GI Anatomy Flashcards
Oral cavity
Includes mouth, teeth, gums, tongue, palate, palatine tonsils
Food is ingested and prepared for digestion
2 parts = oral vestibule (slit-like space between teeth and lips), oral cavity proper (space between upper and lower dental arches, fully occupied by tongue when at rest)
Lips
Upper and lower lips are mobile muscular folds surrounding the mouth
Covered externally by skin and internally by mucous membrane
For grasping food, clearing food, sucking liquids, forming speech, and osculation
Labial frenula are free-edged muscosal folds in midline of lips
Cheeks
Form over zygomatic bones and prominences
Essentially same structure as lips
Buccal fat pad more prominent in babies to reinforce cheeks and prevent collapse when sucking
Gingivae (gums)
Fibrous tissue covered with mucous membrane
Gingivae proper is firmly attached to alveolar processes and teeth
Excellent blood supply and nervous innervation
Gingivitis can spread to other structures (teeth, connective tissue, etc)
Teeth
Hard conical structures set within alveoli of upper and lower jaws
Used in mastication and assist in articulation
Identified and described based on whether it is primary or secondary, type of tooth, and location
Adults normally have 32secondary teeth = medial incisor (1), lateral incisor (1), canine (1), premolars (2), molars (3)
Parts of a tooth = crown, neck, root
Composed of dentin and covered by enamel over crown and cementum over root
Pulp cavity contains connective tissue, vessels, nerves (CN V)
Root canal transmits nerves and vessels
Tongue
Mobile muscle that can assume a variety of shapes
Involved in mastication, taste, degulation, articulation, and oral cleansing
Motor innervation by CN Xll
Root of tongue is posterior 1/3(relatively fixed)
Body of tongue is remaining portion which is visible and most mobile
Mucous membrane on anterior portion
Contains lingual papillae (taste buds) = foliate, vallate, fungiform, filliform
Salivary glands
3 glands = parotid (largest), submandibular, sublingual
Functions = moisten mucous membrane of mouth, lubricate food, begin digestion of starches, intrinsic “mouthwash”, prevent tooth decay
Abdominal viscera
Esophagus Stomach Small intestine Large intestine Spleen Pancreas Liver Gallbladder Kidneys Adrenal glands
Esophagus
Extends from pharynx (laryngopharynx) to stomach
Carry food to stomach
Consists of voluntary muscle (upper 1/3)
Smooth muscle (lower 1/3)
And mixture in middle 1/3
Passes through esophageal hiatus of diaphragm at level T10
Terminates by entering stomach via cardial orifice
Stomach
Expandable portion of digestive tract (can hold 2-3L of food)
Acts as a food blender and reservoir (enzymatic digestion)
Gastric juice gradually convert food mass into liquid (chyme) to pass into small intestine
Parts of stomach
Gastroesophageal sphincter
Greater curvature (convex inferior border)
Lesser curvature (concave superior border)
Cardia (surrounds cardial orifice)
Fundus (superior portion related to left dome of diaphragm)
Body (between fundus and pyloric part)
Pyloric part (funnel-shaped, pylorus thickens to form pyloric sphincter)
Gastric mucosa
Smooth inner surface of stomach
When contracted forms gastric folds (rugae) to increase surface area for increased digestion
Small intestine
3 parts
Duodenum
Jejunum
Ileum
Duodenum
First and shortest part
Widest and most fixated
Majority of digestion and absorption of nutrients
C-shaped around head of pancreas
Receives = chyme (from stomach), bile (via bile duct), pancreatic fluid (via pancreatic duct)
Gallbladder
Small pouch inferior to liver
Stores bile created by the liver
Releases bile to duodenum for digestion (emulsification) of fats
Can be removed with minimal changes to digestive tract
