A Study Of Anatomy And Psychology Essay Example for Free

A Study Of Anatomy And Psychology Essay ? The procedure in lifting the leg to climb a stair is a complex one which involves a huge amount of technology inter-transfer between the brain and the eventual skeletal muscle. There is initiation of the movement at the brain which is transmitted via specialized white fibre tracts to the hip flexors via the intermediate spinal cord, involving a very complex mechanism at the cellular level   The initiation of the   process is at the motor cortex (Ms I) of the brain. The primary motor area is located at the precentral gyrus of the frontal lobe. The area controlling the motion of the lower limbs lies towards the superior surface of the brain. Within this area lies the cell body of the primary neuron. These neurons are known as upper motor neurons (UMN). These UMNs receive modulating impulse from the inputs from the cerebellum and the basal ganglia via the extrapyramidal pathways. These tracts modulate the gross movement initiated at the frontal cortex. In turn these areas are modulated by afferent signals from ascending spino cerebellar, and spino-thalamic pathways. The complex the signal initiated at the nucleus of the cell body is transmitted electronically via the axon of the myelinated neuron via the mode of salutatory conduction. The myelin sheath which surrounds the axon of nerves that involve fast transport, breaks at intermediate regions known as Nodes of Ranvier. The electrical impulse moves in   a jumping manner at these nodes nerve transmission as a neural impulse, generated by the formation of a nerve action potential. Like all excitable tissue, nerves maintain a resting membrane potential that is the difference of voltage across the membrane of the neuron. In neurons this value is   – 70 mV. This voltage difference is maintained by the Na/K pump on the membranes. This impulse generated at the axon hillock is transmitted via the depolarizing phase which allows sodium ions ingress into cells via opening of the Na channels. This entry of Na in one portion allows activation of other Na channels, causing depolarization of the adjacent region of the neuron. Subsequently repolarization occurs via the opening of K channels, which restores the membrane potential. Thus this process continues which allows the transmission of impulse. Many such nerves together descend as the descending cortico spinal tract in the pyramidal system, which travels through the midbrain into the spinal cord, decussating at the level of midbrain( 90% of the fibres decussating and forming the lateral spinothalamic tract) and again at the level of spinal cord ( the other 10%, forming the anterior spinothalamic tract) . It is the former which is responsible for the lower limb movements. The cortico-spinal tract travels in the anterior horn cell of the spinal cord till the lumbar level where they synapse with the spinal ventral root neuron (lower motor neuron). A single post-synaptic neuron receives signals from many neurons. At the axon terminal, the propagation of impulses leads to release of neurotransmitters, which are stored in specialized vesicles. The released Ach diffuses into the synaptic cleft and binds with receptors on the post synaptic membrane to produce excitatory post synaptic potentials. This leads to generation and propagation of impulse in nerves which are destined to innervate the neuro-muscular junction. At the neuro-muscular junction, Ach is released, which diffuses into the synovial cleft and binds to receptors in the motor end plate, and triggers a muscle action potential. The released Ach is destroyed by the acetylcholinestrase. At the level of the sarcolemma of the muscles, the muscle AP travels along T-tubules, opening Ca release channels in the sarcoplasmic reticulum. Ca binds to troponin-tropomysin complex, which releases the myosin heads, these then bind to the actin thin filaments, and draws them closer to the M line. Meanwhile bringing the Z disc closer. This leads to muscle fibre contraction. This is a self propagating sequence eventually leading to the contraction of ilio-psoas muscle, which causes the flexion of thigh on the pelvis. Each nerve fibre innervates many musle fibres ( about 150). This is   the motor unit. The greater the number of motor units recruited by the nerve action potential, the greater the force of contraction of the muscles. In the spinal cord, nerve impulse travels along the lumbar plexus (L1-L5) to innervate the iliopsoas ( hip flexion- ilio-inguinal nerve), biceps femors, semitendinosus and semimembranosus ( knee flexion – sciatic nerve), ankle flexors ( EHl, EDL, TA – tibial nerve), leading to the person climbing the step. This excitatory impulse is also associated with the production of inhibitory action potential ( hyperpolarizing impulse) in the antagonists (eg the glutei, which must relax to allow flexors to act. In the event of raising of the upper limb above the head, to lift a book, the impulse travels along the cortico spinal tract till the level of the cervical cord to synapse with the lower motor neurons of the brachial plexus ( C3-T1). From here the nerve impulses travel to shoulder elevators ( supraspinatus, deltoid, trapezius, and latissimus dorsi)- posterior cord ), elbow extensor ( triceps and anconeus – radial nerve) wrist extensor ( ECRL, ECRB – radial nerve), finger flexors ( FDS, FDP – median nerve and the ulnar nerve)   and the intrinsics – ulnar nerve and the median nerve) A Study Of Anatomy And Psychology. (2017, Mar 25).

Agree or disagree with Hawking's quotation Essay

Agree or disagree with Hawking's quotation - Essay Example While the importance of talking throughout the history of mankind in general and in the contemporary age in particular cannot be overemphasized, the author is too optimistic and unrealistic about the results talking can produce. Talking can or cannot be effective depending upon the context, participants, topic, and means of communication. For example, the governments of Pakistan and India have conducted dialogues with each other several times, but have never been able to end their differences, and the rift between the two neighbor countries continues, to some extent, even to date. Many wars in the history have reached an end as a result of dialogue between the concerned countries. There is yet a long list of world events in which the dialogues among different countries did not produce any meaningful results. Therefore, it cannot be established that no matter what problem is at hand, all that needs to be done is talking for that. If the author’s argument is supposed to be based on reality, then it is obvious that he is not talking about just any kind of talking. It would take a lot of effective talking to reach a point in time when the wildest hopes and thoughts could be materialized into reality. Effective talking can be defined as the kind of talking that occurs at the right place, in the right environment, at the right time, between the right people, and upon the right subject. But this is an ideal situation which requires a range of events to take place many of which are beyond the control of human beings. Talking is not everything. For example, the first hurdle in the way of developing such a technology is reaching a unanimous decision on its creation because such a technology is likely to harm the world in more ways than benefit it. If anybody could do whatever he/she wanted, then this world would be a mess. There are fair chances that if, ever, such a matter is discussed, there would be so many

The Declaration of Independence and Its Irony for Equality Term Paper

The Declaration of Independence and Its Irony for Equality - Term Paper Example Its primary goal is to discuss how the Declaration departs from its true essence based on the undermined state of the minorities within the society throughout history. For research materials, this paper will deal with the American Political Thought by Kenneth M. Dolbeare and Michael S. Cummings as its primary source of information for the Declaration of Independence. It will also use several internet and magazine articles as other sources of information. Keywords: Thomas Jefferson, the Declaration of Independence, equality and the rights of men, racial discrimination, women, gays, lesbians The Declaration of Independence and its Irony for Equality The Declaration of Independence portrays literal power in the usage of rhetoric devices that clearly stands out throughout the document. Thomas Jefferson, as its writer, had such proficiency beyond doubt that he was a very learned and skilled person. The rhetoric devices used to point at the possibility of a good education and literal skill s well developed throughout the writer’s experiences. As the studies of the Declaration of Independence find attest, the document is perhaps one of the most creatively designed state documents. Distinctively enumerated into exceptional divisions, Jefferson demonstrated some rare writing skills that make it one of the best literal state papers. The Declaration of Independence can be divided into an introduction, a clearly developed preamble, a section describing the indictment of the Crown, denunciation of the American oppressors - the British - and a good conclusion (Dolbeare & Cummings, 2009, pp. 49-52). Any paper passing the test of good writing must at least show such organization. With skill in rhetoric and a steadfast soul for nationalism, Jefferson had created some of the most messianic, heroic and memorable lines contained within the Declaration of Independence. Even down to his choice of words, Jefferson managed to immortalize this document throughout the annals of th e United States. Usage of terms such as â€Å"necessary† creates an impression of the strong need for the Americans to take the proposed action, which is well connected to their human nature. The line, â€Å"One people† can be translated to send a strong message that the Americans and the British were different people brought together politically and breaking the â€Å"political bands† which was a necessity for the survival of the Americans. This choice of words was intended to capture the attention of America’s friends. However, there is one line in the Declaration that gathers much controversy and debate. The usage of the line, "We hold these truths to be self evident, that all men are created equal, that they are endowed by their Creator with certain unalienable rights, that among them are Life, Liberty and the Pursuit of Happiness† poses an intention that could have well been deeply thought to bring a diverse interpretation by the Americans, the British and possible allies who could assist the Americans in their quest for independence. This line consists of a group of principles pertaining to human rights that are naturally and rhetorically read and interpreted together.