Digestive 1 Flashcards
Functions of the G.I. tract
Motility
Secretions
Digestion
Absorption
Storage and elimination
Immune barrier 
Function of GI tract: Motility
Push ingested food from the mouth toward the rectum and mixes and reduces the size of the food
 Function of GI tract: secretions
From the salivary glands, pancreas, and liver etc.
(Fluid, electrolytes, enzymes, mucus etc) 
Function of GI tract: digestion
Breakdown of food into absorbable molecules
 Function of GI tract: absorption
Nutrients, electrolytes, water etc. are absorbed from the intestinal lumen into the bloodstream
Function of GI tract: Storage and elimination
Temporary storage and subsequent elimination of indigestible food molecules
Function of GI tract: immune barrier
Prevent pathological organisms and toxins
Role of mouth and oropharynx
Top food, lubrication, initiate carbohydrate/fat digestion, and pushing the food into esophagus
Where does carbohydrate and fat digestion first occur
In mouth and oropharynx
Role of esophagus
Pushes food down to the stomach
Role of the stomach
Temporarily stores food, initiate digestion by churning and by secreting proteases and acid
Role of small intestine
Continues digestion, primary site for nutrient absorption
Where is the primary site for nutrient absorption
Small intestine
Role of large intestine
Reabsorbs fluids/electrolytes , Stores fecal matter before expulsion 
Role of pancreas
Secretes digestive enzymes into duodenum , Secretes bicarbonate to neutralize gastric acid
Role of liver
Secretes bile and stores it in the gallbladder for future delivery to Duodenum during a meal 
Role of bile
Contains bile acids, which play a key role in digestion of fats
What are the four layers of the wall of the G.I. tract
- Mucosa
- Submucosa
- Mascularis
- Serosa
Wall of GI tract: Mucosa
What is it and what does it consist of
It’s the lumen (has direct contact with food)
Consists of 3 things/layers:
- epithelial cells : for absorption and secretion
- lamina propria: connective tissue, blood and lymph vessels
- muscularis mucosa : smooth muscle cells (changes surface area)
Wall of GI tract: submucosa
What is it and what does it consist of
Connective tissue
Consists of:
- blood vessels
- glands
- submucosal plexus (nerves)
Wall of GI tract: mascularis
What is it responsible for, and what does it consist of
Responsible for motility
Consists of:
- inner circular smooth muscle
- outer longitudinal smooth muscle
- myenteric plexus
Wall of GI tract: serosa
What is it and what is its role
Outer most layer for support and protection 
The enteric nervous system is made up of
- Submucosal plexus (Meissner’s plexus)
 - Myenteric plexus
The submucosal plexus (Meissner’s plexus) is between
Submucosa and circular muscle