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
