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
Mastication

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 www.meritnation.com www.studyblue.com www.pray40.com