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63 Cards in this Set

  • Front
  • Back
Types of Secretory Glands

Single Cell - m______ cells or g______ cells

Simple - indentations in epithelium
(crypts of L________)

Tubular - acid secreting o______ gland

Complex - salivary, pancreas
Types of Secretory Glands

Single Cell - mucous cells or goblet cells

Simple - indentations in epithelium
(crypts of Lieberkühn)

Tubular - acid secreting oxyntic gland

Complex - salivary, pancreas
Control of Secretions
L____ - tactile, distention, irritation

R_____ - nervous input

Hormonal - G.I. hormones

Parasympathetic Stim. - incr rate of secretion
Sympathetic Stim. - incr or decr rate of secretion
Control of Secretions
Local - tactile, distention, irritation

Reflex - nervous input

Hormonal - G.I. hormones

Parasympathetic Stim. - incr rate of secretion
Sympathetic Stim. - incr or decr rate of secretion
Basic Mechanism of Secretion
Secrete substance – via ___cytosis

Secrete water and electrolytes to move substance into target area
Basic Mechanism of Secretion
Secrete substance – via exocytosis

Secrete water and electrolytes to move substance into target area
Total daily secretion volume of alimentary tract
6700ml
Mucus Composition - Properties
Thick secretion that is mainly water, electrolytes and g_______________
Essential for digestion because –
Adherent - sticks to food
Body - coats well
Low resistance - lubrication
Self adherent - sticks together
Resistant to digestion
Buffering capacity
Mucus Composition - Properties
Thick secretion that is mainly water, electrolytes and glycoproteins
Essential for digestion because –
Adherent - sticks to food
Body - coats well
Low resistance - lubrication
Self adherent - sticks together
Resistant to digestion
Buffering capacity
Two types of secretion –
Serous - watery secretion, contains an alpha-_______ (ptyalin)
Mucous - contains _____ - lubrication
Two types of secretion –
Serous - watery secretion, contains an alpha-amylase (ptyalin)
Mucous - contains mucin - lubrication
Secrete 800-____ ml/day of saliva
Maximum rate of secretion: 4 ml/min
Secrete 800-1500 ml/day of saliva
Maximum rate of secretion: 4 ml/min
Formation and Secretion of Saliva
Two Stages
A_____ - primary secretion similar to
plasma (Cl- is principle ion that is secreted actively, not Na+)

Salivary D____ - modified as it passes through ducts
Formation and Secretion of Saliva
Two Stages
Acini - primary secretion similar to
plasma (Cl- is principle ion that is secreted actively, not Na+)

Salivary Ducts - modified as it passes through ducts
Parotid glands make serous saliva

Buccal glands make ______ saliva
mucous
Ionic composition depends upon rate of secretion. Resting composition is:
Na+ - 0.1 x plasma (15 mEq/L)
Cl- - 0.15 x plasma (15 mEq/L)
K+ - 7 x plasma (30 mEq/L)
HCO-3 - 3 x plasma (70 mEq/L)
Ionic composition depends upon rate of secretion. Resting composition is:
Na+ - 0.1 x plasma (15 mEq/L)
Cl- - 0.15 x plasma (15 mEq/L)
K+ - 7 x plasma (30 mEq/L)
HCO-3 - 3 x plasma (70 mEq/L)
Saliva is ____tonic
Saliva is hypotonic
Loss of saliva from body can lead to _+ depletion (aldosterone)
Loss of saliva from body can lead to K+ depletion (aldosterone)
Effect of Secretory Rate on Ionic Composition of Saliva

Saliva is always hypotonic, but its __________ increases (and nearly reaches 300 mOsm/L) as flow rate increases.
Effect of Secretory Rate on Ionic Composition of Saliva

Saliva is always hypotonic, but its osmolarity increases (and nearly reaches 300 mOsm/L) as flow rate increases.
Saliva Destroys bacteria - proteolytic enzymes (lysozyme)
- ____cyanate
- antibodies
Saliva Destroys bacteria - proteolytic enzymes (lysozyme)
- thiocyanate
- antibodies
_________ - (absence of saliva)
Xerostomia - (absence of saliva)
Nervous Regulation of Salivary Flow

___________ stimulation directly increases salivation

However, it can decrease a____________ stimulated salivation because it limits blood flow.
Nervous Regulation of Salivary Flow

Sympathetic stimulation directly increases salivation

However, it can decrease acetylcholine stimulated salivation because it limits blood flow.
Drooling
Treatment: - anticholinergics
- surgical removal of the s_________ glands and retropositioning sub__________ ducts.
- Margin between drooling and xerostomia is small
Drooling
Treatment: - anticholinergics
- surgical removal of the sublingual glands and retropositioning submandibular ducts.
- Margin between drooling and xerostomia is small
Xerostomia - dry mouth.
Causes: - drug related
- insufficient capillary perfusion
- _________ treatment (aplasia of glands)
- autoimmune disease
Xerostomia - dry mouth.
Causes: - drug related
- insufficient capillary perfusion
- radiation treatment (aplasia of glands)
- autoimmune disease
Cystic Fibrosis - salivary Ca+, Na+, and protein are elevated (also true for bronchial secretions, pancreatic juice, and sweat).
Chloride secretion is essential for cell secretion.
CF patients lack chloride transporter (CFTR )
CFTR = ______ ________ _____________ ____________ ________
Cystic Fibrosis - salivary Ca+, Na+, and protein are elevated (also true for bronchial secretions, pancreatic juice, and sweat).
Chloride secretion is essential for cell secretion.
CF patients lack chloride transporter (CFTR )
CFTR = cystic fibrosis transmembrane conductance regulator
Primary aldosteronism - (excess aldosterone)
salivary ____ close to zero
salivary __ increases to high levels
Primary aldosteronism - (excess aldosterone)
salivary NaCl close to zero
salivary K+ increases to high levels
Two types glands –
Gastric - HCl
(ox______) pepsinogen
intrinsic factor
mucus
rennin (chymosin)

P______ - gastrin
mucus
(sm. amounts pepsinogen)
Two types glands –
Gastric - HCl
(oxyntic) pepsinogen
intrinsic factor
mucus
rennin (chymosin)

Pyloric - gastrin
mucus
(sm. amounts pepsinogen)
Gastric (oxyntic) Gland
Three cell types -
______ neck cells
- mucus
______ cells (chief cells)
- pepsinogen
- rennin
_________ cells
- HCl
- intrinsic factor
Gastric (oxyntic) Gland
Three cell types -
Mucous neck cells
- mucus
Peptic cells (chief cells)
- pepsinogen
- rennin
Parietal cells
- HCl
- intrinsic factor
Mechanism of HCl Secretion

H+/K+ATPase or "proton pump" in cannalicular membrane is key player.
ATPase is m________-dependent
ATPase is not inhibited by o______
Mechanism of HCl Secretion

H+/K+ATPase or "proton pump" in cannalicular membrane is key player.
ATPase is magnesium-dependent
ATPase is not inhibited by ouabain
Rennin (Ch______)
Proteolytic enzyme - causes milk to curdle in stomach
Milk retained in stomach and released more slowly
Rennin secretion - maximal first few days after birth. Replaced by secretion of ______ as major gastric protease
Secreted as inactive proenzyme (prochymosin) that is activated on exposure to acid
Rennin (Chymosin)
Proteolytic enzyme - causes milk to curdle in stomach
Milk retained in stomach and released more slowly
Rennin secretion - maximal first few days after birth. Replaced by secretion of pepsin as major gastric protease
Secreted as inactive proenzyme (prochymosin) that is activated on exposure to acid
Gastric secretion is stimulated by neural, paracrine and endocrine mechanisms
Acetylcholine - HCl secretion
- mucus, pepsinogen, and gastrin

Histamine - HCl secretion

Gastrin - HCl secretion (____x more
powerful compared to histamine)
Gastric secretion is stimulated by neural, paracrine and endocrine mechanisms
Acetylcholine - HCl secretion
- mucus, pepsinogen, and gastrin

Histamine - HCl secretion

Gastrin - HCl secretion (1500x more
powerful compared to histamine)
Regulation of Gastrin Secretion
Vagal control
Gastrin secretion not blocked by a_______
G______ _________ p______ - stimulates gastrin release
from G-cell
S___________ - inhibits gastrin release from G-cell

Antrum acidification - pH <_ inhibits gastrin release

Small peptides and amino acids - directly stimulate gastrin release from G-cell
Regulation of Gastrin Secretion
Vagal control
Gastrin secretion not blocked by atropine
Gastrin releasing peptide - stimulates gastrin release
from G-cell
Somatostatin - inhibits gastrin release from G-cell

Antrum acidification - pH <3 inhibits gastrin release

Small peptides and amino acids - directly stimulate gastrin release from G-cell
Regulation of Histamine Secretion
Gastrin and acetylcholine stimulate histamine release from _______________-____ (ECL) cells

ECL cells are a specialized endocrine cell in gastric mucosa

Proliferation of ECL cells occurs in association with hypergastrinemic states
Gastrin-secreting _______
Long term therapy with _____ that block acid secretion
Regulation of Histamine Secretion
Gastrin and acetylcholine stimulate histamine release from enterochromaffin-like (ECL) cells

ECL cells are a specialized endocrine cell in gastric mucosa

Proliferation of ECL cells occurs in association with hypergastrinemic states
Gastrin-secreting tumors
Long term therapy with drugs that block acid secretion
Histamine ___________ effects of gastrin and acetylcholine. H2 blockers _________ secretory responses to both acetylcholine and gastrin.

Acetylcholine ___________ effects of gastrin and histamine. Atropine __________ secretory effects of histamine and gastrin.
Histamine potentiates effects of gastrin and acetylcholine. H2 blockers attenuate secretory responses to both acetylcholine and gastrin.

Acetylcholine potentiates effects of gastrin and histamine. Atropine attenuates secretory effects of histamine and gastrin.
Gastric Phase
Accounts for __% of acid response to a meal
Increased pH - gastrin release **
Distention - gastrin release **
Ach stimulation of HCl *
Peptides / AA - gastrin release **

* blocked by ________
** blocked by acidification of _____
Gastric Phase
Accounts for 60% of acid response to a meal
Increased pH - gastrin release **
Distention - gastrin release **
Ach stimulation of HCl *
Peptides / AA - gastrin release **

* blocked by atropine
** blocked by acidification of antrum
Intestinal Phase
Accounts for __% of acid response to a meal

Distention of small intestine - stimulates acid secretion (entero_______ - postulated hormone)

Amino acids - circulating amino acids stimulate acid secretion via direct effect on parietal cell
Intestinal Phase
Accounts for 10% of acid response to a meal

Distention of small intestine - stimulates acid secretion (enterooxyntin - postulated hormone)

Amino acids - circulating amino acids stimulate acid secretion via direct effect on parietal cell
Before meal - pH is low - acid secretion is suppressed
Acid stimulates ____________ release (which decreases gastrin secretion)
____ has direct effect to suppress parietal cell secretion
Before meal - pH is low - acid secretion is suppressed
Acid stimulates somatostatin release (which decreases gastrin secretion)
Acid has direct effect to suppress parietal cell secretion
Describe acid secretion and serum gastrin with pernicious anemia
no acid

high gastrin
Describe acid secretion and serum gastrin with Zollinger-Ellison syndrome
high acid

high gastrin
Gastric ulcers - main problem is decreased ability of ______ to protect itself
Gastric ulcers - main problem is decreased ability of mucosa to protect itself
Duodenal ulcers - main problem is exposure to increased amounts of ____ and ______
Duodenal ulcers - main problem is exposure to increased amounts of acid and pepsin
Duodenal ulcer patients often have 2-3x more ________ cells than normal
Duodenal ulcer patients often have 2-3x more parietal cells than normal
Increased acid secretion lowers plasma _______.
Increased acid secretion lowers plasma gastrin.
H+ back-leaks into mucosa in exchange for Na+. This is a forerunner to gastric _____

Decreased cell pH leads to cell death

Damaged mast cells (ECL cells) leak histamine

Viscous cycle - Histamine .. vascular damage ..
local ischemia .. greater leakage
of H+.. more cell death ...
H+ back-leaks into mucosa in exchange for Na+. This is a forerunner to gastric ulcer

Decreased cell pH leads to cell death

Damaged mast cells (ECL cells) leak histamine

Viscous cycle - Histamine .. vascular damage ..
local ischemia .. greater leakage
of H+.. more cell death ...
H. pylori found in 95% patients with DU and 100% patients with GU (when ______, ______, ______ are eliminated)
H. pylori found in 95% patients with DU and 100% patients with GU (when alcohol, aspirin, NSAIDS are eliminated)
Helicobacter pylori

High u______ activity - high NH4+ activity
- can withstand acid environment
- _____ damages epithelial cells (GU)
- Increases acid secretion (_U)
Helicobacter pylori

High urease activity - high NH4+ activity
- can withstand acid environment
- NH4+ damages epithelial cells (GU)
- Increases acid secretion (DU)
H2 receptor blockers - R_________ (Zantac)
- ___________ (Tagamet)
H2 receptor blockers - Rantidine (Zantac)
- Cimetidine (Tagamet)
Proton pump inhibitors - ___________ (Prilosec)


(Treatment of Peptic Ulcers)
Proton pump inhibitors - Omeparazole (Prilosec)


(Treatment of Peptic Ulcers)
Surgical (rare) - v_______
- a______omy


(Treatment of Peptic Ulcers)
Surgical (rare) - vagotomy
- antrectomy


(Treatment of Peptic Ulcers)
Internal Structure of Pancreas

_____ - grape-like clusters of cells that store and secrete digestive enzymes

Ducts - secrete ___________
--Inter______ ducts - receive secretions from acini
--Intra_______ ducts - receive fluid from intercalated ducts
Internal Structure of Pancreas

Acini - grape-like clusters of cells that store and secrete digestive enzymes

Ducts - secrete bicarbonate
Intercalated ducts - receive secretions from acini
Intralobular ducts - receive fluid from intercalated ducts
Trypsin – cleaves p______ to polypeptides

Chymo_______ - cleaves proteins to polypeptides
Trypsin – cleaves proteins to polypeptides

Chymotrypsin - cleaves proteins to polypeptides
Carboxypeptidase – cleaves polypeptides to __
Carboxypeptidase – cleaves polypeptides to AA
Pancreatic lipase -
fat --> _____ _____ +monoglycerides
Pancreatic lipase -
fat  fatty acids +monoglycerides
Phospholipase -
phospholipids --> _____ ____
Phospholipase -
phospholipids --> fatty acid
Cholesterol esterase -
cholesterol esters --> _____ ____
Cholesterol esterase -
cholesterol esters --> fatty acid
Why Doesn’t the Pancreas Digest Itself?
Pancreatic proteolytic enzymes are stored and secreted in an inactive form - (also, a trypsin inhibitor is present in cells)

trypsinogen --> trypsin

chymotrypsinogen --> chymotrypsin

procarboxypeptidase --> carboxypeptidase
Trypsinogen --> Trypsin with what enyzme?
Enterokinase

Enterokinase - located on intestinal mucosal cells
Trypsin - autocatalytic activation
- activates - c_______________,
- p__________________
- t___________
Trypsin - autocatalytic activation
- activates - chymotrypsinogen,
- procarboxypeptidase
- trypsinogen
Acute pancreatitis -
- a primary lack of _______ inhibitor
- not enough ________ inhibitor is present
Acute pancreatitis -
- a primary lack of trypsin inhibitor
- not enough trypsin inhibitor is present
Secretin induced ___________ secretion neutralizes acid chyme creating optimal conditions (pH = 7-8) for digestive enzymes -
Secretin induced bicarbonate secretion neutralizes acid chyme creating optimal conditions (pH = 7-8) for digestive enzymes -
Secretin is nature’s _________
Secretin is nature’s antiacid
HCO3- moves out of cell in exchange for ___.
HCO3- moves out of cell in exchange for Cl-.
Rate of HCO3- secretion is dependent upon luminal ___ concentration.
Na+ moves down electrochemical gradient. Water
moves into lumen establishing osmotic equilibrium.
(Pancreatic juice is always ___tonic.)
Secretin - acts to open ___ channels and thus increase secretion of bicarbonate.
Rate of HCO3- secretion is dependent upon luminal Cl- concentration.
Na+ moves down electrochemical gradient. Water
moves into lumen establishing osmotic equilibrium.
(Pancreatic juice is always isotonic.)
Secretin - acts to open Cl- channels and thus increase secretion of bicarbonate.
Secretin released when pH < ___.
Secretin released when pH < 4.5.
During meal pH rarely < ___ or ___.
During meal pH rarely < 3.5 or 4.0.
Chronic pancreatitis - (multiple shared causes)
_______ - most common cause in adults
cystic fibrosis - most common cause in _________
Chronic pancreatitis - (multiple shared causes)
alcohol - most common cause in adults
cystic fibrosis - most common cause in children
Acute pancreatitis - (multiple shared causes)
__________ - most common cause
Acute pancreatitis - (multiple shared causes)
gallstones - most common cause
Brunner’s glands secrete an alkaline mucus.
Compound mucus gland in duodenum
Protects mucosa from acid chyme
Stimulated by local irritation - _____ (___)
Inhibited by ____________ (__)

Crypts of _________ - mostly secrete water -like fluid - 1800 ml/day
Brunner’s glands secrete an alkaline mucus.
Compound mucus gland in duodenum
Protects mucosa from acid chyme
Stimulated by local irritation - vagus (Ach)
Inhibited by sympathetics (NE)

Crypts of Lieberkühn - mostly secrete water -like fluid - 1800 ml/day
Large intestine also contains crypts of Lieberkühn but there are no _____ or enzymes.

Crypts mainly secrete alkaline mucus

Mucus secretion increased by _______________ stimulation
Large intestine also contains crypts of Lieberkühn but there are no villi or enzymes.

Crypts mainly secrete alkaline mucus

Mucus secretion increased by parasympathetic stimulation