1. The Digestive System
“alimentary canal”

2. omphalocele

3. Overall Function
Digestion is the chemical and physical breakdown of food into a form usable by cells.

4. Organs of Digestive System
MAJOR ORGANS
Mouth
Oropharynx
Esophagus
Stomach
Small intestine
Large intestine
Rectum
ACCESSORY ORGANS
salivary glands
Tongue
Teeth
Liver
Gallbladder
Pancreas
Vermiform appendix

6. Digestive Tract
Also known as alimentary canal or gastrointestinal (GI) tract.
It forms a tube that separates from digesting food from the body’s internal cavity.

7. Layers of GI tract Mucosa Muscularis
Inner layer of the lumen (open space) & villi
Submucosa
Made of connective tissue, glands, blood vessels and nerves
Muscularis
Surrounds submucosa, smooth muscle that contains nerves that form part of the intramural plexus
Serosa
Outermost layer made of connective tissue

8. The Mouth Lips Cheeks Hard & soft palate Tongue
When closed form the oral fissure
Cheeks
Formed by muscle and adipose tissue
Hard & soft palate
Uvula suspends from soft palate
Tongue
Muscle movements aid in mastication

9. The Mouth

10. Salivary Glands Pairs include parotids, submandibular, and sublingual
Secrete ~1L of saliva per day
Buccal glands in the mucosa lining produces a small amount of saliva

11. The Teeth Three main parts Deciduous teeth(20) are baby teeth
Crown
Neck
Root
Deciduous teeth(20) are baby teeth
Permanent teeth(32) show up from 6-13 yrs

12. The Pharynx
Deglutition is the act of swallowing a bolus, rounded mass of food and saliva from the mouth to the stomach.

13. The Esophagus ~10 inches longs Sits posterior to trachea and heart
It is normally flatted in resting state
Each end is guarded be a sphincter
Upper esophageal (UES)
Lower (cardiac) esophageal (LES)
Esophageal hiatus is opening in diaphragm where esophagus passes
When enlarged can lead to hiatal hernia
GERD- gastro esophageal reflux disorder, severe acid reflux and indigestion caused by weakened LES.

16. The Stomach Located directly below the diaphragm
Normally holds L
3 parts
Fundus (upper left)
Body (central)
Pyloris (lower)
2 sphincter
LES(cardiac)
Pyloric
Esophageal hiatis
fundus
body
pyloris

17. The Stomach
Gastric Mucosa, lining of the stomach contain many folds called rugae and depression called gastric pits
Cells in the stomach produce HCL and intrinsic factor
Intrinsic factor binds to B12 molecules keeping them from being broken down so they can be absorbed in the sm. Intestines

18. The Stomach
Gastric muscles, muscularis, is made of longitudinal, circular and oblique layers. This gives it strong grinding power.

19. The Stomach Overall Functions
Secrete gastric juices and intrinsic factor
Store partially digested food
Churn food with digestive juices and move it into duodenun
Limited absorption, alcohol, some H2O and some fats
Release hormones that regulate digestive functions
Destroy pathogenic bacteria with acidic pH

20. The Small Intestine ~6m in length 3 parts
Duodenum- first section, shaped like a C
Jejunum- 2.5m, begins with abrupt turn
Ileium- last 3.5m
Small projections called villi line the sm. Intestine.
Each contain an arteriole, venuole and lacteal
Microvilli present on the villi increase the surface area of intestinal wall

21. The Small Intestine
Secretion of digestive enzymes and absorption occur in small intestine
Small pockets at the base of the villi, called crypts, contain cells that reproduce rapidly
These cells push up and constantly replace older cells that are shed

22. Large Intestine 1.5-1.8m 3 parts Cecum- first 5-8cm Colon
Ascending
Transverse
Descending
Sigmoid (s-shaped)
Rectum17-20cm
Anal canal has folds with a vein and artery
Hemorrhoids are enlargement of those veins
Anus is made up of two sphincters

23. The Large Intestines

24. Accessory Structures
Vermiform appendix- thought to hold beneficial flora
Peritoneum- serous membrane that lines abdominal cavity
Mesentery- fan shaped part of peritoneum which attaches to small intestine
Omentum- attached to greater curvature of the stomach and is laced with fat deposits

25. The Liver Weighs ~1.5kg Made of two lobes
Left lobe is smaller
Right lobe has 4 parts
Liver is made of small units called hepatic lobules

26. The Liver
Blood enters the lobules from the hepatic portal system to be “cleaned”
The liver:
Destroys old RBCS, bacteria
Vitamins and nutrients are metabolized
Toxins are absorbed and detoxified
Bile formed collects in small bile ducts

27. Bile Ducts
The right and left bile ducts emerge from under the liver to form the common hepatic duct
The common hepatic duct joins with the cystic duct (gallbladder) to form the common bile duct
Common bile duct empties into the duodenum

29. Function of the Liver Detoxify substance-alcohol, medicines
Bile production
Metabolize fats, proteins and carbohydrates
Store substances- Fe, vitamins A, B12, D
Bile salt released by liver aid in absorption of fats

30. Gall Bladder Main function is to store and concentrate bile
Contain tiny folds of rugae that contract to secrete bile during digestion
Jaudice is caused by a buildup of bile in the blood
Cholelithiasis is the formation of gallstones

31. Pancreas
Fish shaped textured organ that is exocrine and endocrine gland
Rests below stomach on top of duodenum
Exocrine portion secrete digestive enzymes that collect in the pancreatic duct, that joins the common bile duct
Endocrine islets cells secrete insulin and glucagon directly into the blood