1A Intro Flashcards
How long is the GI tract?
About 30 feet
What is the GI tract lined with
Epithelia
Where does the GI tract begin and end?
Mouth to Anus
Why is the GI tract 30 feet in a cadaver but only half of that in a living person?
B/c of muscle tone
What are the accessory digestive organs?
Salivary glands, pancreas and biliary system (liver and gall bladder)
What is the basic function of the GI tract?
Separate ingested food into essential nutrients and unnecessary wastes
What are the four functions of the GI tract?
Motility, secretion, digestion, and absorption (MSDA)
T/F The GI tract is its own environment separate from the body
T
What is tone?
Low level contractions of the smooth muscle in the walls of the GI tract
Why is tone important?
To maintain a steady pressure on the contents of the GI tract as well as in preventing its walls from remaining permanently stretched following distenstion
What are the three basic types of motility?
Peristalsis, Segmentation (mixing movements), tonic contractions (of sphincters or valves
What is peristalsis completely dependent on?
Involuntary Contractions of smooth muscle
What does segmentation promote?
Mechanical digestion of food, facilitates absorption by exposing contents to absorbing surfaces of GI tract
Where are sphincters usually found?
In b/w different part of the GI tract
What is the pyloric sphincter?
separate the stomach from the duodenum
Which sphincter separates the small intestine from the large intestine?
Ileocecal sphincter
What kind of muscle is the external anal sphincter made of?
Skeletal
What is the sphincter of Oddi?
regulates movement of contents of the common bile duct into the duodenum
Do we have any voluntary control of GI motility?
Yes, the exceptions are at the ends of the tract - mouth and external anal sphincter
What does secretion in the GI tract involve?
Diverse processes by which water, electrolytes, and proteins are exported out of cells
How many liters of saliva does the body make in typical day? Mucus?
1.5 L, 2.0 L
What is the purpose of digestion?
Break things down and set up for absorption
What are the two modes in which digestion can occur?
Mechanically (motility) and chemically (enzymes)
What is the underlying mechanism of most digestion?
Hydrolysis
Where does digestion occur mainly?
Small intestine and stomach
What two problems does absorption solve in the GI tract?
Reclamation of fluid and recognition of specific nutrients, vitamins, electrolytes
Out of the 9 L entering or secreted into GI tract each day, how much is reclaimed?
8.9 Liters, we only lose 100 mL in stools each day
Where does the most amount of absorption occur?
In the small intestine
What does the visceral peritoneum cover?
External surfaces of most digestive organs
What is the parietal peritoneum?
Lining of walls of abdominal cavity
What does serous fluid do?
Lubricates mobile digestive organs allowing them to glide easily across one another
What is peritonitis?
inflammation of the peritoneum - from a piercing wound in abdomen, perforating ulcer, or ruptured appendix
What is ascites?
Accumulation of peritoneal fluid in the abdomen
What are peritoneal folds?
Large folds that weave between the viscera that usually has fat
What is the greater omentum?
An adipose wall that hangs loosely from the transverse colon and small intestine
What is the mesentery?
Found in b/w the small intestine and anchors it to the posterior abdominal wall
