Chapter 6 (page 28) Flashcards
______________ - The secretion of gastric juice, which helps to break down the bolus in the stomach, is regulated by both _______ and ________ factors.
Food Breakdown
neural
hormonal
What stimulates the PSNS reflexes to increase secretion of gastric juice.
Sight, smell and taste of food
Also presence of food and decrease pH
in the stomach stimulates stomach to secrete the hormone _________.
gastrin
What is the function of gastrin?
It stimulates the stomach to produce
protein-digesting enzymes.
Activity in the stomach
____________ - Once food is mixed it becomes chyme, the chyme moves to the lower ½ of the stomach and is forced through the pyloric sphincter.
Food Propulsion
Only ______ and _________ particles can pass
through this sphincter.
lipids
small food
Only about _________ of chyme can enter the SI at one time.
3ml or less
What will happen if once the duodenum is filled with chyme?
the nervous reflex (enterogastric) reflex stops gastric activity by inhibiting the vagus nerve and tightening the pyloric sphincter.
How many hours does It takes for the stomach to get empty?
It takes about four hours (up to six hours if there is a lot of fat content).
What is the emetic center in the medulla of the brain?
The area postrema is a medullary structure in the brain that controls vomiting.
Activity of the small intestine
___________ and __________ - When the chyme reaches the SI carbohydrate and protein digestion have started (no fats have been digested yet)
Food breakdown
Absorption
It takes approximately _________ for food to
be digested and absorbed in the SI.
3 - 6 hours
Bile does not contain enzymes, bile salts help with actual digestion of fats by emulsifying fats. True or False?
True
Example of enzymes that help in digestion of chyme in the SI.
Brush border enzymes and pancreatic juice
Activity of the small intestine
______________- Food is propelled through the intestine by peristalsis towards the LI. What reaches the large intestine is a liquid residue that contains very few nutrients.
Food Propulsion
Residue reaches the LI it will spend ___________ in the
colon.
12 to 24 hours
Does digestion takes place in the large intestine?
No digestion takes place in the LI. However bacteria do live in the LI and will metabolize the remaining nutrients, which releases gases. There bacteria also make Vit. K and some B Vits.
Absorption of these Vits, some ions and water are the only things absorbed in the LI. What remains, is feces
Feces is composed of:
undigested food residues, mucus, bacteria and some water.
Propulsion of residue and _________ - Peristalsis and ____________ occur in the LI.
Defecation
mass movements
____________are powerful contractile waves that move over large areas of the colon 3 - 4x daily. It force the contents towards the rectum. This occurs during or just after eating.
Mass movements
_____________ is sluggish in the LI and contributes little to propulsion in the LI.
Colon peristalsis
What causes diarrhea or constipation?
Environmental Factors
Stress
Parasites
Toxins
