Digestive System

Digestion System includes

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Terms in this set (39)

1. Gasterointestinal Tract
-Tube running from the mouth to the anus
2. Accessory Glands
-Teeth, Tounge, Salivary Glands, Pancreas, Liver, Gallbladder

Functions of the Digestive System

1. Ingestion
2. Digestion
-Mechanical: Motility eg. Chewing
-Chemical: Enzymes, Acid (secretions)
3. Absorption
-Digested products enter blood and lympth
4. Defraction
-Elimination of wastes that are undigestible

Peritoneum

-Serous membrane (Largest in the body)
-Visceral: serosa lining organ walls
-Parietal: Lines abdominal wall
-Paritoneal Cavity: with serous fluid
-Serosa between organs: 2 fused layers of visceral peritoneum that binds organs to eachother or to cavity wall
1. Greater Omentum
-"Fatty Apron"
-Over transverse colon and small intestine
-Protects, insulats and reserves energy
2. Lesser Omentum
-Suspendes stomach from the liver
3. Mesentary
-Binds Small and Large Intestines to abdominal wall

Serosa/ Adventitia of the GI Tract

-Serosa on stomach, lower part of small intestine, liver, gallbladder and most of large intestine
-Organs with one surface covered by peritoneum= retroperitoneal
eg. pancreas, duodenum
-Ant. = peritoneum
-Post. = CT only, no epith. Adventitia only

Muscularis Externa of the GI Tract

-Viseral smooth muscle
-Non-striated
-Spindle-shaped cells with central nucleas
-Gap junctions between cells
-Contractions responsible for motility
=food movement and mixing
-Inner circular layer and Outer longitudinal layer = tube
-Myenteric nerve plexus between layers

Submucosa of the GI Tract

-CT areolar
-Connects the Mucosa and Muscularis Externa
-Contains blood and lympth vessels
-Submucosal nerve plexus

Mucosa of the GI Tract

-Inner layer
-Faces Lumen
1. Muscularis Mucosa
-smooth muscle
-attached to submucosa
-movement of mucosa
2. Lamina Propria
-CT areloar
-Contains blood and lympth vessels, lympth nodules/tissue (immune)
3. Mucous Epith.
-With goblet cells
-Stratified sq. = esophagus, (mouth and pharynx) and anal canal
-Simple columnar = stomach, small and large intestine

Enteric Nervous System

-Nerve network within wall of tube = "little brain"
-Submucosal plexus= regulates function of mucosal glands and muscle
-Myenteric plexus= regulates motility of Muscularis Externa
-Communicates with Central Nervous System

Mouth

-Oral Cavity
-Includes lips, cheeks and contains the tounge
-Wall= skeletal muscle lined with mucus membrane

Tounge

-Skeletal muscle
-attached to hyoid bone
-dorsal portion contains
a) Papilla- projections of mucosa, 3 types, some have taste buds
b)Lingual Glands- Fluid, Lingual Lipase (enzyme of fat digestion)