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).
The causes of erection problems can be physical, psychological, or a combination of the two. Physical causes of erection problems are more common in older men. They occur because of disorders that can affect the nerves and blood vessels responsible for causing an erection. 1  Physical causes of erectile problems include: 2  heart disease. 3  atherosclerosis (hardening of the arteries). 4  high blood pressure. 5  diabetes. 6  obesity. 7  high cholesterol. 8  Parkinsonâs disease.