ANAT41 Lecture Outline
Digestive System
Part 1
General functions of digestive system:
1. Ingestion - to take food in
2. Movement of food along the digestive tract
Mixing movements
Peristalsis - the rhythmic contraction and relaxation of smooth muscle
3. Digestion
Mechanical - the physical breakdown of food
Chemical - the enzymatic breakdown of food
4. Absorption of digested food - movement of food from the lumen into the blood
5. Elimination - the excretion of waste products
General Anatomy
Organs included
Gastrointestinal (GI) tract or Alimentary Canal
Digestive Organs:
1. Mouth
2. Pharynx
3. Esophagus
4. Stomach
5. Small intestine
6. Large intestine
Accessory:
1.
2.
3.
4.
5.
6.
Tongue
Teeth
Salivary glands
Liver
Gall bladder
Pancreas
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ANAT41 Lecture Outline
Digestive System
Part 1
General wall structure:
1. Mucosa
 Epithelium
 Lamina propria (areolar connective tissue)
 Muscularis mucosae (thin layer of smooth muscle that creates the
folds in the lumen when this layer is contracted)
2. Submucosa - areolar connective tissue, characterized by blood vessels and
nervous tissue
3. Muscular layer
 Inner circular layer (constricts the lumen when contracted)
 Outer longitudinal layer (shortens the length of the tube when
contracted)
4. Serosa - serous membrane (simple squamous epithelium resting on noncellular basement membrane
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ANAT41 Lecture Outline
Digestive System
Part 1
Mouth
Functions:
1. Ingestion of food
2. Mastication (chewing)
3. Begins digestion of starch
4. Taste
5. Swallowing
Anatomy of mouth (oral cavity or buccal cavity)
1. Hard palate: maxilla and palatine bones
2. Soft palate - skeletal muscle
3. Palatine tonsils - lympathic tissue
Tongue
Functions
a. Mechanical digestion
b. Move food around in mouth
c. Taste
d. Swallowing
Structure
a. lingual frenulum
b. papillae
b. lingual tonsils
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ANAT41 Lecture Outline
Digestive System
Part 1
Teeth
Structure:
Regions
1) crown
2) root
Layers
1) enamel
2) cementum
3) dentin
4) pulp cavity
5) periodontal ligament
(periodontal membrane)
Types of teeth
a. incisors
b. cuspids (canines)
c. bicuspids (premolars)
d. molars (polycuspids)
wisdom teeth
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ANAT41 Lecture Outline
Digestive System
Part 1
Number of teeth
a. primary or deciduous teeth: 2 1 0 2 (dental formula for one quarter of
mouth)
b. secondary or permanent teeth: 2 1 2 3
Salivary glands
Functions
Moistens food, holds food together to form a bolus
Begins digestion of starch salivary amylase
Taste
Cleanses mouth
Names and locations of salivary glands:
a. parotid glands
b. submandibular glands
c. sublingual glands
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ANAT41 Lecture Outline
Digestive System
Part 1
Control of secretion of saliva
What division of the nervous system control salivary gland production?
Pharynx
Structure (This is a review from the respiratory system)
1. Nasopharynx
2. Oropharynx
3. Laryngopharynx
B. Function - passageway for food and air
C. Swallowing
1. Voluntary - which portion is voluntary?
2. Involuntary - which portion is Involuntary?
Esophagus
What structures does the esophagus connect?
Structure - What 4 layers make up the esophagus?
Function - conduct food to stomach
Does chemical digestion occur in the esophagus?
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ANAT41 Lecture Outline
Digestive System
Part 1
Stomach
Location Functions:
1. Reservoir for food
2. Mechanical breakdown into chyme
3. Begins chemical digestion of protein
Structure of stomach
1. Cardiac region
2. Fundus
3. Body
4. Pyloric region (pyloric antrum)
5. Lower esophageal sphincter (cardiac or gastroesophageal sphincter)
6. Pyloric sphincter (pyloric valve)
7. Rugae - folds of the mucosa
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ANAT41 Lecture Outline
Digestive System
Part 1
Layers:
What type of epithelium do we find In the stomach?
What structural layer Is different In the stomach than In other digestive structures?
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ANAT41 Lecture Outline
Digestive System
Part 1
Gastric glands
a. chief cells - produce and secretes pepsinogen into the opening of the glands
b. parietal cells - produce and secretes HCl into the opening of the glands
c. mucous cells - produce mucus that coats the lumen
d. G cells - produce gastrin that is dumped into the blood
Which cells are exocrine and which are endocrine?
Control of secretion of gastric juice
1. Nervous control - by the ANS
Which division controls gastric juice production?
2. Hormonal control- gastrin
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