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Digestion and Nutrition

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Presentation on theme: "Digestion and Nutrition"— Presentation transcript:

1 Digestion and Nutrition
By Chaan Harris and Halainna Ramos

2 Digestive System Digestion- the mechanical and chemical breakdown of foods and the absorption of the resulting nutrients by cells Digestive system-consists of the alimentary canal The 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 Wall The 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 layer Mucosa/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 Movement The mouth receives food and begins digestion by mechanically reducing the size of solid particles and mixing them with saliva Cheeks and Lips: The cheeks consist of outer layers of skin, pads of subcutaneous fat, muscles associated with expression and chewing. Lips surround the mouth opening Tongue: 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 bode Palate: 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 tonsils Teeth: 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 Teeth Before 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 molecules Each tooth consists of 2 main portions: The crown and the root Glossy 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 root A 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 Glands The 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 cells Serous cells produce watery fluid that contains that digestive enzyme amylse When a person sees, smells, or thinks, parasympathetic nerve impulses elicit the secretion of a large volume of watery saliva Paratial glands- are the largest of the major salivary glands. -Each gland lies anterior and somewhat inferior to the ear Sybmandibular glands- located on the floor of the mouth on the inside surface of the lower jaw

9 Pharynx and Esophagus The pharynx connects the nasal and oral cavities with the larynx and esophagus. It has 3 parts Nasopharynx- communicates with the nasal cavity and provides a passageway for air during breathing Is posterior to the soft palate and inferior to the nasopharynx Laryngophanrynx is inferior to the orophyrnx; pathway to the esophagus

10 Swallowing Mechanism Food is mixed with saliva and forced into the pharynx Involuntary reflex actions force the food into the esophagus The soft palate raises, preventing food from entering the nasal cavity The hyoid bone and larynx is are elevated. The epiglottis blocks off the top of the larynx so the food doesn’t enter the trachea Peristalis transports food to the stomach

11 Stomach The 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 area The body region is the main part of the stomach and lies between the fundic and pyloric portions The pyloric region narrows and becomes the pyloric canal as it approaches the small intestine

12 Pancreas The pancreas produces pancreatic juice that is secreted into a pancreatic duct Pancreatic juice contains enzymes that split carbohydrates, proteins, lipids, and nucleic acids The carbohydrate digesting enzyme is pancreatic amylase, which splits the molecules of starch/glycogen into double sugars Pancreatic lipase is a fat digesting enzyme that breaks triglyceride molecules to fatty acids and glycerol Nucleases are enzymes that break down nucleic acid molecules into nucleotides Trypsin, chymotypsin and caboxypeptidase are protein splitting enzymes

13 Liver The liver is located in the upper right quadrant of the abdominal cavity and is inferior to the diaphragm Functions: metabolizes carbohydrates, lipids and proteins Filters blood Destroys toxins Secretes bile maintaining normal concentration of blood glucose transports fat to adipose tissue The 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 cavity Has 3 portions: the duodenum, jejunum and the ileum The 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 pelvis It opens to the outside of the body as the anus The 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

15 Small/Large Intestine

16 Vitamins/ Minerals Vitamins are organic compounds other than carbs, lipids and proteins - Fat-soluble vitamins are vitamins A, D, E and K; water –soluble are B and C Fat-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 absorption Dietary minerals are essential in human metabolism Some minerals are part of inorganic compounds, like calcium phosphate of bone They 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 processes They 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 fuel Digestion breaks down complex carbohydrates into monosaccharides which are small enough to be absorbed Lipids: include fats, oils and fatlike substances; they supply energy for cellular processes Mostly 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 tissue Found in meats, fish, poultry, cheese/milk, eggs and cereals

18 Healthy Diets An adequate diet provides sufficient energy, essential fatty acids, amino acids, vitamins and minerals to support growth and repair body tissue If 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 cancer Food pyramids are used to organize foods according to suggested amounts (serving size)


20 Adequate Diet In 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 fruits Grains: Whole-Wheat flour, High-fiber cereal, oatmeal, ground flaxseed and brown rice Proteins- 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 starvation Cachexia-state of chronic malnutrition and physical wasting Cholelithiasis- inflammation of the gallbladder Dysphagia- Difficulty swallowing Enteritis- Inflammation of the intestine Gastrectomy- partial or complete removal of the stomach Glossitis- inflammation of the tongue Hyperalimentation- long-term intravenous nutrition Pharynatitis- inflammation of the pharynx Stomatitis- inflammation of the lining of the mouth

22 Works Cited
Shier, David. Hole’s Essentials of Human Anatomy and Physiology. 9th Edition. Boston: New York, Print. _intestine Jaret, Peter. “Top Nutrition Tips for Athletes”. WebMD. June 17, WebMD.. Web. April 29, 2014 Mayo Clinic Staff. “Heart-healthy diet: 8 steps to prevent heart disease”. 20 April Mayo Clinic. 20 April Web. < conditions>

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