Presentation on theme: "Digestion and Nutrition"— Presentation transcript:
1 Digestion and Nutrition By Chaan Harris and Halainna Ramos
2 Digestive SystemDigestion- the mechanical and chemical breakdown of foods and the absorption of the resulting nutrients by cellsDigestive system-consists of the alimentary canalThe alimentary system includes the mouth, pharynx, esophagus, stomach, small and large intestine, and anus; extends about 8 meters from the mouth to the anus-The accessory organs include the salivary glands, liver, gallbladder, and pancreas
3 Structure of the WallThe wall of the alimentary canal consists of four distinct layers that are developed to different degrees from region to region: Mucosa, submucosa, muscular layer, and serosa/serous layerMucosa/mucous membrane: Surface epithelium, underlying connective tissue and a small amount of smooth muscle.Submucosa: Consists of loose connective tissue as well as glands, blood vessels, lymphatic vessels, and nerves organized into a network called plexus.Muscular layer: This layer produces movement of the tube. It consists of two coats of smooth muscle tissue and some nerves organized into a plexus. When the circular fibers contract, the tube’s diameter decreases.Serosa/Serous layer: The cells of the serosa protect the underlying tissues and secretes serous fluid.
4 MovementThe mouth receives food and begins digestion by mechanically reducing the size of solid particles and mixing them with salivaCheeks and Lips:The cheeks consist of outer layers of skin, pads of subcutaneous fat, muscles associated with expression and chewing.Lips surround the mouth openingTongue:The tongue nearly fills the oral cavity when the mouth is closed. Mucous membrane covers the tongue; the membranous fold is called the frenulum which connects the midline of the tongue to the floor of the mouth.
5 The body of tongue is mostly skeletal muscle The body of tongue is mostly skeletal muscle. These muscles mix food articles with saliva during chewing and move food toward the pharynx during swallowing.Rough projections called papillae on the tongue surface provide friction; also bears taste buds.The posterior region, or the root of the tongue is anchored to the hyoid bodePalate:The palate forms the roof of the oral canal cavity and consists of a hard anterior part and a soft posterior part.In the back of the mouth, on either side of the tongue and closely associated with the palate are masses of lymphatic tissue called palatine tonsilsTeeth:There are 2 different sets of teeth form during development.-The first set, the primary teeth usually erupt through the gums at regular intervals between the ages of six months and two to four years.
6 TeethBefore the primary teeth shed, their roots are resorbed. The pressure from the developing secondary teeth push the primary teeth out of their sockets.Teeth begin mechanical digestion by breaking pieces of food into smaller pieces-This action increases the surface are of food particles, allowing digestive enzymes to react more effectively with the food moleculesEach tooth consists of 2 main portions: The crown and the rootGlossy white enamel covers the crown. Enamel consists of mainly calcium salts and is the hardest substance in the body.
7 Teeth cont. Dentin is a substance close to bone, but is much harder. Surrounds the tooth’s central cavity which contains a combination of blood vessels, nerves , and connective tissue called pulp.Blood vessels and nerves reach this cavity through tubular root canals extending into the rootA thin layer of bonelike material called cementum encloses the root. The periodontal ligament surrounds the cementum. This ligament contains bundles of thick collagenous fibers
8 Salivary GlandsThe salivary glands secrete saliva. – The fluid moistens food particles, helps bind them, and begins the chemical digestion of carbohydrates.Within a salivary gland are two types of secretory cells: serous cells and mucous cellsSerous cells produce watery fluid that contains that digestive enzyme amylseWhen a person sees, smells, or thinks, parasympathetic nerve impulses elicit the secretion of a large volume of watery salivaParatial glands- are the largest of the major salivary glands.-Each gland lies anterior and somewhat inferior to the earSybmandibular glands- located on the floor of the mouth on the inside surface of the lower jaw
9 Pharynx and EsophagusThe pharynx connects the nasal and oral cavities with the larynx and esophagus. It has 3 partsNasopharynx- communicates with the nasal cavity and provides a passageway for air during breathingIs posterior to the soft palate and inferior to the nasopharynxLaryngophanrynx is inferior to the orophyrnx; pathway to the esophagus
10 Swallowing MechanismFood is mixed with saliva and forced into the pharynxInvoluntary reflex actions force the food into the esophagusThe soft palate raises, preventing food from entering the nasal cavityThe hyoid bone and larynx is are elevated. The epiglottis blocks off the top of the larynx so the food doesn’t enter the tracheaPeristalis transports food to the stomach
11 StomachThe stomach is divided into 4 parts: Cardiac, fundic, body and pyloric regions-The cardiac region is a small area near the esophageal opening.The fundic region is a temporary storage areaThe body region is the main part of the stomach and lies between the fundic and pyloric portionsThe pyloric region narrows and becomes the pyloric canal as it approaches the small intestine
12 PancreasThe pancreas produces pancreatic juice that is secreted into a pancreatic ductPancreatic juice contains enzymes that split carbohydrates, proteins, lipids, and nucleic acidsThe carbohydrate digesting enzyme is pancreatic amylase, which splits the molecules of starch/glycogen into double sugarsPancreatic lipase is a fat digesting enzyme that breaks triglyceride molecules to fatty acids and glycerolNucleases are enzymes that break down nucleic acid molecules into nucleotidesTrypsin, chymotypsin and caboxypeptidase are protein splitting enzymes
13 LiverThe liver is located in the upper right quadrant of the abdominal cavity and is inferior to the diaphragmFunctions: metabolizes carbohydrates, lipids and proteinsFilters bloodDestroys toxinsSecretes bilemaintaining normal concentration of blood glucosetransports fat to adipose tissueThe gallbladder stores bile between meals
14 Small/Large Intestine The small intestine is a tubular organ that extends from the pyloric sphincter to the beginning of the large intestine. –fills most of the cavityHas 3 portions: the duodenum, jejunum and the ileumThe large intestine starts in the lower right side of the abdominal cavity where the ileum joins the cecum (beginning of intestine). –It ascends to the right, crosses left, and descends into the pelvisIt opens to the outside of the body as the anusThe narrow tube with a closed end is called the vermiform appendix**Fun Fact: the human appendix has no known digestive function-It absorbs water and electrolytes and forms and stores feces
16 Vitamins/ MineralsVitamins are organic compounds other than carbs, lipids and proteins- Fat-soluble vitamins are vitamins A, D, E and K; water –soluble are B and CFat-soluble vitamins dissolve in fat which associates them with lipids and are influence by the same factors that affect lipid absorption-Fat-soluble vitamins can accumulate in various tissues and can lead to overdose conditions.Vitamin B help oxidize carbohydrates, lipids, and proteins; Vitamin C promotes iron absorptionDietary minerals are essential in human metabolismSome minerals are part of inorganic compounds, like calcium phosphate of boneThey play vital roles in nerve impulse production, muscle fiber contraction and maintenance of the pH of body fluids
17 Carbohydrate, Lipid and Protein Digestion Carbohydrates are organic compounds used to supply energy for cellular processesThey can be ingested in a variety of forms: starch from grains and vegetables, glycogen from meats, disaccharides from cane sugar, and monosaccharides from honey and fruits.-Liver enzymes catalyze reactions that convert fructose and galactose into glucose, which is the carbohydrate form mostly used for cellular fuelDigestion breaks down complex carbohydrates into monosaccharides which are small enough to be absorbedLipids: include fats, oils and fatlike substances; they supply energy for cellular processesMostly found in meats, eggs, milk, nuts and lard (both plant- and animal-based foods)Proteins: Supply energy after digestion breaks them down into amino acids; they control metabolic rates, clotting factors, elastin/collagen of connective tissueFound in meats, fish, poultry, cheese/milk, eggs and cereals
18 Healthy DietsAn adequate diet provides sufficient energy, essential fatty acids, amino acids, vitamins and minerals to support growth and repair body tissueIf a person lacks essential nutrients, malnutrition can be a result. This can be due to undernutrition (symptoms of deficiency diseases) or overnutrition (excess nutrient intake)Individual requirements for nutrients vary with age, sex, growth rate, amount of physical activity, and levels of stress.A measurement called body mass index, or BMI is used to determine whether a person is of adequate weight, overweight, or obese. *Obesity rates are increasing in the U.S and raises the risk of developing cardiovascular disease, diabetes, and/or cancerFood pyramids are used to organize foods according to suggested amounts (serving size)
20 Adequate DietIn order to have an adequate diet, an athlete would have to have a strict diet to follow.They would have to load up on carbohydrates (it’s the main source of energy);For muscle tone, eat about 5 oz. of proteins (but not too much; it doesn’t provide a lot of energy, but its good for building muscle tissue; Calcium for bones (dairy)-For long events like marathons, athletes eat a lot of unsaturated fat from foods like nuts, vegetable oils and fatty fish.A person with a heart condition however, won’t be able to eat the same foods, or the same amount as athletes.They are more likely to eat low-sodium canned vegetables and fruitsGrains: Whole-Wheat flour, High-fiber cereal, oatmeal, ground flaxseed and brown riceProteins- Low-fat dairy products, egg whites, fish (mostly fatty, cold-water), skinless poultry, soybeans and soy products
21 Diseases in the Digestive Sys. There are many types of diseases in the digestive system:Anorexia nervosa- self starvationCachexia-state of chronic malnutrition and physical wastingCholelithiasis- inflammation of the gallbladderDysphagia- Difficulty swallowingEnteritis- Inflammation of the intestineGastrectomy- partial or complete removal of the stomachGlossitis- inflammation of the tongueHyperalimentation- long-term intravenous nutritionPharynatitis- inflammation of the pharynxStomatitis- inflammation of the lining of the mouth
22 Works Cited www.aokain.com/stomach-diagram-labeled/ Shier, David. Hole’s Essentials of Human Anatomy and Physiology. 9th Edition. Boston: New York, Print.En.wikipedia.org/wiki/Small _intestineJaret, Peter. “Top Nutrition Tips for Athletes”. WebMD. June 17, WebMD.. Web. April 29, 2014Mayo Clinic Staff. “Heart-healthy diet: 8 steps to prevent heart disease”. 20 April Mayo Clinic. 20 April Web. <http://www.mayoclinic.org/diseases- conditions>