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On This Page Related Anatomy. Axe on Facebook Dr. For Nutrition in animals, see Animal nutrition. The decreased risk of CVD may be due, in part, to a reduction in arterial stiffness and blood pressure. Next page Origin and development. Animal nutrition and Human nutrition.
According to a study by the International Agency for Research on Cancer , "In the developing world, cancers of the liver, stomach and esophagus were more common, often linked to consumption of carcinogenic preserved foods, such as smoked or salted food, and parasitic infections that attack organs.
Several lines of evidence indicate lifestyle-induced hyperinsulinemia and reduced insulin function i. For example, hyperinsulinemia and insulin resistance are strongly linked to chronic inflammation, which in turn is strongly linked to a variety of adverse developments such as arterial microtrauma and clot formation i. Hyperinsulinemia and insulin resistance the so-called metabolic syndrome are characterized by a combination of abdominal obesity , elevated blood sugar , elevated blood pressure , elevated blood triglycerides , and reduced HDL cholesterol.
The state of obesity clearly contributes to insulin resistance, which in turn can cause type 2 diabetes. Virtually all obese and most type 2 diabetic individuals have marked insulin resistance.
Although the association between overweight and insulin resistance is clear, the exact likely multifarious causes of insulin resistance remain less clear. It has been demonstrated that appropriate exercise, more regular food intake, and reducing glycemic load see below all can reverse insulin resistance in overweight individuals and thereby lower their blood sugar level , in those with type 2 diabetes.
In addition, reduced leptin signaling to the brain may reduce leptin's normal effect to maintain an appropriately high metabolic rate. In any case, analogous to the way modern man-made pollution may possess the potential to overwhelm the environment's ability to maintain homeostasis , the recent explosive introduction of high glycemic index and processed foods into the human diet may possess the potential to overwhelm the body's ability to maintain homeostasis and health as evidenced by the metabolic syndrome epidemic.
Antinutrients are natural or synthetic compounds that interfere with the absorption of nutrients. Nutrition studies focus on antinutrients commonly found in food sources and beverages. The relatively recent increased consumption of sugar has been linked to the rise of some afflictions such as diabetes, obesity, and more recently heart disease. Increased consumption of sugar has been tied to these three, among others.
In the same time span that obesity doubled, diabetes numbers quadrupled in America. Increased weight, especially in the form of belly fat, and high sugar intake are also high risk factors for heart disease. Elevated amounts of Low-density lipoprotein LDL cholesterol, is the primary factor in heart disease. In order to avoid all the dangers of sugar, moderate consumption is paramount. Since the Industrial Revolution some two hundred years ago, the food processing industry has invented many technologies that both help keep foods fresh longer and alter the fresh state of food as they appear in nature.
Cooling is the primary technology used to maintain freshness, whereas many more technologies have been invented to allow foods to last longer without becoming spoiled.
These latter technologies include pasteurisation , autoclavation , drying , salting , and separation of various components, all of which appearing to alter the original nutritional contents of food.
Pasteurisation and autoclavation heating techniques have no doubt improved the safety of many common foods, preventing epidemics of bacterial infection. But some of the new food processing technologies have downfalls as well.
Modern separation techniques such as milling , centrifugation , and pressing have enabled concentration of particular components of food, yielding flour, oils, juices, and so on, and even separate fatty acids, amino acids, vitamins, and minerals. Inevitably, such large-scale concentration changes the nutritional content of food, saving certain nutrients while removing others. Heating techniques may also reduce food's content of many heat-labile nutrients such as certain vitamins and phytochemicals, and possibly other yet-to-be-discovered substances.
In addition, processed foods often contain potentially harmful substances such as oxidized fats and trans fatty acids. A dramatic example of the effect of food processing on a population's health is the history of epidemics of beri-beri in people subsisting on polished rice.
Removing the outer layer of rice by polishing it removes with it the essential vitamin thiamine , causing beri-beri. Another example is the development of scurvy among infants in the late 19th century in the United States.
It turned out that the vast majority of sufferers were being fed milk that had been heat-treated as suggested by Pasteur to control bacterial disease.
Pasteurisation was effective against bacteria, but it destroyed the vitamin C. As mentioned, lifestyle- and obesity-related diseases are becoming increasingly prevalent all around the world. There is little doubt that the increasingly widespread application of some modern food processing technologies has contributed to this development.
The food processing industry is a major part of modern economy, and as such it is influential in political decisions e. In any known profit-driven economy, health considerations are hardly a priority; effective production of cheap foods with a long shelf-life is more the trend.
In general, whole, fresh foods have a relatively short shelf-life and are less profitable to produce and sell than are more processed foods. Thus, the consumer is left with the choice between more expensive, but nutritionally superior, whole, fresh foods, and cheap, usually nutritionally inferior, processed foods.
Because processed foods are often cheaper, more convenient in both purchasing, storage, and preparation , and more available, the consumption of nutritionally inferior foods has been increasing throughout the world along with many nutrition-related health complications. From Wikipedia, the free encyclopedia.
This article is about Nutrition in general. For Nutrition in humans, see Human nutrition. For Nutrition in animals, see Animal nutrition. For nutrition in plants, see Plant nutrition. For the medical journal, see Nutrition journal. Mineral nutrient and Composition of the human body. List of antioxidants in food. Animal nutrition and Human nutrition. Nutrition portal Food portal. Food Balance Wheel Biology: Bioenergetics Digestion Enzyme Dangers of poor nutrition Deficiency Avitaminosis is a deficiency of vitamins.
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Retrieved 13 December Understanding Nutrition 13 ed. Deficiency, How Much, Benefits, and More. The New York Times. Archived from the original on The Profession of Dietetics. A History of Nutrition. The Riverside Press Houghton Mifflin. Perspectives in Clinical Research. Eat, Drink, and be Healthy: The Molecular Nature of Matter and Change 5 ed.
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Liquid diets Very low calorie. Category Commons Cookbook Food portal, Health and fitness portal. Retrieved from " https: Applied sciences Food science Nutrition Self care. Even though the two openings do not quite coincide in position, blood still passes through, from the right atrium to the left. At birth, increased blood pressure in the left atrium forces the primary partition against the secondary one, so that the two openings are blocked and the atria are completely separated.
The two partitions eventually fuse. The ventricle becomes partially divided into two chambers by an indentation of myocardium heart muscle at its tip. This developing partition is largely muscular and is supplemented by membranous connective tissue that develops in conjunction with the subdivision of the truncus arteriosus by a spiral partition into two channels, one for systemic and one for pulmonary circulation the aorta and the pulmonary artery , respectively.
At this time, the heart rotates clockwise and to the left so that it resides in the left thorax, with the left chambers posterior and the right chambers anterior. The greater portion of blood passing through the right side of the heart in the fetus is returned to the systemic circulation by the ductus arteriosus , a vessel connecting the pulmonary artery and the aorta.
At birth this duct becomes closed by a violent contraction of its muscular wall. Thereafter the blood in the right side of the heart is driven through the pulmonary arteries to the lungs for oxygenation and returned to the left side of the heart for ejection into the systemic circulation. A distinct median furrow at the apex of the ventricles marks the external subdivision of the ventricle into right and left chambers. To prevent backflow of blood, the heart is equipped with valves that permit the blood to flow in only one direction.
There are two types of valves located in the heart: The atrioventricular valves are thin, leaflike structures located between the atria and the ventricles. The right atrioventricular opening is guarded by the tricuspid valve , so called because it consists of three irregularly shaped cusps, or flaps.
The leaflets consist essentially of folds of endocardium the membrane lining the heart reinforced with a flat sheet of dense connective tissue. At the base of the leaflets, the middle supporting flat plate becomes continuous with that of the dense connective tissue of the ridge surrounding the openings.
Tendinous cords of dense tissue chordae tendineae covered by thin endocardium extend from the nipplelike papillary muscles to connect with the ventricular surface of the middle supporting layer of each leaflet.
The chordae tendineae and the papillary muscles from which they arise limit the extent to which the portions of the valves near their free margin can billow toward the atria. The left atrioventricular opening is guarded by the mitral , or bicuspid, valve, so named because it consists of two flaps.
The mitral valve is attached in the same manner as the tricuspid, but it is stronger and thicker because the left ventricle is by nature a more powerful pump working under high pressure. Blood is propelled through the tricuspid and mitral valves as the atria contract. When the ventricles contract, blood is forced backward, passing between the flaps and walls of the ventricles. The flaps are thus pushed upward until they meet and unite, forming a complete partition between the atria and the ventricles.
The expanded flaps of the valves are restrained by the chordae tendineae and papillary muscles from opening into the atria. The semilunar valves are pocketlike structures attached at the point at which the pulmonary artery and the aorta leave the ventricles. The pulmonary valve guards the orifice between the right ventricle and the pulmonary artery.
The aortic valve protects the orifice between the left ventricle and the aorta. The three leaflets of the aortic semilunar and two leaflets of the pulmonary valves are thinner than those of the atrioventricular valves, but they are of the same general construction with the exception that they possess no chordae tendineae. Closure of the heart valves is associated with an audible sound, called the heartbeat.
The first sound occurs when the mitral and tricuspid valves close, the second when the pulmonary and aortic semilunar valves close. These characteristic heart sounds have been found to be caused by the vibration of the walls of the heart and major vessels around the heart. The low-frequency first heart sound is heard when the ventricles contract, causing a sudden backflow of blood that closes the valves and causes them to bulge back.
Another effect is that the sympathetic nervous system makes the heart beat harder, forcing out a larger volume of blood with each beat, and forcing blood out with greater strength. These factors combine to produce increased blood flow to hard-working body tissues.
In addition to direct neural innervation of the heart, the nervous system can also affect the cardiovascular system through releasing chemical messengers, or neurotransmitters, into the bloodstream.
One important neurotransmitter is epinephrine, sometimes called adrenaline. Thibodeau notes that this compound is released by nerves in a gland that sits on top of each kidney, and when released, travels through the bloodstream to target organs.
One such target is the heart; when the neural product epinephrine reaches the heart, it increases pulse rate and contractility, increasing cardiac output and increasing the amount of blood that reaches the body tissues. Video of the Day. What Are the Organs of the Cardiovascular System? Chemoreceptors in the Cardiovascular System.