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.
All of the above processes have a devastating impact on the brain, and over time, it shrinks dramatically, affecting nearly all of its functions. The rate of progression of the disease varies greatly. People with Alzheimer's live an average of eight years, but some people may survive up to 20 years. The course of the disease depends in part on age at diagnosis and whether a person has other health conditions. The medical community uses stages to apply a timeframe to the progression of the disease.