Fluent Essays

Can you write Chapter 3 outline? ppt/presentation.xml ppt/slideMasters/slideMaster1.xml Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 9/2/2021 ‹#› ppt/slides/slide1.xml The Alimentary Canal Digestion and Absorption Chapter 3 ppt/slides/slide2.xml The Digestive System The digestive system is designed to: Ingest foods Digest or divide compled molecules into simple, soluble materials that can be absorbed Eliminate unused residues  Only energy providing macronutrients must be digested for absorption (carbohydrate, protein, and fat) Vitamins, minerals, alcohol, and water do not have to be digested to be absorbed ppt/slides/slide3.xml The GI Tract The digestive system includes the alimentary canal and other accessory organs Alimentary canal Extends from the mouth to the anus (including the oral cavity) It is approximately 30 feet long Small intestine Duodenum, jejunum, and ileum Large intestine Cecum, colon, and rectum Accessory organs Salivary glands, liver, gallbladder, and pancreas ppt/slides/slide4.xml The GI Tract Digestion involves two types of action on food Mechanical Chewing Peristalsis The involuntary constriction and relaxation of the muscles of the intestine or another canal, creating wave-like movements that push the contents of the canal forward (moving the food in digestion) Chemical Salivary enzymes Digestive juices ppt/slides/slide5.xml Chemical Action Hydrolysis reactions occur in the digestive tract for nutrients in the food to be utilized Hydrolysis is the breakdown of a compound due to reaction with water A typical chemical reaction: Protein + H2O > amino acids  Fat + H2O > fatty acids + glycerol Carbohydrate + H2O > monosaccharides ppt/slides/slide6.xml Mechanical Reaction The wall of the digestive tract is similar from the esophogus to the rectum. Muscles encircle the tube which allow the tube to expand and contract Food particles are separated by churning and mixing Outer fibers of the muscular coat are responsible for peristalsis Door like mechnisms between the digestive systems are called sphincter muscles ppt/slides/slide7.xml Sphincter Muscles Sphincter muscles are designed to: Retain food with each segment until completion of the mechanical actions and digestive juices Allow measured amounts of foods to pass into the next segment Prevent food from backing up into the prior area It is complex ppt/slides/slide8.xml Food Food stimulates taste buds and aromas stimulate olfactory nerves Olfactory nerves transmit impulses to the brain from the smell receptors in the mucous membrane of the nose. An unlimited number of odors can be detected Taste disorders often originate from smell Increasing age affects a person's ability to smell food Preferences are known to change with aging ppt/slides/slide9.xml Food In the U.S. taste is the primary reason for the choice of foods Food can create feelings of pleasure or aversion Approximately 75% of flavor is derived from odors Taste and smell are essential for maintaining nutrition and meeting the needs of the body ppt/slides/slide10.xml Oral Cavity The mouth plays and important role in the digestive system It is the port of entry Taste buds are located in the oral cavity Papillae are the cells embedded in the taste bud Taste papillae appear as little red dots on the tongue or raised bumps Taste papillae are also located all over the oral cavity The cells replace themselves continually but can be affected by: Disease Drugs Nutritional status Radiation Age (most taste buds degenerate causing a decrease in taste sensitivity) ppt/slides/slide11.xml Oral Cavity As food is chewed gustatory (sense of taste) receptors come into contact with chemicals dissolved in saliva Nerve cells carry messages to the brain which interprets flavors Sweet Sour Salty Bitter Umami (savory taste) ppt/slides/slide12.xml Anosmia Anosmia is the loss of smell which limits the ability to taste foods The ability to smell affects the choice of food Odors are helpful to determine whether food is rotten Many disorders can cause the inability to smell food (anosmia): Upper respiratory infections Nasal or sinus problems Neurologic disorders Endocrine abnormalities Aging Head trauma Receptor cells in the nasal cavity can be depressed when a person is malnourished or by the use of some antibiotics ppt/slides/slide13.xml Dysgeusia (Distortion of Taste) Taste and its role in the enjoyment of food is something that many of us take for granted. However, a taste disorder can have a negative effect on our quality of life and nutrition; it may also indicate an underlying problem. Causes: Medication Cancer treatment Diabetes Zinc deficiency Dry Mouth (xerostomia) Autoimmune diseases Pregnancy Aging ppt/slides/slide14.xml Hypogeusia Hypogeusia is a reduced ability to taste things (to taste sweet, sour, bitter, or salty substances) Causes of hypogeusia include the chemotherapy drug bleomycin , an anti-tumor antibiotic as well as zinc deficiency. ppt/slides/slide15.xml Hypergeusia Hypergeusia is a taste disorder where the sense is abnormally heightened It can be associated with a lesion of the posterior fossa of the brain and Addison's disease; where a patient will crave for salty and sour taste due to the abnormal loss of ions with urine Addison's disease Is characterized by progressive anemia, low blood pressure, great weakness, and bronze discoloration of the skin. It is caused by inadequate secretion of hormones by the adrenal cortex ppt/slides/slide16.xml Anorexia Anorexia is a lack or loss of appetite for food (as a medical condition) This can be caused when taste acuity is lost due to medications An eating disorder causing people to obsess about weight and what they eat (phsycological disorder) ppt/slides/slide17.xml Saliva Adequate saliva is needed for oral health For maintenance of soft tissues For maintenance of the taste buds Essential in taste sensations Essential in functioning Lubricates Removes debris and microorganisms Provides antibacterial action Neutralizes Dilutes Buffers bacterial acids ppt/slides/slide18.xml Saliva Saliva re-mineralizes areas damaged by: Incipient caries (early cavities) Abrasion Erosion Maintains the integrity of the teeth against Physical Chemical Microbial insults ppt/slides/slide19.xml Saliva Saliva is supersaturated with calcium phosphates that allow demineralized areas of hydroxyapatite to in enamel to be re-mineralized Demineralization occurs when minerals are lost from the enamel causing it to dissolve Acids are produced when fermentable carbohydrates are utilized by the bacteria present in the oral cavity A myth is that it is caused from a lack of calcium Saliva is stimulated by tastes An increase in saliva leads to a decrease in caries ppt/slides/slide20.xml Saliva The beginning of digestion takes place in the mouth Salivary amylase (enzyme) initiates the digestion of carbohydrates If a cracker is chewed and held in the mouth for a few seconds, it will begin to taste sweet; indicating the beginning of the digestion of the carbohydrate to sugars ppt/slides/slide21.xml Xerostomia Xerostomia is a condition that leads to decreased salivary flow or dry mouth Problems with dry mouth include: Ulcerations Increased sensitivity of the tongue to spices and flavors Increased risk of dental caries Xerostomia can be caused by: Medications especially diuretics (water pills, blood pressure medications) ppt/slides/slide22.xml Teeth Teeth play a major role in crushing and grinding food Tooth enamel or dentin cannot be repaired or replaced naturally like bone Only a very small amount of enamel and dentin can be re-mineralized Alveolar bone holds the teeth in place and is composed of: Trabecular bone (bony spikes) Cancellous bone (bone within the spaces of the trabecular bone and appears spongy)  Negative calcium balance increases the susceptibility of resorption of bone and bone loss This can happen without the presence of teeth to prevent calcium resorption Chewing helps to stimulate bone formation ppt/slides/slide23.xml Mastication (Chewing) Reduces food particles Food asphyxiation may occur when individuals have poorly fitting dentures Food is not chewed well enough leaving large chunks  Even when a patient adjusts to dentures; chewing is less effective Missing one tooth can cause a decrease in masticatory function ppt/slides/slide24.xml Masticatory Efficiency This is usually a factor when the elderly patient has digestive problems When masticatory efficiency declines individuals will: Choose foods that require less chewing Use techniques to soften food Hypersensitive, poorly restored, decayed, abcessed, or periodontally involved teeth affect food choices and limit the variety ppt/slides/slide25.xml Esophagus The esophagus is a continuous tube that is approximately 10 inches connecting the pharynx with the stomach Bolus Swallowing moves the mass of food to the esophagus and then it is transported to the stomach by peristalsis and gravity Lower esophageal sphincter  Group of circular muscles just above the stomach which allows the food into the stomach but tightens and prevents the contents from regurgitation ppt/slides/slide26.xml Gastric Digestion (Stomach) The bolus enters the stomach and is mixed with gastric secretions by peristaltic contractions This produces chyme which is a semifluid material produced by gastric juices onto ingested food The low pH of the stomach is beneficial Kills or inhibits growth of most food bacteria Facilitates the hydrolysis (breakdown) of proteins into amino acids Activates gastric enzymes Hydrolyzes some carbs Increases solubility of absorption of calcium and iron ppt/slides/slide27.xml Gastric Digestion Two major enzymes: Pepsin The chief digestive enzyme in the stomach, which breaks down proteins into polypeptides (chains of amino acids) Lipase  Enzyme that catalyzes the breakdown of fats to fatty acids and glycerol Mucous forms an alkaline coating in the stomach to protect it against digestion by pepsin ppt/slides/slide28.xml Gastric Digestion (Stomach) Functions as a reservoir for food for 3-4 hours  The rate of passage is liquids, carbohydrates, and proteins (from fastest to slowest) Very little absorption occurs in the stomach because few foods are completely broken down at this point  The smaller the stomach; the more quickly it empties This is why babies have to be fed more often (smaller stomach) ppt/slides/slide29.xml Small Intestine  https://www.youtube.com/watch?v=gkERcbBFyOs https://www.youtube.com/watch?v=Og5xAdC8EUI Most of the energy providing nutrients are completely broken down and absorbed in the small intestine Most vitamins and minerals are absorbed in the small intestine The small intestine is designed for this secreting juices from the accessory organs The accessory digestive organs are the tongue, salivary glands, pancreas, liver, and gallbladder The small intestine is about 15 feet long Foods are retained in the small intestine for about 3-10 hours ppt/slides/slide30.xml Absorption of Nutrients Most nutrients are absorbed in the small intestine Only after absorption of the nutrient into the intestinal mucosa is the nutrient considered to be "in the body"  Normally absorption occurs by passive diffusion Passive transport is a movement of ions and other atomic or molecular substances across cell membranes without need of energy input Osmosis is the movement across a semipermeable membrane in order to create equalization (passive transport) Active transport is the movement of molecules across a membrane from a region of their lower concentration to a region of their higher concentration—against the concentration gradient. Active transport requires cellular energy to achieve this movement   ppt/slides/slide31.xml Large Intestine Only about 5% of the ingested foods will move on to the large intestine For most adults it takes about 16-24 hours for the foods to move through the entire digestive system ppt/slides/slide32.xml Functions of the Large Intestine It has little to no digestive function  It mainly reabsorbs water and electrolytes (sodium and potassium) It stores feces until defecation  Residue in the intestinal tract is the total amount of undigested or unabsorbed foods, bile pigments and bacterial products  The inner lining is smooth; lacking villi It secretes mucous which protects the intestinal wall ppt/slides/slide33.xml Undigested Residues Fiber results in increased residue Fiber is obtained from fruits, vegetables, whole grain products Fiber contributes to bulkier feces Dietary fiber is not digested and works as a laxative Foods may contain other substances that increase fecal output such as prune juice Existing chemicals increase the volume of the stool  ppt/slides/slide34.xml Microflora The trillions of microorganisms that thrive in the intestine are called microflora  Microflora are friendly bacteria They are essential for good health A diet rich in high fiber foods is most beneficial for the health promoting gut microbes The most common bacteria are: Lactobacillus Bifidobacterium ppt/slides/slide35.xml The Role of Microflora They break down fiber and other complex carbohydrates that humans are unable to digest Synthesize vitamins needed  Boost the immune system to protect against infection Inhibit disease causing bacteria An imbalance can impact overall health ppt/slides/slide36.xml Probiotics Probiotics are living microorganisms (usually bacteria) that give a health benefit to the person using them if taken in adequate amounts  They are not classified as nutrients It is not currently known exactly how they work but they are studied and have to be shown that they work in order to be called probiotics Sound research studies only support a small number of probiotic strains Knowledge is limited about which strains are needed, how much, and in what conditions  ppt/slides/slide37.xml Probiotics Probiotics are considered food or dietary supplements They are found in fermented products such as cheese and yogurt They can also be found in non-animal sources such as coconut milk, pickled or fermented vegetables or fruit; fermented soy products They are being added to many new products They are commercially available and can be found in various forms Capsules Tablets Powders ppt/slides/slide38.xml Probiotics The FDA has not established a definition for probiotics The U.S. government does not test the quality or require companies to demonstrate the health benefits before labeling it a probiotic  They are not scrutinized as closely as medication and not required to meet standards for effectiveness Quality issues include: Viability of organisms Presence of harmful microorganisms Protection of organisms from stomach acid Ability of the pill to break apart to release its ingredients Pasteurization can kill the bacteria ppt/slides/slide39.xml Prebiotics Prebiotics are types of dietary fiber that feed the friendly bacteria in your gut. Both prebiotics and probiotics are important for human health. However, they play different roles: Probiotics : are live bacteria found in certain foods or supplements. Prebiotics : are substances that come from types of carbs (mostly fiber) that humans can't digest. The beneficial bacteria in your gut eat this fiber Prebiotics are present in fiber-rich foods, such as fruits, vegetables, and whole grains. Probiotics occur in many fermented foods, including yogurt and sauerkraut   Box 3.1 on page 59 has a good guide for increasing microflora  ppt/slides/slide40.xml Peristalsis of the Large Intestine The purpose of peristalsis is to force the feces into the rectum These large waves only occur about 2-3 times daily ppt/notesMasters/notesMaster1.xml 9/2/2021 Click to edit Master text styles Second level Third level Fourth level Fifth level ‹#› ppt/presProps.xml ppt/viewProps.xml ppt/theme/theme1.xml ppt/tableStyles.xml ppt/slideLayouts/slideLayout1.xml Click to edit Master title style Click to edit Master subtitle style 9/2/2021 ‹#› ppt/slideLayouts/slideLayout2.xml Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 9/2/2021 ‹#› ppt/slideLayouts/slideLayout3.xml Click to edit Master title style Click to edit Master text styles 9/2/2021 ‹#› ppt/slideLayouts/slideLayout4.xml Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level Click to edit Master text styles Second level Third level Fourth level Fifth level 9/2/2021 ‹#› ppt/slideLayouts/slideLayout5.xml Click to edit Master title style Click to edit Master text styles Click to edit Master text styles Second level Third level Fourth level Fifth level Click to edit Master text styles Click to edit Master text styles Second level Third level Fourth level Fifth level 9/2/2021 ‹#› ppt/slideLayouts/slideLayout6.xml Click to edit Master title style 9/2/2021 ‹#› ppt/slideLayouts/slideLayout7.xml 9/2/2021 ‹#› ppt/slideLayouts/slideLayout8.xml Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level Click to edit Master text styles 9/2/2021 ‹#› ppt/slideLayouts/slideLayout9.xml Click to edit Master title style Click icon to add picture Click to edit Master text styles 9/2/2021 ‹#› ppt/slideLayouts/slideLayout10.xml Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 9/2/2021 ‹#› ppt/slideLayouts/slideLayout11.xml Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 9/2/2021 ‹#› ppt/theme/theme2.xml ppt/media/media1.m4a ppt/media/image1.jpg ppt/media/image2.png ppt/media/media2.m4a ppt/media/media3.m4a ppt/media/image3.jpg ppt/media/media4.m4a ppt/media/media5.m4a ppt/media/image4.png ppt/media/media6.m4a ppt/media/media7.m4a ppt/media/image5.png ppt/media/media8.m4a ppt/media/media9.m4a ppt/media/image6.png ppt/media/media10.m4a ppt/media/media11.m4a ppt/media/image7.png ppt/media/media12.m4a ppt/media/media13.m4a ppt/notesSlides/notesSlide1.xml …