Chapter 26 - Digestive System Flashcards
Digestive System
-ingests, mixes, transports, and breaks down food mechanically and chemically
-absorbs digested nutrients and expels waste
Gastrointestinal (GI) Tract/Digestive Tract Parts
Main role in digestion and absorption
-oral cavity
-pharynx
-esophagus
-stomach
-small intestine
-large intestine
-anus
Accessory Digestive Organs
Help carry out digestion and reabsorption
-teeth
-tongue
-salivary glands
-liver
-gallbladder
-pancreas
Ingestion
eating; food and liquid
Motility (peristalsis and mixing)
the capability to smooth muscle to mix and move the food contents
Secretion
acids, bile, mucus, digestive enzymes (7L/day)
Digestion
mechanical and chemical (CHO, lipids & proteins)
Absorption
nutrients, ions and fluids
Elimination of wastes/defecation
Removal of metabolic wastes
Peristalsis
involuntary contraction and relaxation of smooth muscle in the digestive tract
Lumen
hollow passageway in gi tracts
Initial sit of mechanical and chemical digestion?
oral cavity
Oral Cavity
lips, cheeks, hard and soft palates, tongue
Covering of Oral Cavity
-externally: skin
-internally: mucous membrane
Vestibule
space between the cheeks (lips) and the gums
Oral Cavity Proper
lies in the centre between the mandible and maxillae
Tongue
-accessory organ
-skeletal muscle
Tongue Functions
-manipulation of the food
-mixing with saliva
-converting food into bolus
-assisting in swallowing
Bolus
-semi-liquid ball of food
Salivary Glands
produce and secrete saliva into the oral cavity
Function of Saliva
-moistens ingested material into bolus
-moistens, cleanses, and lubricates oral cavity
-begins chemical digestion of carbs with AMYLASE
-antibacterial action with lysozyme
-dissolves food so taste receptors can be stimulated
-3 types:
Parotid Glands
-middle amount
-25-30% of saliva
-parotid duct
Submandibular Glands
-most saliva
-60-70%
-submandibular ducts
Sublingual Glands
-least amount
-3-5%
-lesser sublingual ducts
Innervation of Salivary Glands
sympathetic and parasympathetic
Salivary Amylase
carbohydrates digesting enzyme in the oral cavity/mouth
Lingual Lipase
lipid/fat digesting enzyme secreted by lingual glands
Dentin
-70% of hydroxyapatite
-lies deep to enamel
Enamel
-outer/visible par of tooth
-made of calcium phosphate crystals
Gomphoses
-fixed/immovable joints
Peritoneum
folds each other and to other organs of the digestive system
Mesenteries
folds of the peritoneum that support and stabilize intraperitoneal GI tract organs
What lies between the folds?
-blood and lymphatic vessels
-nerves
all supply the digestive organs
Parietal Peritoneum
outer layer
Visceral Peritoneum
inner layer surrounding organs
Greater Omentum (mesenteries)
-longest peritoneal fold
extends from stomach to cover most abdominal organs
-beer belly
Lesser Omentum (mesenteries)
-connects the stomach and duodenum from the liver
Mesentary Proper (mesenteries)
suspends most of small intestine from posterior abdominal wall
Mesocolon (mesenteries)
attaches part of the large intestine to the posterior abdominal wall
Retroperitoneal Organs
-ascending and descending colon
-duodenum
-pancreas
Peritoneal Ligaments
folds of the peritoneum that connect structures
Coronary Ligament
liver to diaphragm
Falciform Ligament
liver to abdominal wall
Lienorenal Ligament
spleen to kidney
