Alzheimer s Disease

Alzheimer’s disease is a common problem in today’s society and within the older population this disease makes up the largest form of dementia. Although it is a problem in mainly older people, this disease can still occur in the younger population also. People in their 30s-50s can be diagnosed with this disease, even though it is not as common as people in their 60s-90s. The number of people with Alzheimer’s in the U.S. is close to five million and is expected to double within the next 30 years. With our modern medicine and advancements one would think a cure would be available, however, getting to the cause of the disease is a major factor. The cause of Alzheimer’s disease is one that is very debatable and questionable and most likely is a result of multiple factors rather than one. The main issue with finding the cause is because this disease affects the brain and can

Alzheimer 's disease (AD) is a progressive degenerative disease of the brain from which there is no recovery. There are three brain abnormalities that are the hallmarks of the Alzheimer’s disease is initially caused by plaques buildup in the brain’s neurons as illustrated in figure 1. The support structure that allows the flow of the nutrients through the neurons gets damaged and ultimately there is loss of connection among the neurons and they die off (National Institute of Health, 2015). This causes the brain tissue to shrinks, which is called atrophies. All this ultimately lead the victim of this disease to face difficulties in governing emotions, recognize errors and patterns, coordinate movement, and remember. Ultimately, a person with AD loses all memory and mental functioning.

Neurons, nerve cells, have three basic parts: the cell body, dendrites, and axon. Neurons transmit signals to other nerve cells and throughout the body. They are simple components in the nervous system. The cell body includes the nucleus, which is the control center of the neuron. The dendrite branches off the cell body and receives information. The axon is attached to the cell body and sends information away from the cell body to other cells. When the axon goes through myelination, the axon part of the neuron becomes covered and insulated with fat cells, myelin sheath. This increases the speed and efficiency of information processing in the nervous system. Synapse are gaps between neurons, this is where connections between the axons and dendrites.

As well as these there are also the axon of the cell which is covered in myelin sheaths which carried information away from the cell body and hands the action potentials, these are small short bursts of change in the electrical charge of the axon membrane through openings of ion channels, off to the following neurons dendrites through terminal buttons at the end of the axons. Whenever an action potential is passed through these terminal buttons it releases a chemicals that pass on the action potential on to the next neuron through the terminal button and dendrite connection. The chemicals that are

Alzheimer’s is a systemic disease, meaning that it affects more than one part of the body. There are three major systems that are affected by Alzheimer’s. The first involves the Central Nervous System. The CNS includes the brain and spinal cord, allowing the nervous system to make the spinal cord and brain function. The Central Nervous System is affected because specific brain proteins begin to malfunction and brain cells die. The loss of brain cells is the reason for memory loss and

This stage is called repolarisation. The K+ channels then close, the sodium-potassium pump restarts, restoring the normal distribution of ions either side of the cell surface membrane and thus restoring the resting potential. In response to this the Na+ channels in that area would open up, allowing Na+ ions to flood into the cell and thus reducing the resting potential of the cells. If the resting potential of the cell drops to the threshold level, then an action potential has been generated and an impulse will be fired.

Once a presynaptic neuron is passive, an electrical current is spread along the length of the axon (Schiff, 2012). This is known as action potential (Pinel, 2011). Action potential happens once an abundant amount of depolarisation reaches the limit through the entry of sodium, by means of voltage gated sodium channels

1. Neurons is a basic building block of the nervous system. The sensory nerves carry the message from body tissues to the brain and spinal chord to be processed. The motor neurons are then used to send instructions to the body tissue from the brain and spinal cord. Dendrites, which are connected to the body cell (soma) receive information and pass it through the axon. Myelin sheath covers the axon and helps speed the process. When triggered by a signals from our senses or other neurons, the neuron fires an impulse called the action potential. The resting potential is the neuron’s visual charge of positive

As an action potential travels down the axon of the presynaptic neuron, the action potential reaches the axon terminal synaptic vesicles which migrate toward the synapse. They then release neurotransmitters into the synaptic cleft. The neurotransmitters travel through the synaptic cleft and bind to ligand-gated ion channels on the postsynaptic neuron membrane. The channels open and allow chemicals to enter the cell (i.e. sodium). Then positively charged sodium enters the cell and causes the cell to depolarize. The depolarization spreads down the axon and an action potential is generated. The process then starts over at the axon terminals.

Alzheimer's and dementia is one of the many diseases that affects the nervous system, particularly the brain. Acute memory loss is known as dementia. Thus, Alzheimer's is a severe form of dementia. The diagnosis is the brain lacking brain cells and connections due to degradation. Symptoms of Alzheimer's includes memory loss which can range from minor to severe as well as confusion which directly corresponds to memory loss. Groups of nerves work together to focus on specific jobs such as communication and memory. The brain cells work together and “receive supplies, generate energy, construct equipment and get rid of waste.” Alzheimer's is believed to prevent parts of the cell to not function properly. Scientists are not thoroughly sure where the cells malfunction begins. As the cell continues to divide and spread, the infected cells begin to die off leading to damaged brain connections. Scientists believe that plaques and tangles are the cause of the disease. Plaques are “deposits of a protein fragment called beta-amyloid that build up in the spaces between nerve cells.” Tangles are “twisted fibers of another protein called tau that build up inside cells.” Age results in developed plaques and tangles though, Alzheimer patients have an abnormal amount of these

In 1906, Dr. Alois Alzheimer had a patient named Auguste D. He described this patient by saying she had “profound memory loss and unfounded suspicions about family” (Alzheimer, 1906). After his patient had died, he performed an autopsy to rule the cause of death. Alzheimer claims he found “dramatic shrinkage and abnormal deposits in and around the nerve cells”. His findings set new standards for understanding neuro-degenerative disorders around the world. In 1910, this newly discovered abnormality was coined as “Alzheimer’s Disease” (healthline.com). Researching soon ensued and scientists now had more information than ever. In 1976, Alzheimer’s was recognized as the most common cause of dementia. By 1984 Beta-amyloid was found present in brain

Once in the synapses, the impulses triggers the release of chemical messages called neurotransmitters; which then bind to receptors on the receiving cell as the transmission of the impulse repeated again. The message or impulse continues traveling from one neuron to the next throughout the body until it reaches its destination as it relays a signal. All of this activity happens in less than a split second and without conscious thought. At the end of this process, the brain has the task of interpreting the message and making the decision as to what to do with this new information. (Carlson, 2011.Pg.45-52)

When a membrane is excited depolarization begins. When the membrane depolarizes the resting membrane potential of -70 mV becomes less negative. When the membrane potential reaches 0 mV, indicating there is no charge difference across the membrane. the sodium ion channels start to close and potassium ion channels open. By the time the sodium ion channels finally close. The membrane potential has reached +35 mV. The opening of the potassium channels allows K+ to flow out of the cell down its electrochemical gradient ( ion of like charge are repelled from each other). The flow of K+ out of the cell causes the membrane potential to move in a negative direction. This is referred to as repolarization. ( Marieb & Mitchell, 2009). As the transmembrane potential comes back down towards its resting potential level and the potassium channels begins to close, the trasmembrane potential level goes just below -90mV, causing a brief period of hyperpolarization (Martini, Nath & Bartholomew, 2012). Finally, as the potassium channels close, the membrane turns back to its resting potential until it is excited or inhibited again.

Neuronal messages are transmitted by electrical impulses called the Action Potential. This is actually a net positive inward ion flux that leads to depolarization or voltage change in the neuronal membrane. The ions involved include sodium, potassium, calcium and chloride. Normally brain tissues prevent hyper excitability by several inhibitory mechanisms involving negative ions like chloride ions.

Nerve cells generate electrical signals to transmit information. Neurons are not necessarily intrinsically great electrical conductors, however, they have evolved specialized mechanisms for propagating signals based on the flow of ions across their membranes.