Exam 1 Physiology Flashcards
(251 cards)
1
Q
Form Soluble Complexes with Free Iron
A
1) Ascorbic Acid (Vitamin C)
2) Citric Acid
2
Q
Myenteric Plexus
A
Network of enteric nervous system found throughout GI tract. Controls motility.
3
Q
Inhibition of Gastrin Secretion
A
1) Somatostatin
2) Secretin
3) low pH
4
Q
Monoglyceride Acylation Pathway
A
Triglyceride synthesized inside Enterocytes by:
1) 2-monoglyceride
2) CoA-activated Fatty Acids
Fatty-acid binding proteins then transport long-chain fatty acids to smooth ER for re-esterification
5
Q
Primary Bile Acid
A
Synthesized directly in liver from cholesterol.
6
Q
What does GRP stand for?
A
Gastrin-Releasing Peptide
7
Q
Gastrocolic Reflex
A
Urge to defecate shortly after starting meal. Triggered by the presence of food in the stomach.
Causes increased colonic motility.
8
Q
Peptides Regulating CCK Release
A
1) CCK-Releasing Peptide (CCK-RP)
2) Monitor Peptide
9
Q
Cause of retrograde movement from Rectum to Sigmoid Colon
A
Frequency of Segmental Contractions greater in Rectum than Sigmoid Colon
10
Q
Cause: Secretory Diarrhea
A
Caused by bacterial infection in intestine (V. Cholerae or E. coli) or a tumor. Enterotoxins from E. coli activate gunaylin receptors in intestine.
11
Q
Treatment for Hirschsprung’s Disease
A
Removal of the aganglionic segment
12
Q
Function of Intrinsic Factor
A
Bind Vitamin B12 to prevent acid degradation and allow for absorption in the Ileum
13
Q
Insoluble Form of Mucus
A
Secreted by Surface Mucus Cells as gel forming unstirred layer over mucosa. HCO3 gets trapped in this layer, keeping surface pH near neutral.
14
Q
Site of Carbohydrate Digestion
A
Brush Border Membrane (Small Intestine)
15
Q
Mechanism for Di/Tripeptide Uptake into Enterocytes
A
- Faster than single amino acids.
- H-Dependent Co-Transporter Peptide Transporter 1 (PEPT1).
- Pairs with NHE (H/Na Exchanger) on same membrane
- Peptides then hydrolyzed into amino acids by Cytoplasmic Peptidases
16
Q
Trigger of Somatostatin Release
A
Acid in the lumen
17
Q
Transport Protein for Uptake of Short-Chain Fatty Acids
A
SCFA/Na Cotransporter (SMCT1)
18
Q
Lipid Malabsorption: Conditions Affecting/Decreasing Absorbing Cells
A
1) Tropical Sprue (flattening of villi from inflammation)
2) Gluten Enteropathy / Celiac Sprue
19
Q
Usually conjugated with Bile Salts
A
Glycine or Taurine
20
Q
Basolateral Membrane Transporter Bringing Chlorine into Crypt Cell
A
NKCC1 Cotransporter (2Cl-K-Na)
21
Q
Short-Chain Fatty Acids Generated by Colonic Flora
A
1) Acetate
2) Propionate
3) Butyrate
22
Q
Location of Enkephalin Secretion
A
Nerves in Mucosa and Smooth Muscle of GI tract
23
Q
Location of Guanylin Secretion
A
Intestines
24
Q
Function of Histamine
A
Increases Gastric Acid Secretion
1) Directly – Acting on Parietal Cells
2) Indirectly – Potentiating Gastrin and ACh
25
Dominant Na Absorption Mechanisms: Duodenum and Jejunum
1) Na-Glucose or Na-AminoA Co-Transport
| 2) Na-H Exchange
26
Secretion of GLP-1
Triggered by ingested nutrients (proteins and carbs). Biphasic release: early release (minutes), later release (about an hour)
27
Secretion of PYY
Secreted by L cells in Intestine, in proportion to caloric load.
28
What form of mucus is not present in the resting stomach?
Soluble Form
29
Enzyme Converting Trypsinogen to Trypsin
Enterokinase. secreted by brush border in small intestine
30
Result of Excess Iron: Pancreas
Diabetes
31
Transporter for Bile Acids: Enterocyte -> Portal Blood
Organic Solute Transporter (OST)
32
Location of Histamine Release
Enterochromaffin-like (ECL) Cells in Stomach
33
Triggers of CCK Secretion
(In small intestine)
1) Small peptides / amino acids
2) fatty acids
3) Monoglycerides
34
Cause of Gastric Ulcers
Breakdown of protective barrier of stomach by acid/pepsin.
35
Location of Cholecystokinin (CCK) Secretion
I Cells of Proximal Small Intestine
36
Suppositories
Dosage inserted into (in this case) rectum for local and systemic action
37
Action of Ghrelin
Stimulates NPY and AgRP neurons.
38
Most Easily Absorbed Form of Iron
Heme Iron
39
Fructose absorption mechanic
Can only be by facilitated diffusion
40
Location of Intrinsic Factor Release
Parietal Cells of Gastric Mucosa
41
Starches digested by Salivary/Pancreatic α-amylases
1) Amylopectin
| 2) Amylose
42
Receptive Relaxation
Vagaovagal reflex where proximal stomach relaxes to accommodate an ingested meal
43
Function of Guanylin
Binds to Guanylyl Cyclase to increase Cl- secretion and thus fluid secretion
44
Na Absorption Mechanisms in Enterocytes
1) Restricted Diffusion
2) Na-Glucose or Na-AminoA Co-Transport
3) Na-Cl Co-Transport
4) Na-H Exchange
45
Cells generating Slow Waves
Interstitial Cells of Cajal
46
Location of GRP Release
Nerves in Gastric Mucosa
47
Breakdown Products of Pancreatic Enzyme Hydrolysis of Lipids
1) Fatty Acids
2) Monoglycerides
3) Lysophospholipids
4) Cholesterol
48
Functions of Leptin
1) Increase metabolic and energy expenditure rate (Sympathetics)
2) Decrease energy storing (by decreasing insulin secretion)
49
Leptin Actions on Arcuate Nucleus
Represses:
1) NPY
2) AgRP
Stimulates:
1) α-MSH
2) CART
50
Mucous Neck Cells (Oxyntic Gland)
Secrete mucus and serve as Stem Cells.
51
Activate CFTR Channels
Increase in cAMP or Ca2+ levels
52
Goblet Cells
Interspersed with enterocytes in small intestine. Secrete mucus
53
Bile-Dependent Biliary Secretion
Bile salts/acids stimulate bile SECRETION and inhibit bile SYNTHESIS.
54
Nucleus Tractus Solitarus (Brainstem)
Reciprocal connections between hypothalamus and NTS. Has a high density of Y Receptors (Y1 and Y5). Satiety center is also present.
Responds to:
1) Peripheral circulating signals
2) Vagal afferents from GI Tract (inhibitory)
55
Intestinal Phase of Pancreatic Secretion
1) S Cells release Secretin in Duodenum. Triggered by Acid/Fat/Protein in Duodenum. Secretin increases Ductule Cell HCO3 secretion.
2) I Cells release CCK in Duodenum. Triggered by Fat/Protein/CRP/Monitor Peptide. CCK acts on Acinar Cells to increase enzyme secretion
3) Vagovagal Reflexes triggered by acid/fat/protein
56
Hypothalamic Nuclei in Appetite/Energy Expenditure Regulation
1) Lateral Nuclei
2) Ventromedial Nucleus
3) Paraventricular Nucleus (PVN)
4) Dorsomedial Nucleus (DVN)
5) Arcuate Nucleus (ARC)
57
Pancreatic Enzymes Catalyzed by Trypsin
1) Autocatalysis
2) Chymotrypsinogen -> Chymotrypsin
3) Proelastase -> Elastase
58
Functions of VIP
1) Relaxation of smooth muscle (main)
| 2) Stimulates Intestinal/Pancreatic Secretion
59
Haustra
Sac-like segments in the colon, present when empty. Appear during contraction of a segment and then disappear after.
60
Inhibitors of Motilin Release
Eating
61
Pancreatic Lipase
Cleaves fatty acids from 1 and 3 positions of Triglycerides.
Produces:
1) two fatty acids
2) 2-monoglyceride
62
Brush Border Iron Importer
Ferrous Iron Transporter (DMT1)
63
Enzymes hydrolyzing oligosaccharides to glucose
1) Glucoseamylase
2) Isomaltase
3) Maltase
64
Cholelithiasis
Gallstones
65
Phospholipase A2
Releases fatty acids from 2 position of Phospholipids
Produces:
1) Lysophospholipids
2) Free Fatty Acids
66
Enzyme Types Which Digest Proteins
1) Endopeptidases
2) Exopeptidases
3) Peptidases in Brush Border
67
Cephalic and Gastric Phases of Pancreatic Secretion
MOSTLY DIGESTIVE ENZYMES
1) Distended Stomach -> ACh (Vagovagal) -> Acinar and Ductule Cells
2) CCK-RP and Monitor Peptide (nerve input) released
68
Peristaltic Reflex
Contraction moving contents along in small intestine. Initiated by chyme in the intestine (distention or irritation).
Mediated by Enteric Nervous System
69
Functions of Gastrin Secretion
1) Stimulate HCl secretion by Parietal Cells
| 2) Stimulate growth of gastric mucosa and motility
70
Phases of Acid Secretion
1) Basal Secretion
2) Cephalic Phase
3) Gastric Phase
4) Intestinal Phase
71
Bind to Bile Acids inside Ileal Enterocyte
Ileal Bile Acid Binding Protein (IBABP)
72
Mechanism for Amino Acid Uptake into Enterocytes
Na+-Dependent Co-Transport. Separate ones for neutral, acidic, basic, and imino amino acids. Moves into blood via facilitates diffusion
73
Location of Motilin Secretion
M Cells in Stomach and Small Intestine
74
Enterocytes
Most common cell in small intestine.
Function:
1) Digestion
2) Absorption
3) Secretion
75
Pathways for Heme Iron Uptake into Enterocytes
1) Receptor-Mediated Endocytosis
| 2) Transporter Protein HCP1
76
Cystinuria
Defect in uptake of basic amino acids in gut and kidney.
77
Basal Secretion (Acid Secretion)
In absence of stimulation. Associated with Circadian Rhythm.
78
Main Components of Flatus
1) N2 (Swallowed Air)
2) H2 and CO2 (Bacterial fermentation of sugars; CO2 also from acid reactions in stomach)
3) Methane in 1/3 of adults (genetic)
79
Orexin (Hypocretin)
Released by Hypothalamus during deprivation. Promotes food intake
80
Symptoms: Acute Pancreatitis
Severe abdominal pain, swollen/tender abdomen, nausea, vomiting, diarrhea, fever
81
Achalasia
Neuromuscular disorder of lower 2/3 esophagus, which has an absence of peristalsis and LES which fails to relax.
Causes food to accumulate in esophagus.
82
Gastric Lipase
Hydrolyzes Triglycerides into Diglycerides and Free Fatty Acids in the Stomach
83
Osmotic Diarrhea
Accumulation of nonreabsorbable solutes in small intestine
84
Exopeptidases
Hydrolyze one amino acid at a time from the C Terminus. Secreted from pancreas as proenzymes and activated by Trypsin.
Examples: Carboxypeptidases A and B
85
Function of Motilin
Stimulate Migrating Myoelectric Complexes in the Stomach and Intestine
86
Production of Ghrelin
1) Increases with weight loss
2) Increases with stress and sleep deprivation
3) Decreases with weight gain and exercise
4) (increase following gastric bypass surgery)
87
Proopiomelaocortin (POMC) Neurons
Decrease food intake and increase energy expenditure. Release α-MSH and CART. Have Nicotinic ACh Receptors which enhance firing.
88
Fold of Kerckring
Longitudinal folds in the Small Intestine to increase surface area
89
Ileus
Loss/reduction of contractile activity in small intestines in absence of obstruction as a result of the irritation of the peritoneum.
Caused by:
1) Surgery
2) Acute/Systemic Illness
3) Electrolyte Imbalance
4) Tricyclic Antidepressants
90
Gastric Phase (Acid Secretion)
Initiated by entry of food into stomach (both pH and distention). Stopped by negative feedback of acid in stomach.
(more detail in notes)
91
Bilirubin
Principal pigment in bile. Metabolite of hemoglobin. Heme breakdown product, first forming biliverdin then becoming bilirubin. Insoluble in water.
92
More readily absorbed form of Free Iron
Ferrous (Fe2+)
93
Gallbladder Modification of Liver Bile
Active Removal:
1) Na
2) Cl
3) HCO3
Osmotic Gradient Removal:
1) Water
94
Intestinal Phase (Acid Secretion)
Initiated by protein digestion products in the Duodenum. Proximal duodenum secretes gastrin.
95
Acid Secretion Mechanism: Acetylcholine
1) Binds Muscarinic Receptor on Parietal Cell
2) Activates Phospholipase C
3) Forms IP3
4) Ca2+ released as Second Messenger
96
CCK-Releasing Peptide (CCK-RP)
Peptide regulator of CCK release secreted by Paracrine Cells within Small Intestine epithelium
97
Transports Iron from Enterocyte to Plasma
Ferroportin
98
Production of Leptin
Adipocytes
1) Increased when amount of adipose tissue increases
2) Increased by Insulin
3) Inhibited by fasting and weight loss
99
H+ Levels in Duodenal Ulcers
Increased
100
Pathologies where VIP plays central role
1) Pancreatic Islet Cell Tumor
| 2) Pancreatic Cholera / Watery Diarrhea Syndrome
101
When do Migrating Myoelectric Complexes begin?
After two hours of fasting
102
Location of Serotonin Release
Enteric Neurons and ECL Cells
103
Triggers of GIP Release
(in small intestine)
1) Fatty acids
2) Glucose
3) Amino Acids (lesser extent)
104
Lesion of Dorsomedial Nucleus
Depresses eating beahvior
105
Precursor to GLP-1
Proglucagon
106
Acid Secretion Mechanism: Histamine
1) Binds to H2 Receptor on Parietal Cell
2) Activates Adenylate Cyclase
3) cAMP second messenger
107
Dominant Na Absorption Mechanism: Colon
Restricted Diffusion
108
Core Contents of Chylomicrons
1) Triglycerides
2) Esterified Cholesterol
3) Fat-Soluble Vitamins
109
Stimulants of Gastric Acid Secretion
1) Acetylcholine
2) Histamine
3) Gastrin
110
Location of GI Sympathetics Synapse
Prevertebral Ganglia
111
Glucagon-like Peptide-1 (GLP-1)
Anorexigenic peptide produced by L Cells (Ileum and Colon).
112
Dominant Na Absorption Mechanisms: Ileum
1) Na-Glucose or Na-AminoA Co-Transport
2) Na-Cl Co-Transport
3) Na-H Exchange
113
Agouti-Related Peptide (AgRP)
Orixgenic released from ARC Neurons. Natural antagonist of MCR-3 and MCR-4. Excessive formation due to mutation associated with obesity.
Release inhibited by Insulin.
114
Muscle forming Upper Esophageal Sphincter
Cricopharyngeal Muscle
115
Most Common Causes of Jaundice
1) Hemolytic Anemia
2) Obstruction of Bile Duct
3) Liver cell damage
116
Gastroparesis
Impaired or delayed gastric emptying. Most common cause is diabetes (neurodamage from glycosylated Vagal nerve proteins)
117
Functions of CCK
1) Stimulate Gall Bladder Contraction
2) Stimulate Pancreatic Enzyme Secretion
3) Potentiate Pancreatic Bicarbonate Secretion (Stimulated by Secretin)
4) Inhibits gastric emptying
118
Enzymes Cleaving Sucrose into Glucose and Fructose
Sucrase
119
Ca2+ and cAMP actions in Parietal Cell
[Apical Membrane]
1) Increase Concentration of H/K-ATPases
2) Increased Concentration of Cl Channels
120
Muscle forming Lower Esophageal Sphincter
No distinct muscle (just thickening)
121
Destination for Chylomicrons after leaving Enterocyte
Enter Lacteals, central lymphatic vessels in the Villi, through gaps in lymphatic endothelial cells. Too large to enter capillaries so they enter bloodstream in the Thoracic Duct
122
Rectospincteric Reflex
Relaxation of Internal Anal Sphincter after the Rectum contracts upon fecal matter being forced in. Involuntary
123
Lipid Malabsorption: Absence of Bile Salts
1) Liver Disease (ex: Hepatitis)
2) Obstruction of Common Bile Ducts by Gallstones
3) Bacterial Overgrowth of Small Intestines (deconjugate)
4) Increased Duodenal Acidity (bile salts less soluble)
124
Cholesterol Ester Hydrolase
Cleaves fatty acid from cholesterol esters.
Produces:
1) Free cholesterol
2) Fatty Acid
125
Protein Plug
High protein in Pancreatic Juice creates plug in ducts. Can lead to liver damage, malabsorption, steatorrhea
126
Mechanism of Action of GLP-1
1) Delays gastric emptying
2) Activates α-MSH and CART neurons
3) Inhibits AgRP and NPY Neurons
127
Ventromedial Nucleus
Satiety center. Has MC3R Melanocortin Receptor
128
Tehalose
Glucose Dimer
129
Mechanism of Pancreatitis
Activated enzymes digest pancreatic tissue. Enzymes leak into blood, increases serum amylase/lipase levels.
130
Surface Contents of Chylomicrons
1) Phospholipids
2) Apoprotein
3) Free Cholesterol
131
Physiological Functions of Colonic Flora
1) Digest Carbohydrates
2) Form Secondary Bile Acids and Deconjugate Bile Acids
3) Generate Short-Chain Fatty Acids `(absorbed by colon)
132
Soluble Form of Mucus
Secreted by Mucous Neck Cells after Vagal Stimulation. Mix with other secretions and lubricates chyme.
133
Actions of CCK on Gallbladder
1) Major Stimulator of Contraction (direct action on smooth muscle and indirectly via Vagus and Intrinsic Nerves)
2) Relaxes Sphincter of Oddi
134
Route for Na to follow Cl into intestinal lumen
Paracellular
135
Mechanism: Secretory Diarrhea
1) Activation of Cl channels (V. cholerae toxin causes constitutive activation)
2) Na and Water follow
3) Na reabsorption by Ileal Enterocytes via Cl Cotransport inhibited
136
Causes of Pancreatitis
Most Common: Alcoholism or Gallstones
Also: High triglycerides and smoking
137
Inhibited by Somatostatin
1) Gastric Acid Secretion
2) Gastrin Release
3) Release of all GI hormones
138
Enterocyte processing of Lysophospholipids
Combined with fatty acids to form phospholipid
139
Cholecystectomy
Removal of the gallbladder
140
Barret's Esophagus
Metaplasia from long-term exposure to acid
141
Inflammatory / Infectious Diarrhea
Caused by infection by bacteria (salmonella, Campylobacter Clostridium difficile) or viruses (rotaviruses, norovirus)
Inflammatory and/or immune response kills intestinal cells.
142
Types of Gallstones
1) Cholesterol Type (most common)
| 2) Pigment Type
143
Hemochromatosis
Chronic over-absorption of Iron. Hereditary form is a defect in the HFE gene, causing Hepcidin levels to drop.
144
Cholestasis
Reduced or lack of bile flow. Can be caused by a defect in Hepatocyte BSEP pump.
145
Cocaine-Amphetamine-Regulated Transcript (CART)
Released from POMC Neurons. Also binds to MCR Receptors. Mutations can cause obesity.
146
Phases of Pancreatic Secretion
1) Basal (Insignificant)
2) Cephalic
3) Gastric
4) Intestinal (majority)
147
Bile-Independent Biliary Secretion
Volume of water and electrolytes secreted. Secretin stimulates secretion of HCO3 and water.
148
Gastroileal Reflex
Increased peristalsis in Ileum. Relaxation of Ileocecal sphincter so Ileal contents move into Large Intestine.
Triggered by gastric secretion and emptying
149
Surface Mucus Cells (Oxyntic Gland)
Extend into the duct's opening
150
Triggers of Motilin Secretion
Just a cyclical release every 90 minutes
151
Neuropeptide Y (NPY)
Orixgenic which binds to Y Receptors (for example in Nucleus Tractus Solitarus).
Released when energy stores are low from ARC Neurons.
152
Inhibited by Enkephalin Release
Intestinal secretion of fluid and electrolytes
153
Cell Types in Oxyntic Gland
1) Mucous Neck Cells
2) Surface Mucus Cells
3) Parietal Cells
4) Chief Cells
5) Endocrine Cells
154
Crypt Cells
Stem cells in the Small Intestine (crypt base). Form both Enterocytes and Goblet Cells.
Secrete fluids and electrolytes.
155
Endopeptidases
Hydrolyze interior peptide bonds.
1) Gastric Pepsin
Pancreatic Enzymes
1) Trypsin
2) Chymotrypsin
3) Elastase
156
Ferritin
Cytosolic iron storage protein. Product of Iron + Apoferritin
157
Function of PYY
Anorexigenic. Reduces gastric emptying and delays intestinal transit.
Increased levels in disease state. Fasting plasma concentrations reduced in obesity.
158
What does GIP stand for?
Glucose-Dependent Insulinotropic Peptide
159
Appetite/Energy Expenditure Regulating Neurons in ARC
1) Propiomelocortin (POMC) Neurons
| 2) Orexigenic-Producing Neurons
160
Inhibitors of Gastric Emptying
1) Low pH
2) Presence of fat/protein digestion products
3) Non-Isotonic Solutions
4) Proximal Stomach Distention
5) Pressure in proximal Small Intestine
161
Function of Enkephalins
Stimulate contraction of Smooth Muscle
Especially Lower Esophageal, Pyloric and Ileocecal Sphincters
162
What does VIP stand for?
Vasoactive Intestinal Peptide
163
H+ Levels in Gastric Ulcers
Reduced (acid leaks into gastric mucosa and is lost)
164
Lipid Malabsorption: Failure to Digest Fat
Pancreatic enzymes either not secreted or inactivated by low pH
Ex: Pancreatitis, Pancreatic Carcinoma, Cystic Fibrosis
165
Salivary Glands (Ordered by amount)
1) Submaxillary
2) Parotid
3) Sublingual
166
Function of Centroacinar and Duct Cells
Secrete pancreatic juices with high bicarbonate concentration. Brings pH to optimal enzymatic range
167
Ductule/Centroacinar Cell Modification of Pancreatic Secretion
1) Secrete HCO3
2) Na follows HCO3
3) Absorb Cl
168
Trigger for GRP Release
Vagal Stimulation
169
Late Phase of Dumping Syndrome
Hypoglycemia 1-3 hours later. Rise in insulin means you absorb glucose too quickly.
Sweating, weakness, dizziness
170
Exception where both Parasympathetics and Sympathetics are Stimulatory
Both stimulate saliva secretion with ACh!
171
Oxyntic Gland Mucosa
Located in Proximal Stomach (80% of secretion).
Secretes:
1) Acid
2) Pepsinogen
3) Intrinsic Factor
4) Mucus
172
Hirschsprung's Disease
Congenital megacolon, caused by an absence of Enteric innervation in a segment of the colon. Constriction and loss of coordinated movement of involved segment.
Contents accumulate proximal to constriction, leading to dilation. Severe constipation.
173
Peptide Forms Proteins Can Be Absorbed As
1) Amino Acids
2) Dipeptides
3) Tripeptides
Larger ones can be absorbed poorly if at all
174
Hepcidin
Regulates entry of iron into plasma by binding directly to Ferroportin. Causes internalization and degradation of Ferroportin.
175
Early Phase of Dumping Syndrome
Nausea, vomiting, diarrhea
176
Function of GIP
Stimulate insulin release from the Pancreas
177
Bilirubin Glucoronide
Soluble salt. Product of Bilirubin conjugated by Glucoronic Acid in Liver.
178
Reduce Ferric Iron to Ferrous Iron
1) Vitamin C
2) Citric Acid
3) Duodenal Cytochrome b (Dcytb) -- Brush Border Enzyme
179
Acid Secretion Mechanism: Gastrin
1) Binds to Gastrin/CCK-B receptors on Parietal Cell
2) Activates Phospholipase C
3) Forms IP3
4) Ca2+ released as Second Messenger
180
Phosphatidic Acid Pathway
Enterocyte processing in starving state. Phosphatidic Acid formed from:
1) two Acyl CoA
2) α-Glycerophosphate
Phosphatidic Acid then reacts with one more Acyl-CoA. Forms:
1) Triglyceride
2) Phosphate
181
Breakdown products from Amylopectin and Amylose by α-amylases
All oligosaccharides
1) Maltose
2) Maltotriose
3) α-limit dextrins
182
Triggers of Gastrin Secretion
1) Peptides/amino acids in stomach
2) Distention of stomach
3) Vagal Stimulation (Mediated by GRP)
183
Absorbs Glucose and Galactose into Enterocyte
Na-Dependent Active Transport System (SGLT-1)
Facilitated diffusion, then, into blood
184
Intestinointestinal Reflex
Inhibition of contractile activity in more proximal portions of the small intestine to prevent movement of materials into severely distended sections.
Mediated by Extrinsic Nervous System
185
Pyloric Gland Mucosa
Located in Distal Stomach.
Secretes:
1) Gastrin (mostly)
2) Some mucus and pepsinogen
186
Location of Somatostatin Release
D Cells throughout GI tract
187
Reabsorbed and Secreted in Striated Duct (Salivary Glands)
Reabsorbed:
1) Na
2) Cl
Secreted:
1) K
2) HCO3
188
Location of Secretin Release
Secreted from S Cells of proximal Small Intestine
189
Function of GRP
Stimulates Gastrin release
190
Location of GIP Secretion
K Cells in proximal Small Intestine
191
Function of GI Longitudinal Muscle
Change length
192
Parietal Cells (Oxyntic Gland)
Secrete Acid and Intrinsic Factor
193
Pathologies Which Lead to High Protein Concentration in Pancreatic Juice
1) Chronic Pancreatitis
| 2) Cystic Fibrosis
194
Gastric emptying mainly controlled by signals from _____
Duodenum
195
Functional Regions of Gastric Secretion
1) Oxyntic Gland Mucosa (80%)
| 2) Pyloric Gland Mucosa (20%)
196
Pernicious Anemia
Anemia resulting from absence of Vit B12
197
Major Causes of Lipid Malabsorption
1) Failure to Digest
2) Absence of Bile Salts
3) Condition Affects/Decreases Number of Absorbing Cells
4) Failure to Synthesize Apoproteins
198
Cause of Pigment Gallstone
Bilirubin becomes unconjugated and precipitates with Calcium.
Calcium Bilirubinate
199
Zollinger-Ellison Syndrome
Overproduction of gastric acid due to gastrin-releasing Gastrinoma
200
Relationship: Pressure in Proximal Stomach and Gastric Emptying
Inverse.
201
α-Melanocyte-Stimulating Hormone (α-MSH)
Melanocortin type released from POMC neurons. Binds to Paraventricular Nuclei Neurons (among other nuclei) to reduce eating. Activation of receptor mediate by Paraventricular Nucleus to Nucleus Tractus Solitarus pathway (stimulates sympathetics).
202
Physiologically-Active Components of Gastric Juice
1) HCl
2) Pepsin
3) Mucus
4) Intrinsic Factor
203
Result of Excess Iron: Liver
1) Cirrhosis
| 2) Liver Cancer
204
Hepatocyte Bile Salt Secretion Pumps
1) ATPase-Dependent Bile Salt Export Pump (BESP)
| 2) MRP2 (lesser extent)
205
Endocrine Cells (Oxyntic Gland)
Secrete products regulating gastric function
206
Functions of Secretin
1) Stimulates bicarbonate and water secretion in Pancreas/Liver
2) Increases Liver Bile Production
3) Inhibits Gastric Acid Secretion
207
Monitor Peptide
Peptide regulator of CCK release secreted by Pancreas
208
Phases of Migrating Myoelectric Complexes
Phase I: Quiescent Phase
Phase 2: Small, irregular activity
Phase 3: Regular Activity
209
Apical Membrane Transporter Secreting Cl into Lumen from Crypt Cell
CFTR Channel
210
Abetalipoproteinemia
Lipid malabsorption due to inability to synthesize ApoB (component of Chylomicrons).
211
Absorbed free cholesterol in Enterocytes
Significant portion re-esterified with fatty acids. Some left free. Both transported into Chylomicrons
212
Lateral Nuclei (Hypothalamus)
Feeding center. Cause hyperphagia when stimulated
213
Cell Types in Pancreas
1) Acinar Cells
2) Centroacinar Cells
3) Duct Cells
214
Sphincter of Oddi
Sphincter from Common Bile Duct to Duodenum
215
Location of Active Reabsorption of Bile Salts
Terminal Ileum
216
Colipase
Prevents inhibition of pancreatic lipase by bile salts.
Non-enzymatic protein secreted as inactive by pancreas (trypsin activates).
217
Ghrelin
Orexigenic hormone produced in Stomach and Proximal Small Intestines.
218
Hiatal Hernia
LES and Stomach move up through Esophageal Hiatus in Diaphragm
219
Location of Bile Salt Conjugation
Liver
220
Choleretics
Substances stimulating increased bile secretion
221
Location of Gastrin Secretion
G Cells in Stomach
222
Oxyntomodulin (OXM)
Anorexigenic proglucagon-derived peptide. Secreted from Distal intestine in proportion to ingested calories. Short-term action.
223
Familial Iminoglycinuria
Defect in uptake of proline and hydroxyproline
224
Fate of Flatus
All except Nitrogen can diffuse through intestinal mucosa to reduce volume.
225
Breaks heme down to release free iron
Heme Oxygenase
226
Lecitithins
Primary phospholipid in bile. Improves solubilizing-ability of micelles after itself being solubilized by bile salts.
227
External Anal Spincter
Prevents defecation. Tonically-contracted
228
Transports Ferric Iron in Blood
Plasma Transferrin
229
Location of most water absorption in Large Intestine
Proximal colon
230
Hepatocyte Transporter Extracting Bile Salts from Portal Blood
Sodium-Taurocholate Cotransporting Peptide (NTCP)
231
Cephalic Phase (Acid Secretion)
Initiated by thought, sight, taste, or smell of food. Vagus nerve increases acid secretion by:
1) ACh stimulation of Parietal Cells
2) ACh-caused release of GRP
232
Hartnup Disease
Defect in uptake of neutral amino acids
233
Monosaccharides absorbed by intestine
1) Glucose
2) Galactose
3) Fructose
234
Enzymatic Components of Pancreatic Secretion
Secreted in Active Forms:
1) Pancreatic Lipase
2) Pancreatic Amylase
Secreted in Inactive Forms:
1) Trypsin
2) Chymotrypsins
235
Secreted by Acinar Cells
1) Peptidases
2) Lipases
3) Amylases
236
Luminal-side Structure of Parietal Cells which enlarges when activated
Canliculus
237
Stimulator of Pepsin Secretion
Vagal Stimulation
238
Secondary Bile Acid
Converted by bacteria from Primary Bile Acids in the intestines.
239
Dumping Syndrome
Lower end of the small intestine fills too quickly with undigested food. Common after stomach surgery
240
Causes Ileocecal Sphincter to relax
Ileum distention
241
Function of GI Circular Muscle
Change diameter
242
Location of VIP Release
Nerves in Mucosa and Smooth Muscle of GI Tract
243
Primary excretory pathway for cholesterol
Loss of bile salts in feces. Usually equal to dietary input.
244
Brush Border Peptidases
"Finish the job" started by Endo/Exopeptidases. Breaks further down into oligopeptides and amino acids.
245
Chief Cells (Oxyntic Gland)
Secrete Pepsinogen
246
Functions of Serotonin
1) Stimulate Intestinal Fluid and Mucus Secretion
| 2) Stimulate Gut Motility
247
Convert Ferrous Iron to Ferric Iron
1) Ferroportin
| 2) Ferroxidase Hephaestin
248
Transporter for Active Reabsorption of Bile Salts
Apical Sodium-Dependent Bile Salt Transporter (ASBT)
249
Trigger of Secretin Release
Released in response to acid
250
Submucosal Plexus
Network of enteric nervous system found in the intestines. Controls secretion
251
Proteins in Saliva
1) α-amylase
2) Lingual Lipase
3) Mucin
4) Epidermal/Nerve Growth Factors
