Overview - Sheet1 Flashcards
constituents of secretion (inorganic, organic)
inorganic - ions (H only in stomach, HCO3 only in small int; organic - enzymes, growth factors, immunoglobins
phases of integrative response; what integrates these?
cephalic and oral; integrated by chemosomes (olfactory and gustatory cells)
flavor =
taste and odor
type of secretions: parotid, submandibular, sublingual
parotid - serous; subman - both; sublingual - mucous
how much saliva produced per day
1.5 L
saliva: primary secretion? main driving force?
isotonic, Na K ATPase
saliva: ductal secretion? main driving force? net absorption and secretion?
hypotonic and alkaline, Na K ATPase; absorption of Na Cl, secretion of K and HCO3
increase in amount of saliva -> effect on electrolytes?
K - CONSTANT; Na Cl - increase, HCO3 - inc to a certain level
control of salivary secretion? compare with the rest of GI tract
predominantly neural (PARASYMPATHETIC greater control); rest of GI under hormonal control
gastric juice: components (inorganic, organic)
inorganic - HCl, K, Na, HCO3; organic - pepsinogen, IF, mucous
gastric juice: which electrolyte is always higher than in plasma? main anion?
K, Cl
gastric juice: effects of high/low flow rates
low flow -> hypotonic; high flow -> isotonic
gastric juice: effect of high/low secretion (ions)
high secretion -> high H, Cl; low Na; low secretion -> high Na, low H, K CONSTANT (parang salivaaa)
rate of secretion of gastric acid (basal, maximal, when greatest secretion?)
basal - 1-5 mEq/hr; maximal stimulation - 6-40 mEq/hr; greater at night
how to treat hyperacidity?
give proton pump inhibitors (H K ATPase)
2 shits that increase intracellular calcium, opening Cl channels and H K ATPases, hence more H secretion
Ach and CCK
primary stimulator for acid secretion
Ach
T/F? Ach - neurocrine; gastrin - endocrine; histamine - paracrine; which is the strongest agonist?
T; HISTAMINE
antagonists of acid secretion? which is most important?
acid (
pepsin: pH activation? how much can it digest?
pH 3 or below; 20% OF PTN IN A MEAL
what is required for normal absorption of vitamin b12
INTRINSIC FACTOR
enhance secretion of mucous and bicarbonate
Ach
how thick is the gastric mucosal barrier? pH at cell surface vs lumen?
0.2 mm; cell surface - 7; lumen - 1-2
inhibits secretion of mucus and bicarbonate, may lead to
NSAIDS (aspirin), may lead to gastric ulcer
