Hi my dear steemian friends. Welcome to my third episode on science series. Today we are discussing about a disease which will occur after our 5th decade of our lives.

Alzheimer's disease is the most common cause of dementia in elderly. It is a degenerative disease which cause gradual loss of neurons over many years. And dementia is most commonly found in elderly as it was seen in mine grandparents too. Now how many of us would like to live up to our 80's, most of us would like to but sadly many of us might be haunted by this disease. This disease might be the ultimate fate of the human brain after 85 years of age and statistics shows 1 out of 10 people aged 65 or older has this disease.

Synapses in human brain |credits|

Neuroscience of alzheimers

Synapse is the junction of two neurons where neurotransmitter are released. This is the place where signals are transmitted, place where our desires, memories and actions are communicated from one place to another. There are two neurons - presynaptic neurons and post synaptic neurons. The presynaptic neurons sends chemical messenger to post synaptic neurons and the receptors on the post synaptic neurons gives response according to chemical messenger. There are trillions of neurons in our brain and for every action we do the neurons send chemical messenger (neurotransmitter) to perform our activities.

credits

Can a protein cause Alzheimer's disease?

                Now along with the neurotransmitters neurons also release a small peptide known as  Aβ (Amyloid Beta precursor protein). Normally they are cleared by microglial cells. Microglial cells acts as immune defence mechanism of CNS (central nervous system). Alzheimers disease occurs when the Aβ (Amyloid proteins) starts to accumulate in the synapse. It occurs due to over production of Aβ  or reduced clearance by microglial cells. Accumulation of Aβ  cause formation of amyloid plaques. The formation of these plaques starts after the 4th-5th decade of life. The amyloid plaques builds up for 15-20 years to reach the threshold level or tipping point and triggers the cascade of clinical symptoms.

credits

            As the Aβ pile up the microglial cells starts to function more vigorously and damage the cell function and homeostasis. Instead of clearing the Aβ they cause inflammation and cause hyper phosphorylation of protein called tau causing it to be insoluble and forms neurofibrillary tangles (it twits the neuron cells ). Eventually due to these inflammation and tangle formation the neuron cells dies.

Normal brain vs alzheimers brain grossly credits

There is shrinkage of alzheimers brain due to destruction of neurons. The brain cells are damaged and progressively dementia occurs as temporal lobes and sulcus and gyrus are also atrophied.

How do we know that we have alzheimers?

The early symptoms of alzheimers starts with dementia. We can't remember peoples name or why did i come here or where did I keep my keys? Although this happens to most of us daily but in case of Alzheimers we start to keep the things in unusual places such as our toothbrush in our bedroom or keys in refrigerator. We cant even remember our close mates names. The dementia progresses and we will have problem in language, decision makings, judgements. We also cant do familiar tasks and have confusion about time and places.

How likely we are affected and how can we prevent it ?

If our parents have alzheimers then we are more prone to get this genetically. Although we cannot prevent alzheimers we surely can delay it. During our deep sleep cycles the microglial cells functions more effectively and clears most of the Aβ proteins. So if we sleep less or have bad sleep cycle then Aβ proteins accumulates more rapidly. research also show Obesity and cardiovascular disease can potentiate alzheimers. so having a good exercise and healthy lifestyle modification can prevent the tipping of Aβ ( prevent Aβ to reach threshold).

            As we know that due to inflammation and tangles the neurons die but new neurons can be formed too. The more knowledge we acquire the more we try to learn there are formation of new-neurons. So learn new things, languages, go new places and make more interesting friends.

Quick Facts about Alzheimers disease (credit)

So to my readers even if you are diagnosed with alzheimers some day then that doesn't mean you will die tomorrow so live happily you still will can feel love and happiness.

Reference used

All the credits for images are cited below them.

 |source 1|

 |source 2|

 |source 3|

 |source 4|

My previous science articles:

1 Cancer, Chemotherapy and Hair fall !!!

2 Is head transplant possible??