be psychological.  Organic causes are usually the result of an underlying medical condition affecting the blood vessels or nerves supplying the penis.