Download Nerve activates contraction

The Digestive System
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Functions of the Digestive System
 Ingest food
 Digest food
 Absorb nutrients
 Eliminate indigestible waste
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Digestive anatomy overview
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Organization of the Digestive organs
Alimentary Canal
Accessory organs
Mouth
Teeth
Pharynx
Tongue
Esophagus
Salivary glands
Stomach
Gall bladder
Small intestine
Liver
Large intestine
Pancreas
Anus
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Digestive Process
Ingestion
Propulsion
Mechanical
Digestion
Chemical
Digestion
Absorption
Defecation
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
This is your basic alimentary tract structure.
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Sagittal view of abdominal viscera
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Peristalsis
Figure 24–4
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Segmentation
 Cycles of contraction:
 Churn and fragment bolus
 mix contents with intestinal secretions
 Does not follow a set pattern:
 does not push materials in any 1 direction
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The oral cavity and pharynx Say “ahhh”
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Salivary Glands
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Road map of the tongue
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Anatomy of Teeth
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Primary and Secondary Dentitions
Figure 24–9
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Histology of the Esophagus
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Gastroesophageal junction
Stomach
Esophagus
Stratified squamous epithelium
Simple columnar epithelium
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Swallowing Process
Figure 24–11
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Stomach
Figure 24–12a
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Stomach
Figure 24–12b
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Stomach Lining
Figure 24–13
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
It’s the pits! (Gastric pits that is…)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Micrograph of the Fundic region of the gastric
mucosa
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The duodenum, gall bladder and pancreas
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Hormonal Regulation of Pancreatic secretions
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The small intestine
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Histology of the small intestine
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Cells of the mucosa
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Duodenal wall
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Duodenal mucosa
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Brunner’s (duodenal) glands
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Crypts of Lieberkuhn!
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Peyer’s patches in the ileum
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Pancreas
Figure 24–18
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Exocrine tissues of the pancreas
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Pancreas: Acinar cells
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Liver
 Is the largest visceral organ (1.5 kg)
 Lies in right hypochondriac and epigastric
regions
 Extends to left hypochondriac and umbilical
regions
 Performs essential metabolic and synthetic
functions
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Anatomy of the Liver
Figure 24–19
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Liver Histology
Figure 24–20
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
3 Functions of the Liver
1.
Metabolic regulation
2.
Hematological regulation
3.
Bile production
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Metabolic Regulation

The liver regulates:
1. composition of circulating blood
2. nutrient metabolism
3. waste product removal
4. nutrient storage
5. drug inactivation
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Metabolic Activities of the Liver
 Carbohydrate metabolism
 Lipid metabolism
 Amino acid metabolism
 Waste product removal
 Vitamin storage
 Mineral storage
 Drug inactivation
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Gallbladder and Bile Ducts
Figure 24–21
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Gallbladder
 Stores bile
 Releases bile into duodenum:
 only under stimulation of hormone
cholecystokinin (CCK)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Gallstones
 Are crystals of insoluble minerals and salts
 Form if bile is too concentrated
 Small stones may be flushed through bile duct
and excreted
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Activities of Major Digestive Tract Hormones
Figure 24–22
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Hormones of Duodenal Enteroendocrine Cells
 Coordinate digestive functions:
 secretin
 cholecystokinin (CCK)
 gastric inhibitory peptide (GIP)
 vasoactive intestinal peptide (VIP)
 gastrin
 enterocrinin
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Absorption of Nutrients
 Nearly all occurs in the small intestine.
 80% of the electrolytes and virtually all food
 Most nutrients are absorbed by active transport.
 Glucose, amino acids, & nucleic acids are absorbed by
secondary active transport with sodium.
 Iron and calcium require transport proteins (ferritin) or
cofactors (vitamin D).
 Anions follow Na+.
 Vitamins  Fat soluble (A, D, E & K) vitamins are carried with micelles.
Much of the K is absorbed in the colon.
 Water soluble vitamins diffuse with the exception of B12,
which requires intrinsic factor.
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Protein digestion in the small intestine
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Bile salts emulsify fats
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Absorption of lipid
Dietary fats are
absorbed into the
“lacteals” of the
lymphatic system
before being
transferred to the
circulatory system.
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Digestive Secretion and Absorption
Figure 24–27
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Absorption of Ions and Vitamins
Table 24–4
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Anatomy of the large intestine
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The rectum and anus
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
3 Parts of the Large Intestine
1.
Cecum:

2.
the pouchlike first portion
Colon:

3.
the largest portion
Rectum:

the last 15 cm of digestive tract
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Characteristics of the Colon
 Lack of villi
 Abundance of goblet cells
 Presence distinctive intestinal glands
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The End
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings