Understanding Nutrition, 10th edition , p. This in turn will reduce the volume of the cavity. Dietary Intake and Type 2 Diabetes Editor: A workshop and farm visit over two days provided a great opportunity to exchange ideas and get to know one another. Your Lungs and Respiratory System. Vasodilation is the expansion of an artery as the smooth muscle in the arterial wall relaxes after the fight-or-flight response wears off or under the effect of certain hormones or chemicals in the blood. Probiotics and Nutrition Editors:
Digestive System Physiology
These fluids include saliva, mucus, hydrochloric acid, enzymes, and bile. Saliva moistens dry food and contains salivary amylase, a digestive enzyme that begins the digestion of carbohydrates. Mucus serves as a protective barrier and lubricant inside of the GI tract. Hydrochloric acid helps to digest food chemically and protects the body by killing bacteria present in our food. Enzymes are like tiny biochemical machines that disassemble large macromolecules like proteins, carbohydrates, and lipids into their smaller components.
Finally, bile is used to emulsify large masses of lipids into tiny globules for easy digestion. Digestion is the process of turning large pieces of food into its component chemicals. Mechanical digestion is the physical breakdown of large pieces of food into smaller pieces. This mode of digestion begins with the chewing of food by the teeth and is continued through the muscular mixing of food by the stomach and intestines. Bile produced by the liver is also used to mechanically break fats into smaller globules.
While food is being mechanically digested it is also being chemically digested as larger and more complex molecules are being broken down into smaller molecules that are easier to absorb. Chemical digestion begins in the mouth with salivary amylase in saliva splitting complex carbohydrates into simple carbohydrates.
The enzymes and acid in the stomach continue chemical digestion, but the bulk of chemical digestion takes place in the small intestine thanks to the action of the pancreas. The pancreas secretes an incredibly strong digestive cocktail known as pancreatic juice, which is capable of digesting lipids, carbohydrates, proteins and nucleic acids. By the time food has left the duodenum , it has been reduced to its chemical building blocks—fatty acids, amino acids, monosaccharides, and nucleotides.
Once food has been reduced to its building blocks, it is ready for the body to absorb. Absorption begins in the stomach with simple molecules like water and alcohol being absorbed directly into the bloodstream.
Most absorption takes place in the walls of the small intestine, which are densely folded to maximize the surface area in contact with digested food. Small blood and lymphatic vessels in the intestinal wall pick up the molecules and carry them to the rest of the body.
The large intestine is also involved in the absorption of water and vitamins B and K before feces leave the body. The final function of the digestive system is the excretion of waste in a process known as defecation.
Defecation removes indigestible substances from the body so that they do not accumulate inside the gut. The timing of defecation is controlled voluntarily by the conscious part of the brain, but must be accomplished on a regular basis to prevent a backup of indigestible materials. Deficiencies can be due to a number of causes including an inadequacy in nutrient intake, called a dietary deficiency, or any of several conditions that interfere with the utilization of a nutrient within an organism.
In the United States and Canada, recommended dietary intake levels of essential nutrients are based on the minimum level that "will maintain a defined level of nutriture in an individual", a definition somewhat different from that used by the World Health Organization and Food and Agriculture Organization of a "basal requirement to indicate the level of intake needed to prevent pathologically relevant and clinically detectable signs of a dietary inadequacy". In setting human nutrient guidelines, government organizations do not necessarily agree on amounts needed to avoid deficiency or maximum amounts to avoid the risk of toxicity.
Governments are slow to revise information of this nature. Recommended Dietary Allowances; higher for adults than for children, and may be even higher for women who are pregnant or lactating. From Wikipedia, the free encyclopedia. Substance that an organism uses to live. This article is about Nutrients.
For Nutrition in humans, see Human nutrition. For Nutrition in animals, see Animal nutrition. For Nutrition in plants, see Plant nutrition. Plant nutrition and Fertilizer. Essential nutrient Food composition Nutrient cycle Nutrient density Nutrition Nutritionism List of macronutrients List of micronutrients List of phytochemicals in food. Retrieved 12 October Understanding Nutrition, 10th edition , p. Retrieved 14 October Handbook of plant nutrition. Retrieved 17 August CRC desk reference on sports nutrition.
NetBiochem Nutrition, University of Utah. The new Oxford book of food plants. Oxford University Press US. Retrieved 13 October European Journal of Clinical Nutrition. American Journal of Clinical Nutrition. Neonatal Nutrition and Metabolism. Journal of Cardiovascular Nursing. Archived from the original on Modern Nutrition in Health and Disease 6th ed. Understanding Nutrition 11th ed. The Journal of Nutrition.
The American Journal of Clinical Nutrition. It works in coordination with respiratory system as well as digestive system to supply nutrients and oxygen to different body parts. The messenger chemicals or hormones present in the blood are secreted by the endocrine system. Hence the circulatory system also performs the function of circulating hormones for proper communication between the organs. What is the function of the Circulatory system? Print Email Save Image Credit: Content What is circulatory system?
What are the different organs associated with circulatory system? How does the Circulatory System Work? What are the other functions of the circulatory system? The Heart - globalclassroom. Circulatory System - buzzle. Blood pressure - about. View the discussion thread. What are the different kinds of Pain Killers? What herbs can be used for Dogs?
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