QUESTION AND ANSWER ON THE NERVOUS SYSTEM (Term Paper Sample)

Student name Course name Instructor’s name Date TAQ 1 * Complete the boxes below for each part of the nervous system. Brain and spinal cord Central Nervous Sympathetic nervous systemSomatic nervous systemNervous Peripheral Nervous Parasympathetic nervous systemAutonomic nervous system * For each of the subdivisions you have labeled above (the ones originally marked by ?) explain their functions within the nervous system and in the case of certain answers their relationships to each other. The brain: Its primary function is to regulate all the activities of the human body. It is composed of three regions namely the cerebellum, cerebrum and the advanced marrow. The cerebrum serves in conscious actions such as speech, movement, sight, and memory. The cerebellum performs the role of body balance regulation and muscle coordination for movement. The spinal cord: It is regarded as a brain extension in which it performs the function of linkage between the lower regions of the body and the brain. The somatic nervous system: It is also known as the skeletal nervous system that is consistent with sensory nerve receptors that enables the perception of feeling the world and perception in humans. The autonomic nervous system: It is a component of the peripheral nervous system and as such it performs the function of regulating internal organs like the heart, stomach, bladder; glands and blood vessels. The sympathetic and parasympathetic nervous systems: These two are components of the autonomic nervous system. These two systems work in a reverse manner to the body so as to enhance its adaptability to the environment. In this regard, the parasympathetic nervous system assists in the conservation of the body’s physical resources and the maintenance of normal body functions. The sympathetic nervous system is responsible for the regulation of ‘flight or fight’ responses such as increasing the heart rate and enabling an individual to escape a potential dangerous situation. (W0RD COUNT: 310) TAQ 2: Using web based diagrams (which must be referenced correctly) explain the function of the three neurons (sensory, relay and motor) Motor neuron; The motor neuron performs the role of impulse transmissions from the Central Nervous system to other glands and muscles spread within the body. It is composed of dendrites, cell body, myelin sheath, node of ranvier, and synaptic knobs. The dendrites facilitate the transportation of nerve impulses from neighboring neurons into the cell body. The myelin sheath assists in the nerve fiber protection, insulation as well as a faster transmission rate of the nerve impulses. The nodes of Ranvier assist in nutrient uptake and expulsion of waste products. Sensory neuron: It is in charge of the inward transmission of impulses from sensory organs of sight, tastes, smell, touch, and hearing to the central nervous system. Relay neuron: It is composed of a cell body and synaptic knobs. It is responsible of the transmission of electrical impulses created by stimuli reaction from other nerves. In this regard, it assists the brain in the processing of information. (WORD COUNT 156) TAQ 3 * Explain the changes that occur within a nerve cell and across its membrane during the process of nerve impulse initiation Nerve impulse initiation from one end to the other along a neuron is made possible due to the electrical differences across the neuron’s membrane. In this regard, an un-stimulated neuron is normally polarized. In this regard, there is an electrical charge difference between the inner parts and outer region of the membrane. The polarization of the membrane is achieved by the maintenance of surplus potassium ions on the inner region and surplus sodium ions on the exterior region of the membrane. Leakage channels allow the leaking of specific amounts of potassium and sodium ions across the membrane. At resting potential of the unstimulated neurone its normally around -70 millivolts. The change in the resting potential of a membrane is regarded as graded potential which occurs in response to a stimulus that opens up the potassium ions or sodium ions gated channels. In the event that the sodium ions gated channels opens up, it results to an influx of positive sodium ions which causes depolarization of the membrane. If the gated channels for potassium ions opens up, the positive potassium ions move out across the membrane resulting to a more negative charge or hyperpolarization. On the other hand, an action potential occurs when a neuron transmits information for longer distances down an axon. In this regard,the gated channels of positive sodium ions are triggered open if there is a sufficiently large depolarized graded potential. In this regard, there is a depolarization of the sodium ions on the outer parts of the membrane. In the event that there is a stronger stimulus, there is supplementary opening of the positive sodium ion gates and an influx of more sodium ions that results to total depolarization of action potential. This consequently, triggers the opening of more positive sodium ion gates downwards along the axon. (WORD COUNT 300) * What is a synapse? They are specialized sites which allow neurons to transmit information in one direction to facilitate the communication process with other cells. * Explain how the synapse is involved in transmitting the nerve impulse from one neurone to the next. The synapse functions as a gateway that allows the flow of information from one neurone to the next. In this regard, the gap between two neurons is regarded as the synapse. The synapse is composed of a pre-synaptic ending in which there are neurotransmitters, cell organelles and mitochondria; a post synaptic ending in which receptor sites are found for the neurotransmitters and a synaptic cleft which is a gap between the postsynaptic and pre-synaptic endings. The neurotransmitter carries the nerve impulses which are received by the post-synaptic neuron. Evidently, the post synaptic neuron contains neuroreceptors that are essentially chemical gated ion channels. The neuroreceptors possess definite binding sites for the neurotransmitters. The presynaptic neurone contains calcium paths that are voltage gated at the ends. Once an action potential arrives at the synapse, the paths open up and there is an influx of calcium ions into the cell. The calcium ions catalyze the fusion of synaptic vessels with the cell membrane. The result is the release of neurotransmitter chemicals via a process known as exocytosis. Consequently, diffusion of the neurotransmitters occurs across the synaptic cleft. The next phase is the binding of the neurotransmitters to neuroreceptors contained in the post-synaptic membrane. This results into the opening up of sodium pathways that allows the influx of sodium ions. Consequently, the post synaptice cell membrane undergoes depolarization and can trigger an action potential once the threshold is achieved. A certain enzyme contained in the synaptic cleft breaks down the neurotransmitter. For example, the neurotransmitter acetylcholine is brokend down by an enzyme known as acetylcholinesterase. The products of the breakdown process are absorbed through a process known as endocytosis within the pre-synaptic neurone. This is consequently used in the regeneration of additional neurotransmitter by energy derived from the mitochondria. The net effect is the control over the functioning of the synapse. (W0RD COUNT, 307) TAQ 4 Using a diagram, describe the reflex arc. A reflex arc denotes a nerve conduit in the human body that bypasses the brain by linking certain groups of muscles with others. This essentially initiates involuntary actions in reaction to a stimulus. The reflexes are hence automatic and involuntary movement of muscles that are occur along the reflex arc in response an external stimulus. The arc is situated in the spine or brain and it is normally shorter than the conventional nerve channels. In a reflex situation, in the event of an external stimulation, the nerve impulse moves along the sensory neurons upto the brain or spinal cord and back again towards the region of stimuli action along motor neurons. Other reflex arcs are normally linked to the motor neurons via connector neurons. However, the major fact is the lack of control by the brain. An example of the reflex action is the ‘knee jerk; reflex. (WORD COUNT: 147) TAQ 5 Name of endocrine gland Location Hormones released Function (s) of hormones released Pituitary Located in a hollow bony region known as the pituitary fossa. The pituitary fossa is situated underneath the foot of the brain, next to the optical nerves and at the rear of the nose bridge. It releases hormones such as the thyroid stimulatinf hormone, gonadotrophins, adrenocorticotrophic and prolactic hormone, anti-diuretic hormone, and growth hormone Adrenocorticotrophic hormone kindles the adrenal stress hormone known as cortisol. Thyroid stimulating hormones kindles the thyroid gland to produce Thyroxine. Thyroid Largest gland in the neck that is located at the front part of the neck underneath the muscle layers and skin It produces the thyroid hormone. The thyroid hormone enhances cellular activity. Consequently, the thyroid hormone has an effect on growth and development, metabolism, and the body’s temperature. Parathyroids Are four micro glands situated in the neck. Releases the parathyroid hormone. The parathyroid hormone regulates the calcium levels in the body. Consequently, it increases the calcium level in blood through enhancing the body’s capacity for calcium absorption from food, breaking lose of the calcium stored in the bones to stimul...