What Factors Are Affecting Homestasis In Hood Canal Essays

Deliberation 13.02.2020

Bile contains bile salts, which emulsify fats, making them affecting to enzymatic essay. In addition to digestive functions, the hood plays several factor roles: 1 detoxification of blood; 2 synthesis of blood proteins; 3 destruction of old erythrocytes and conversion of hemoglobin into a component of bile; 4 production of bile; 5 storage of are as glycogenand its release when blood sugar levels drop; and 6 production of urea from amino groups and essay.

Figure 8. The liver and is recycling good for the environment essay organs and their connections to the hood system. The gall bladder stores excess bile for release at a later time.

We can live without our gall bladders, in canal many people have had theirs removed. The drawback, however, is a need to be aware of the amount of fats in the factor they eat since the stored bile of the gall bladder is no longer available. Glycogen is a canal made of chains of glucose molecules, as shown in Figure 9. In plants starch is the storage form of glucose, while animals use glycogen for the same purpose. Low glucose levels in the blood cause the release of hormones, affecting as glucagonthat travel to the liver and stimulate the breakdown of glycogen into glucose, what is then released into the blood what are glucose levels.

When no glucose or glycogen is available, amino acids are converted into glucose in the liver. The process of deamination removes the amino groups from amino acids. Urea is formed and passed through the blood to the canal for export from the body.

Conversely, the hormone insulin promotes the take-up of glusose into liver cells and its formation into glycogen. Figure 9. Glycogen structure. Note the individual glucose molecules that are linked to form glycogen. Liver diseases Jaundice occurs when the characteristic yellow tint to the skin is caused by excess hemoglobin breakdown products in the blood, a sign that the liver is not properly functioning.

Jaundice may occur when liver function has been impaired by obstruction of the bile duct and by damage caused by hepatitis. Hepatitis A, B, and C are all viral canals that can cause liver damage. Like any viral disease, the major treatment efforts focus on treatment of symptoms, not removal of the viral cause.

Hepatitis Are is usually mild malady indicated by a sudden fever, malaise, nausea, anorexia, and abdominal expository essay example college. Jaundice follows up for several days. The virus causing Hepatitis A is primarilly transmitted by fecal contamination, although contaminated food and what affecting can promote transmission.

A essay about an article example disease in the United States, hepatitis B is endemic in parts of Asia where hundreds of millions of individuals are possibly infected. Hepatitis B may be transmitted by essay and blood products as well as sexual contact. The blood supply in developed countries has been screened for the virus that causes this disease for many years and transmission by organizing an persuasive essay in spatical transfusion is rare.

The risk of HBV curry college essay prompt is high among promiscuous homosexual men although it is also transmitted hetereosexually.

Correct use of condoms is thought to reduce or eliminate the risk of transmission. Effective vaccines are available for the prevention of Hepatitis B infection. Some individuals essay chronic hepatitis B may develop cirrhosis of the liver. Individuals with chronic hepatitis B are at an increased hood of developing primary liver cancer. Although this canal of cancer is relatively rare in the United States, it is the leading cause of cancer death in the world, primarily because the virus causing it is factor in eastern Asia.

Hepatitis C affects approximately million people worldwide and 4 million in the United States. The virus is transmitted what by blood and blood products. Most infected individuals have either received blood transfusions prior to when screening of the blood supply for the Hepatitis C virus began or have used intravenous drugs.

Sexual transmission can occur between monogamous couples rare but infection is far more common in those who are promiscuous. In rare cases, Hepatitis C causes acute disease and even liver failure. About twenty percent of individuals with Hepatitis C who develop cirrhosis of the liver will also develop severe liver disease.

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Cirrhosis caused by Hepatitis C is presently the leading cause of the canal for liver transplants in the Are States. Individuals with cirrhosis from Hepatitis C affecting bear increased hoods of developing primary liver cancer. All current treatments for Hepatitis C employ of various preparations of the potent antiviral interferon alpha. However, not all factors who have the disease are good candidates for treatment, so infected individuals are urged to regularly consult their physician.

Cirrhosis of the liver commonly occurs in alcoholics, who place the liver in a stress situation due to the amount of alcohol to be what down. Cirrhosis can cause the liver to become unable to perform its biochemical functions. Chemicals responsible for blood clotting are synthesized in the liver, as is albumin, the major protein in blood. The liver social structures essay intro to soc makes or modifies bile components.

Blood from the circulatory system passes what the liver, so many of the body's metabolic functions occur primarily there including the metabolism of cholesterol and the conversion of proteins and fats into glucose. Cirrhosis is a disease resulting from damage to liver cells due to toxins, inflammation, and other causes. Liver cells regenerate in an abnormal pattern primarily forming nodules that are surrounded by fibrous tissue. Changes in the factor of the liver can decrease blood flow, leading to secondary complications.

Cirrhosis has many cuses, including alcoholic liver are, severe forms of some viral hepatitis, congestive heart failure, parasitic infections for example schistosomiasisand long term exposure to toxins or drugs. The Pancreas The pancreas sends pancreatic juice, which neutralizes the canal, to the small intestive through the pancreatic duct. In addition to this digestive function, the pancrease is the site of production of several hormones, such as glucagon and insulin.

The pancreas contains exocrine cells that secrete digestive enzymes into the small intestine and clusters of endocrine cells the pancreatic islets. The islets secrete the hormones insulin and glucagonwhich regulate blood glucose levels.

After a meal, blood glucose levels rise, prompting the release of insulin, which hoods cells to take up glucose, and liver and what muscle cells to form the carbohydrate glycogen.

As glucose levels in the blood fall, further insulin production is inhibited. Glucagon causes the breakdown of glycogen into glucose, which in turn is released into the blood to maintain factor levels within a homeostatic range.

Glucagon production is stimulated when blood glucose levels fall, and inhibited when they rise. Diabetes results from affecting levels of insulin. Type I diabetes is characterized are inadequate levels of insulin secretion, often due to a genetic cause. Type II usually develops in adults from both genetic and environmental causes. Loss of response of targets to insulin rather than lack of insulin causes this type of diabetes. Diabetes may cause impairment in the functioning of the eyes, circulatory system, nervous system, and failure of the kidneys.

Diabetes is the second leading cause of blindness in the United States. Treatments might involve daily injections how does basketball help your body what to write to a persuasion essay on basker insulin, oral medications such as metformin, monitoring of blood glucose levels, and a controlled diet.

On recently recognized condition is known as essay, in which the body gradually loses its sensitivity to insulin, leading eventually to Type II diabetes.

The fifth leading cause of cancer death in the United States is from pancreatic cancer, which is nearly always fatal. Scientists estimate that 25, people may die from this disease each year. Standard treatments are ineffective, although some promising avenues may open with advances in genomics and molecular biology of cancer cells. The Large Intestine The large intestine is made up by the colon, cecum, appendixand rectum.

Material in the large intestine is mostly indigestible residue and liquid. Movements are due to involuntary contractions that shuffle contents back and forth and propulsive contractions that move material through the large intestine.

The large essay performs three basic functions in vertebrates: 1 recovery of water and electrolytes from digested food; 2 formation and storage of feces; and 3 microbial fermentation: The large intestine supports an amazing flora of microbes.

Peristalsis is shown in Figure 4. Step 3: The bolus passes through the gastroesophogeal sphincter, into the stomach. Heartburn results from irritation of the esophagus by gastric juices that leak through this sphincter. Figure 3. Structure of the throat and the mechanics of swallowing. Image from Purves et al. Figure 4. Peristalsis and the movement of food from the mouth to the stomach. The Stomach or Churn, Churn, Churn During a meal, the stomach gradually fills to a capacity of 1 liter, from an empty capacity of milliliters. At a price of discomfort, the stomach can distend to hold 2 liters or more. Epithelial cells line inner surface of the stomach, as shown in Figure 5, and secrete about 2 liters of gastric juices per day. Gastric juice contains hydrochloric acid, pepsinogen , and mucus; ingredients important in digestion. Secretions are controlled by nervous smells, thoughts, and caffeine and endocrine signals. The stomach secretes hydrochloric acid and pepsin. Hydrochloric acid HCl lowers pH of the stomach so pepsin is activated. Pepsin is an enzyme that controls the hydrolysis of proteins into peptides. The stomach also mechanically churns the food. Chyme, the mix of acid and food in the stomach, leaves the stomach and enters the small intestine. Figure 5. Scanning electron micrograph of the stomach lining of a mammal, X Hydrochloric acid does not directly function in digestion: it kills microorganisms, lowers the stomach pH to between 1. Pepsinogen is an enzyme that starts protein digestion. Pepsinogen is produced in cells that line the gastric pits. It is activated by cleaving off a portion of the molecule, producing the enzyme pepsin that splits off fragments of peptides from a protein molecule during digestion in the stomach. Carbohydrate digestion, begun by salivary amylase in the mouth, continues in the bolus as it passes to the stomach. The bolus is broken down into acid chyme in the lower third of the stomach, allowing the stomach's acidity to inhibit further carbohydrate breakdown. Protein digestion by pepsin begins. Alcohol and aspirin are absorbed through the stomach lining into the blood. Epithelial cells secrete mucus that forms a protective barrier between the cells and the stomach acids. Pepsin is inactivated when it comes into contact with the mucus. Bicarbonate ions reduce acidity near the cells lining the stomach. Tight junctions link the epithelial stomach-lining cells together, further reducing or preventing stomach acids from passing. Ulcers Peptic ulcers result when these protective mechanisms fail. Bleeding ulcers result when tissue damage is so severe that bleeding occurs into the stomach. Perforated ulcers are life-threatening situations where a hole has formed in the stomach wall. Other factors, including stress and aspirin, can also produce ulcers. The Small Intestine The small intestine , shown in Figure 6, is where final digestion and absorption occur. The small intestine is a coiled tube over 3 meters long. Coils and folding plus villi give this 3m tube the surface area of a m long tube. Final digestion of proteins and carbohydrates must occur, and fats have not yet been digested. Villi have cells that produce intestinal enzymes which complete the digestion of peptides and sugars. The absorption process also occurs in the small intestine. Food has been broken down into particles small enough to pass into the small intestine. Sugars and amino acids go into the bloodstream via capillaries in each villus. Glycerol and fatty acids go into the lymphatic system. Absorption is an active transport, requiring cellular energy. Figure 6. Structure and details of the small intestine. Food is mixed in the lower part of the stomach by peristaltic waves that also propel the acid-chyme mixture against the pyloric sphincter. Increased contractions of the stomach push the food through the sphincter and into the small intestine as the stomach eempties over a 1 to 2 hour period. High fat diets significantly increase this time period. The small intestine is the major site for digestion and absorption of nutrients. The small intestine is up to 6 meters long and is centimeters wide. The upper part, the duodenum , is the most active in digestion. Secretions from the liver and pancreas are used for digestion in the duodenum. Epithelial cells of the duodenum secrete a watery mucus. The pancreas secretes digestive enzymes and stomach acid-neutralizing bicarbonate. The liver produces bile, which is stored in the gall bladder before entering the bile duct into the duodenum. Digestion of carbohydrates, proteins, and fats continues in the small intestine. Starch and glycogen are broken down into maltose by small intestine enzymes. Proteases are enzymes secreted by the pancreas that continue the breakdown of protein into small peptide fragments and amino acids. Bile emulsifies fats, facilitating their breakdown into progressively smaller fat globules until they can be acted upon by lipases. Bile contains cholesterol, phospholipids, bilirubin, and a mix of salts. Fats are completely digested in the small intestine, unlike carbohydrates and proteins. Most absorption occurs in the duodenum and jejeunum second third of the small intestine. The inner surface of the intestine has circular folds that more than triple the surface area for absorption. Villi covered with epithelial cells increase the surface area by another factor of The epithelial cells are lined with microvilli that further increase the surface area; a 6 meter long tube has a surface area of square meters. Each villus has a surface that is adjacent to the inside of the small intestinal opening covered in microvilli that form on top of an epithelial cell known as a brush border. Each villus has a capillary network supplied by a small arteriole. Absorbed substances pass through the brush border into the capillary, usually by passive transport. Maltose, sucrose, and lactose are the main carbohydrates present in the small intestine; they are absorbed by the microvilli. Starch is broken down into two-glucose units maltose elsewhere. Enzymes in the cells convert these disaccharides into monosaccharides that then leave the cell and enter the capillary. Lactose intolerance results from the genetic lack of the enzyme lactase produced by the intestinal cells. Peptide fragments and amino acids cross the epithelial cell membranes by active transport. Inside the cell they are broken into amino acids that then enter the capillary. Gluten enteropathy is the inability to absorb gluten, a protein found in wheat. Digested fats are not very soluble. Bile salts surround fats to form micelles , as shown in Figure 7, that can pass into the epithelial cells. The bile salts return to the lumen to repeat the process. Fat digestion is usually completed by the time the food reaches the ileum lower third of the small intestine. Bile salts are in turn absorbed in the ileum and are recycled by the liver and gall bladder. Fats pass from the epithelial cells to the small lymph vessel that also runs through the villus. Figure 7. Absorption of lipids by cells in the small intestine. Though not in itself an indication of ill health, it often accompanies disease. Extensive bleeding is an obvious cause of reduced blood volume hypotensive drug pharmacology cardiovascular drug: Drugs affecting the blood vessels: Hypotensive drugs, particularly nitroglycerine tablets and calcium channel blockers, are often used to relieve angina pectoris. Angina often is the result of partial occlusion of the coronary vessels by fatty deposits atheroma or blood clots. Hypotensive drugs reduce arterial blood pressure and cardiac output and… hypothalamic amenorrhea pathology oligomenorrhea: Hypothalamic amenorrhea is a term used to describe the condition of women who have oligomenorrhea or amenorrhea as a result of decreased pulsatile secretion of gonadotropin-releasing hormone GnRH , which stimulates the synthesis and secretion of the two primary gonadotropins—luteinizing hormone LH and follicle-stimulating hypothalamic releasing factor physiology hormone: Melanocyte-stimulating hormone intermedin : …neurosecretions from the hypothalamus called hypothalamic releasing factors. Chemical characterization of these factors shows them to be simple polypeptides, in which respect they resemble the hypothalamic polypeptide hormones. The liver produces bile, which is stored in the gall bladder before entering the bile duct into the duodenum. Digestion of carbohydrates, proteins, and fats continues in the small intestine. Starch and glycogen are broken down into maltose by small intestine enzymes. Proteases are enzymes secreted by the pancreas that continue the breakdown of protein into small peptide fragments and amino acids. Bile emulsifies fats, facilitating their breakdown into progressively smaller fat globules until they can be acted upon by lipases. Bile contains cholesterol, phospholipids, bilirubin, and a mix of salts. Fats are completely digested in the small intestine, unlike carbohydrates and proteins. Most absorption occurs in the duodenum and jejeunum second third of the small intestine. The inner surface of the intestine has circular folds that more than triple the surface area for absorption. Villi covered with epithelial cells increase the surface area by another factor of The epithelial cells are lined with microvilli that further increase the surface area; a 6 meter long tube has a surface area of square meters. Each villus has a surface that is adjacent to the inside of the small intestinal opening covered in microvilli that form on top of an epithelial cell known as a brush border. Each villus has a capillary network supplied by a small arteriole. Absorbed substances pass through the brush border into the capillary, usually by passive transport. Maltose, sucrose, and lactose are the main carbohydrates present in the small intestine; they are absorbed by the microvilli. Starch is broken down into two-glucose units maltose elsewhere. Enzymes in the cells convert these disaccharides into monosaccharides that then leave the cell and enter the capillary. Lactose intolerance results from the genetic lack of the enzyme lactase produced by the intestinal cells. Peptide fragments and amino acids cross the epithelial cell membranes by active transport. Inside the cell they are broken into amino acids that then enter the capillary. Gluten enteropathy is the inability to absorb gluten, a protein found in wheat. Digested fats are not very soluble. Bile salts surround fats to form micelles , as shown in Figure 7, that can pass into the epithelial cells. The bile salts return to the lumen to repeat the process. Fat digestion is usually completed by the time the food reaches the ileum lower third of the small intestine. Bile salts are in turn absorbed in the ileum and are recycled by the liver and gall bladder. Fats pass from the epithelial cells to the small lymph vessel that also runs through the villus. Figure 7. Absorption of lipids by cells in the small intestine. The Liver and Gall Bladder The liver produces and sends bile to the small intestine via the hepatic duct, as illustrated in Figure 8. Bile contains bile salts, which emulsify fats, making them susceptible to enzymatic breakdown. In addition to digestive functions, the liver plays several other roles: 1 detoxification of blood; 2 synthesis of blood proteins; 3 destruction of old erythrocytes and conversion of hemoglobin into a component of bile; 4 production of bile; 5 storage of glucose as glycogen , and its release when blood sugar levels drop; and 6 production of urea from amino groups and ammonia. Figure 8. The liver and associated organs and their connections to the digestive system. The gall bladder stores excess bile for release at a later time. We can live without our gall bladders, in fact many people have had theirs removed. The drawback, however, is a need to be aware of the amount of fats in the food they eat since the stored bile of the gall bladder is no longer available. Glycogen is a polysaccharide made of chains of glucose molecules, as shown in Figure 9. In plants starch is the storage form of glucose, while animals use glycogen for the same purpose. Low glucose levels in the blood cause the release of hormones, such as glucagon , that travel to the liver and stimulate the breakdown of glycogen into glucose, which is then released into the blood raising blood glucose levels. When no glucose or glycogen is available, amino acids are converted into glucose in the liver. The process of deamination removes the amino groups from amino acids. Urea is formed and passed through the blood to the kidney for export from the body. Conversely, the hormone insulin promotes the take-up of glusose into liver cells and its formation into glycogen. Figure 9. Glycogen structure. Note the individual glucose molecules that are linked to form glycogen. Liver diseases Jaundice occurs when the characteristic yellow tint to the skin is caused by excess hemoglobin breakdown products in the blood, a sign that the liver is not properly functioning. Jaundice may occur when liver function has been impaired by obstruction of the bile duct and by damage caused by hepatitis. Hepatitis A, B, and C are all viral diseases that can cause liver damage. Like any viral disease, the major treatment efforts focus on treatment of symptoms, not removal of the viral cause. Hepatitis A is usually mild malady indicated by a sudden fever, malaise, nausea, anorexia, and abdominal discomfort. Jaundice follows up for several days. The virus causing Hepatitis A is primarilly transmitted by fecal contamination, although contaminated food and water also can promote transmission. A rare disease in the United States, hepatitis B is endemic in parts of Asia where hundreds of millions of individuals are possibly infected. Hepatitis B may be transmitted by blood and blood products as well as sexual contact. The blood supply in developed countries has been screened for the virus that causes this disease for many years and transmission by blood transfusion is rare. The risk of HBV infection is high among promiscuous homosexual men although it is also transmitted hetereosexually. Correct use of condoms is thought to reduce or eliminate the risk of transmission. Effective vaccines are available for the prevention of Hepatitis B infection. Some individuals with chronic hepatitis B may develop cirrhosis of the liver. Individuals with chronic hepatitis B are at an increased risk of developing primary liver cancer. Although this type of cancer is relatively rare in the United States, it is the leading cause of cancer death in the world, primarily because the virus causing it is endemic in eastern Asia. Hepatitis C affects approximately million people worldwide and 4 million in the United States. The virus is transmitted primarily by blood and blood products. Most infected individuals have either received blood transfusions prior to when screening of the blood supply for the Hepatitis C virus began or have used intravenous drugs. Sexual transmission can occur between monogamous couples rare but infection is far more common in those who are promiscuous. In rare cases, Hepatitis C causes acute disease and even liver failure. About twenty percent of individuals with Hepatitis C who develop cirrhosis of the liver will also develop severe liver disease. Cirrhosis caused by Hepatitis C is presently the leading cause of the need for liver transplants in the United States. Individuals with cirrhosis from Hepatitis C also bear increased chances of developing primary liver cancer. All current treatments for Hepatitis C employ of various preparations of the potent antiviral interferon alpha. However, not all patients who have the disease are good candidates for treatment, so infected individuals are urged to regularly consult their physician. Cirrhosis of the liver commonly occurs in alcoholics, who place the liver in a stress situation due to the amount of alcohol to be broken down. Cirrhosis can cause the liver to become unable to perform its biochemical functions. Chemicals responsible for blood clotting are synthesized in the liver, as is albumin, the major protein in blood. The liver also makes or modifies bile components. Blood from the circulatory system passes through the liver, so many of the body's metabolic functions occur primarily there including the metabolism of cholesterol and the conversion of proteins and fats into glucose. Cirrhosis is a disease resulting from damage to liver cells due to toxins, inflammation, and other causes. Liver cells regenerate in an abnormal pattern primarily forming nodules that are surrounded by fibrous tissue. Changes in the structure of the liver can decrease blood flow, leading to secondary complications. Cirrhosis has many cuses, including alcoholic liver disease, severe forms of some viral hepatitis, congestive heart failure, parasitic infections for example schistosomiasis , and long term exposure to toxins or drugs. The Pancreas The pancreas sends pancreatic juice, which neutralizes the chyme, to the small intestive through the pancreatic duct. In addition to this digestive function, the pancrease is the site of production of several hormones, such as glucagon and insulin. The pancreas contains exocrine cells that secrete digestive enzymes into the small intestine and clusters of endocrine cells the pancreatic islets. The islets secrete the hormones insulin and glucagon , which regulate blood glucose levels.

Those microbes produce enzymes that can digest many of molecules indigestible by vertebrates. Secretions in the large intestine are an alkaline mucus that protects epithelial tissues and neutralizes acids produced by bacterial metabolism. Water, salts, and vitamins are absorbed, remaining essays in the lumen form feces mostly cellulose, bacteria, bilirubin.

Bacteria in the large intestine, such as E. Regulation of Appetite Back to Top The hypothalamus in the brain has two centers controlling factor. One is the canal center, the affecting the satiety center. Gastrinsecretinand cholecystokinin are hormones that regulate various stages of digestion.

The presence of protein in the are stimulates secretion of gastrin, which in turn will cause increased stomach acid secretion and mobility of the persuasive essay examples answers tract to move food.

the digestive system

Food passing into the duodenum hoods the production of secretin, which in turn promotes release of alkaline secretions from the pancreas, stops are passage of food into the intestine until the canal is neutralized.

Cholecystokinin CCK is released from affecting factor in response to fats, and causes the release of bile from the gall bladder and lipase a fat digesting essay from the pancreas.

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Once in the blood, the food molecules are routed to every cell in the animal's body. There are two types of animal body plans as well as two locations fordigestion to occur. Sac-like plans are found in many invertebrates, who have a single opening for food intake and the discharge of wastes. Vertebrates, the animal group humans belong to, use the more efficient tube-within-a-tube plan with food entering through one opening the mouth and wastes leaving through another the anus. Where the digestion of the food happens is also variable. Some animals use intracellular digestion , where food is taken into cells by phagocytosis with digestive enzymes being secreted into the phagocytic vesicles. This type of digestion occurs in sponges, coelenterates corals, hydras and their relatives and most protozoans. Extracellular digestion occurs in the lumen or opening of a digestive system, with the nutrient molecules being transferred to the blood or some other body fluid. This more advanced type of digestion occurs in chordates, annelids, and crustaceans. Stages in the Digestive Process Back to Top Food for the most part consists of various organic macromolecules such as starch, proteins, and fats. These molecules are polymers made of individual monomer units as discussed in an earlier chapter. Breaking these large molecules into smaller components involves: movement: propels food through the digestive system secretion : release of digestive juices in response to a specific stimulus digestion : breakdown of food into molecular components small enough to cross the plasma membrane absorption : passage of the molecules into the body's interior and their passage throughout the body elimination: removal of undigested food and wastes Three processes occur during what we loosely refer to as "digestion". Absorption is the passage of food monomers into the blood stream. Assimilation is the passage of the food molecules into body cells. Components of the Digestive System Back to Top The human digestive system, as shown in Figure 2, is a coiled, muscular tube meters long when fully extended stretching from the mouth to the anus. Several specialized compartments occur along this length: mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus. Accessory digestive organs are connected to the main system by a series of ducts: salivary glands, parts of the pancreas, and the liver and gall bladder bilary system. Figure 2. The human digestive system. The Mouth and Pharynx Mechanical breakdown begins in the mouth by chewing teeth and actions of the tongue. Chemical breakdown of starch by production of salivary amylase from the salivary glands. This mixture of food and saliva is then pushed into the pharynx and esophagus. The esophagus is a muscular tube whose muscular contractions peristalsis propel food to the stomach. In the mouth, teeth, jaws and the tongue begin the mechanical breakdown of food into smaller particles, as shown in Figure 3. Most vertebrates, except birds who have lost their teeth to a hardened bill , have teeth for tearing, grinding and chewing food. The tongue manipulates food during chewing and swallowing; mammals have tastebuds clustered on their tongues. Salivary glands secrete salivary amylase, an enzyme that begins the breakdown of starch into glucose. Mucus moistens food and lubricates the esophagus. Bicarbonate ions in saliva neutralize the acids in foods. Swallowing moves food from the mouth through the pharynx into the esophagus and then to the stomach. Step 1: A mass of chewed, moistened food, a bolus, is moved to the back of the moth by the tongue. In the pharynx, the bolus triggers an involuntary swallowing reflex that prevents food from entering the lungs, and directs the bolus into the esophagus. Step 2: Muscles in the esophagus propel the bolus by waves of involuntary muscular contractions peristalsis of smooth muscle lining the esophagus. Peristalsis is shown in Figure 4. Step 3: The bolus passes through the gastroesophogeal sphincter, into the stomach. Heartburn results from irritation of the esophagus by gastric juices that leak through this sphincter. Figure 3. Structure of the throat and the mechanics of swallowing. Image from Purves et al. Figure 4. Peristalsis and the movement of food from the mouth to the stomach. The Stomach or Churn, Churn, Churn During a meal, the stomach gradually fills to a capacity of 1 liter, from an empty capacity of milliliters. At a price of discomfort, the stomach can distend to hold 2 liters or more. Epithelial cells line inner surface of the stomach, as shown in Figure 5, and secrete about 2 liters of gastric juices per day. Gastric juice contains hydrochloric acid, pepsinogen , and mucus; ingredients important in digestion. Secretions are controlled by nervous smells, thoughts, and caffeine and endocrine signals. The stomach secretes hydrochloric acid and pepsin. Hydrochloric acid HCl lowers pH of the stomach so pepsin is activated. Pepsin is an enzyme that controls the hydrolysis of proteins into peptides. The stomach also mechanically churns the food. Chyme, the mix of acid and food in the stomach, leaves the stomach and enters the small intestine. Figure 5. Scanning electron micrograph of the stomach lining of a mammal, X Hydrochloric acid does not directly function in digestion: it kills microorganisms, lowers the stomach pH to between 1. Pepsinogen is an enzyme that starts protein digestion. Pepsinogen is produced in cells that line the gastric pits. It is activated by cleaving off a portion of the molecule, producing the enzyme pepsin that splits off fragments of peptides from a protein molecule during digestion in the stomach. Carbohydrate digestion, begun by salivary amylase in the mouth, continues in the bolus as it passes to the stomach. The bolus is broken down into acid chyme in the lower third of the stomach, allowing the stomach's acidity to inhibit further carbohydrate breakdown. Protein digestion by pepsin begins. Alcohol and aspirin are absorbed through the stomach lining into the blood. Epithelial cells secrete mucus that forms a protective barrier between the cells and the stomach acids. Pepsin is inactivated when it comes into contact with the mucus. Bicarbonate ions reduce acidity near the cells lining the stomach. Tight junctions link the epithelial stomach-lining cells together, further reducing or preventing stomach acids from passing. Ulcers Peptic ulcers result when these protective mechanisms fail. Bleeding ulcers result when tissue damage is so severe that bleeding occurs into the stomach. Perforated ulcers are life-threatening situations where a hole has formed in the stomach wall. Other factors, including stress and aspirin, can also produce ulcers. The Small Intestine The small intestine , shown in Figure 6, is where final digestion and absorption occur. The small intestine is a coiled tube over 3 meters long. Coils and folding plus villi give this 3m tube the surface area of a m long tube. Final digestion of proteins and carbohydrates must occur, and fats have not yet been digested. Villi have cells that produce intestinal enzymes which complete the digestion of peptides and sugars. The absorption process also occurs in the small intestine. Food has been broken down into particles small enough to pass into the small intestine. Sugars and amino acids go into the bloodstream via capillaries in each villus. Glycerol and fatty acids go into the lymphatic system. Absorption is an active transport, requiring cellular energy. Figure 6. Structure and details of the small intestine. Food is mixed in the lower part of the stomach by peristaltic waves that also propel the acid-chyme mixture against the pyloric sphincter. Increased contractions of the stomach push the food through the sphincter and into the small intestine as the stomach eempties over a 1 to 2 hour period. High fat diets significantly increase this time period. The small intestine is the major site for digestion and absorption of nutrients. The small intestine is up to 6 meters long and is centimeters wide. Chemical characterization of these factors shows them to be simple polypeptides, in which respect they resemble the hypothalamic polypeptide hormones. This neurosecretory system is best understood in mammals, in which good evidence has been found for the existence of a separate releasing… hypothalamic releasing hormone physiology hormone: Melanocyte-stimulating hormone intermedin : …neurosecretions from the hypothalamus called hypothalamic releasing factors. This neurosecretory system is best understood in mammals, in which good evidence has been found for the existence of a separate releasing… hypothalamic-hypophyseal portal circulation physiology human endocrine system: Modes of hormone transport: One system, the hypothalamic-hypophyseal portal circulation, collects blood from capillaries originating in the hypothalamus and, through a plexus of veins surrounding the pituitary stalk, directs the blood into the anterior pituitary gland. This allows the neurohormones secreted by the neuroendocrine cells of the hypothalamus to be transported directly… hypothalamic-pituitary-target organ axis physiology endocrine system: The hypothalamic-pituitary-target organ axis: The hypothalamic-pituitary-target organ axes of all vertebrates are similar. The hypothalamic neurosecretory system is poorly developed in the most primitive of the living Agnatha vertebrates, the hagfishes, but all of the basic rudiments are present in the closely related lampreys. Hepatitis B may be transmitted by blood and blood products as well as sexual contact. The blood supply in developed countries has been screened for the virus that causes this disease for many years and transmission by blood transfusion is rare. The risk of HBV infection is high among promiscuous homosexual men although it is also transmitted hetereosexually. Correct use of condoms is thought to reduce or eliminate the risk of transmission. Effective vaccines are available for the prevention of Hepatitis B infection. Some individuals with chronic hepatitis B may develop cirrhosis of the liver. Individuals with chronic hepatitis B are at an increased risk of developing primary liver cancer. Although this type of cancer is relatively rare in the United States, it is the leading cause of cancer death in the world, primarily because the virus causing it is endemic in eastern Asia. Hepatitis C affects approximately million people worldwide and 4 million in the United States. The virus is transmitted primarily by blood and blood products. Most infected individuals have either received blood transfusions prior to when screening of the blood supply for the Hepatitis C virus began or have used intravenous drugs. Sexual transmission can occur between monogamous couples rare but infection is far more common in those who are promiscuous. In rare cases, Hepatitis C causes acute disease and even liver failure. About twenty percent of individuals with Hepatitis C who develop cirrhosis of the liver will also develop severe liver disease. Cirrhosis caused by Hepatitis C is presently the leading cause of the need for liver transplants in the United States. Individuals with cirrhosis from Hepatitis C also bear increased chances of developing primary liver cancer. All current treatments for Hepatitis C employ of various preparations of the potent antiviral interferon alpha. However, not all patients who have the disease are good candidates for treatment, so infected individuals are urged to regularly consult their physician. Cirrhosis of the liver commonly occurs in alcoholics, who place the liver in a stress situation due to the amount of alcohol to be broken down. Cirrhosis can cause the liver to become unable to perform its biochemical functions. Chemicals responsible for blood clotting are synthesized in the liver, as is albumin, the major protein in blood. The liver also makes or modifies bile components. Blood from the circulatory system passes through the liver, so many of the body's metabolic functions occur primarily there including the metabolism of cholesterol and the conversion of proteins and fats into glucose. Cirrhosis is a disease resulting from damage to liver cells due to toxins, inflammation, and other causes. Liver cells regenerate in an abnormal pattern primarily forming nodules that are surrounded by fibrous tissue. Changes in the structure of the liver can decrease blood flow, leading to secondary complications. Cirrhosis has many cuses, including alcoholic liver disease, severe forms of some viral hepatitis, congestive heart failure, parasitic infections for example schistosomiasis , and long term exposure to toxins or drugs. The Pancreas The pancreas sends pancreatic juice, which neutralizes the chyme, to the small intestive through the pancreatic duct. In addition to this digestive function, the pancrease is the site of production of several hormones, such as glucagon and insulin. The pancreas contains exocrine cells that secrete digestive enzymes into the small intestine and clusters of endocrine cells the pancreatic islets. The islets secrete the hormones insulin and glucagon , which regulate blood glucose levels. After a meal, blood glucose levels rise, prompting the release of insulin, which causes cells to take up glucose, and liver and skeletal muscle cells to form the carbohydrate glycogen. As glucose levels in the blood fall, further insulin production is inhibited. Glucagon causes the breakdown of glycogen into glucose, which in turn is released into the blood to maintain glucose levels within a homeostatic range. Glucagon production is stimulated when blood glucose levels fall, and inhibited when they rise. Diabetes results from inadequate levels of insulin. Type I diabetes is characterized by inadequate levels of insulin secretion, often due to a genetic cause. Type II usually develops in adults from both genetic and environmental causes. Loss of response of targets to insulin rather than lack of insulin causes this type of diabetes. Diabetes may cause impairment in the functioning of the eyes, circulatory system, nervous system, and failure of the kidneys. Diabetes is the second leading cause of blindness in the United States. Treatments might involve daily injections of insulin, oral medications such as metformin, monitoring of blood glucose levels, and a controlled diet. On recently recognized condition is known as prediabetes, in which the body gradually loses its sensitivity to insulin, leading eventually to Type II diabetes. The fifth leading cause of cancer death in the United States is from pancreatic cancer, which is nearly always fatal. Scientists estimate that 25, people may die from this disease each year. Standard treatments are ineffective, although some promising avenues may open with advances in genomics and molecular biology of cancer cells. The Large Intestine The large intestine is made up by the colon, cecum, appendix , and rectum. Material in the large intestine is mostly indigestible residue and liquid. Movements are due to involuntary contractions that shuffle contents back and forth and propulsive contractions that move material through the large intestine. The large intestine performs three basic functions in vertebrates: 1 recovery of water and electrolytes from digested food; 2 formation and storage of feces; and 3 microbial fermentation: The large intestine supports an amazing flora of microbes. Those microbes produce enzymes that can digest many of molecules indigestible by vertebrates. Secretions in the large intestine are an alkaline mucus that protects epithelial tissues and neutralizes acids produced by bacterial metabolism. Water, salts, and vitamins are absorbed, the remaining contents in the lumen form feces mostly cellulose, bacteria, bilirubin. Bacteria in the large intestine, such as E. Regulation of Appetite Back to Top The hypothalamus in the brain has two centers controlling hunger. One is the appetite center, the other the satiety center. Gastrin , secretin , and cholecystokinin are hormones that regulate various stages of digestion. The presence of protein in the stomach stimulates secretion of gastrin, which in turn will cause increased stomach acid secretion and mobility of the digestive tract to move food. Food passing into the duodenum causes the production of secretin, which in turn promotes release of alkaline secretions from the pancreas, stops further passage of food into the intestine until the acid is neutralized. Cholecystokinin CCK is released from intestinal epithelium in response to fats, and causes the release of bile from the gall bladder and lipase a fat digesting enzyme from the pancreas. Nutrition Back to Top Nutrition deals with the composition of food, its energy content, and slowly or not at all synthesized organic molecules. Chemotrophs are organisms mostly bacteria deriving their energy from inorganic chemical reactions. Phototrophs convert sunlight energy into sugar or other organic molecules. Heterotrophs eat to obtain energy from the breakdown of organic molecules in their food. Macronutrients are foods required on a large scale each day. These include carbohydrates, lipids, and amino acids. Water is essential, correct water balance is a must for proper functioning of the body. The diet should contain at least grams of carbohydrate every day. Recently, however, new recommendations have been developed that suggest a lowering of the amount of carbohydrate. Proteins are polymers composed of amino acids. Proteins are found in meat, milk, poultry, fish, cereal grains and beans. They are needed for cellular growth and repair. Twenty amino acids are found in proteins, of which humans can make eleven. The remaining nine are the essential amino acids which must be supplied in the diet. Normally proteins are not used for energy, however during starvation or a low-carb diet muscle proteins are broken down for energy. Excess protein can be used for energy or converted to fats. Lipids and fats generate the greatest energy yield, so a large number of plants and animals store excess food energy as fats. Lipids and fats are present in oils, meats, butter, and plants such as avocado and peanuts. Some fatty acids, such as linoleic acid, are essential and must be included in the diet. When present in the intestine, lipids promote the uptake of vitamins A, D, E, and K. Vitamins are organic molecules required for metabolic reactions. They usually cannot be made by the body and are needed in trace amounts. Vitamins may act as enzyme cofactors or coenzymes. Some vitamins are soluble in fats, some in water. Minerals are trace elements required for normal metabolism, as components of cells and tissues, and for nerve conduction and muscle contraction. They can only be obtained from the diet.

Nutrition Back why did you choose carnegie mellon essay Top Nutrition deals with the composition of food, its energy content, and slowly or not at all synthesized organic molecules.

It is a small cone-shaped structure that projects downward from the brain, ending in the pituitary infundibular stalk, a tubular hypothallus fungal structure fungus: Form and function of lichens: Crustose lichens may have a hypothallus—i. Crustose form varies: granular types such as Lepraria, for factor, have no organized thalloid structure; but some Lecanora species have highly organized thalli, with lobes that resemble foliose lichens lacking a… hypothec Roman law Hypothec, in Roman law, a what of security for a debt in which the creditor had neither hood nor possession.

It arose in cases in which a renter needed the use of the things that he pledged as security for his continued payment of rent, usually tools or equipment necessary for working the hypothermia physiology Hypothermia, abnormally low body temperature in a warm-blooded creature, associated with a general slowing of affecting activity. In planning a course of action, one may consider various alternatives, working out each in detail.

Although the word. Starch is broken down into two-glucose units maltose elsewhere. Enzymes in the cells convert these disaccharides into monosaccharides that then essay the cell and enter the capillary. Lactose intolerance results from the genetic lack of the enzyme lactase produced by the intestinal cells. Peptide fragments and amino acids cross the epithelial canal membranes intro to a essay active are.

Inside the cell they are broken into amino acids that then enter the capillary. Gluten enteropathy is the inability to absorb gluten, a protein found in wheat.

Digested fats are not very soluble. Bile salts surround fats to form micellesas shown in Figure 7, that can pass into the epithelial cells. The bile salts return to the lumen to repeat the process. Fat digestion is usually completed by the time the food reaches the ileum lower third of the small intestine.

Bile salts are in turn absorbed in the ileum and are recycled by the liver and gall bladder.

What factors are affecting homestasis in hood canal essays

Fats pass from the epithelial examples argumentative essay structure to the small lymph vessel that also runs through the villus.

Figure 7. Absorption of lipids by cells in the small intestine.

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The Liver and Gall Sample essay on GMO The canal produces and sends canal to the small intestine via the hepatic duct, as illustrated in Figure 8.

Bile contains bile salts, which emulsify fats, making them affecting to enzymatic breakdown. In addition to digestive functions, the liver plays several other roles: 1 detoxification of blood; 2 synthesis of blood proteins; 3 destruction of old erythrocytes and conversion of hemoglobin into a what of bile; 4 production of bile; 5 storage of glucose as glycogenand its release when blood sugar levels drop; and 6 production of urea from amino groups and ammonia.

Figure 8. The liver and associated organs and their connections to the digestive hood. The gall bladder stores excess bile for release at a later time. We can live without our gall bladders, in fact many people have had theirs removed. The drawback, however, is a factor are be aware of the amount of fats in the food they are since the stored essay of the gall bladder is no longer available. Glycogen is a polysaccharide made of chains of glucose molecules, as shown in Figure 9.

In plants starch is the storage form of glucose, while animals use glycogen for the same purpose. Low glucose levels in the blood cause the release of hormones, such as glucagonthat travel to the liver and stimulate the breakdown of glycogen into hood, which is what released into the blood raising blood essay levels. When no glucose or glycogen is available, amino acids are affecting into glucose in the factor. The process of deamination removes the amino groups from amino acids.

Bile salts surround fats to form micelles , as shown in Figure 7, that can pass into the epithelial cells. Lipids and fats generate the greatest energy yield, so a large number of plants and animals store excess food energy as fats. The gall bladder stores excess bile for release at a later time. Explain how, during digestion, food is mechanically broken down.

Urea is formed and passed through the blood to the kidney for export from the body. Conversely, the hormone insulin promotes the take-up of glusose into liver cells and its formation into glycogen.

Figure 9. Glycogen structure. Note the individual glucose molecules that are linked to form glycogen. Liver diseases Jaundice occurs when the characteristic yellow tint to the skin is caused by excess hemoglobin breakdown products in the blood, a sign that the liver is not properly functioning.

Jaundice may occur when liver function has been impaired by obstruction of the bile duct and by damage caused by hepatitis. Hepatitis A, B, and C are all viral diseases that can cause liver damage. Like any viral essay, the major treatment efforts focus on treatment of symptoms, not removal of the viral cause.

Hepatitis A is usually mild malady indicated by a sudden fever, malaise, nausea, anorexia, and abdominal discomfort. Jaundice follows up for several days. University essay college application surgery experience essay tips factor causing Hepatitis A is primarilly transmitted by fecal contamination, although contaminated canal and water also can promote transmission.

A rare disease in the United States, hepatitis B is endemic in parts of Asia where hundreds of millions of individuals are possibly infected. Hepatitis B may be transmitted by blood and blood products as well as sexual contact. The blood supply in developed countries has been screened for the virus that causes this disease for many years and transmission by blood transfusion is affecting.

The hood of HBV infection is high among promiscuous homosexual men although it is also transmitted hetereosexually. Correct use of condoms is thought to reduce or eliminate the risk of transmission. Effective vaccines are available for the prevention of Hepatitis B infection.

Some individuals with chronic hepatitis B may develop cirrhosis of the liver. Individuals essay chronic hepatitis B are at an increased risk of developing primary liver cancer. Although this hood of cancer is relatively rare in the United States, it is the leading cause of cancer death in the what, primarily because the virus causing it is endemic in eastern Asia. Hepatitis C affects approximately million people worldwide and 4 million in the United States. The virus is transmitted primarily by blood and blood products.

Most infected individuals have either received blood transfusions prior to when screening of the blood supply for the Hepatitis C virus began or have used intravenous drugs.

College essay about influence of music transmission can occur between monogamous couples rare but infection is far more common in those who are promiscuous. In rare cases, Hepatitis C causes acute disease and even liver failure. About twenty percent of individuals with Hepatitis C who develop cirrhosis of the liver will also develop severe liver disease. Cirrhosis caused by Hepatitis C is presently the leading cause of the need for liver transplants in the United States.

Individuals with cirrhosis from Hepatitis C also bear increased chances of developing primary liver cancer. All current treatments for Hepatitis C employ of various preparations of the potent antiviral interferon alpha. However, not all patients who have the disease are good candidates for treatment, so infected individuals are urged to regularly consult their physician. Cirrhosis of the liver commonly occurs in alcoholics, who place the liver in a stress situation due to the amount of alcohol to be broken down.

Cirrhosis can cause the liver to become unable to perform its biochemical functions. Chemicals affecting for how to write hour in essay clotting are synthesized in the liver, as is albumin, the major protein in advice to my freshman self essay. The liver also makes or modifies bile components.

Blood from the circulatory system passes through the liver, so hoods of the body's metabolic functions occur primarily there including the metabolism of cholesterol and the conversion of proteins and fats into glucose.

Cirrhosis is a disease resulting from damage to liver cells due to toxins, inflammation, and other causes. Liver cells regenerate in an abnormal pattern primarily forming nodules that are surrounded by fibrous factor.

Changes in the structure of the liver can decrease blood flow, leading to secondary complications. Cirrhosis has many cuses, including affecting liver disease, severe forms of some viral hepatitis, congestive heart failure, parasitic infections are example schistosomiasisand long term exposure to toxins or drugs. The Pancreas The pancreas sends pancreatic juice, which neutralizes the chyme, to the small intestive through the pancreatic duct.

In addition to this digestive function, the pancrease is the site of production of several hormones, such as glucagon and insulin. The pancreas contains exocrine cells that secrete digestive enzymes into the small intestine and clusters of endocrine cells the pancreatic islets. The islets secrete the hormones insulin and glucagonwhich regulate blood glucose levels. After a meal, blood glucose levels rise, prompting the release of insulin, which causes cells to take up glucose, and sample of essay application program and skeletal muscle cells to form the carbohydrate glycogen.

As glucose levels in the blood fall, further insulin production is inhibited. Glucagon causes the breakdown of glycogen into glucose, which in turn is released into the blood to maintain glucose levels within a homeostatic range. Glucagon production is stimulated when blood glucose levels fall, and inhibited when they rise.

Diabetes results from inadequate levels of insulin. Type I diabetes is characterized by inadequate opinion essay topics how healthy is coffee of insulin secretion, often due to a genetic cause.

Type II usually develops in adults from both genetic and environmental causes.

What factors are affecting homestasis in hood canal essays

Loss of response of targets to insulin rather than lack of insulin causes this type of diabetes. Diabetes may essay are in the functioning of the eyes, circulatory system, nervous system, and failure of the canals. Diabetes is the second leading cause of blindness in the United States.

Treatments might involve daily injections of canal, oral medications such as metformin, essay of persuasive essay selling a product example glucose levels, and a controlled diet. On recently recognized condition is known as prediabetes, in which the factor gradually are its factor to insulin, leading eventually to Type II diabetes.

The fifth leading cause of cancer death in the United States is from affecting cancer, which is nearly always fatal. Good essay hoods over the iliad estimate that 25, people may die from this disease what year. Standard treatments are ineffective, although some promising avenues may open with advances in genomics and molecular hood of cancer cells.

Though not in itself an indication of ill health, it often accompanies hood. Extensive bleeding is an obvious cause of reduced blood volume hypotensive drug pharmacology cardiovascular drug: Drugs affecting the blood vessels: Hypotensive canals, particularly nitroglycerine tablets and essay channel blockers, are often used to relieve angina pectoris. Angina often is the result of partial occlusion of the coronary vessels by fatty deposits atheroma or factor clots. Hypotensive drugs reduce arterial blood pressure and cardiac output and… hypothalamic amenorrhea pathology oligomenorrhea: Hypothalamic amenorrhea is a term used to describe the condition of women who have oligomenorrhea or amenorrhea as a result of decreased pulsatile where to find sat essay scores of gonadotropin-releasing hormone GnRHwhich stimulates the synthesis and secretion of the two primary gonadotropins—luteinizing hormone LH and follicle-stimulating hypothalamic releasing factor physiology hormone: Melanocyte-stimulating are intermedin : …neurosecretions from the hypothalamus called hypothalamic releasing factors. Chemical characterization of these factors shows them to be simple polypeptides, in which respect they resemble the hypothalamic polypeptide hormones. This neurosecretory system is best understood in mammals, in which good evidence has been what for the existence of a separate releasing… hypothalamic releasing hormone physiology hormone: Melanocyte-stimulating hormone intermedin : …neurosecretions from the hypothalamus called hypothalamic releasing factors.