Practical Applications in Sports Nutrition

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  1. What happens to nutrients after they are ingested?
    When nutrients are ingeseted they have not technically entered the body. The digestive tract is merely and internalized conduit that connects the mouth to the anus. Substances in the digestive tract are technically still outside of the body until they are absorbed across the membrane linings of the system

    Once absorbed across the membranes of the digestive tract, the nutrients have officially entered the body and can be transported via blood and lymph throughout the body.
  2. How are carbohydrates digested, absorbed, transported and assimilated in the body
    Digestion of carbs begins in the mouth as a result of the mechanical process of mastication and the enzymatic actions of salivary amylase. However, the majority of digestion occurs in the smalll intestine wehre the foodstuffs are subjected to the actions of various pancreatic and intestinal enzymes.

    During digestions carbs are broken down into their component parts monosaccharides

    Absorbsion of monosaccharides occurs in the small intestine via facilitated diffusion or "active transport", depending on the type of sugar

    Once the bloodborne simple sugars reach the cells of the liver those that are not int he form of glucose (fructose) are converted to glucose. The gluscose can then be stored as glycogen in the liver cells or released back into the bloodstream to be used for energy or stored by other cells of the body.
  3. How are fatty acids digested etc
    Fatty acids in the blood are transported into muscle cells via facilitated diffusion while triglycerides in blood borne chylomicrons are acted upon by lipoprotein lilapse in the capilaries found in muscle. Lipoprotein lipase breaks down teh triglycerides into fatty acids, which are then transported across the muscle cell membrane. Once inside the muscle cells, the fats can be stored or used for energy. .
  4. How are fats digested absorbed, transported, and assimilated in the body?
    Digestion of dietary fats begins in the mouth via mastication and the enzymatic actions of salivary lipase. The digestive process continues in the stomach through muscle actions of the stomach wall and the enzymatic actions of gastric lipase. However, the majority of fat digestion occurs in the small intestine where various lipases acto on the dietary fats (triglcerides) breaking them into free fatty acids and monoglycerides.

    Aborption of fats also occurs in the small intestine. The short and medium chain fatty acids are absorbed viapassive diffusion and enter directly into the blood stream. Long chain fatty acids and monoglycerides are wrapped by bile salts to form micelles and carried to the intestinal wall, where the fats are released from the micelles and absorbed via passive diffusion. The absorbed fatas from the micelles are resynthesized into triglycerides and packaged into chylomicrons. The chylomicrons are released from the cells and enter into the circulatory system via the lumph.
  5. How are proteins digested absorbed transported and assimilated in the body?
    During digestion dietary proteins are broken into their basic building blocks known as amino acids.

    Digestion of proteins beigins in the mouth via mastication and continues in the stomach where they are denatured by hydrochloric acid. Once they leave the stomach, protease enzymes in the small intestine continue to break the proteins into single amino agids or small chains of two or three amino acids.

    The small digested protein remnants are absorbed via gacilitated diffusion or active transport in the small intestine. Once inside the intestinal cells, any existing chains of amino acids are broken up into single amino acids and then released into the bloodstream.

    When ingested amino acids make it into the bloodstream, they become part of the body's amino acid pool. The amino acid pool also includes amino acids found in the other tissues primarily skeletal muscle and the liver. The blood with its circulating levels of amino acids, makes up the central part of the amino acid pool, which remains in equilibrium with the other compartments. This helps to maintian the blood's levels of amino acids, thereby serving as a constant and readily available source of amino avides for the body.

    Amino acid absorption from the bloodstream into the cells of the body tissues occurs through facilitated diffusion. Once inside the amino acids can be used to make needed proteins through the processes of transcription and translation. Genes in the nucleus are transcribed to form mRNA. mRNA leave the nucleus and is translated by ribosomes, which attach the amino acids together to form the specific protein required.
  6. How are minerals, vitamins and water absorbed and transported in the body?
    Minerals vitamins and water do not need to be broken down into smaller units via digestion to be absorbed into the body.

    Digestion of food releases minerals and vitamins, thereby making them available for absorption. Most ovitamins and minerals are absorbed in the small intestine. The exceptions are sodium, potassium, and chloride, and some Vitamin K, which are all absorbed in the large intestine.
  7. What is energy metabolism and why is it important?
  8. What is energy?
    Energy is an entity that is better explained of defined than shown because it has no shape, no describable featurs and no physical mass. Energy enables athletes to perform physical work and is measured in kilocalories (kcals). All cellular and bodily functions require energy. The sum total of all the energy (ie total daily calories) required by the body to power cellular processes and activites is known as metabolism.

    Energy exists in 6 basic forms. Chemical, nuclear, electrical, mechanical, thermal, and radiant. However, the form of energy that humans and animals directly rely upon for survival is chemical energy.
  9. What is the human body's source of chemical energy?
  10. How do cells make ATP?
  11. What are the three energy systems?
  12. What pathways are associated with aerobic breakdown of carbohydrates?
  13. What pathways are associated with aerobic breakdown of fats and proteins?
  14. How do the energy systems work together to supply ATP during sport performance?
Card Set
Practical Applications in Sports Nutrition
Nutrients: Ingestion to Energy Metabolism
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