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Role of Kidney in Homeostasis

Role of Kidney in Homeostasis. Water is a vital molecule for the human body. Approximately 98% of the human body is made up of water. Human beings cannot survive if their water content decreases below 12%; hence the homeostasis of water is an important mechanism. Water has many important functions in our body. Water acts as a transport medium in blood and secretion e.g. in digestive juices, tears. Water is a good lubricant and acts to reduce friction when combined with particular proteins e.g. mucus to aid external movement. Many chemical reactions take place in an aqueous medium (Jones M.et al, 2000) Water mainly enters the human body through the food and drink we consume. A small proportion of water is obtained from oxidative metabolism e.g. in respiration. Human beings mainly lose water by excretion in urine and faeces. Water is also lost through evaporation e.g. as sweat (Campbell N. A. et al, 1999, Frederic H.M, 2006) The kidneys are located at the back of the abdominal cavity, just above the waist. The kidney has three main areas: the outside of the kidney is covered with a tough capsule known as the renal capsule , beneath the capsule is the renal cortex and the central area of the kidney is made up of the renal medulla. Each kidney contains many nephrons. Each nephron starts at the cortex of the kidney, runs through the medulla of the kidney and back into the cortex and finally runs back into the medulla attaching to the pelvis below. The kidneys are highly specialised organs of the body and play an important role in homeostasis. The kidney maintains homeostasis by regulating water balance, waste removal and blood composition and pressure. The kidneys dispose of waste by-products of metabolism and hence prevent the build up of toxic products in the body and to regulate the chemical components of the body’s fluids by responding to any imbalances of body fluids. These functions are fulfilled by a process of filtration of blood, which mainly includes the movement of solutes between the internal fluid and external environment. The movement of solutes is normally through a transport epithelium, in the case of the kidney it is in the form of a tubular channel; this tubular channel gives the kidney a large surface area. Blood enters each kidney via the renal artery and leaves via the renal vein. The kidneys weigh less than 1% of the human body, they receive approximately 2 % of blood pumped with each heartbeat. Urine exits the kidney through a duct called the ureter. The ureters of both kidneys drain into a common urinary bladder. Urine leaves the body from the urinary bladder to the urethra which empties near the vagina in females or through the penis in males. (Campbell N. A. et al, 1999, Michael F. et al, 2001) From the glomerulus a tube runs towards the centre of the kidney first forming a twisted region called the proximal convoluted tubule and then a long hair-pin loop in the medulla, it runs back upwards into the cortex where it forms another twisted region called the distal convoluted tubule, this then joins a collecting duct which leads down the medulla and into the renal pelvis The functional unit of the kidney is a nephron. Microscopic sections of the kidney show that the kidney is made up of thousands of nephrons. Fig1b shows the location of a nephron and Fig2 shows the detailed structure of a nephron. Each renal capsule is supplied with blood by the afferent arteriole – a branch of the renal artery this splits into many capillaries in the capsule which then rejoin to form the afferent arteriole. The nephrons structure is closely related to its function of regulating solutes Osmoregulation is maintaining constant levels of water in the body. Cells cannot survive a huge deviation from its osmolality. Hence, cells have a continuous movement of water across their plasma membranes. A net gain of water will cause the cell to swell up and burst, while a net loss of water will cause the cell to shrivel up and die. Water is transported by osmosis around the body. Osmoregulation is accomplished by creating an osmotic gradient; this requires lots of energy and is done by maintaining solute concentrations in the body fluids. The osmolality of the body is fixed at a mean of 290±5 mosmos/g. The kidney is able to maintain a constant osmolality as it’s able to adjust the rate of water excretion over a wide range. The volume of the extra-cellular fluid is mainly determined by the concentration of sodium ions, hence slight adjustments to the renal excretion rate have a major impact on the extracellular fluid volume. Changes in tubular sodium transport is accompanied by parallel movements of water, this results in no net change in body fluid osmolality (Campbell N. A. et al. 1999, Frederic H.M. 2006, Michael F. et al. 2001) The loop of Henle creates a longitudinal osmotic gradient across the medulla; this aids the reabsorption of water and other important solutes. Ascending and descending limb are parallel and adjacent to each other with a layer of tissue fluid in between. Fluid enters from the proximal convoluted tubules flows down the descending limb and then up the ascending limb. This is known as a counter-current flow. Thewalls of the descending limb are permeable to water, while the walls of the ascending limb are impermeable to water. The ascending limb of the Loop of Henle is made up of a thick walled tubule which is impermeable to the outward movement of water but not salt. The red arrows on fig3 show the movement of water amd solutes along the loop of Henle and the collecting duct. Also, the walls of the ascending limb contain pumps to remove sodium chloride from the lumen and add it to the surrounding interstitial fluid. Hence sodium and chloride ions are actively transported out of the ascending limb. This is the site of reabsorption in the kidney, here fluid from the…enters and the kidney reabsorbs all the useful solutes and water. The permeability of the loop and the collecting duct depends on the osmolality of the blood and is controlled by a negative feedback mechanism by osmoreceptors in the hypothalamus A high concentration of salt builds up in the medullary tissue, this together with urea retention by these tissues, helps build up a high osmotic pressure in the medullary tissue. This creates a gradient of 200 mosm/g across the tubular wall at any point and causes a loss of water from the descending limb. The loss of water concentrates sodium and chloride ions in the descending limb. Salt concentration in the medullary tissue is highest at the apex of the loop, the tissue in the deeper layers of the medulla contain a very concentrated solution of sodium ions, chloride ions and urea. The fluid leaving the ascending limb is hypo-osmolar as compared to the fluid that enters and has a osmolality of approximately 100 mosm/g .Sodium and chloride ions diffuse out in the lower part of the ascending limb. Fluid passes down the collecting duct through the medullary tissue of increasing salt concentration, water can pass out of it by osmosis. The reabsorbed water is carried away by blood capillaries (Campbell N. A. et al. 1999, Frederic H.M. 2006, Michael F. et al. 2001) Control of water regulation Osmoregulation by the kidney involves a negative feedback mechanism. The osmoreceptors are in the hypothalamus and the effectors are the pituitary gland and the walls of the distal convoluted tubules. Osmoreceptors detect alterations of water levels and send impulses to the pituitary gland which then increase or decrease the production of antidiuretic hormone (ADH). In the case of a low osmolality,when the nerve cells are stimulated by osmoreceptors action potentials travel down them, this causes ADH to be released from their endings into the blood capillaries in the posterior pituitary gland from here it is distributed throughout the body. ADH acts on the plasma membranes of the cells of the collecting ducts. ADH is picked up by a receptor on the plasma membrane which then activates an enzyme. This causes vesicles with water permeable channels to fuse with the plasma membrane hence ADH makes the membrane more permeable to water than usual. Hence more water will be reabsorbed by the collecting duct and more concentrated urine will be produced. On the other hand, when the blood water content rises the osmoreceptors are no longer stimulated and hence do not lead to the secretion of ADH. Hence, ADH secretion slows down and the collecting duct cells become less permeable to water, so less water is reabsorbed and more diluted urine is produced (Campbell N. A. et al. 1999, Frederic H.M. 2006, Michael F. et al. 2001) In conclusion, the regulation of water is essential for the survival of human beings and is carried out by the kidneys and monitored by osmoreceptors in the hypothalamus and controlled by the pituitary gland. Each of these plays an equally important role in the regulation of water and without any one of them the body will not be able to function in a normal manner. Role of Kidney in Homeostasis

This is a writing assignment on the documentary called “the color of fear”. My paper is 90 percent finished

This is a writing assignment on the documentary called “the color of fear”. My paper is 90 percent finished – its just missing the introduction to the cast members( SEE ON SAMPLE PAPER). I am going to send you my paper – as well as the sample paper that was given in class so you can see what is missing. This addition should only be a paper long – Thank you

Baltimore City Community College Shifts in Demand and Supply Presentation

custom essay Baltimore City Community College Shifts in Demand and Supply Presentation.

Part A:Draw and label the Y and X axis for this marketDraw a supply and demand curve/line, making sure to properly label the linesLabel the equilibrium e1Now consider the effect of the following two events on the market for interior paint: *An increase in the cost of labor *A decrease in the price of a paint brushes *You are to create an event that would shift either the supply or demand curve for paint. Draw the new supply and demand curve/linesLabel the new equilibrium e2Part B -Elasticity :What would be the price elasticity (Ed) a long the demand curve if the price decrease from $1.80 at a quantity of 10 paint brushes to$1.60 at a quantity of 20 paint brushes. Use the mid-point formula.
Baltimore City Community College Shifts in Demand and Supply Presentation

ENGH 202 GMU The Naked and the Dead by Author Norman Mailer Book Report

ENGH 202 GMU The Naked and the Dead by Author Norman Mailer Book Report.

Do not do research for posts. They are responses to the readings; not a test of your ability to Google.Reading Response Post — The Naked and the Dead, by Norman Mailer. Part Two: Argil and Mold, Chapters 5 through 7.Q. Sam Croft — One of the novel’s more memorable characters is Staff Sergeant Sam Croft. Discuss him.Instructions from Instructor:A Reading Response Post is your opportunity to record whatever thoughts, questions, and emotional or aesthetic reactions you have as you read. For every reading assignment, I will create a new discussion board forum on which I will post possible issues or questions as individual threads. When your group has a reading post due, you should pick one of them and respond to it as best you can.Because these responses represent the early stages of your thinking about the readings, you should feel free to use them to test out ideas, ask questions, and admit confusion; indeed, summary judgments and easy answers aren’t much use to me or your classmates, whereas confusion, when clearly expressed, can be stimulating. On the other hand, I admire students who are willing to venture an opinion and back it up. What is important is that your response demonstrates your engagement with these works.The key to reading posts is to keep them focused by quoting specific passages — you must support your argument with textual evidence by quoting and citing the reading for that thread at least once during your post — and commenting on those quotations in order to support a point. Do not simply quote and expect us to see what you see in the passage; explain. That means you should never begin or end a paragraph with a quotation. Start by establishing a point you want to make or an issue you want to explore. Quote (do not paraphrase) the text to provide evidence for what you are saying. Then, comment on the quotation: never assume that your peers or I will see what you see in the passage you quote, let alone see it the same way. Quotations provide evidence; they do not make your case for you. Always set quotations up substantively. That means that setting up a quotation with a simple phrase like “Shakespeare writes,” is unacceptable. If the set-up for a quotation tells readers nothing other than the information a citation could give them, it’s not substantive.Do not do research for posts. They are your responses to the readings; not a test of your ability to Google. (See Honor Code note below.)Your audience for these posts is people in the class. You should therefore assume everyone reading your post has also read the assignment to which it responds; do not engage in plot summary or waste time presenting background information we all know. Call your readers’ attention to specific elements of the text (characters, scenes, plot points, and so on) and quote textual evidence, but do not summarize as if you are writing for people who have not read the work in question.Reading Response Posts should be between 275 and 325 words long, not including the quotations. Note that longer does not mean better: if you post 500 words I will not be happy, because I do not want reading the posts to be burdensome for your peers or correcting them to be burdensome for me. If you find yourself going over 350 words of your own writing, cut something; you can always bring up additional points in our weekly class meetings.Following is an example of a superb Reading Response Post. It is from a different course and focuses on a book you are not reading (Frankenstein), but you can still use it as a model. Note the effective use of quotation: the writer does not quote just to quote, but uses the quotations to provide evidence for points she wants to make. She also sets up every quotation in substantive way (again, not just by saying “Shelley writes”) and comments on it, rather than expecting readers to see her point on their own. The post is also clearly focused and organized, it meets the length requirement at 316 words (not counting quotations), and the writing throughout is clear. The question to which this post responds was “The novel is divided among three narrative perspectives: those of Robert Walton, Victor Frankenstein, and the creature. What effect is Mary Shelley trying to create with these different narrators? You may focus on one or contrast any two.”Subject: Is Frankenstein is the real monster?Most first-person accounts elicit the reader’s instinctive sympathy for the narrator. As Frankenstein progresses, however, Victor becomes less than sympathetic. When confronted with the reality of creature that he has brought to life, he flees and loses track of it. He has become so caught up in the science of creation that he never thinks ahead to the reality, except to daydream about how “A new existence would bless me as its creator and source” (78). This desire to be blessed by his creation suggests he may be too human, too needy, to be taking on the role of Creator. When the creature awakens, Frankenstein feels an immediate revulsion based solely on the creature’s appearance: he is “unable to endure the aspect of the being” (81). The choice of endure is overwrought, especially given all he ends up enduring later in the novel. He immediately regrets what he has done, abandons his creation and accepts the conventional view that he has crossed boundaries better left uncrossed.If his irresponsibility were directed only toward his creation, I might be more forgiving. However, he also fails to step forward at Justine’s trial. Despite his insistence that nobody would believe him, he doesn’t even try. I couldn’t help but roll my eyes at his certainty that he suffers more than anyone else, which demonstrates his narcissism and obsessive nature.I don’t mean this evaluation of Victor’s character as an attack on the novel. His unlikeability makes it more intriguing. Instead of turning Victor into a deity, which his status as a creator already threatens to do, Shelley portrays flaws that keep him human, ultimately raising questions about who the real monster is. The creature may be overly kind in offering to “be mild and docile” to Victor (123). Should he owe gratitude to the man who abandoned him, simply because Victor is his creator — a creator who built him to be without real hope of companionship or happiness? Without the first-person narration, I suspect Victor’s passivity and irresponsibility would paint him in an even less flattering light.So why is this post — which was written by a student, by the way — worthy of the highest possible grade?1) The author explores a specific topic thoughtfully.2) The author uses quotations effectively by setting them up in a substantive way that integrates them with the overall argument and by commenting on them at length. The ratio of commentary on a quotation to the quotation itself is generally a strong indication of how good a post is.3) The author writes well — not just grammatically but clearly and concisely.4) All quotations are correctly formatted and cited.
ENGH 202 GMU The Naked and the Dead by Author Norman Mailer Book Report

Geology multiple choice

Geology multiple choice.

Q1. What causes substantial changes in carbon dioxide concentrations over the course of a single day?Group of answer choiceshuman activities which produce carbon dioxideday/night cycles of plant photosynthesisseasonal changes in plant growth/deaththere are no substantial changes on this timescaleFlag this QuestionQuestion 21 ptsQ2. What causes substantial changes in carbon dioxide concentrations over timescales of months?Group of answer choiceshuman activities which produce carbon dioxideday/night cycles of plant photosynthesisseasonal changes in plant growth/deaththere are no substantial changes on this timescaleFlag this QuestionQuestion 31 ptsQ3. What causes substantial long-term changes in carbon dioxide concentrations (changes over the course of years and decades)?Group of answer choiceshuman activities which produce carbon dioxideday/night cycles of plant photosynthesisseasonal changes in plant growth/deaththere are no substantial changes on this timescaleFlag this QuestionLet’s have a look at how carbon dioxide has varied over the past decades. Below is a graph made from individual measurements of the atmosphere taken regularly throughout the year. The measurements are of carbon dioxide (CO2) in the atmosphere, measured in parts per million, or “ppm” (how many out of 1 million molecules in the atmosphere are carbon dioxide molecules).Remember Mauna Loa in Hawaii? This shield volcano, sticking way up into the atmosphere, way out in the middle of the Pacific away from big cities and such, is one of the fairly ideal places where such measurements are taken. Note that CO2 levels wiggle up and down with a set frequency: these are the seasonal cycles from Q2. Note also the long-term trend, averaging out these little wiggles. Look at this long-term trend for the following questions.Flag this QuestionQuestion 41 ptsQ4. What was the approximate level of carbon dioxide in the atmosphere measured in 1960 (60 years ago)?Group of answer choices300 ppm315 ppm365 ppm415 ppmFlag this QuestionQuestion 51 ptsQ5. What is the approximate level of carbon dioxide in the atmosphere this year (2020)?Group of answer choices300 ppm315 ppm365 ppm415 ppmFlag this QuestionQuestion 61 ptsQ6. This represents an increase of about how much?Group of answer choices50 ppm100 ppm115 ppm165 ppmFlag this QuestionQuestion 71 ptsQ7. Dividing the current value by the earlier value, then multiplying by 100%, indicates proportionally how much higher the current levels are. Take your answer to Q5, divide by your answer to Q4, and multiply by 100%. The current level of carbon dioxide in the atmosphere is about:Group of answer choices50% what it was in 1960100% what it was in 1960130% what it was in 1960150% what it was in 1960Flag this QuestionNow, let’s look at temperature measurements. These are easier to make than measurements of carbon dioxide concentration, and so our record of these goes back farther. NASA shows the global temperatures as how much below (negative numbers) or above (positive numbers) an average value they are:https://climate.nasa.gov/vital-signs/global-temperature/ (Links to an external site.)These measurements are in degrees Celsius, rather than degrees Fahrenheit.Flag this QuestionQuestion 81 ptsQ8. From 1880 to 1926, the curve is fairly flat, indicating that global temperature did not change substantially. If this trend were extrapolated to the present day, what global average temperature anomaly would be predicted?Group of answer choicesabout 0.25 C below average (-0.25 C)about 0.25 C above average (+0.25 C)about the average (0 C)Flag this QuestionQuestion 91 ptsQ9. What did the temperature do between 1940 and 1964?Group of answer choicesincreasedecreasestay the sameFlag this QuestionQuestion 101 ptsQ10. From 1964 to the present, temperature has increased steadily overall, though with lots of up-and-down fluctuations. About what was the global temperature anomaly last year (in 2019)?Group of answer choices-0.5 C0.5 C1.0 CFlag this QuestionQuestion 111 ptsQ11. How much higher is the value in Q10 from the value in Q8?Group of answer choices0.75 C1.00 C1.25 CFlag this QuestionQuestion 121 ptsQ12. How much of a temperature difference is this in Fahrenheit?To convert, take the value in Celsius, then multiply by 1.8.Group of answer choices1.251.82.252.75Flag this QuestionThis is how much the global temperature has risen in the past century (and mostly in the past 60 years).The primary cause of this increase has been the increase in carbon dioxide in the atmosphere, as shown in your previous plot. However, if carbon dioxide was the only factor influencing temperature, then there wouldn’t be these wiggles in the temperature plot. Whereas carbon dioxide is the single most important factor, various other things can impact the climate. Two of them are volcanic eruptions and the El Niño–Southern Oscillation (ENSO): https://en.wikipedia.org/wiki/El_Ni%C3%B1o%E2%80%93Southern_Oscillation (Links to an external site.)Let’s look at each of these in turn. First, volcanic eruptions. Here are some major eruptions from the past century, and the years that they occurred:1883 Krakatau1902 Santa Maria1968 Fernandina Island1991 PinatuboFlag this QuestionQuestion 131 ptsQ13. Hover your cursor over the data points on the plot, and it will display the year and the temperature anomaly for that data point. Find the years of the volcanic eruptions listed above, and examine the temperature anomaly that year, and the year after the eruption.In general, in the year after the eruption, the temperature:Group of answer choicesrises by about 1 Crises by about 0.1-0.3 Cdoes not changedrops by about 0.1-0.3 Cdrops by about 1 CFlag this QuestionQuestion 141 ptsQ14. Volcanoes release heat and greenhouse gases (remember all those trapped gases in the lava?), which contribute to warming, but also lots of material into the atmosphere, which partially blocks sunlight and contributes to cooling. Based on your answer to Q14, which effect is more important in the year following the eruption?Group of answer choiceswarming from released heat and greenhouse gasescooling from released material shading sunlightFlag this QuestionSecond, the El Niño–Southern Oscillation (ENSO). Below are El Niño years of this oscillation, or cycle, from the past seventy years:1951, 1953, 1957, 1963, 1965, 1969, 1973, 1977, 1983, 1987, 1991, 1997-1998. (For El Niño events starting near Christmas time, the following year is listed, since that is when the peak temperature anomaly usually occurs.)Flag this QuestionQuestion 151 ptsQ15. Wave your cursor over the data points again, finding these years and looking at the temperature anomaly during these El Niño years and comparing them to the temperature anomaly the year before. In general, going from the year before an El Niño year to an El Niño year, the global temperature:Group of answer choicesrises by about 0.1-0.2 Cdoes not changedrops by about 0.1-0.2 CFlag this QuestionYou may have noticed that some of the El Niño years don’t have the typical pattern as the rest. Most of these are years when volcanic eruptions also occurred, and the two effects are stacking!Hopefully, this illustrates some of the complexity in climate patterns through time. There is also complexity by location. Please watch this video illustrating this: warmer than average temperatures for a given region are shown in warmer colors, and colder than average temperatures for that region are shown in cooler colors. Note both the overall warming trend, and also that this pattern is not uniform across the Earth. https://svs.gsfc.nasa.gov/4787 (Links to an external site.)Flag this QuestionLast year was the second warmest year on record (for now; the warmest was 2016). Let’s look at one of these temperature anomaly maps specifically for last year. Go to: https://data.giss.nasa.gov/gistemp/maps/ (Links to an external site.)Then, change “Mean Period” to “Annual (Jan-Dec)”, so that we are considering the entire year. Set the “Time Interval” to “Begin” 2019 and “End” 2019. Leave the other settings in their defaults, and click “Make Map.”Flag this QuestionQuestion 161 ptsQ16. In 2019, what part of the Earth experienced the most anomalously warm temperatures?Group of answer choicesthe middle of North America (the midwest of the northern U.S.A. and Canada)central and eastern Europenortheastern Siberia and northwestern Alaskacoastal Antarctica south of the Atlantic OceanFlag this QuestionQuestion 171 ptsQ17. What inhabited area experienced anomalously cold temperatures?Group of answer choicesthe middle of North America (the midwest of the northern U.S.A. and Canada)central and eastern Europenortheastern Siberia and northwestern Alaskasouthwestern AfricaFlag this QuestionQuestion 181 ptsQ18. What part of the Earth experienced the most anomalously cold temperatures?Group of answer choicesthe middle of North America (the midwest of the northern U.S.A. and Canada)central and eastern Europenortheastern Siberia and northwestern Alaskacoastal Antarctica south of the Atlantic Ocean
Geology multiple choice