Alzheimer's disease is a degenerative brain disease that mainly affects the elderly. As the symptoms of Alzheimer's disease grow worse, the damage to the brain increases. According to the Alzheimer's Association, Alzheimer's disease results in nerve death and tissue loss. As a result, the brain becomes dramatically smaller when compared to a normal brain. Due to the loss of nerves and brain tissue, brain functions are severely impaired. When an Alzheimer's disease patient's brain is compared to a brain of a healthy person, there are stark differences in brain structures and size, including the presence of plaques and tangles.
Cortex
The cerebral cortex is the outermost layer of the cerebrum, which is the largest part of the brain. According to the Stroke Center at Washington University in St. Louis' School of Medicine, the cerebrum is responsible for multiple functions, like movement, sensory stimuli, emotion, speech and higher intellectual function. In the brain of an Alzheimer's disease patient, the cortex is severely impaired. According to the Alzheimer's Association, the cortex shrivels up, which damages the area involved in thinking, planning and remembering.
Hippocampus
According to the Stroke Center at Washington University in St. Louis' School of Medicine, the hippocampus is integral in the creation of new memories. Located in the medial temporal lobe of the brain, the hippocampus is in the shape of a seahorse. According to the Alzheimer's Association, the hippocampus in the Alzheimer's disease patient's brain shrivels up. As a result, memory functions are severely impaired.
Ventricles
Fluid-filled spaces that look like large indents, called ventricles, occur naturally in the brain. However, according to the Alzheimer's Association, the ventricles in an Alzheimer's patient's brain grow larger, attributing to the smaller size of the brain.
Plaques
According to the Alzheimer's Association, one of the changes to the Alzheimer's disease patient's brain is the formation of plaques. Plaques are an abnormal cluster of protein fragments---beta-amyloid proteins that clump together. As a result, the cluster of beta-amyloid proteins build up between the nerve cells, affecting normal brain function.
Tangles
Another change in the Alzheimer's disease patient's brain, according to the Alzheimer's Association, is the creation of tangles. Tangles are twisted strands of proteins, which are contained in dead or dying nerve cells. Like plaques, tangles also affect the normal function of brain cells. An example of brain disruption cause by tangles is the destruction of cell transport.
