Abstract
Bipolar cells serve as the bridge cell between the photoreceptor cell and the ganglion cell that located in the INL and span from the OPL down towards the IPL of the retina. Like the photoreceptor cell it also must transduce a chemical signal in order to signal ganglion cells or amacrine cells. The transduction pathway in the bipolar cell is different from the photoreceptor transduction pathway in that there are two distinct bipolar cells that do not use photons as the trigger but instead the neurotransmitter glutamate that is activated by hyperpolarization of the photoreceptors. ON-bipolar cells are depolarized by a central stimuli to the receptive field that is position in the center while OFF-bipolar cells are hyperpolarized by
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Within the retina lay different cells capable of handling and directing different pathways. From the photoreceptors, to horizontal cells, bipolar cells, amacrine cells, and the ganglion cells. Of these cells it is the bipolar cell which conducts visual signals to the brain using parallel ON-Center and Off-Center pathways (4). The pathways these signals travel from the bipolar cells are considered ON when depolarized and when OFF are hyperpolarized. In the mammalian retina metabotropic glutamate receptors (mGluRs) are associated with the ON pathway and ionotropic glutamate receptors (iGluRs) are associated with the OFF pathway …show more content…
The implication for this occurrence is that glutamate must block a certain cation-permeable channel keeping the cell continuously depolarized (7). The mGluR6 couples to heterotrimeric G protein complex, known as GO. For phototransduction to occur the GOα ¬ complex must be able close the non-selective melastatin-related transient receptor-1 (TRPM1) cation-channel at the moment when activation of the ON bipolar cell occurs (8). The mechanism of exactly how this complex was able to close the cation-channel was unknown until recently. The dominant α subunit of the G¬O is Gαo and Gαo2 has been noted to help during the ON polar light response (9). Furthermore, Gβϒ in the latest studies in many signaling processes has shown to act differently with different effectors giving array to a multitude of assembly and movement of receptor based signaling complexes (9). Because of Gβϒ there has been signaling mechanisms based on G-proteins range that has increased its
Stone, J. (1972). Morphology and physiology of the geniculocortical synapse in the cat: The question of parallel input to the striate cortex. Investigative Ophthalmology & Visual Science, 11, 338-46.
G-protein-linked receptors are protein receptors, located in the plasma membrane of a cell, that work with G-proteins to activate a cell-signaling pathway. These receptors are structured similarly in most organisms, with seven α helices and specific loops for binding sites for signal molecules and G-proteins. When a signal molecule from the extracellular fluid attaches to the signal-binding site it activates the G-protein-linked receptor by changing its shape. When this happens, the G-protein, loosely attached to the cytoplasmic side of the cellular membrane, attaches to its binding side on the receptor protein. The inactive G-protein becomes activated when GDP is displaced by GTP, a molecule similar to ATP. When the signal molecule is released, the G-protein diffuses along the cell membrane and attaches to an inactive enzyme. This newly activated enzyme triggers the cellular response. When the protein detaches itself from the enzyme, it releases a phosphate group turning GTP back into GDP, making the G-protein inactive once again.
I have chosen to do a paper on Bipolar Disorder. Bipolar is a disorder in when a person’s mood inappropriately alternates between feelings of mania and depression. A bipolar mania is a mental illness classified by psychiatry as a mood disorder. Also individuals with bipolar disorder experience episodes of an elevated or agitated mood known as mania or hypomania, depending on the severity alternating with episodes of depression.
Action potentials in neurons are facilitated by neurotransmitters released from the terminal button of the presynaptic neuron into the synaptic gap where the neurotransmitter binds with receptor sites on the postsynaptic neuron. Dopamine (DA) is released into the synaptic gap exciting the neighboring neuron, and is then reabsorbed into the neuron of origin through dopamine transporter...
glutamate receptors using antibodies, that tag on to the receptor itself. The proteins that make up the
Bipolar II disorder is a treatable mental illness that is often confused with Bipolar I disorder. The two are similar but still have many differences such as with Bipolar II it consists of two main symptoms, depression and hypnomania. The major difference between bipolar I and bipolar II is that with bipolar II the patient never reaches a full state of mania, rater they experience hypnomania which is a less elevated form of mania; where with the depression aspect of the disorder it can last much longer in bipolar II than in bipolar I. There are around 6 million people currently in the United States who suffer from some form of bipolar disorder yet most people don’t really have an accurate perception of what this condition is or how life is for those living with it.
Q1.The cell cycle is the series of events which occur in a cell leading to its division and replication.
Bipolar Disorder can be classified by the occurrence of manic episodes followed by hypomanic or major depressive episodes. A manic episode is a distinct period of abnormally and persistently elevated, extensive, or irritable mood and abnormally and persistently increased goal-directed activity or energy, lasting at least 1 week and present most of the day, nearly every day. During the specific period of mood disturbance and increased energy or activity, many symptoms are present. Some examples of these symptoms can include: -Inflated self-esteem or grandiosity, decreased need for sleep, and are more talkative than usual (“Bipolar and Related Disorders, “n.d.). There is a 10- 15% risk of completed suicide associated with Bipolar Disorder (“Bipolar Depression”, 2)
... over normal proliferating cells (Figure 1) It is important to target events taking place at the same time in the cell cycle in order to boost effectiveness of the arrest and the results. In addition, it is important to characterize tumors precisely in order to clarify where the deficiencies on the cell cycle control are accrued and which of the phases have to be targeted for successful therapy. Furthermore, in the future, identification of new tumor specific isoenzymes will be necessary to characterize the cell cycle accurately and comprehend the differences between normal cells and cancer cells for the design of novel anticancer therapies (Diaz-Moralli, et al. 2013).
The cell cycle is the process by which cells progress and divide. In normal cells, the cell cycle is controlled by a complex series of signaling pathways by which a cell grows, replicates it’s DNA and divides, these are called proto-oncogenes. A proto-oncogene is a normal gene that could become an oncogene due to mutations. This process has mechanisms to ensure that errors are corrected, if they are not, the cells commit suicide (apoptosis). This process is tightly regulated by the genes within a cell’s nucleus. In cancer, as a result of genetic mutations, this process malfunctions, resulting in uncontrolled cell proliferation. Mutations in proto-oncogene or in a tumour suppressor gene allow a cancerous cell to grow and divide without the normal control imposed by the cell cycle. A change in the DNA sequence of the proto-oncogene gives rise to an oncogene, which
Bipolar disorder is also known as manic-depression disorder, may cause unusual changes in mood and behavior such as grandiosity, decreased energy, distractibility, diminished interest, insomnia, pressured speech, suicidal thoughts, and decrease in the ability to carry out day to day tasks (Diagnostic and Statistical Manual of Mental Disorders; 5th Ed.; DSM-5; American Psychiatric Association, 2013). According to Jann (2014) the symptoms of bipolar disorders are severe alternating between normal ups and downs leading in damaged relationships, poor job and school performance, and even suicide among the most severe. There are four types of bipolar disorder which include bipolar I disorder, bipolar II disorder, bipolar disorder not otherwise specified, and cyclothymic disorder Jann (2014).
The retina contains rods and cones which detect the intensity and frequency of incoming light and, in turn, send nerve impulses to the brain.
These electrical signals arise from ion fluxes produced by nerve cell membranes that are selectively permeable to different ions. Neurons and glia (cells that support neurons) are specialized cells for electrical signaling over long distances. Understanding neuronal structure is important for understanding neuronal function. The number of synaptic inputs received by each nerve cell in our (human) nervous system varies from 1-100,000! This wide range reflects the fundamental purpose of nerve cells, to integrate information from other neurons.
Eric Beck meets criteria for Bipolar 1 disorder. He shows some signs of General Anxiety Disorder as well. Anxiety disorders are the most coming co-occurring disorder with Bipolar 1. To be diagnosed with Bipolar 1 disorder you must meet criteria for Major Depressive Episode and Manic Episode. Eric meets criteria for part A of Major Depressive Episode due to his extensive history of depression. He stated that “I suffer even when doing things, I should enjoy.” He often had feelings of guilt or worthlessness. Along with this Eric struggled from a lack of concentration. He also had recurrent thoughts of death and has tried to commit suicide.
Bipolar disorder is a lifelong condition that can affect how you feel and how you act. It is a mood disorder caused by chemical imbalances in the brain that can result in extreme mood swings, from manic highs to depressive lows. Also known as manic-depressive disorders, bipolar disorder is categorized and determined as “a psychological state in which a person experiences a mood disorder causing radical alterations in their moods”. Elevated levels of either manic or depression are very common with a person affected by a bipolar disorder.