General Characteristics
In general, how does the PSNS affect digestion?
increase GI motility and secretions
Which teeth are best for puncturing and shredding food?
canines
Mostly what type of digestion happens here? Why?
mechanical because circular, longitudinal, and oblique muscle is present
What is the starting point in the pathway for the cephalic phase?
sight/smell/thought of food
This organ detoxifies blood leaving the GI tract.
liver
Name two basic processes of digestion and explain their functions.
motility (mixing + propulsion)
secretion (exocrine + endocrine)
digestion (mechanical + chemical)
absorption (designed to maximize)
Name two functions of saliva.
dissolve food for taste
lubricate food (mucus)
digest starch (salivary amylase)
kill bacteria (lysozyme, IgA)
Draw what receptive relaxation looks like. Include the stomach before and after food is swallowed.
see document
How does the PSNS react to the sight, smell, or thought of food in the cephalic phase to increase/decrease (choose one) gastric motility and exocrine secretions?
increase; increase
Which organ secretes bile, and which organ stores and concentrates it?
liver; gallbladder
peritoneum
When this structure is weak, it causes acid reflux or heart burn?
lower esophageal sphincter
Increased action potentials increase/decrease (choose one) the force of contraction. How does this affect the rate of contraction?
increase
no effect
What is the starting point for the gastric phase?
food in stomach (stretch, increased pH, increased amino acids)
How can cholesterol be secreted from the body?
via bile only
What is the difference between the motions of circular and longitudinal muscle?
circular makes narrowing motions, longitudinal makes shortening motions
Swallowing is organized by neurons in what structure?
medulla oblongata
How does intrinsic factor interact with important nutrients? Where does IF come from? Be detailed!
binds vitamin B12; the complex is absorbed in the ileum
parietal cells
How do the PSNS and enteric NS react to food in the stomach?
they increase to release ACh, gastrin, and histamine
What is one function of HCO3-, and which hormone stimulates its release?
neutralize HCl from stomach (buffer); secretin stimulates release
Which nerve plexus regulates secretions as part of the enteric nervous system?
submucosal
What is the difference between mastication and peristalsis?
mastication is chewing, peristalsis is the wave of muscle contraction that allows food to be moved down the esophagus
Prilosec blocks what pump to help ulcers and acid reflux?
H+/K+ ATPase pump
makes stomach less acidic
The enterogastric reflex means that chyme in the small intestine will increase all of the following except:
secretin, PSNS to stomach, SNS, CCK
Justify the one you chose.
PSNS to stomach to slow stomach emptying and give duodenum time to work
What substance activates all other proteases from the pancreas?
trypsin