Lecture digestive system Flashcards
Provides most of the ATP
Mitochondria
What two bones make up the Hard palate?
Horizontal plates of the Maxilla and palantine bones
Soft palate
Posterior roof; no bone; closes off
nasopharynx during swallowing
Begins mechanical manipulation & processing and sensory input
Tongue
On the dorsum of the tongue
Papillae
Two lymphoid nodules at
the root of the tongue
Lingual tonsils
Masticate food into a bolus
Teeth
aka “wisdom teeth”
Third molars
Salivary glands produce
Digestive enzymes (carbohydrate digestion) Produce lubricant
Largest salivary gland; anterior to the ears, extending over masseter
Parotid
Deep; floor of the mouth; empties just lateral to lingual frenulum.
Submandibular
Shallow; floor of the mouth; under the tongue
Sublingual
Stratified squamous (non-keratinized)
Pharynx, Esophagus
Where the esophagus penetrates the diaphragm
Esophageal hiatus
Simple columnar; tunica muscularis has a 3rd layer (oblique) inside the usual circular & longitudinal muscle layers. Watery contents is called chyme
Stomach
Four regions of the stomach (in order)
Cardia, fundus, body, pyloris
G cells
Enteroendocrine cells
90% of the nutrients are absorbed here due to amounts of mucosal surface area.
Small intestine
permanent internal ridges visible to the naked eye
Plicae circulares
Absorb lipids NOT blood capillaries; part of lymph system.
Lacteals
(crypts of Lieberkuhn): found near the base of intestinal villi; secrete hormones and enzymes; Goblet cells secrete protective mucus.
Intestinal glands
From the pancreas & the intestinal glands digest all classes of molecules..
Digestive enzymes
Segmentation: a movement characteristic of the small intestine; a churning motion that does NOT produce any net movement down the GI tract; mixes chyme with
intestinal secretions
Segmentation
Starts in the esophagus; net movement down the GI tract
Peristalsis
the first region of the small intestine, begins after the pyloric sphincter and ends at the duodenojejunal flexure
Duodenum
Duodenum forms a loop around the
Pancreas
Where the common bile duct fuses with pancreatic duct; wide variation
Hepatopancreatic ampulla
opens to allow juices out, but keeps chyme from reversing back up
hepatopancreatic sphincter
Accessory Digestive Organs are
salivary glands, pancreas, liver & gallbladder
Tail, body and head; mixed gland; exocrine & endocrine
Pancreas
break down all classes of molecules..
Digestive enzymes
Endocrine or exocrine: Pancreatic islets
Endocrine
Exocrine cells- secrete into ducts
Acinar cells
Has four lobes
Liver
Divides the right lobe from the left lobe of the liver
Falciform ligament
The remnant of the fetal umbilical vein
continuous with the falciform ligament
Round ligament
Suspends the liver from the diaphragm
Coronary ligament
Blood supply to the liver
Two ways to enter (hepatic artery proper & hepatic portal vein, only one way out (hepatic vein)
8 ft long; supported by mesentery; the bulk of chemical digestion & nutrient absorption occurs here
Jejunum
Longest (≈12 ft); continues absorption; ends at the ileocecal valve (controls the rate of emptying); Large amount of MALT to counteract bacteria found in the large intestine
Ileum
An expandable pouch; the ileum attaches to the medial side of
the cecum at the opening called the ileocecal valve
Cecum
Dangles from the cecum; about 3.5 inches long; mucosa & submucosa dominated by lymphatic nodules (like a tonsil).
Vermiform appendix
From the hepatic flexure to the splenic flexure
Transverse colon
From the splenic flexure to the sigmoid flexure.
Descending colon
(S- shaped colon) from the sigmoid flexure to the rectum; posterior to the urinary bladder; suspended by the sigmoid mesocolon
Sigmoid colon
From the cecum to the hepatic flexure (right colic flexure)
Ascending colon
Temporary storage of feces, presence of feces in rectum triggers the urge to defecate; epithelium changes from simple columnar to non-
keratinized stratified squamous
Rectum
Terminus of the rectum
Anal canal
small longitudinal folds allow for stretching..
Anal columns
(2): smooth muscle forms the internal anal sphincter & skeletal muscle encircles the distal portion of the canal forming the external anal sphincter (voluntary control)
Anal sphincters
Epithelium becomes keratinized, stratified squamous
Anus
Steps in digestion
1) Ingestion
2) Mechanical processing
3) Secretion
4) Digestion
5) Absorption
6) Compaction
7) Egestion
Putting the food/liquid in your mouth
Ingestion
Starting with mastication in the mouth, swallowing the bolus at pharynx, churning in the stomach & segmentation in the small intestine
Mechanical processing
Enzymes, mucus, water & bile.
Secretion
The chemical & enzymatic breakdown of large macromolecules into smaller more absorbable compounds; starting with amylase in the saliva in the mouth & ending with many enzymes in the small intestine..
Digestion
Small organic molecules, water, electrolytes, vitamins & minerals through digestive epithelium and into the body. Small intestine.
Absorption
Reabsorption of water in large intestine
Compaction
Includes indigestible material, as well as some waste products from the liver in bile. Enters the rectum, anal canal and out the anus
Egestion
