Digestive System Walkthrough Powerpoint


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  • Digestive System Walkthrough Powerpoint

    1. 1. Digestive System Walkthrough November 18 2008 Mark Ealy
    2. 2. Digestion
    3. 3. Digestion and its 3 Functions <ul><li>Digestion is the process of breaking larger food particles into smaller particles that can pass through the plasma membrane . </li></ul><ul><li>Every cell in the body needs nutrients </li></ul><ul><li>Absorption- The circulation of nutrients in the body </li></ul><ul><li>Elimination- Undigested waste material </li></ul>
    4. 4. Digestive Tract
    5. 5. Mouth/ Oral Cavity <ul><li>Receives Food </li></ul><ul><li>Breaks food into smaller particles by chewing </li></ul><ul><li>Salivary glands in the mouth secrete saliva to help lubricate the food </li></ul><ul><li>Saliva also has a digestive enzyme named Salivary amylase, which jump starts starch digestion </li></ul><ul><li>Tongue aids in chewing and swallowing and is a muscular organ, that contains taste buds that differentiate taste of different foods. </li></ul>
    6. 6. Teeth <ul><li>Also housed in the mouth/oral cavity. </li></ul><ul><li>32 in a complete set for adults </li></ul><ul><li>Are used to break food down into smaller particles for absorption </li></ul><ul><li>Covered in enamel the hardest substance in body to keep </li></ul>
    7. 7. Pharynx/ Throat <ul><li>Separated into parts </li></ul><ul><li>Oropharynx- contains the tonsils and is visible when you look into the mouth </li></ul><ul><li>Nasopharynx – upward to the nasal cavity </li></ul><ul><li>Laryngeal Pharynx- Downward Extend </li></ul><ul><li>The Tongue pushes food into the pharynx, swallowing is involuntary and happens quickly </li></ul><ul><li>Soft Palate and uvula raise to prevent food from entering nose cavity </li></ul><ul><li>Food enters Esophagus </li></ul>
    8. 8. Esophagus <ul><li>Muscular Tube Measuring about 25 cm </li></ul><ul><li>No additional digestion occurs in the esophagus </li></ul><ul><li>Food is lubricated with mucus and moved by peristalsis into the stomach </li></ul><ul><li>Must pass through the Esophageal Hiatus located in the Diaphragm before connecting with the stomach </li></ul>
    9. 9. Stomach <ul><li>J Shaped organ in upper left region of the abdominal cavity. </li></ul><ul><li>Has an Angled layer that aids in the grinding of food and mixing of digestive juices. </li></ul><ul><li>Contains Sphincters that regulate the size of the opening </li></ul><ul><li>Pylorus- Leads to the sphincter that regulates how fast food moves into the small intestines </li></ul><ul><li>Functions as a digestive organ, churn, and storage pouch. </li></ul><ul><li>Can stretch to hold one half of a gallon of food or water </li></ul><ul><li>Gastric Juice formed by special cells in the lining of the stomach </li></ul>
    10. 10. Stomach Cont. <ul><li>Active components of Gastric Juice are : </li></ul><ul><li>Hydrochloric acid- strong acid that helps break down protein and destroy foreign organisms </li></ul><ul><li>Pepsin- Inactive form of protein digesting enzyme only activated when food enters stomach and HCl is produced </li></ul><ul><li>Chyme- Highly Acidic , mixture of gastric juice and food that leaves stomach and enters small intestine. </li></ul>
    11. 11. The Small Intestine <ul><li>Longest part of digestive tract! </li></ul><ul><li>Larger than larger intestines but smaller in diameter average width of 2.5 cm </li></ul><ul><li>Duodenum- first 2mcm of the small intestines </li></ul><ul><li>Jejunum- next 2/5 cm </li></ul><ul><li>Ileum- the remaining portion </li></ul><ul><li>Mucus protect the intestine from the highly acidic chyme from the stomach. </li></ul><ul><li>Most digestion occurs here, due to the juices secreted by many glands that help aid in the breakdown of carbs and proteins. </li></ul><ul><li>Most absorption of digested food, water, and minerals also occur here. </li></ul><ul><li>Microvilli- increase the surface area of absorption in the small intestines </li></ul><ul><li>Contains a specialized lymphatic capillary called a lacteal, which absorbs fats. </li></ul>
    12. 12. The Large Intestine <ul><li>Named for its wide diameter </li></ul><ul><li>Cecum- first part small pouch </li></ul><ul><li>Ileocecal valve- between the ileum of the small intestines a sphincter that prevents food from traveling backward into the small intestines </li></ul><ul><li>Veriform- blind tube containing lymphoid tissue </li></ul><ul><li>Contains the colon that empty in the rectum </li></ul><ul><li>Rectum- temporary storage area for indigestible or nonabsorbable food </li></ul><ul><li>Narrows into the anal canal, which leads to the outside of the body called the anus </li></ul>
    13. 13. The Large Intestines Cont. <ul><li>Secretes a great amount of mucus, but no enzymes. </li></ul><ul><li>No food is digested, but some water is reabsorbed and undigested food is stored and formed into solid waste, called feces and eliminated </li></ul><ul><li>Propels solid waste toward the rectum , aided by voluntary contractions defecation is achieved. </li></ul><ul><li>Contains an anal sphincter that provides voluntary control over defecation </li></ul><ul><li>Some bacteria that live in the colon produce vitamin k and some B complex vitamins </li></ul>
    14. 14. The Accessory Organs
    15. 15. The Salivary Glands <ul><li>Food mixes with salvia in the mouth which moistens the food and facilitates chewing and swallowing </li></ul><ul><li>Contains antibodies and lysozyme that help reduce bacterial growth </li></ul><ul><li>Contains salivary amylase which begins the digestive process by converting sugar to starch. </li></ul><ul><li>Manufactured in 3 pairs of glands. </li></ul>
    16. 16. Liver <ul><li>Body's largest glandular organ </li></ul><ul><li>Manufactures bile- substance needed for digestion of fats </li></ul><ul><li>Stores Glycogen and coverts it to glucose to restore normal blood sugar levels </li></ul><ul><li>Stores some vitamins and iron </li></ul><ul><li>Destruction of red blood cells and recycling or elimination of their breakdown products </li></ul><ul><li>Synthesis of urea- waste product of protein metabolism </li></ul><ul><li>Detoxification of harmful substances such as alcohol and drugs </li></ul><ul><li>The main digestive function of the liver is the production of bile, breaks fats into smaller droplets that can be acted upon by digestive enzymes </li></ul>
    17. 17. The Gallbladder <ul><li>Muscular sac on the inferior surface the liver that stores bile </li></ul><ul><li>Contracts and squeezes bile through the cystic duct and into the common bile duct, when chyme enters the duodenum </li></ul><ul><li>Stores bile because the body only needs it a few times a day. </li></ul>
    18. 18. The Pancreas <ul><li>Long gland that extends from the duodenum to the spleen </li></ul><ul><li>Produces enzymes that digest fats, proteins, carbohydrates, and nucleic acids </li></ul><ul><li>Protein digesting enzymes are produced in inactive form and must be converted into active forms in the small intestines </li></ul><ul><li>Produces Alkaline fluid, that balances the acidic chyme protecting the lining of the SI </li></ul><ul><li>Can also function as an endocrine gland, producing insulin and glucagon to regulate sugar metabolism </li></ul>
    19. 19. Enzymes/ Water <ul><li>Enzymes are proteins that are catalyst, that speed the rate of chemical reactions </li></ul><ul><li>Highly Specific in its action </li></ul><ul><li>Water – is added to nutrient molecules as they are split by enzymes. </li></ul><ul><li>Hydrolysis- digestion by water </li></ul><ul><li>7 liters of water are secreted into the digestive tract each day, in addition to 2 liters taken in with food and drink </li></ul><ul><li>Helps dilute food to move more easily through tract </li></ul>
    20. 20. Hormones Active In Digestion <ul><li>Gastrin- Stimulates release of gastric Juice </li></ul><ul><li>Gastric-Inhibitory Peptide- Stimulates insulin release from pancreas when glucose enters duodenum; inhibits release of gastric juice </li></ul><ul><li>Secretin- Stimulates release of water and bicarbonate from pancreas, stimulates release of bile from liver: inhibits the stomach </li></ul><ul><li>Cholecystokinin- Stimulates release of digestive enzymes from pancreas, stimulates release of bile from gallbladder inhibits the stomach. </li></ul>