then the system is called a severe tropical cyclone. These are referred to as hurricanes or typhoons in other countries. The circular eye or centre of a tropical cyclone is an area characterised by light winds and often by clear skies. Eye diameters are typically 40 km but can range from under 10 km to over 100 km.hen the system is called a severe tropical cyclone. These are referred to as hurricanes or typhoons in other countries. The circular eye or centre of a tropical cyclone is an area characterised by light winds and often by clear skies. Eye diameters are typically 40 km but can range from under 10 km to over 100 km.
A UCLA Health answered. Alzheimer's disease affects the brain. The disease causes degeneration of brain tissue and nerve cells. With less nerve cells present, it becomes harder for the brain to communicate with the body and function properly. Specifically, the neurotransmitter (a chemical that passes among cells relaying messages) acetylcholine isn't produced at a high enough volume.
Alzheimer's and dementia basics. 1  Alzheimer's is not a normal part of aging. The greatest known risk factor is increasing age, and the majority of people with Alzheimer's are 65 and older. But Alzheimer's is not just a disease of old age. Approximately 200,000 Americans under the age of 65 have younger-onset Alzheimerâs disease (also known as early-onset Alzheimerâs). Learn more: Early Onset Alzheimer's and Risk Factors ; Alzheimer's worsens over time. Alzheimer's is a progressive disease, where dementia symptoms gradually worsen over a number of years. In its early stages, memory loss is mild, but with late-stage Alzheimer's, individuals lose the ability to carry on a conversation and respond to their environment.