Figures & Tables

Trnspcy. Acetates

Masters

I. General Overview

Fig. 24.1, p.777

TA-321

A. Digestive Tract; Alimentary Tract; Alimentary Canal = Mouth to Anus (G.I. Tract = Stomach & Intestines only)

B. Accessory Organs

1

II. Anatomy Overview

Fig. 24.1, p.777

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2

III. Histology Overview

Fig. 24.2, p.778

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1. Types of Glands

a. Unicellular

b. Multicellular Glands within Tract Wall

c. Multicellular Glands outside of Tract (Accessory Glands)

A. Mucosa ñ Mucous Epithelium, Lamina Propria, Muscularis Mucosae

B. Submucosa - Connective Tissue, Nerves, Blood Vessels, Glands

C. Muscularis - Longitudinal and circular Smooth Muscle, Myenteric Plexus

Fig. 24.2, p.778

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D. Serosa or Adventitia - Connective Tissue

3

IV. Physiology Overview

Table 24.1, p.780

A. Ingestion ñ Taking in Food

B. Mastication - Chewing, Mechanical Digestion

C. Propulsion - Movement Through Tract; Peristalsis

Table 24.2, p.781; Fig. 24.3a, p.781

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TM-85

D. Mixing ñ Mechanical digestion, Aids Chemical Digestion

Fig. 24.3b, p.781

TM-85

E. Secretion ñ Lubricate, Liquify and Chemically digest

F. Digestion ñ Breakdown into Components by Mechanical and Chemical Means

G. Absorption - Transport (From Tract to Blood, Lymph) by simple Diffusion, Facilitated Diffusion, Active Transport, and Cotransport

H. Transportation - Distribution Throughout Body

I. Elimination - Removal of Waste Products of Digestion, Defecation

J. Regulation - Coordination of Activities by Nerves (Vagus Nerve) and Hormones

V. Anatomy and Histology of the Digestive Tract

4

A. Oral Cavity

1. Boundaries

a. Anterior - Lips

b. Posterior - Fauces

c. Lateral - Cheeks

d. Superior - Palate (Hard & Soft)

e. Inferior - Tongue and Muscular Floor

f. Regions

1). Vestibule = Between Lips/Cheeks and Alveolar Processes

2). Oral Cavity Proper = Medial to Alveolar Processes

2. Lips and Cheeks

• a. Buccinator Muscle and Buccal Fat Pad
• b. Important in Mastication and Speech

Fig. 24.4, p.782

3. Tongue

a. Frenulum

Fig. 24.4, p.782; Clinical Notes 1-3, pp.782-783

b. Intrinsic and Extrinsic Muscles

c. Papillae

d. Functions in Speech, Taste, Mastication, Swallowing

5

4. Teeth

a. Deciduous and Permanent

Fig. 24.5, p.783; Clinical Note, p.783

b. Tooth Structure

Fig. 24.6, p.784; Clinical Note, p.784

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1). Root, Neck, Crown

2). Pulp with Vessels and Nerves

3). Dentin, Enamel, Periodontal Ligaments

5. Muscles of Mastication

Fig. 11.8, p.316

a. Mandible to Skull - Masseter, Temporal

b. Floor to Roof of Mouth - Medial and Lateral Pterygoids

6. Palate and Palatine Tonsils

Fig. 24.4a, p.782

6

7. Salivary Glands

Fig. 24.7, p.785

TA-324

a. Parotid Glands

Clinical Notes 1 & 2, p.785

b. Submandibular Glands

C. Sublingual Glands

B. Pharynx ñ Nasopharynx, Oropharynx, and Laryngopharynx

Predict Quest. 1

7

C. Esophagus

1. Length - 25 cm

2. Muscle Layers = Skeletal Muscle in Superior Portion, Smooth Muscle in Inferior Portion

3. Upper and Lower Esophageal Sphincters

Clinical Note, p.786

4. Mucosal Lining = Moist Stratified Squamous Epithelium with Mucous Glands in Submucosa

8

D. Stomach

Fig. 24.8, p.787

TA-325

1. Stomach Anatomy

a. Gastropharyngeal Opening and Cardiac Sphincter

b. Greater and Lesser Curvatures

c. Pyloric Region, Opening and Sphincter

Clinical Note, p.786

2. Stomach Histology

a. Serosa = Visceral Peritoneum

b. Muscularis has Three Layers

Fig. 24.8a, p.787

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c. Rugae

d. Gastric Pits and Glands

Fig. 24.8b,c, p.787

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1). Surface Mucous Cells

2). Mucous Neck Cells

3). Parietal Cells, Produce Hydrochloric Acid and Intrinsic Factor

4). Chief Cells, Produce Pepsinogen

5). Endocrine Cells, Produce Regulatory Hormones

e. Simple Columnar Epithelium

9

E. Small Intestine

Fig. 24.9, p.788

1. Length = 4.6 to 9 m

2. Duodenum

Fig. 24.10, p.789

TA-326

a. 180^o Arc

b. Papillae

1). Greater Duodenal Papilla and Hepatopancreatic Ampulla

2). Lesser Duodenal Pa-pilla and Accessory Pan-creatic Duct

c. Modifications that Increase Surface Area

Fig. 24.11, p.790

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1). Plica Circularis

2). Villi

3). Brush Borders and Microvilli

d. Mucosa = Simple Columnar Epithelium

1). Absorptive Cells

2). Goblet Cells

3). Granular Cells

4). Endocrine Cells

e. Intestinal Glands

3. Jejunum and Ileum

Fig. 24.9, p.788

10

F. Liver

1. Liver Anatomy

Fig. 24.12, p.791

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a. Largest Internal Organ - 1.36 Kg

b. Four Lobes - Right, Left, Caudate and Quadrate

c. Porta - Inferior Surface

1). Blood Vessels

a). Hepatic Portal Vein

b). Hepatic Artery

2). Lymphatic Vessels

3). Nerves

4). Ducts

Fig. 24.13, p.792

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a). Two Hepatic Ducts Combine to Form Common Hepatic Duct

b). Join with Cystic Duct to Form Common Bile Duct

2. Liver Histology

Clinical Note, p.793

a. Connective Tissue Capsule and Bare Area

Fig. 24.12c, p.791

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b. Lobule Structure - Hexagonal

Fig. 24.12d, p.791

TA-328

1). Central Veins - Blood Leaving Liver

2). Portal Triads at Corners

a). Hepatic Duct - Bile Leaving Liver

b). Hepatic Portal Vein - Blood Entering Liver

c). Hepatic Artery - Blood Entering Liver

3). Hepatic Cords of Hepatocytes Between

4). Hepatic Sinusoids - Mixing of Venous and Arterial Blood

a). Endothelial Cells

b). Hepatic Phagocytic Cells (Kupffer Cells)

G. Gallbladder

Fig. 24.13, p.792

TA-329

1. Size - 8 cm. X 4 cm.

2. Wall Structure

a. Mucosa with Rugae

b. Muscularis of Smooth Muscle

c. Outer Serosa

H. Pancreas

Fig. 24.10, p.789

TA-326

1. Structure - Head, Body, Tail

2. Endocrine Portion - Pancreatic Islets

3. Exocrine Portion - Acini

a. Interlobular Ducts

b. Pancreatic Duct to Hepatopancreatic Ampulla

Fig. 24.13, p.792

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11

I. Large Intestine

Fig. 24.14, p.794; Fig. 24.15, p.795

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TA-331

1. Cecum and Vermiform Appendix

Clinical Note, p.793

2. Colon

a. Size = 1.5 - 1.8 m.

b. Parts

1). Ascending Colon

2). Descending Colon

3). Transverse Colon

4). Sigmoid Colon

c. Incomplete Longitudinal Muscle Layer

1). Teniae Coli

2). Haustra

d. Epiploic Appendages

e. Crypts = Tubular Glands

3. Rectum

4. Anal Canal with Internal and External Anal Sphincters

Clinical Note, p.794

12

J. Peritoneum

1. Serous Membranes

Clinical Note, p.795

2. Visceral Peritoneum and Parietal Peritoneum

3. Mesenteries

Fig. 24.16, p.796

TA-332

a. Retroperitoneal Organs

b. Greater Omentum

Predict Quest. 2

c. Lesser Omentum

d. Omental Bursa

e. Coronary and Falciform Ligaments

f. Mesentery Proper

1). Transverse Mesocolon

2). Sigmoid Mesocolon

3). Mesoappendix

VI. Functions of the Digestive System

Table 24.3, p.797; Systemic Inter-actions, p.821

1. Movement, Secretion, and Absorption

2. Regulation is Neural and Hormonal

13

A. Functions of the Oral Cavity

1. Secretions of the Oral Cavity, 1-1.5 L / Day

a. Serous Saliva

b. Salivary Amylase

d. Mucin

e. Primarily Parasympathetic Control

14

2. Mastication

a. Chewing = Mastication

b. Mastication Reflex Integrated in Medulla Oblongata

14

B. Deglutition

Fig. 24.17, p.799

TA-333

a. Swallowing = Deglutition

b. Voluntary Phase

c. Pharyngeal Phase (1-2 sec.)

1). Reflex Stimulus = Tactile Receptors in Oropharynx

2). Afferent - Cranial Nerves V, IX

3). Swallowing Center in Medulla Oblongata

4). Efferent - Cranial Nerves V, IX, X, XI

5). Effectors are Pharyngeal Constrictor Muscles

Predict Quest. 3; Predict Quest. 4

d. Esophageal Phase (5-8 sec.)

Fig. 24.17e, p.799

TA-333

1). Peristaltic Waves

Clinical Note, p.800

2). Stimulus = Bolus in Upper Esophagus

3). Intramural Nerve Plexus

15

C. Stomach Functions

1. Secretions of the Stomach (2 -3 L/ Day)

Clinical Note, p.800; Table 24.3, p.797; Table 24.4, p.802

a. Mucus - Surface Mucous Cells and Mucous Neck Cells

b. Hydrochloric Acid - Parietal Cells

Fig. 24.18, p.801; Predict Quest. 5

TM-86

c. Gastrin - Endocrine Cells

d. Intrinsic Factor - Parietal Cells

e. Pepsinogen - Chief Cells

2. Regulation of Stomach Secretion

Clinical Focus, p.804

a. Neural Mechanisms

b. Hormonal Influences

Table 24.4, p.802; Clinical Note, p.801

16

c. Phases

1). Cephalic Phase

Fig. 24.19a, p.803

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2). Gastric Phase

Fig. 24.19b, p.803

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3). Intestinal Phase

Fig. 24.19c, p.803

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3. Stomach Filling

4. Mixing of Stomach Contents - Formation of Chyme

Fig. 24.20, p.805

a. Mixing Waves (80%)

b. Peristaltic Waves (20%)

5. Stomach Emptying

Clinical Note, p.805

a. Time

1). Liquids = 1.5-2.5 hrs.

2). Meal = 3-4 hrs.

b. Pyloric Pump

17

6. Regulation of Stomach Movements

Clinical Note, p.805

a. Coordinated with Control of Secretion

b. Too Fast or Slow Impairs Normal Absorption

18

D. Functions of the Small Intestine

1. Secretions of the Small Intestine

Table 24.3, p.797; Table 24.4, p.802

a. Primarily Mucus, Electrolytes, and Water from Intestinal Mucosa

Clinical Note, p.807

b. Hormones - Secretin and Cholecystokinin

c. Digestive Enzymes Bound to Microvilli - Disaccharidases, Peptidases and Nucleases

2. Movement in the Small Intestine - 3-5 hr. from Pylorus to Ileocecal Valve

a. Segmental Mixing Contractions

Fig. 24.3b, p.781

TM-85

b. Peristaltic Propulsive Contractions

Fig. 24.3a, p.781

TM-85

c. Local Neural and Chemical Signals

3. Absorption from the Small Intestine

a. Nutrients

b. Water from Food and from Digestive Secretions

19

E. Liver Functions - Most by Hepatocytes

Clinical Note, p.808

1. Bile Production

a. 600-1000 ml / Day

b. Functions

1). Bile Salts - Emulsify Fats

2). Contains Bilirubin and Other Excretory Products

c. Control

Fig. 24.21, p.806

TA-337

2. Nutrient Storage - Glycogen, Fat Soluble Vit., Fat, Iron, and Copper

3. Nutrient Interconversion - Hepatocytes

4. Detoxification - Hepatocytes

5. Phagocytosis - Kupffer Cells

6. Synthesis - Especially Plasma Proteins

19

F. Functions of the Gallbladder

1. Temporary Bile Storage (40 -70 ml.)

2. Control

Fig. 24.21, p.806

TA-337

3. Gallstones

Clinical Note, p.809

19

G. Functions of the Pancreas

Clinical Note, p.810

1. Formation of Pancreatic Juice

a. Aqueous Component with High Bicarbonate Ion Concentration

Fig. 24.22, p.809

TM-87

b. Pancreatic Enzymes

Table 24.3, p.797; Table 24.4, p.802

1). Proteolytic Enzymes

2). Pancreatic Amylase

3). Lipases

4). Deoxyribonucleases and Ribonucleases

2. Control of Pancreatic Secretion

Fig. 24.23, p.810

TA-338

a. Neural Controls - Parasympathetic and Sympathetic

b. Secretin and Cholecystokinin

Predict Quest. 6

20

H. Functions of the Large Intestine

1. Transit Time = 18 -24 hr.

Clinical Note, p.811

2. Secretions of the Large Intestine

Table 24.3, p.797

a. Primarily Mucus

b. Bicarbonate/Chloride Exchange

3. Water Reabsorption with Na⁺ /Cl^- Gradient

4. Symbiotic Bacteria

a. 30% of Dry Weight Feces

b. Vit. K Production

c. Flatus

5. Movement in the Large Intestine

Fig. 24.24, p.812

TA-339

a. Mass Movements

b. Gastrocolic Reflexes

c. Duodenal Reflexes

d. Defecation Reflex Aided by Voluntary Movements

Clinical Note, p.812

21

VII. Digestion, Absorption, and Transport

Table 24.5, p.813; Clinical Focus, p.819

A. Carbohydrates

1. Digestion

Clinical Note 1, p.813

a. Amylases

b. Disaccharidases in Intestinal Epithelium

2. Absorption and Transport

Fig. 24.25, p.814; Clinical Note 2, p.813

TA-340

a. Sodium Cotransport Mechanism

b. Role of Insulin

B. Lipids

1. Emulsification by Bile Salts

Clinical Note, p.814

2. Digestion by Pancreatic Lipases

3. Absorption

a. Micelle Formation

b. Simple Diffusion Across Intestinal Epithelium

Fig. 24.26, p.815

TA-341

c. Formation of Chylomicrons = 85% Triacylglycerol, 7% Cholesterol, 7% Phospholipid, and 1% Protein

4. Lipid Transport - in Lacteals

• a. Lipoproteins

1). Very Low Density Lipoproteins (VLDL)

2). Low-Density Lipoprotein (LDL) ñ to Cells ñ Receptor-Mediated Endocytosis

3). High-Density Lipoproteins (HDL) ñ Back to Liver for Recycling or Disposal

Fig. 24.27, p.816

Fig. 24.28, p.817

Fig. 24.29, p.817

Fig. 24.28, p.817

Clinical Note, p.816

C. Proteins

Table 24.5, p.813

1. Digestion

a. Pepsin

b. Pancreatic Peptidases to Small Peptides

c. Tripeptides, Dipeptides and Amino Acids by Peptidases on Intestinal Epithelium

2. Absorption

a. Separate Sodium Cotransport Mechanisms for Acidic, Basic and Neutral Amino Acids

b. Most Enter as Di- and Tri-peptides

c. Final Digestion to Single Amino Acids is Intracellular ñ to Hepatic Portal System

Fig. 24.30, p.818

TA-342

3. Uptake by Other Cells = Active Transport under Hormonal Control

D. Water

1. 92% Absorbed in Small Intestine, 6-7% Absorbed in Large Intestine

Fig. 24.31, p.818

2. Direction of Diffusion Determined by Osmotic Gradients

E. Ions

1. Active Transport of Sodium, Potassium, Magnesium, and Phosphate

2. Passive Diffusion of Chloride Following Sodium; Active Transport of Chloride in Ileum

3. Active Transport of Calcium Requires Vit. D and is Under Hormonal control

VIII. Systems Pathology: Diarrhea

Predict Quest. 7