LAB - THE DIGESTIVE SYSTEM

know the pathway through the GI tract. make sure to include the sub-regions of the small and large intestines.

• Mouth (oral cavity)

  • histology: stratified squamous epithelium

• Oropharynx —→ Laryngopharynx

  • histology: stratified squamous epithelium

• Esophagus

  • histology: stratified squamous epithelium

• Stomach

  • histology: simple columnar epithelium

• Small Intestine

  • histology: simple columnar epithelium

    • Duodenum

    • Jejunum

    • ileum

• Large Intestine

  • histology: simple columnar epithelium (no villi)

    • Cecum

    • Ascending Colon —→

    • Transverse Colon —→

    • Descending Colon —→

    • Sigmoid Colon —→

• Rectum

  • histology: stratified squamous epithelium

• Anus

  • internal sphincter —→ smooth muscle

  • external sphincter —→ skeletal muscle

what are the main functions of the salivary glands/saliva? what molecule do the enzymes found in saliva digest?

SALIVARY GLANDS ARE PAROTID, SUBMANDIBULAR, AND SUBLINGUAL

functions: lubrication; primary carbohydrate digestion

breaks down starch or carbohydrates

what is the function of the esophagus? know the histology of the esophagus.

-function: initiates peristalsis to move food down to the stomach

-histology: lined with stratified squamous epithelium

• upper 1/3 = voluntary (skeletal muscle)

• lower 2/3 = involuntary (smooth muscle)

what is the histology of the lining of the stomach? how does this tissue help protect the stomach?

histology: lined with simple columnar epithelium

• secretes mucus to protect the walls from acids

what are the 3 regions of the small intestine? which are suspended by the mesentery?

-duodenum

• receives chyme from the stomach and digestive enzymes from the pancreas and liver

-jejunum: middle

-ileum: distal

-the jejunum and ileum are suspended by the mesentery

what is the taenia coil? what pouch-like structure does the taenia coil help form?

• what is the histology of the taenia coil?

taenia coli = external strips of longitudinal smooth muscle forming pouches called haustra

-histology: smooth muscle

where is the liver located? what ligaments are associated with the liver?

-location: right side, superior portion of the abdominal cavity

-associated ligaments:

• falciform ligament: anchors liver to diaphragm

• round ligament: former umbilical vein; extends from liver to navel

know the pathway of bile from the liver and gallbladder to the duodenum.

• produced by the liver —→

• hepatic duct —→

• cystic duct —→

• gall bladder (for storage)* —→

• cystic duct* —→

• common bile duct —→

• duodenum

* = when bile is being stored