G Proteins
Proteins play various important roles in inter-neuronal communication. Receptor sites are made up of proteins and the ion channels in the cell membranes are proteins. The link between the receptor sites and the protein channels sometimes is the guanine nucleotide-binding protein, better known as G Protein. (1) The basic structure and function of these shall be explored in the following.
In order for neuron communication to occur, the post-synaptic neuron must have receptor sites for the neurotransmitters released by the pre-synaptic neuron. Also, these neurotransmitters, by binding on to the receptors, must bring about a change in the post-synaptic neuron, namely an EPSP (excitatory post-synaptic potential) or an IPSP (inhibitory post-synaptic potential), which may or may not lead to an action potential triggering in the post-synaptic neuron.
EPSPs and IPSPs are produced in the post-synaptic neuron due to variations in either the Na+ or Cl- concentrations within the neuron. A change in concentration occurs when the protein channels which gate ion flow, permit Na+ or CL- to migrate across the cell membrane. The question now is, what causes the protein channels to open to Na+ or Cl-. In essence, there are three manners in which the ion flow can come about.
The simplest way in which neurotransmitter-receptor binding can cause the opening of the protein channels is when the receptor is located immediately on top of the protein channel. Once a neurotransmitter binds on to the receptor, it causes the protein channel to permit ion flow. Receptors can also be acting on protein channels in more indirect fashion, via a second messenger system. A second messenger system is characterized by a G Protein's inclusion in the transduction of "signals from the transmembrane receptors to intracellular effectors." (1) That means, the binding of a neurotransmitter to a receptor activates a G Protein, which causes the protein channels gating ion flow to open. For this, two general mechanisms exist. Before they can be explained, however, the structure and dynamics of the G Protein must be considered.
G Proteins are heterotrimic substances, i.e. they are composed of three subunits, alpha, beta and gamma. The alpha subunit of a G Protein is looked upon as the active subunit, as it binds GDP (guanine diphosphate) when it is inactive, but exchanges GDP for GTP (guanine triphosphat) when active (2) and acts as the "messenger" between the receptor sites and the effector. The beta and gamma subunits aid the alpha subunit to bind to membranes.
Although Arthur Conan Doyle was raised in an ordinary Roman Catholic family, he turned out to be a well-known spiritualist who encouraged others to communicate with the dead. On May 22, 1859, an Irish infant was born into a Roman Catholic family. Arthur Conan Doyle was the second oldest of ten siblings. Arthur’s father, Charles Doyle, came from a wealthy family. He came from a family of artists. He himself was successful in his younger years but afterwards he went broke because his art works were not so popular anymore. The family came into a time of crisis as Charles started to drink. Arthur became hurt through Charles’s attitude yet remained proud of him; in A Study in Scarlet Arthur used his father’s painting as an illustration. "My father's life was full of the tragedy of unfulfilled powers and of underdeveloped gifts. He had his weaknesses, as all of us have ours, but he also had some very remarkable and outstanding virtues"(The Chronicles). Arthur found comfort in his mother. He gave credit to her as an inspiration t...
When a chemical signal is transmitted, the presynaptic neuron releases a neurotransmitter into the synapse. The signal is then sent to the postsynaptic neuron. Once the postsynaptic neuron has received the signal, additional neurotransmitter left in the synapse will be reabsorbed by the presynaptic
When something changes in the inner environment it sends information to the receptor. The receptor sends information to the control center and then the control center sends instructions to the effector once the information is received from the control center it proceeds to either oppose or increase the stimulus. This process is designed to repeatedly work at restoring or maintaining homeostasis.
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...
Before taking the StrengthsFinder® assessment I didn’t know what type of leader I was, but I felt I had leadership traits that I could not describe. After answering several questions from the Clifton StrengthsFinder® 2.0, I found out my top five strengths. These strengths consist of individualization, arranger, learner, input and responsibility. The purpose of this paper is to go over my top five strengths to talk about which four domains of leadership these strengths fall under, how class material is applied, and the actions to best utilize my strengths.
First when a leader focuses on the strengths of the employees the odds of the employee being engaged will increase dramatically. This compares to chapter one of our text book in that it says an effective leader is one who helps group members attain productivity. The second key is that the most effective leaders surround themselves with the right people and maximize their team. The book suggest when leaders try to be good at everything they will not be great at anything. Although it is often preached to be well-rounded this results in mediocrity. So instead trying to be good at everything, find and know your strengths and hone those skills to be a more effective leader. The authors say there are four domains of leadership with thirty-four themes that break-down under the domains and these explain the actual strengths of the leader. The domains are executing, influencing, relationship building and strategic thinking. In our text book all but influencing are listed as one of the ten roles of leadership. ...
Arthur Conan Doyle’s early life in England contributed a lot to his writing. While he was still in school there were people around him who influenced the characters that he would write about later in life, including one of his professors. “If he needed a model for his detective, he need look no further than a lean figure in Edinburgh, with long white dexterous hands and a humorous eye, whose deductions startled patients as they would readers” (Carr, 2003). He also started looking at things differently which affected his writing style. “He had encountered a curious facility of being able to drop a mental curtain between himself and the world; and by inducing an artificial state of mind, becoming himself the character he wrote about” (Carr, 2003).
The brain is part of the central nervous system, which consists of neurons and glia. Neurons which are the excitable nerve cells of the nervous system that conduct electrical impulses, or signals, that serve as communication between the brain, sensory receptors, muscles, and spinal cord. In order to achieve rapid communication over a long distance, neurons have developed a special ability for sending electrical signals, called action potentials, along axons. The way in which the cell body of a neuron communicates with its own terminals via the axon is called conduction. In order for conduction to occur, an action potential which is an electrical signal that occurs in a neuron due to ions moving across the neuronal membrane which results in depolarization of a neuron, is to be generated near the cell body area of the axon. Wh...
Neurotransmitters are chemicals made by neurons and used by them to transmit signals to the other neurons or non-neuronal cells (e.g., skeletal muscle; myocardium, pineal glandular cells) that they innervate. The neurotransmitters produce their effects by being released into synapses when their neuron of origin fires (i.e., becomes depolarized) and then attaching to receptors in the membrane of the post-synaptic cells. This causes changes in the fluxes of particular ions across that membrane, making cells more likely to become depolarized, if the neurotransmitter happens to be excitatory, or less likely if it is inhibitory.
The article “Adolescent Brain Development and Underage Drinking in the United States: Identifying Risks of Alcohol Use in College Populations” written by Marisa Silveri, PhD, aims to emphasize the the negative behavioral consequences with underage alcohol use. Silveri is a highly decorated professor of psychiatry at Harvard Medical School, who has been studying the neurobiology of brain development and consequences of alcohol and drug abuse using preclinical and clinical models for two decades. Her substantial background in psychology and neurobiology make her a highly credible source, and improves the author’s chance of making the point really stick. The article is easy to follow, and split up in subcategories that each cover a specific point the author is trying to make. Professor Silveri, with great credibility, uses logic and also emotional appeal to effectively convince the reader that alcohol use affects the brain negatively, and the importance to discourage the excessive consumption of alcohol by adolescents.
Early in the novel Morrison, uses the juxtaposition of Ruth Foster and Pilate dead, when she tells of the flight of Mr. Robert Smith from Mercy Hospital. Ruth Foster, not yet described as such, is known as the “dead doctor’s daughter” (5). During this scene her insignificance is made clear, “the rose-petal scramble, got a lot of attention, but the pregnant lady’s moans did not” (5). This scene perfectly embodies Ruth Foster’s character, as diminutive, and unimportant, she also ignores the flight of the Mr. Smith as the pedestrians ignore her and Mr. Smith. On the other hand, Pilate Dead, is the singer in the crowd that notices Mr. Smith’s flight and says, “O Sugarman done fly away” (6), introducing the theme of the novel, flight, and representing her understanding of it, while others remain oblivious. This is important, because this is Milkman’s journey, the discovery of the flight of his people, or the realization of his people’s culture. Pilate, Milkman’s aunt, also foreshadows his “flight”, which is a main theme of the novel, ‘A little bird’ll be here with the morning” (9), whereas his mother, Ruth, says, “It can’t be...It’s too soon,” (9) this shows her role in the novel as keeping Milkman from his flight, while Pilate teaches him he can fly. "Mr. Smith's blue silk wings must have left their mark, because when the little boy discovered, at four, the same thing Mr. Smith had learned earlier - that only birds and airplanes could fly - he lost all interest in himself" (9). Tis loss of flight symbolizes Milkman’s loss of his heritage, which Pilate tries to reinstall in him, ...
There are many factors that are integrated into the successful development of a child from Prenatal growth into toddlerhood. Teratogens (outside factors) have a great impact on the babies’ inutero development. Some outside factors like second-hand smoke, smog, or fumes from cleaning chemicals can cause negative effects on the child inside the womb. A few major affects from teratogens could result in low birth weight, head circumference, slow physical growth as well as an effect on mental, behavioral and motor skills (Berk, 2003). The environment around the mother provides many of these outside factors affecting the baby’s growth. But the main link to teratogens during the gestation period is most likely the mother. Daniel S. Messinger and the National Institute on Drug Abuse found that 2.8% of pregnant women admitted to using illicit drugs during their pregnancy (1996). Through illicit drug use, tobacco use and alcohol use, the mother disrupts her baby’s growth with possibly permanent damage.
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.
The neuron plays an important role in the occupation of the brain (Rollin Koscis). A neuron is...
Sir Arthur Conan Doyle was born in Edinbutgh, Scotland May 22, 1853. He is the oldest kid of Charles Doyle and Mary Doyle, both his parents are Irish Roman Catholics. His father, Charles Altamont Doyle, was not a good example unlike his mother, Mary Foley, who was a bright educated woman. Since his pa...