Editing Haemodynamic response (section)

==== Alzheimer's disease ====
In this disease, there is a build of the [[amyloid beta]] protein in the brain. This ultimately leads to a reduction in the haemodynamic response and less blood flow in the brain. This reduced cerebral blood flow not only kills neuronal cells because of shortages in oxygen and glucose but it also reduces the brain's ability to remove amyloid beta. In a healthy brain, these protein fragments are broken down and eliminated. In Alzheimer's disease, the fragments accumulate to form hard, insoluble plaques which reduce blood flow. Two proteins are involved in this accumulation of amyloid beta: [[serum response factor]] or [[serum response factor|SRF]] and myocardin.<ref>"Blood Flow In Alzheimer's Disease." ScienceDaily. ScienceDaily, 29 June 2009. Web. 04 Nov. 2012. https://www.sciencedaily.com/releases/2009/06/090624211135.htm</ref> Together, these 2 proteins determine whether smooth muscle of blood vessels contract. SRF and myocardin are more active in the brains of people with Alzheimer's disease. When these proteins are active, they turn on SREBP2 which inhibits LRP-1. LRP-1 helps the brain remove amyloid beta. Therefore, when SRF and myocardin are active, there is a buildup in amyloid beta protein which ultimately leads to less blood flow in the brain because of contracted blood vessels.<ref>"Doc Blog." Cardiovascular System Proteins Play a Role in Alzheimer's. N.p., n.d. Web. 04 Nov. 2012. http://www.docblog.org/cardiovascular-system-proteins-play-a-role-in-alzheimers.html</ref>