1. Understand the functions of the digestive system

2. 2.08 Understand the functions of the
Digestive System Essential questions
What are the functions of the digestive system?
How do the functions of chemical and physical digestion interrelate?
2.08 Understand the functions and disorders of the digestive system 2

3. Functions of the digestive system
2.08 Understand the functions and disorders of the digestive system 3

4. Functions of the digestive system
Mouth (buccal cavity)
Food enters digestive system through mouth
Inside of the mouth is covered with mucous membranes
Roof of mouth is HARD PALATE (bone) and soft palate
Uvula
flap that hangs off soft palate
prevents food from going up the nose
when you swallow
What is bolus?
Bolus is a ball of food that has just been chewed

5. Functions of the digestive system
Tongue
Helps in chewing and swallowing
Made of skeletal muscle attached to four bones
Taste buds on the surface
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6. Functions of the digestive system
Teeth
Mastication, a.k.a chewing
teeth help in mechanical digestion
How is the tooth’s shape related to its function?
Incisors - have sharp edges for biting
Cuspids - flat top and are used for grinding
Bicuspids - are pointed and like a nutcracker to grind food
Molars - designed for crushing
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7. Functions of the digestive system
Salivary glands
Secrete saliva
Chemical action takes place as a result of saliva
Amylase, mucin and ptyalin are enzymes that start chemical breakdown of food
Ptyalin converts starches into simple sugar 7

8. Functions of the digestive system
Palate
Separates mouth and sinuses
Uvula
Prevents food from going into the nasal cavity when swallowing
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9. Functions of the digestive system
Pharynx
Passageway (tube) for food, liquids and air
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10. Functions of the digestive system
Esophagus
Passageway for food and liquids only
What is its relevance to your health?
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11. Functions of the digestive system
Stomach
Functions of the stomach:
Chemical digestion occurs with gastric (digestive juices)
Mechanical digestion occurs with stomach walls churning and mixing
This mixture is called Chyme

12. Functions of the digestive system
Stomach
How long does it take for
stomach to empty?
Takes 2-4 hours
for stomach to empty
Small amount of chyme enters
duodenum a little at a time which is controlled by the pyloric sphincter

13. Functions of the digestive system
Gastric juices (chemicals) used in digestion
Enteroendocrine glands
gastrin
Parietal cells
HCL and intrinsic factor
Chief type cells
pepsinogen
Mucus cells
alkaline mucus
Rennin 13

14. Functions of the digestive system
Small Intestine
Digestion is completed and absorption occurs.
Addition of enzymes
pancreas which produces insulin
bile produced by liver/gallbladder 14

15. Functions of the digestive system
Small Intestine Villi: Projections
that look like hair that add more surface
room and absorb the nutrients 15

16. Functions of the digestive system
Small Intestine
Relevance to your health
Absorb most of the nutrients 16

17. Functions of the digestive system
Pancreas
Function of digestive enzymes secreted by the pancreas?
Lipase - breaks down lipids
Amylase - breaks down starches
Trypsin - breaks down proteins 17

18. Functions of the digestive system
Pancreas
Pancreas is a gland of the endocrine system secreting insulin which regulates the homeostasis of sugar (glucose) in the blood.
Which other system does the pancreas function? 18

19. Functions of the digestive system
Liver
Functions:
Produces and stores glucose in the form of glycogen
Detoxify alcohol, drugs and other harmful substances
Manufactures blood proteins
Manufactures bile which breaks down fats 19

20. Functions of the digestive system
Liver
What is the function of
Bile - breaks down fats
Glycogen - easily broken down to
glucose for immediate use for the cells
What vitamin is produced by the liver?
Vitamin D
The liver stores Vitamin A, D and B complex
All necessary for production of red blood cells 20

21. Functions of the digestive system
Gallbladder
Small green organ, inferior surface of
the liver
Stores and concentrates bile until
needed by the body
When fatty foods digested, bile is
released by the gallbladder
Bile flows into small intestine at the duodenum
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22. Functions of the digestive system
Large intestine
Absorb liquids from Chyme, concentrating to what you know as stool
Relevance to health: allows for absorption of fluids and micromolecules to aid in homeostasis
Type of diet promotes colon health:
High in fiber
What is chyme?
What is the semi-solid liquid secreted
from the ileum through the ileoceccal valve
called that enters the large intestine? 22

23. Functions of the digestive system
Large intestine
Approximately 2 inches in diameter
a.k.a. the colon
Cecum - lower right portion of large intestine
Appendix - flinger like projection of the cecum
Rectum - last portion of large
intestine - where stool is stored
Anus - external opening 23

24. Functions of the digestive system
What can healthcare professionals learn from observing stool specimens?
Blood
Undigested food
Mucous
Strange color or shape
On average, how much flatus does a person produce per day? 1-3 pints / day pass through rectum, bacteria produce the gas

25. Functions of the digestive system
News Flash... New treatment!!!!
Fecal transplant
Allows the bacteria from the healthy stool to repopulate the gut of the patient who has lost healthy bacteria in their gut
Used to treat Clostridium difficile that grows in human intestines
Symptoms range from persistent diarrhea to life- threatening inflammation of the colon to death
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26. Functions of the digestive system
Discuss the processes of digestion and their relevance to health.
Chemical: mouth and stomach, limited in small intestine
Physical: mouth and stomach
Absorption of nutrients: small intestine
Absorption of fluids: large intestine
Elimination: large intestine
(rectum and anus)
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27. 2.08 Understand the functions and disorders of the digestive system
Act of Digestion
Each action of the digestive system… 6 actions
Ingestion: the taking in of food or liquids
saliva softens food to make it easier to swallow
Ptyalin in saliva converts starches into simple sugar
Under nervous control - just thinking of food can cause your mouth to water
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28. 2.08 Understand the functions and disorders of the digestive system
Act of Digestion
Each action of the digestive system… 6 actions
Mastication is the process of chewing up food
creates a bolus which is a soft, pliable ball created from chewing and and the addition of saliva which slides down esophagus
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29. 2.08 Understand the functions and disorders of the digestive system
Act of Digestion
Each action of the digestive system… 6 actions
Digestion is the breaking down of food for the body’s use
Gastric juices are released for chemical digestion
Stomach walls churn and mix this mixture becomes chyme
Small amount of chyme enters duodenum a little at a time which is controlled by the pyloric sphincter
Takes 2-4 hours for the stomach to empty
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30. 2.08 Understand the functions and disorders of the digestive system
Act of Digestion
Each action of the digestive system… 6 actions
Secretion is digestive enzymes are secreted to break down different types of food
of enzymes secreted in liver, gallbladder and pancreas.
These secretions aid in completing digestion
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31. 2.08 Understand the functions and disorders of the digestive system
Act of Digestion
Each action of the digestive system… 6 actions
Absorption is taking in nutrients to feed the body
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32. Act of Digestion Each action of the digestive system… 6 actions
Excretion is to take things out of the body that are not usable
occurs in large intestine.
Bacterial action on undigested food - decomposed products excreted through colon
Bacterial form moderate amounts of B complex and vitamin K
Bacteria produce gas which accumulates and is released through rectum
Feces are undigested semi-solid consisting of bacteria, waste products, mucous and cellulose 32

33. Functions of the digestive system
Check your
knowledge… 33