1. Digestive System
Chapter 15

2. Tongue Mostly muscle tissue
What type of muscle would it be?
Frenulum – connects the tongue to the bottom of the mouth
What is the purpose of the tongue?
Papillae – rough projections that contain taste buds
Why would these be rough?
Four types of taste buds – sweet, sour, salt, bitter

3. Palate 2 sections Hard Palate Soft Palate
Also known as the maxilla
Anterior Portion
Soft Palate
Posterior Portion
This and the uvula are drawn up during swallowing
Why is this important?
Blocks off the nasal passage during swallowing

4. Tonsils Lingual – at the base of the tongue
Used as anchor, covered by lymphatic tissue
Palatine – Located on the side of the tongue
Which do you think is removed when you have tonsillitis?
Palatine – exposed to many pathogens so they can easily become infected.

5. Teeth 2 sets Primary (baby) – 10 on each jaw They are lost
What happens to these?
They are lost
The roots are resorbed and teeth are pushed out by secondary teeth
Secondary (permanent) – 16 on each jaw
Begin to appear around age six

6. Secondary Teeth Incisors – total of eight, front teeth
Function?
Tearing off bites
Cuspids (Canine) – total of four, sharper teeth (fangs)
Rip and Tear tough food.

7. Secondary Teeth
Bicuspids (premolar) – total of eight, behind cuspids, a bit flatter
Function?
Mash and grind, little bit of tearing
Molars – total of 12, back teeth much flatter (4 first, 4 Second, 4 Third)
Third also known as wisdom teeth
Mash and Grind
Why do we need so many types of teeth?

8. Tooth Structure Based on the name where do you think each part is?
Crown –
Root –
Enamel –
Hardest substance in the body and cannot be replaced
What problem does this pose?
Dentin – deep to the enamel and surrounds the pulp cavity (nutrient supply)

9. Salivary Glands Main Secretions What triggers secretions?
Amylase – breaks down large starch and glycogen molecules
Mucus –
What is its purpose?
Bind food particles and lubricate alimentary canal
What triggers secretions?
Parasympathetic nervous system

10. Salivary Glands – 3 different glands
Paratid – Located anterior and inferior to the ear
Secretes saliva rich in amylase
Submandibular – Located where?
Secretes thicker saliva than paratid.
Why thicker?
Sublingual – Located where?
Secretes primarily mucus

11. Pharynx Connects nasal and oral cavities with the esophagus
Contains the epiglottis
What is this?
Flaplike structure used to seal off trachea during swallowing.
Has three sections
- nasopharynx attaches nasal cavity
- oropharynx attaches mouth
- laryngopharynx attaches esophagus

12. Wall Structure
4 layers
Mucosa –
Submucosa –
Muscular layer -
Serosa –

13. Esophagus Connects pharynx to stomach
Function -
Ends at lower esophageal sphincter
What is a sphincter?
This one connects the stomach and the esophagus, what will its function be?

14. Stomach
Location –
Size is small when empty, yet it can hold one liter. How?
What happens in the stomach?

15. Stomach Regions of the stomach Stomach ends at Pyloric Sphincter
Cardiac - posterior to lower esophageal sphincter
Function-
Fundic – Most anterior portion
Function –
Body – Main region
Pyloric – most posterior region
Stomach ends at Pyloric Sphincter

16. Gastric Juice 4 Components Pepsin – Pepsinogen – Hydrochloric Acid –
Mucus

17. Gastric Regulation Produced regularly, but rate can vary Gastrin –
What might cause it to vary?
Gastrin –
What stimulates the release?

18. Gastric Mixing How will the stomach perform its functions? Chyme –
Where does food go to exit stomach?
How does the stomach move it there?

19. Pancreas Located near posterior abdominal wall inferior to stomach
Secretes____ into the ___.
Amylase
Lipase
Nuclease
What other important function?

20. Liver Located… Lobed Multiple Functions Digestive functions Blood –
Storage -
Digestive functions
Metabolism of Carbohydrates, Lipids and Proteins
Secretes ____ through the ___into the ____.

21. Bile Consists of: 1. 2. 3. Two types biliverdin and bilirubin
Only part of the bile that has digestive function
Emulsification 3.

22. Gallbladder Storage area Reabsorbs water to concentrate __________.
What does it store?
Reabsorbs water to concentrate __________.
Hormones stimulate sphincter to relax, open duct
Causing what to happen?

23. Questions
If a person had a condition which limited their ability to produce hydrochloric acid in the stomach, how might this affect digestion and why?
If someone lost control of their pyloric sphincter and was unable to contract it, how would this affect digestion?
Thinking about the contents of the stomach, what might happen to a person with a lower esophageal sphincter that does not contract completely?