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Eric Soza, Nick Soto, Andres Padilla Period 2 2/10/15

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Presentation on theme: "Eric Soza, Nick Soto, Andres Padilla Period 2 2/10/15"— Presentation transcript:

1 Eric Soza, Nick Soto, Andres Padilla Period 2 2/10/15
The Digestive System Eric Soza, Nick Soto, Andres Padilla Period 2 2/10/15

2 Alimentary Canal Extends from the mouth to the anus, includes accessory organs Mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anal canal Accessory organs- salivary glands, liver, gallbladder, and pancreas About 8 meters long 4 layers Mucosa Submucosa Muscular layer Serosa Segmentation and Peristalsis

3 Mouth 1st portion of alimentary canal Receives food, begins digestion

4 Cheeks and Lips Form lateral walls of mouth Subcutaneous fat
Muscles associated with chewing Stratified squamous epithelium Mobile structure Skeletal muscles and sensory receptors Red color due to blood vessels

5 Tongue Oral cavity, thick Lingual frenulum Papillae Lingual tonsils

6 Palate Roof of oral cavity Hard and Soft Uvula Palatine tonsils
Pharyngeal tonsils

7 Teeth Hardest structures in the body Types (primary, etc.)
Crown, enamels, root canals Help break down food into pieces

8 Salivary Glands Function: Two types of secretory cells:
Overall saliva begins chemical digestion of carbohydrates, cleans teeth and mouth, and binds food Two types of secretory cells: Serous Cells- secrete salivary amylase Mucous Cells- secrete thick liquid

9 Salivary Glands Three major glands:
Parotid Glands- Largest, secretes salivary amylase rich liquid Submandibular Glands- Secretes a fluid that is equally serous and mucus Sublingual Glands- Secretes a thick mucus fluid


11 Salivary Glands Two types of secretion Stimuli:
Sympathetic- impulses that secrete viscous saliva Parasympathetic- secrete watery saliva, activated by sight, taste, smell, or thought of pleasant food

12 Swallowing 3 stages Voluntary; food chewed and mixed with saliva; bolus. Swallowing reflex at pharyngeal opening Peristalsis transports food from esophagus to stomach

13 Pharynx and Esophagus Pharynx connects nasal and oral cavities with larynx and esophagus Nasopharynx Oropharynx Laryngopharynx Swallowing stages Peristalsis

14 Stomach Has three regions:
Cardiac region: small area near esophageal opening Funic region: temporary storage area Pyloric region: narrows and becomes pyloric canal Pyloric sphincter is the valve that control gastric emptying

15 Stomach Gastric Glands:
Mucous cell- alkaline secretion that protects stomach wall Parietal cells- (oxyntic cells) release hydrochloric acid Also secretes intrinsic factor needed for absorption of vitamin B12 Chief cells- (peptic cells) release digestive enzymes

16 Stomach All three cell secretions together create gastric juice
Releases pepsinogen which becomes pepsin from HCl Digests most dietary proteins All three cell secretions together create gastric juice Gastric lipase is a weak secretion that breaks down fats

17 Stomach Regulation: Cholecystokinn (from intestine), intestinal somatostatin, urogastrone Acetylcholine from nerve endings Parasympathetic impulses release gastrin Both of these release histamine from mucous cells which stimulates gastric secretion

18 Stomach Gastric secretion occurs in three phases:
Cephalic- sight, taste, smell, or thought of food releases gastric secretions Gastric- Food in stomach releases gastrin Intestinal- small intestine releases intestinal gastrin which increases gastric juice secretion

19 Stomach Absorption: Mixing and Emptying:
Not very effective at absorbing water, some salts, lipid-soluble drugs, and alcohol Mixing and Emptying: Chyme produced from mixing Peristalsis pushes it to pyloric sphincter which causes it to relax Length of time in stomach depends: Liquids very rapid, fats long, proteins quick, carbohydrates very quick

20 Liver Location/Background Hepcidin Structure Functions Angiotensinogen
Thrombopoietin Hepcidin Betatrophin Structure Functions Produces Metabolic Activities Stores

21 Bile Background Contains

22 Gallbladder Location/Background Structure Functions Chyme Storage
Bile salts Chyme

23 Pancreas Location Structure Secretions Pancreatic Juices Contains…
Enzymes Nuclei Amylase Lipase Trypsin Chymotrypsin Carboxytrypsin They digest…

24 Small Intestine The small intestine is about six meters long and contributes to digestion, absorption, and transportation Contains three parts: Duodenum- shortest part and is responsible for most chemical digestion Contains a large amount of mucus secreting cells and receives digestion aid from pancreas and liver

25 Small Intestine Jejunum- Contains most of the absorption. Villi and microvilli absorb what the body needs Ileum- Primarily absorbs B12 and bile salts. Also absorbs anything the jejunum missed

26 Small Intestine Secretions: Regulation: Secretin- in duodenum
Motilin- also in duodenum Peptidase- breaks down peptides into amino acids Sucrase, maltase, lactase- break down disaccharides into monosaccharides Intestinal lipase- breaks down fatty acids and glycerol Enterokinase- Shortens trypsinogen and trypsin Regulation: Direct contact with chyme stimulates secretions, parasympathetic reflexes trigger secretions as well

27 Small Intestine Absorption:
Carbohydrates are absorbed by both facilitated diffusion and active transportation through villi Proteins are broken down into amino acids and are absorbed into villi by active transportation

28 Small Intestine Fat molecules are absorbed in several steps:
Fatty acid diffuses through villi Resynthesized into previously digested forms Encased in proteins Large molecules of lipoprotein called chylomicrions go to lacteals of the villi Molecules are emptied into the lymphatic system

29 Small Intestine Water and electrolytes such as sodium and potassium are absorbed Movement: Peristalsis occurs along with segmentation Segmentation- ring like contractions that cut chyme into segments and slow its movements Parasympathetic impulses enhance movement and sympathetic impulses inhibit movement

30 Large Intestine Contains several parts:
Cecum, colon, rectum, and anal canal Colon divided as well: Ascending, transverse, descending, and sigmoid colons

31 Large Intestine Function: Very little digestion
Secrete large amounts of mucus regulated by chyme and parasympathetic impulses Absorption limited to water and certain ions such as sodium Bacteria is prevalent and can aid in digestion of certain substances

32 Large Intestine Movement: Rectum:
Mainly relies on peristalsis but is much slower. Generally only two to three mass movements per day Rectum: Feces enters the rectum which causes the defecation reflex to occur Peristalsis movements increase, the glottis closes and the diaphragm lowers The external anal sphincter is signaled to relax and feces is forced out

33 Works Cited /

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