Digestive System

CONTENTS:

Oral cavity, Esophagus, Esophageal Groove, Rumen, Reticulum, Omasum, Abomasum, Pylorus, Small Intestine, Pancreas, Liver, Gall Bladder, Large Intestine, Rectum, Peritoneum

Oral Cavity

Function: To receive food by ingestion, break it into small particles by mastication, and mix it with saliva

Description: teeth, tongue, stratified squamous epithelium

Dental Pad

Function: Helps them gather large quantities of grass and other plant matter

Description: a thick, hard gum line where the animal can pinch blades of grass

Tongue

Function: to harvest forages during grazing or to consume harvested feedstuffs

Description: long, raised appearance, rough and scratchy

Esophagus

Function: Allow for the passage of material from the mouth and throat to the stomach, innervated by Vagus nerve

Description: Muscular tube extending from pharynx to stomach, dorsal to trachea

Esophageal Groove

Function: Suckling causes reflex contraction of muscles forming a solid tube that bypasses the rumen and reticulum

Description: Mucosa of cardia creates 2 muscular folds that form a groove from the cardia to omasum

Four Chambered Stomach

Rumen

Function: Absorption of volatile fatty acids, Fermentation chamber: 30-60 gallons volume

Description: Dorsal and ventral sacs, largest portion of stomach

Rumen Papillae

Function: Essential for rumen function, they increase the surface area for greater potential to absorb nutrients

Description: Finger-like projections that line the inside of the rumen

Reticulum

Function: Collect smaller digesta particles and move them into the omasum while the larger particles remain in the rumen for further digestion

Description: Honeycomb appearance

Omasum

Function: Absorption of water and some minerals

Description: Muscular laminae lie in sheets with papillae

Abomasum

Function: Site of chemical digestion, Produces hormones that regulate mood, appetite, etc.

Description: Simple Columnar epithelium, only compartment lined with glands

Small Intestine

Function: Continued digestion, absorption of nutrient, Mucosa thrown into Villi, Crypts of Lieberkuhn, Cells have microvilli

Description: Consists of three sections (duodenum, jejunum and ileum)

Duodenum

Function: Ducts from pancreas and liver

Description: Duodenal Papilla, forms a loop, pancreas inside of loop

Jejunum

Function: Absorb sugars, amino acids, and fatty acids

Description: Largest part of intestine, after duodenum

Illeum

Function: Absorbs any final nutrients, with major absorptive products being vitamin B12 and bile acids

Description: Peyer’s Patches ( numerous areas of lymphoid tissue) , the last and longest section of the small intestine

Pancreas

Function: synthesizes and secretes several digestive enzymes to digest feedstuff

Description: next to the stomach, liver, and small intestine. within duodenum

Main Pancreatic Duct

Function: Drains most of the pancreas

Description: runs through the center of the gland from left to right

Accessory Pancreatic Duct

Function: a second drainage system for the main pancreatic duct to reduce the pressure in the main pancreatic duct and prevent acute pancreatitis

Description: runs the length of the pancreas

Ampulla of Vater

Function: Pancreatic and bile ducts release their secretions into the intestines

Description: a small opening that enters into the first portion of the small intestine

Sphinctor of Oddi

Function: Opens only in response to a meal so that digestive juices can enter the duodenum and mix with food for digestion

Description: Muscular valve surrounding the exit of the bile duct and pancreatic duct into the duodenum

Liver

Function: Makes and secretes bile

Description: On the right side and caudal to the diaphragm, Hepatic lobes and lobules

Hepatic Duct

Function: Drain bile from the liver

Description: Connection between the left and right hepatic ducts

Common Bile Duct

Function: Carry bile from the Gallbladder and empty it into the upper part of the small intestine

Description: Many very tiny tubes in the liver collect bile from the liver cells

Gall Bladder

Function: Storage and concentration of bile

Description: Bile duct empties into duodenum via duodenal papilla

Cystic Duct

Function: Provides the conduit through which bile enters and then discharges from the gallbladder

Description: merges the gallbladder to the common bile duct

Large Intestine

Function: Water, electrolytes, and some vitamins absorbed in cecum and colon

Description: made up of the cecum and colon

Cecum

Function: Can hold extra water for absorption

Description: Between ileum and ascending colon

Colon

Function: Spiral in shape

Description: Ascending, transverse, descending

...final stops!

Rectum

Function: Stores feces prior to defecation

Description: a chamber that begins at the end of the large intestine, followed by the colon, and ends at the anus

Peritoneum

Function: Support the organs of the abdomen and acts as a conduit for the passage of nerves, blood vessels, and lymphatics

Description: a membrane, a sheet of smooth tissue that lines your abdominal cavity and surrounds your abdominal organs

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