1. Human Health and Physiology Ms. Scott J205
Digestion
Human Health and Physiology Ms. Scott J205

2. Digestion Assessment Statements
Explain why digestion of large food particles are essential.
Explain the need for enzymes in digestion.
State the source, substrate, products, and optimum pH for amylase, protease, and lipase.
Draw and label a diagram of the digestive system.
Outline the function of the stomach, small intestine, and large intestine.
Distinguish between absorption and assimilation.
Explain the structure of the villus is related to its role in absorption and transport of the products of digestion.

3. Digestion of Food Mouth and the Esophagus Absorption Assimilation
Figure 1. Structure of Villus

4. Fatty Acids and Glycerol
Need for Digestion
Amylase
Protease
Lipase
Example of this Enzyme
Salivary Amylase
Pepsin
Pancreatic Lipase
Source
Salivary Glands
Wall of Stomach
Pancreas
Substrate
Starch
Proteins and peptides
Triglycerides
And phospholipids
Products
Maltose
Small Polypeptides
Fatty Acids and Glycerol
Optimum pH 7
1.5
Amylase
Protease
Lipase
Example of this Enzyme
Source
Substrate
Products
Optimum pH
Food we consume are substances that are made by other organisms
Molecules in food are to large to absorb
Diffusion and Facilitated Diffusion
Active Transport
Body Temperature and Enzyme Activity

5. Pancreatic Juices
The pancreas secretes enzymes into the lumen of the small intestine.
Secrete hormones insulin and glucagon into the blood.
Synthesizes and secretes digestive enzymes into the gut.
Figure 2. Intestinal Structure

6. Pancreatic Juices
Synthesized in pancreatic gland on ribosomes on the RER.
Processed in the Golgi Apparatus
Ducts form one large pancreatic duct
1 liter/day secreted in the lumen of the small intestine
Figure 3. Arrangement of cells and ducts in a part of the pancreas that secretes digestive enzymes

7. Structure of the Digestive System
Function
Mouth
Voluntary Control of Eating . Mechanical digestion of food by chewing and mixing with saliva, which contains lubricants and enzymes that start starch digestion.
Esophagus
Movement of food by peristalsis from the mouth to the stomach
Stomach
Churning and mixing with the secreted water and acid which kills foreign bacteria and other pathogens in food, plus initial stages of protein digestion.
Small Intestine
Final stages of digestion of lipids carbohydrates, proteins, and nucleic acids, neutralizing stomach acid, plus absorption of nutrients.
Pancreas
Secretion of lipase, amylase and protease
Liver
Secretion of surfactant in bile to break up lipid droplets
Gall Bladder
Storage and regulate release of bile
Large Intestine
Reabsorption of water, further digestion carbs by symbiotic bacteria , plus formation and storage of feces.
Figure 4. The Human Digestive System

8. Have You Ever Wondered ???
What would happen to the normal function of the digestive tract if part of one of the following organs were removed or greatly reduced in size ( for example, as a result of a surgery or accident)? How would a person’s eating habits need to be changed to accommodate reduction in size ?
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9. Peristalsis
Peristalsis –the contraction of circular and longitudinal muscles layers from the esophagus to the small intestine mixes the food with the enzymes and moves it along the gut
Wave-like motion
One Direction – away from the mouth
Enteric Nervous System – controls unconscious contraction of food.
Process time
Swallowed food moves quickly down the esophagus to the stomach
In the intestines the food is moved at a slower progression, only a few centimeters at a time.
Main function in the intestine is churning of the semi- digested food to mix it with enzymes and thus speed up the process of digestion.
Figure 5. Peristalsis movement from esophagus to small intestines

10. Digestion In Small Intestine
Enzymes digest most macromolecules into monomers for food in the small intestine
Wall of small intestine
Nuclease
Maltase
Lactase
Sucrase
Exopeptidases and Dipeptidases
Duration of Digestion
Figure 6. Detail structure of the small intestine

11. Structure of the Wall of the Small Intestine
Four layers of living tissues from outside moving inwards
Serosa – Outer coat
Muscular layers – longitudinal muscle and circular muscle
Sub Mucosa – a tissue containing blood and lymph vessels
Mucosa – lining of the small intestine, with the epithelium that absorbs nutrients on the inner surface

12. Villi and the Surface Area for Digestion
Villi increase the surface area of the epithelium over which absorption is carried out.
Absorption – the process of taking substances into the cells and the blood
Rate of absorption
Adult: 7 meters long and millimeters wide with fold in the inner surface
Inside the intestinal wall
Figure 7. Structure of the an intestinal villus

13. Villi and the Surface Area for Digestion
Small finger like projections of the mucosa.
Size: 0.5 and 1.5 mm long
Increase surface area by factor of 10.
Figure 8. Scanning electron micrograph of villi in small intestine

16. Absorption by Villi
Villi absorbs monomers formed by digestion as well as mineral ions and vitamins
The epithelium that covers the villi must form a barrier to harmful substances, while at the same time being permeable enough to allow useful nutrients to pass through.
Villus absorb these products of digestion of macromolecules in food.
Glucose, fructose, galactose, and other monosaccharides
Any of the twenty amino acids used to make protein
Fatty acids, monoglycerides, and glycerol
Bases from digestion of nucleotides
Also absorb substances required by the body and present in foods but not needing digestion:
Mineral ions such as calcium, potassium and sodium
Vitamins such as ascorbic acid (vitamin C)

17. Methods of Absorption
Different methods of membrane transport are required to absorb different nutrients.
Simple Diffusion
Facilitated Diffusion
Active Transport
Exocytosis
Figure 9. Example of methods of absorption in the small intestine

18. Methods of Absorption Example 1 Lipid Absorption
Fatty acids and monoglycerides can be absorbed into the villus of epithelium by simple diffusion
Fatty acids are also absorbed in the microvilli by facilitated diffusion via fatty acid transporters
Triglycerides are reformed and can not diffuse back into lumen
Form lipoproteins that are then released by exocytosis through the plasma membrane
Carried away in lymph or enter the blood capillaries in villi
Figure 10. Lipid Absorption

19. Methods of Absorption Example 2 Glucose Absorption
Glucose uses active transport, sodium potassium pumps, from the cytoplasm to the interstitial spaces inside the villus.
With facilitated diffusion (passive, depends of concentration gradient) sodium-glucose co-transport protein in the microvilli transfer sodium ion and glucose molecule together from the intestinal lumen to cytoplasm of epithelial cells.
Facilitated diffusion also enables glucose to pass through the glucose channels from the cytoplasm to the interstitial spaces inside the villus into the blood capillaries.
Figure 11. Glucose Absorption

20. Final Destinations of Digestion Products
Starches  bloodstream
Fats  lymph vessels (lacteals)
Proteins  bloodstream

21. HHP Digestion – Assignment #1 Due 9/11 A and 9/12 B (Typed Response with references)
Tapeworms sometimes infect humans, anchoring themselves to the wall of the small intestines. Based on how digestion is compartmentalized along the mammalian alimentary canal, what digestive functions would you expect these parasites to have?
A single sandwich is likely to contain carbohydrates, lipids, and proteins. From a biochemical viewpoint, what will happen to each molecule of digestion?
You ingest glucose molecule in the starch of a breakfast cereal. State as many specific locations as you can for this single glucose molecule from the time it is in your mouth to the time it enters a muscle cell of your right forearm.
Lastly, Using materials you provide from home, create a labeled model of all digestive system structures beginning with the mouth and ending with the anus.  Focus on the materials used to demonstrate the physical structure of each organ or tissue.  Be sure to include the accessory organs too! (Rubric on next slide)

22. Assignment # 1 Rubric CATEGORY 4 = A 3 = B 2 = C 1= D
Assignment #1: Digestion Diagram
Diagram or model has all of the following: -structures present -materials are creatively linked to the original structure -final product is neat and well organized - shows thought and a clear understanding of the digestive process (score x6)
Diagram or model has 3 of the following: -structures present -materials are creatively linked to the original structure -final product is neat and well organized - shows thought and a clear understanding of the digestive
process (score x6)
Diagram or model has 2 of the following: -structures present -materials are creatively linked to the original structure -final product is neat and well organized - shows thought and a clear understanding of the digestive
Diagram or model has 1 of the following: -structures present -materials are creatively linked to the original structure -final product is neat and well organized - shows thought and a clear understanding of the digestive process (score x6)

23. HHP Digestion – Assignment #2 Due 9/18 A and 9/19 B
Problems with the Digestive System
Choose a specific problem with the digestive system from the list below.  Create an interactive poster on Glogster – ( designed to educate patients with that disorder to be given to the school nurse to share with other students.
Information that must be included in your Glog:
Describe the Problem
Causes
Symptoms
Treatments
Those affected (if applicable)
Questions with answers to age appropriate questions concerning this disorder
Age appropriate diagrams and videos that help explain this disorder (at least one of each)
Choices of Digestive Disorders:
Anorexia, Alactasia (lactose intolerance), achalasia, Anal fistula, Appendicitis, Bulimia, Diverticulitis, gastric ulcer, Celiac disease, constipation, diarrhea, Cholelithiasis (gall stones),Esophageal reflux, Hiatal hernia, gastritis, ileus, colorectal cancer, hepatitis, cholecystitis, IBS (irritable bowel syndrome), pancreatitis, Crohn’s disease, volvulus, or an approved digestive problem of your choice.  (Rubric on next slide)

24. Assignment # 2 Rubric CATEGORY 4 = A 3 = B 2 = C 1= D
Assignment #2: Problems with the Digestive System
-Source information is clear for all content -Makes excellent use of font, color, graphics, effects, etc. to enhance Glog -Covers topic in depth with details and examples -Subject knowledge is excellent -Met all requirements and exceeded -Excellent Spelling and Grammar (score x7)
-Source information collected for all content with few errors -Makes excellent use of font, color, graphics, effects, etc. to enhance Glog -Covers topic and subject area knowledge appears to be good -All requirements are met -Few spelling and grammatical errors (score x7)
-Source information collected for all content with some errors -Makes use of font, color, graphics, effects, etc. but some distract from Glog content -Covers topic and subject area with a few errors -One or two requirements are not met -Few spelling and grammatical errors (score x7)
-Very little or no information collected for all content with many errors -Makes use of font, color, graphics, effects, etc. but some distract from Glog content -Covers topic and subject area with a few errors -Two or more requirements are not met -Multiple spelling and grammar errors (score x7)

25. HHP Digestion – Assignment #3 Due 9/18 A and 9/19 B
Assignment #3: A Day in the Life
Using the digestive disorder studied in Assignment #2, write a one-page diary entry, in first person, reflecting on what it would be like to have this disorder.  How does this disorder affect daily life?  How does it affect what is eaten?  What is done to overcome the symptoms of this disorder?  How does it affect your interaction with others?  How does it affect your overall mood and behavior? 
The diary entry must be submitted in Microsoft Word using 1 inch margins, 12 point, Times New Romans Font, double spaced, and heading the paper with the title and your name.  Use spell and grammar check before submitting. (Rubric on next slide)

26. Assignment # 3 Rubric CATEGORY 4 = A 3 = B 2 = C 1= D
Assignment #3: A Day in the Life - Diary Entry
Narrative has all requirements-Creative -Focused on assignment story -Clear organization -Excellent Spelling and Grammar (score x5)
Narrative is missing one requirements-Creative -Assignment story is apparent -Good organization - One or two spelling and grammar errors (score x5)
Narrative is missing some requirements -Lacks creativity -Assignment story is missing connection to person -Lacks organization - Many spelling and grammar errors (score x5)
Narrative is missing requirements -Lacks creativity -Assignment story lacks empathy - Lacks organization - multiple spelling and grammar errors (score x5)

27. That’s All Folks !!!