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Digestivesystem / Cardio-respiratory System Assignment

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Digestive system/Cardio-respiratory System Assignment Normally, as food moves along the digestive tract, digestive juices and enzymes digest and absorb calories and nutrients. After we chew and swallow our food, it moves down the oesophagus to the stomach, where a strong acid continues the digestive process. The stomach is a sack-like portion of the digestive tract. Its inner surface is highly convoluted, enabling it to fold up when empty and open out like an expanding balloon as it fills with food. Thus while the human stomach has a volume of only about 50ml when empty, it may expand to contain 2 - 4 litres of food when full. Gastric bypass surgery promotes weight loss by closing off parts of the stomach to make it much smaller. To perform the surgery, doctors create a small pouch at the top of the stomach where food enters from the oesophagus. Initially, the pouch holds about 1 ounce of food and later expands to 2-3 ounces. The lower outlet of the pouch usually has a diameter of only about 3/4 inch. This small outlet delays the emptying of food from the pouch and causes a feeling of fullness. http://www.upmc.edu/NewsBureau/medsurg1/gastric_bypass_study.htm With this surgery, a section of the upper stomach is stapled to form a gastric pouch. Then, a portion of the upper intestine called a Roux limb is attached to the pouch. Food goes into the gastric pouch and through the Roux limb, bypassing the rest of the stomach. This bypass reduces the amount of calories and nutrients the body can absorb. Most patients will then lose weight quickly and continue to do so for 18-24 months. There will usually be a dramatic improvement in virtually every medical problem associated with obesity - high cholesterol, high blood pressure, type 2 diabetes, sleep apnea, arthritis etc. Although there can be complications with the surgery itself and follow-up surgery is sometimes needed. ...read more.


After the required 200 days, all the prisoners except two, shed the excess weight easily and returned to the weight they were before the experiment had begun, both had in fact found it the least difficult to put the weight on in the first instance. It was later discovered that both men had a family history of obesity. The prisoners with obesity in their background were, it seemed, genetically inclined to reach homeostasis at a higher weight, than the other participants; the high-calorie diet only helped manifest their genetic proclivity. Other evidence linking genetics with body weight regulation, has been found in adopted twin studies. The body mass index (BMI) of identical twins separated at birth and raised apart, usually correlated nicely with that of their biological parents, rather than with that of their adopted parents. This strongly suggests that genetics, not psychology, play the larger role in human obesity. Leptin it seems has evolved to prevent the body from starving. A dramatic decline in fat cells, where leptin is manufactured, triggers the body into a starvation response. Automatically the need to eat arises to eat, to protect itself from dying. This could have evolved at a time when food was sometimes scarce, the body would then build up it's fat supplies in case there were harsh times ahead. It has been speculated that television viewing is one of the most easily modifiable causes of obesity among children. Television viewing may reduce energy expenditure, that is reduce the amount of energy a child would usually burn up while partaking in other activities, such as playing sports. It has been shown that even reading expends more energy than watching TV (thought to be because of an increase in brain activity). An increase in TV viewing has also been shown to increase dietary energy intake, that is an increase in the amount of calories a child consumes per day compared to a child who watches less TV. ...read more.


The study suggests that a mother's health should be improved before and during birth for the long-standing welfare of the child. British Medical Journal 1 (Volume 315, No. 7114) The pancreas is a soft, greyish-pink, lobulated gland. It is approximately 12-15cm long and is located deeply on the posterior abdominal wall, near the liver and small intestine. It produces insulin and secretes it into the bloodstream to regulate blood sugar and help the body use sugar as a fuel to move muscles, make new cells and promote healing. If a person's pancreas stops producing insulin, then the person develops diabetes, a serious disease that can damage the eyes, nerves, the kidney and small blood vessels. Late onset diabetes, also known as 'type 2' diabetes, is a heterogeneous disease that is caused both by genetic & environmental factors. The disease is characterised by chronic hyperglycaemia, owing to a combination of insulin resistance and changed insulin secretion. As a result there is insufficient insulin action to keep the blood glucose level within normal limits. A low volume-density of blood vessels in the pancreas could make a rat susceptible to late onset diabetes. This is because the blood vessels may struggle to get enough insulin into them, and then around the body, to control the blood sugar level. http://www.umassmed.edu/diabeteshandbook/chap01.htm Regular physical activity can help increase lung capacity and strengthen all muscles in the body, including the heart. This will help improve circulation and also help the body use oxygen more efficiently. Being active can control weight by helping to burn off extra pounds, build lean muscle mass and reduce body fat. It also helps build and maintain healthy bones and joints. Other benefits include, helping to control blood pressure, lessening a diabetic's need for insulin, and boosting the levels of "good" HDL-cholesterol, which can help stop the build-up of fatty deposits in the coronary arteries, therefore reducing the risk of coronary heart disease. http://www.suttersantarosa.org/education/exheart. ...read more.

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