Physiology Flashcards
1
Q
Which sphincter holds the highest resting pressure in the GI tract?
A
Upper esophageal spinchter
2
Q
What is the function of the lower esophageal sphincter?
A
To coordinate the passage of food into the stomach and prevent reflux of gastric contents.
3
Q
What does the pyloric sphincter regulate?
A
Gastric emptying
4
Q
What sphincter prevents back flow from the colon?
A
The ileocecal sphincter (valve)
5
Q
The enteric nervous system is made up of which two nerve plexuses?
A
myenteric and submuscosal
6
Q
Which nerve plexus helps keep the tone of the gut and is located in between the longitudinal and circular muscle layers of the GI tract?
A
The myenteric plexus (Auerbachs)
7
Q
Which nerve plexus controls secretions, absorption, and contraction?
A
The submucosal plexus (Meissner’s)
8
Q
The parasympathetic nervous system to the gut signals through which sets of nerves?
A
Vagus and pelvic nerves
9
Q
Sympathetic nervous system innervates the ENS via:
A
celiac plexus, hypogastric, and the superior and inferior mesenteric ganglia
10
Q
Norepinephrine is used in the (sympathetic/parasympathetic) nervous system and inhibits ________ neurons.
A
sympathetic and it inhibits excitatory cholinergic neurons.
11
Q
What cells are the pacemakers in the GI tract?
A
interstitial cells of Cajal
12
Q
What type of contractions move material from mouth to colon?
A
Peristaltic contractions
13
Q
Contractions that mix chyme with intestinal secretions are called ______
A
segmental/mixing/non-propulsive
14
Q
What does the enterogastric reflex do?
A
It decreases gastric motility and secretions and stimulates contraction of the pyloric sphincter (to optimize digestion)
15
Q
A peristaltic rush is associated with what?
A
Diarrhea
16
Q
The myenteric reflex has a propulsive segment that ______ longitudinal muscles and ________ circular muscles. Whereas, the receiving segment _______ longitudinal muscles and ________ circular muscles.
A
The myenteric reflex has a propulsive segment that relaxes longitudinal muscles and contracts circular muscles. Whereas, the receiving segment contracts longitudinal muscles and relaxes circular muscles.
17
Q
What is a symptom of pathological ileus?
A
Too long quiescence that inhibit passage of stool and gas = constipation and bloating #womp
18
Q
What is the function of the migration motor complex?
A
To “sweep” stomach and SI of undigested food, bacteria, desquamated cells, quarters, etc.
19
Q
Motilin is associated with which phase of the migrating motor complex?
A
The active phase - it is synthesized in the duodenal MO cells and it stimulates contrations
20
Q
What is a bezoar?
A
A bezoar occurs in the absence of the MMC and is an indigestible material that can cause obstruction of the stomach.
21
Q
What is a voluntary movement of food to the pharynx activates swallowing reflexes including a primary peristaltic wave in the esophagus?
A
deglutition
22
Q
In the pharyngeal phase, cranial nerves __ and __ transmit sensory information.
A
CN V and IX
23
Q
The pharynx and upper 1/3 of the esophagus are striated muscle controlled by CN __ and __
A
CN IX and X
24
Q
Disorders of swallowing can occur with damage to cranial nerves __, __ or __
A
damage to CN V, IX, or X
poliomyelitis and encephalitis (swallowing center damage)
muscular dystrophy and myasthenia gravis (muscle damage)
patients under deep anesthesia
25
After a meal, transient relaxation of the proximal stomach is required. What is this called?
Receptive relaxation
26
Receptive relaxation increases intragastric (volume/pressure)
volume, not pressure
27
Relaxation of the fundus during gastric filling is a result of which nerve?
The vagus nerve - vagovagal reflex
28
What is achalasia?
Failure of LES to relax during swallowing. Failure of receptive relaxation
29
When LES tone is not properly maintained, ____ can develop
Gastroesophageal reflux disease (GERD)
30
The gastric reservoir portion of the stomach is adapted for what?
Maintaining continuous contractile tone - allow for accommodation of a meal without sign. increase in intragastic pressure
31
The muscles in which part of the stomach physically contract?
The antral pump
32
What three terms are used to describe the stomachs churning of a meal?
Propulsion, grinding, and retropulsion.
33
Where is the submucosal plexus located?
Between the circular muscle and submucosa
34
These GI regulators travel through portal, then liver, then systemic circulation (hormones/paracrines/neurocrines)
hormones
35
Histamine, Vagal stimulation and Gastrin (increases/decrease) stomach acid sectretion
increase
36
Somatostatin, Glucose insulinotropic peptride (GIP) and Secretin all (increase/decrease) stomach acid sectretion
decrease
37
G cells in the stomach secrete _____
gastrin
38
Major inhibitory mechanism for reducing HCl secretion into the stomach is by the hormone ______
somatostatin
39
These cells (in the stomach antrum and corpus) secrete Somatostain
D cells
40
These cells in the stomach antrum secrete gastrin
G cells
41
These cells in the stomach body secrete Histamine
ECL cells
| Enterochromaffin-like cells
42
In islets of langerhans, alpha cells produce ____
Glucagon
43
In islets of langerhans, delta cells produce _____
Somatostatin
44
In islets of langerhans, beta cells produce _____
Insulin
45
What GI hormone acts to increase secretion by parietal cells?
Gastrin
46
Which GI hormone causes the gallbladder to contract due to ingestion of fats?
CCK
47
Which GI hormone acts to increase HCO3- and fluid secretion by the pancreas?
secretin
48
What GI hormone helps to 'clear' the GI tract of indigestible materials?
Motilin
49
Which GI hormone acts on the pancreas to stimulate insulin secretion and on parietal cells to inhibit HCl secretion?
GIP
50
The acinar cells of the parotid glands secrete what?
Serous substance rich in amylase
51
The acinar cells of the sublingual and submandibular glands secrete what?
A sero-mucous product rich in mucin glycoproteins
52
What two cells types live in Oxyntic glands?
Parietal cells and chief cells
53
Pyloric glands contain what type of cells?
G cells and mucus cells
54
Pepsin is most active at (acidic/basic) pH
acidic
55
What is an alkaline tide?
As hydrogen ions are secreted, bicarbonate ions enter the blood so that gastric venous blood has a higher pH than arterial blood when the stomach is secreting acid
56
Gastric parietal cells demonstrate net secretion of ___ and net absorption of ____
Secret HCl and absorb HCO3-
57
Vomitting can cause dehydration and what two other physiological symptoms?
alkalosis and hypokalemia
58
Parietal cells have what type of neuro receptor?
ACh
59
In the cephalic phase, HCl is secretion is moderated directly by ___ and indirectly by _____.
directly by the vagus nerve and indirectly by gastrin
60
In the corpus of the stomach, the vagus directly stimulates what three cells?
Parietal cells, ECL cells, and D cells
61
In the antrum of the stomach, the vagus stimulates what two cells?
G cells and D cells
62
Vagal stimulation of D cells via ACh (promotes/inhibits) the release of somatostatin
Inhibits
63
What directly stimulates D cells to release somatostatin?
Luminal H+
64
Besides hormones and neural stimulation, what else can stimulate the G cells to release gastrin?
The products of digestion
65
Glucagon, insulin, and somatostatin make up the (exo/endocrine secretions) of the pancreas?
Endocrine secretions
66
Pancreatic aqueous secretion is important for what?
Neutralizing acids from stomach using HCO3-
67
What is the most powerful stimulus for HCO3- secretion?
Secretin
68
What is the initial step in bicarb secretion by duct cells?
Diffusion of CO2 from the blood acrossthe basolateral membrane into the duct cell
69
Bicarb moves across the apical membrane of PANCREATIC duct cells via _____.
Cl-/HCO3- exchanger
70
The CFTR channel is activated by which hormone?
Secretin
71
The CFTR channel uses what as it's secondary messenger to stimulate secretion of bicarb?
cAMP
72
What pump on the basolateral membrane is the driving force for the Na+/H+ exchanger?
Na+/K+ pump
73
Secretin and CCK stimulate what type of secretion by pancreatic duct cells?
Aqueous secretion
74
Secretion fluid is high in HCO3+ when secretion rates are ______
fast
75
From where is pepsinogen secreted?
Gastric chief cells
76
CCK (Cholecystokinin) (slows/quickens) gastric emptying
slows
77
Blood glucose levels less than 50mg/dL is called ____
Hypoglycemia
78
Increase in amino acids ____ and ____ indicate protein degradation and stimulates glucagon breakdown
Arginine and Alanine
79
What causes more insulin production, oral glucose or IV glucose?
Oral (cephalic phase insulin release)
80
Epinephrine at alpha receptors (increases/decreases) insulin release
Decreases (inhibits)
81
Epinephrine at beta receptors (stimulates/inhibits) insulin release
Stimulates
82
Parasympathetic nervous system (stimulates/inhibits) insulin secretion
stimulates
83
Sympathetic nervous stimulation (stimulates/inhibits) insulin secretion
inhibits
84
Somatostatin (stimulates/inhibits) insulin secretion
inhibits
85
In both muscle and adipose, insulin stimulates glucose uptake via the _____ receptor
GLUT4
86
The hunger center is located in the _____ area
lateralhypothalamic area
87
The satiety center is located in the ______ nucleus
ventromedial nucleus
88
Most iron is absorbed in the ____ of the small intestine
Duodenum
89
Iron can only be absorbed in the (2+\3+) state
2+.
90
Calcium is absorbed in the ____ of the small intestine
Duodenum
91
Endocrine secretions from the pancrease, including glucagon, insulin and somatostatin come from the _____ __ _______
islets of langerhans
92
In the pancreas, acinar cells secrete (digestive protein/bicarb) while duct cells secrete (digestive protein/bicarb)
Acinar cells secrete proteins (such as enzymes)
| Duct cells secrete bicarb
93
Gastrin released by G cells stimulates secretion of gastric acid, or ____ from parietal cells
HCl
94
Secretin and CCK are secreted by pancreatic ____ cells
acinar
95
Bicarbonate is secreted by pancreatic ____ cells
duct
96
Secretin and Cholecystokinin (CCK) (stimulate/inhibit) aqueous secretions by pancreatic duct cells
stimulate
97
Bicarbonate from duct cells is driven into the lumen by an exchange with a ___ ion
Cl-
98
What hormone is released by S cells in the duodenal mucosa?
Secretin
99
What peptide promotes gallbladder emptying and relaxation of the sphincter of Oddi?
Cholecystokinin (CCK)
100
"Nature's antacid:" inhibits gastric acid secretion and release of gastrin
Secretin
101
Causes pancreatic section to be 1) low volume 2) high [enzyme]
cholecystokinin CCK
102
Causes pancreatic enzyme secretion to be 1) high volume 2) high [HCO3-] 3) low [enzyme]
Secretin
103
An agent that stimulates the gall bladder to release bile is called a _____
Choleretic
104
Bile salts are conjugated with either _____ (75%) or _____ (25%) in the liver
glycine or taurine
105
After traveling though the duodenum, most bile acids get (secreted/reabsorbed)
reabsorbed
106
The Gall bladder can be triggered to release via 1. Neural control of _____ or 2) hormonal control of _____
Vagus
| CCK (cholecystokinin)
107
Insulin is an (anabolic/catabolic) hormone
anabolic (promotes storage)
108
Glucagon is an (anabolic/catabolic) hormone
catabolic (promotes breakdown)
109
-Hypoglycemia
-Alanine and Arginine
-Exercise
-Stress
Are (stimulators/inhibitors) of Glucagon secretion
stimulators
110
-Somatostatin
-Insulin
-Hyperglycemia
Are (stimulators/inhibitors) of Glucagon secretion
inhibitors
111
The primary target organ of glucagon release is the ____
liver
| to catabolize glycogen
112
Measuring levels of C-peptide can be used to measure the amount of (glucose/insulin/glucagon) secrete
insulin
113
More insulin is released when given (oral/IV) glucose
oral
114
Epinephrin at α receptors (stimulates/inhibits) insulin release while Epinephrin at β (stimulates/inhibits) insulin release
alpha receptors: inhibit
| beta receptors: stimulate
115
-GIP
-Glucagon
-Gastin
-CCK
-Secretin
-VIP
Are hormones that (stimulate/inhibit) insulin release
stimulate
116
During exercise, the net result of α and β receptors is to (increase/decrease) insulin secretion
decrease
| prevent hypoglycemia
117
In adipose tissue, insulin promotes ____ ____ synthesis, which moves to the surface where it can pull in fatty acids from chylomicrons and VLDV
Lipoprotien Lipase
118
Elevated levels o insulin in the blood is called _____
insulinemia
119
Neurotransmitters that stimulate feeding are called ______
Orixigenic
120
Neurotransmitters that inhibit feeding are called _____
Anorexigenic
121
GI peptides that signal satiety: (5)
1. CCK (Cholecystokinin)
2. GLP-1 (glucagon-like peptide 1)
3. GLP-2
4. Glicentin
5. PPY (peptide tyrosine-tyrosine)
122
Adiposity signals that tell the amount of fat in the body are: (2)
1. Leptin
| 2. Insulin
123
The peptide produced in the gastrointestinal tract called the "hunger hormone" is ______
Ghrelin
124
Vitamin B12 gets absorbed in the (duodenum/proximal jejunum/distal ileum)
distal iluem
125
Na+ and HCO3- are secreted by the _____ and are later re-absorbed in the ____
pancreas
| jejunum
126
HCO3- is reabsorbed across the membrane of Jejunal absorptive cell separating it into ____ and ___
H20 and CO2
127
NaCl secreted by the liver and pancreas and mostly reabsorbed in the ______
Ileum
128
NaCl absorption in the ileum can be inhibited by _____, which is the target of production of E. coli and Vibriocholera toxins
Cyclic AMP
129
NaCl is secreted into the gut lumen using CFTR channels by ____ cells
crypt cells
130
In the crypt cell, increased _____ will increase conductance of the CFTR channels
cAMP
131
Vibriocholera toxin causes diarrhea by _____
increasing cAMP --> more NaCl secretion by crypt cells
| --> less NaCl absorption in the ileum
132
Endogenous Secretory stimuli include: (7)
```
Acetyl choline
histamine
secretin
gastrin
gastric inhibitory polypeptide (GIP)
Motilin
vasoactive intestinal peptide (VIP)
```
133
Endogenous Absorptive stimuli include: (5)
α-adrenergics (epi/norepi)
Dopamine
Enkephalins (endogenous opoids->runner's high)
Somatostatin
Mineralcorticoids (aldosterone in the colon)
134
Iron can only be absorbed in the (Fe2+ ferrous/Fe3+ ferric) state
Fe2+ ferrous
135
Ca2+ is absorbed in the (duodenum/proximal jejunum/distal ileum)
duodenum
136
High Ca2+ in plasma (increases/decreases) secretion of parathyroid hormone (PTH)
decreases
137
Vitamin D is important because it increases absorption of
```
(CIMPZ)
calcium
iron
magnesium
phosphate
zinc
```
138
Which cells secrete pepsinogen?
gastric chief cells
139
The enteropepsidase for aromatic L-amino acids secreted from gastric chief cells is called ______
pepsin
140
Membrane bound enzymes in the brush boarder of the intestine are called _______
Ectoenzymes
141
Trypsinogen is activated to trypsin by the enzyme ______
enterokinase
142
The only time proteins are digested as whole proteins is in _____
infants
143
```
How are
1. chymotrypsin
2. elastase
3. carboxylpeptide 1 and
4. carboxylpeptide 2
activated?
```
by activated trypsin
144
The brush boarder can absorb peptides up to ___ residues in length
4
145
Single A.A. are driven across the brush boarder by a (H+/Na+) gradient while peptides are drive across by a (H+/Na+)
single A.A. Na+ gradient
| peptides H+ gradient
146
The only peptide transporter that moves peptides across the brush boarder is called _____
PepT1
147
In Hartnup's disease "system B" is is afected preventing the amino acid _____ from being absorbed
phenylalanine
148
In Cystinuria, "system B0+" is affected preventing basic amino acids such as ______ from being absorbed
Cystine
149
Digestion of fats is done in the jejunum by 3 major enzymes:
Pancreatic phospholipase A2
Cholesterol esterase
*Pancreatic Lipase
150
The Fat Soluble vitamins are: (4)
A
D
E
K
151
The required transporter for the absorption of cholesterol is _______
NPC1L1
| Niemann-Pick C1-like 1
152
For long chain fatty acid absorption by brush boarder cells, the required transport protein is ______
FATP
153
In the enterocyte, the [Na+] is (greater/less) than the [Na+] in the lumen
less
| gradient drives AA uptake
154
D cells (also called delta cells) are located in both the _____ and the ____ __ ____
```
GI tract (stomach/intestines)
islets of langerhans (pnacreas)
```
155
Mutations in the MTP gene can cause ________
Abetalipoproteinemia
fat accumulation in enterocytes
(lack of chylomicron export)
156
Both micturition and defecation rely on an internal sphincter under _______ control and `an external shincter under ______ control
internal: reflexive (autonomic)
external: voluntary
157
The ______ micturition center controls the detrussor muscle and urinary sphincter.
pontine
158
Tonic control over the detrusor and urinary sphincters originates in the _______ centers
suprapontine
| prefrontal cortex
159
Voiding of the bladder begins with relaxation of the _____ then relaxation of the _____
external sphincter
| internal sphincter
160
SNS inhibiting contraction of the detrusor is a __-adrenergic response while contracting of the internal sphincter is a __-adrenergic
β
| α
161
The 3 functions of the colon are:
1. moving
2. eliminating
3. extracting (water, nutrients, electrolytes)
162
Explain the two types of diarrhea
1) osmotic: due to non-absobed solutes (e.g. lactose intolerance)
2) secretory: excessive fluid secretion (e.g. cholera toxin)
163
Activated when food enters and empty stomach --> intensifies peristalsis -->promotes passage from ileum to colon
Gastroileal reflex
164
The colon is unique form the ileum because it does both absorption by _____ cells and secretion by _____ cells
absorptive
| goblet
165
Colonic water reabsorption is dependent on the reabsorption of ___
Na+
166
Histamine is a Gastric Secretory (inhibitor/stimulus)
stimulus
167
The rate-limiting step in acid secretion is _____ _____ activity
Proton pump (H+/K+ ATPase) activity
168
How can you completely cut the cephalic phase of gastric secretion?
Vagotomy
169
In the SMALL INTESTINE, primary bile salts cholic acid and chenodeoxycholic acid are conjugated with glycine and taurine to form _____ and ______
Deoxycholic acid
| Lithocholic acid
170
As in the stomach, the gallbladder can react to vagal stimulation by cephalic stimuli OR _______ situations
emotional
171
Glucose enters the pancreatic beta cells by the ______ transporter
GLUT2
172
Facilitated diffusion of fructose into the enterocyte is mediated by the _____ transporter
GLUT5
173
Reflex stimulation of mass movement in the colon by standing up from sleeping in the AM is called _____
Orthocolic reflex
174
Intrinsic factor is important for the absorption of vitamin _____
B12
175
Intrinsic factor is secreted by _____ _____ cells, complexes with B12, but is absorbed until the distal ileum
gastric parietal
176
CCK, ACh and gastrin increase what?
intracellular Ca2+
177
Secretin and VIP increase what?
cAMP
