Foundations in human physiology- structure, function and permeability Assignment

Foundations in human physiology- structure, function and permeability of cells - Assignment Example One or more cells constitute all forms of life. Cells can only develop from pre-existent cells. The smallest form of life is cell. The human cell consists of an outer plasma membrane which encloses the minute organelles dispersed within the cytoplasm. These organelles include endoplasmic reticulum, Golgi apparatus, mitochondria, ribosome, chromosomes, nucleus, lysosome, vacuoles and centrioles. A typical human cell (Carone, 2001) The outer cell membrane is made up of lipid molecules and provides the passage for interaction of cells with each other. Different kinds of human cells have distinct structures that aid in the functioning of their particular activity, such as the axons of nerve and brain cells which transmit signals out across distances to other cells via neurotransmitters. The neurons are specially adapted to perform this function as the axons are as long as one meter in length and the nerve impulse is transmitted from one neuron to another. The various functions performed by human cells include enzyme production, movement, transmission of electrical impulses and demolishing invaders. Among the various cells constituting the human body five main are: epithelial, nerve or neuron, connective, adipose and muscle cells. The four main selected to be explained in the given text include epithelial cells, neuron, connective and adipose cells (Marieb & Hoehn, 2010). Nerve Cells Nerve cells or neurons are specialized cell often referred as the structural and functional unit of nervous system. A characteristic neuron consists of a cell body known as soma, an axon and dendrites. The thin structures arising from the cell body are dendrites that frequently extend for hundred micrometres and forming multiple branches thus forming a complex called "dendritic tree". An axon on the other hand is a peculiar cellular extension that originates from the axon hillock and travels as far as one meter (Chudler, 2012). A typical Neuron (Chudler, 2012) Synapse is a specialized c onnection of these neurons with other cells that facilitates chemical signal. Neurons communicate by electrical and chemical (via neurotransmitters like GABA, dopamine and glutamate) synapses in a process referred as synaptic transmission. Action potential is the basic process that activates synaptic transmission, a disseminating electrical signal that is produced by tapping the electrically impulsive membrane (the myelin sheath) that encloses the axon of the neuron. This is also known as a wave of depolarization. Neurons are the central part of the nervous system consisting of the spinal cord, the brain and peripheral ganglia. A great number of these specialized neurons exist and are classified on the basis of their function as sensory, motor and inter-neurons. The inter-neurons connect other neurons within the spinal cord or brain while the motor neurons transmit the response generated from brain and spinal cord to the organs. Sensory neurons respond to light, sound, touch, taste and legion other stimuli impacting the epithelial cells of the sensory organs (Levitan & Kaczmarek, 2001). Dorsal root ganglion The sensory neurons cell bodies are settled outside the spinal cord and brain in ganglia or in the sensory organs. Ganglia situated along specific cranial and spinal nerves accommodate the sensory neurons

Learn About PC Virus :: Computer Virus

Learn About PC Virus A computer virus is a potentially damaging computer program designed to affect, or infect, your computer negatively by altering the way it works without your knowledge or permission. More specifically, a computer virus is a segment of program code that implants itself in a computer file and spreads systematically from one file to another. Viruses can spread to your computer if an infected floppy disk is in the disk drive when you boot the computer, if you run an infected program, or if you open an infected data file in a program. Computer viruses, however, do not generate by chance. Creators, or programmers, of computer virus programs write them for a specific purpose – usually to cause a certain type of symptom or damage. Some viruses are harmless pranks that simply freeze a computer temporarily or display sounds or messages. When the Music Bug virus is triggered, for example, it instructs the computer to play a few chords of music. Other viruses, by contrast, are designed to destroy or corrupt data stored on the infected computer. Thus, the symptom or damage caused by a virus can be harmless or cause significant damage, as planned by its creator. Viruses have become a serious problem in recent years. Currently, more than 45,000 known virus programs exist and an estimated six new virus programs are discovered each day. The increased use of networks, the Internet, and e-mail has accelerated the spread of computer viruses, by allowing individuals to share files – and any related viruses – more easily than ever. Types of Viruses Although numerous variations are known, four main types of viruses exist: boot sector viruses, file viruses, Trojan horse viruses, and macro viruses. A boot sector virus replaces the boot program used to start a computer with a modified, infected version of the boot program. When the computer runs the infected boot program, the computer loads the virus into its memory. Once the virus is in memory, it spreads to any disk inserted into the computer. A file virus attaches itself to or replaces program files; the virus then spreads to any file that accesses the infected program. A Trojan horse virus (named after the Greek myth) is a virus that hides within or is designed to look like a legitimate program. A macro virus uses the macro language of an application, such as word processing or spreadsheet, to hide virus code. When you open a document that contains an infected macro, the macro virus loads into memory. Certain actions, such as opening the document, activate the virus.

Be Fruitful and Multiply

â€Å"Be fruitful and multiply. † This is a line we commonly hear at Mass, but what does it really mean? If we read the bible, we can find this line in Genesis, at that moment after God has created heaven and earth, plants and animals, and Adam and Eve. This sentence is redundant and simple, yet it holds a deep meaning.â€Å"Be fruitful and multiply†Ã¢â‚¬â€this is God’s way of telling us to reproduce, to have children who represent God as we represent Him as we are created after His likeness. In the bible, however, there are certain instances that somehow contradict this line’s purpose.Two examples are the tower of Babel and the pharaoh’s order to gather and eliminate all Hebrew male babies. The tower of Babel was constructed after the Great Flood. Noah’s descendants have already multiplied—they have formed a very large family that uses the same language.They have built the tower to raise themselves to the heavens and seek glory highe r than God’s. At such insolence, God punished them by scattering them throughout the world and confusing their language. Thereafter, God’s people continue to multiply and be fruitful. However, they started to bear fruits of different natures, different colors, and different tongues.The pharaoh, at the time of Moses’ birth, ordered for all male Hebrew babies to be killed and cast to the sea for fear that, as their population continued to thrive, the Egyptians will be overthrown. This act contradicted God’s command of being fruitful and multiplying. However, though this had been the case, God’s words still found its way to being made possible.The Hebrews, led by the grown-up Moses, were able to break free from the Egyptians’ oppression. They were able to reach the Promised Land that overflows with milk and honey, and since that time, they were again able to be fruitful and multiply.

Analysis of Falling Hazards of Workers in the Construction Industry Free Essay Example, 4000 words

Take for example, when an employee refuses to wear a headgear, for protective purposes, then chances are high that he may be vulnerable to some head injuries. Some of the reasons that may be advanced for his refusal may emanate from the lack of comfort in using the headgears or lack of trust in their capability to protect the worker. More than 21% of the occupational fatalities in the United States is always found within the construction industry. This is despite the industry attracting a mere 8% of the total workforce in the United States. In the United Kingdom, the rate of injury in the construction industry has increased between 2004, and the year 2007. This period of time, saw the rates of injuries in their construction industry at 16 people, out of every 1000 construction workers. Furthermore, in China, the rates of injury at their construction sites have been very high. Nearly, a third of all injuries or accidents in their industries emanated from the construction industry. It is important to understand that China is one of the countries in the world, which is experiencing a construction boom, because of its high economic growth rate. We will write a custom essay sample on Analysis of Falling Hazards of Workers in the Construction Industry or any topic specifically for you Only $17.96 $11.86/pageorder now Kuwait is also one of the countries that are experiencing a high percentage of construction accidents or fatalities (Dong, Fujimoto, Ringen and Men, 2009). The rate stands at 40% of injuries that are experienced in industries in Kuwait. This is a report, which provides an analysis of the risk perception, of the injuries caused by falls, in the construction industry. This paper analyzes their perceptions, from the views of different actors who are found within the construction industry. Furthermore, this report contains an evaluation of the appropriate tools used for purposes of assessing the risks of the fall, and the identification of the relevant sources of uncertainty. Furthermore, this report would contain a synthesis of evidence, in the example of a briefing note, for a particular stakeholder, who will provide the best policy for preventing injuries that emanate from the falls.