Green - Stomach Flashcards

(81 cards)

1
Q

Distal region of stomach that contracts to mix food and propel it into duodenum

A

Caudad stomach

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2
Q

Semifluid mass of partially digested food passed from the stomach to small intestine

A

Chyme

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3
Q

Impaired/delayed gastric emptying

A

Gastroparesis

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4
Q

Protein produced by the parietal cell that is required for the absorption of vitamin B12

A

Intrinsic factor

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5
Q

Peristaltic contractions that occur in the stomach every 90 minutes during fasting; mediated by motilin

A

Migrating myoelectric complex

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6
Q

Proximal region of stomach that receives ingested meal

A

Orad stomach

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7
Q

Stomach cell that produces acid and intrinsic factor

A

Parietal cell

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8
Q

What does the parietal cell produce ?

A

Acid

Intrinsic factor (B12 absorption)

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9
Q

Disorder caused by lack of intrinsic factor, patient has decreased RBC”s due to lack of vitamin B12

A

Pernicious anemia

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10
Q

Relaxation of the proximal stomach when food enters it

A

Receptive relaxation

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11
Q

Closure of the pyloric sphincter that forces food back into the stomach

A

Retropulsion

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12
Q

Receptive relaxation is mediated by _____ which is initiated by distention of the stomach and abolished by vagotomy

A

Vagovagal reflex

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13
Q

________ causes the distal stomach to increase contractions, which mixes food w/ gastric secretions and reduces size of particles

A

Presence of food

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14
Q

Peristaltic contractions of the stomach begin in the _______ and proceed distally . As they move distally towards pylorus, both velocity and force of contractions increase

A

Midstomach

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15
Q

This part of the stomach is responsible for the regulation of intragastric pressure

A

Fundus

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16
Q

Hunger pangs start _____ hours after last meal and continue for 3-4 days before subsiding

A

12-24 hours

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17
Q

When does gastric emptying occur ?

A

When chyme is decomposed into small enough pieces to fit thru pyloric sphincter

(Following normal mixed meal this may take about 3 hours )

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18
Q

What is the order of gastric emptying for protein-rich food
Fat-rich food
Carbohydrate rich food

A

Carbohydrate rich food leaves faster than protein rich food which leaves faster than fat rich food

(Will feel full longer on fat rich diet)

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19
Q

The rate of gastric emptying is _______ to the pressure in the proximal stomach ?

A

Inversely proportional

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20
Q

The rate of gastric emptying is controlled Mostly by >

A

Signals from the duodenum

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21
Q

What are some things that can inhibit gastric emptying ?

A

High [H+] concentration, high protein or fats, non-isotonic solutions

Increased distention of proximal stomach

Increased pressure of the proximal small intestine

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22
Q

Impaired/delayed emptying

S/s: fullness, loss of appetite, nausea, vomiting

most common cause DM but can be 2ndry to meds that slow contractions in intestine (anticholinergics), neuro disorders

A

Gastroparesis

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23
Q

Why can increased gastric emptying cause diarrhea?

A

Because there is an increased osmotic load in the small intestine

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24
Q

What can increased gastric emptying cause?

A

Diarrhea - increased osmotic load in small intestine

Duodenal ulcers - stomach acids reach the duodenum bc they aren’t equalized in stomach and cause ulcers

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25
Explain dumping syndrome
Lower end of small intestine fills to quickly w/ undigested food from stomach Common after stomach sx Early phase (during or right after meal); nausea, vomiting, diarrhea Late phase (1-3 hours after meal)- sweating, weakness, dizziness Symptoms are due to too much fluid in intestine and hypoglycemia
26
What are the two regions of the stomach in regards to secretory function ?
Oxyntic gland mucosa Pyloric gland mucosa
27
Functional secretory area of the stomach Secretes mostly gastrin Secretes some pepsinogen and mucous
Pyloric gland mucosa
28
Functional secretory area of the stomach. Secretes pepsinogen, acid, intrinsic factor, and mucous
Oxyntic gland mucosa
29
Parietal cells secrete
Acid and intrinsic factor
30
Chief cells secrete ?
Pepsinogen
31
Stem cells of the oxyntic gland are located in the mucous neck (some of these also secrete mucous) and can proliferate and differentiate into: (x4)
Mucous cells - mucous Parietal cells - acid and intrinsic factor Chief cells - pepsinogen Endocrine cells - regulatory products
32
What are the four components of the gastric juice with physiological function ?
HCl Mucous Intrinsic factor Pepsin
33
Begins digestion of dietary proteins Converts pepsinogen to pepsin (for further protein degredation) Kills most bacteria that enter stomach Secreted from parietal cells
HCl
34
Activated by gastric acid and itself Begins digestion of proteins by breaking internal peptide bonds in the proteins Vagal stimulation causes the greatest increase in secretion
Pepsin Stored and secreted as pepsinogen
35
______ stimulation causes the greatest increase in the secretion of pepsinogen
Vagal
36
Secreted by stomach | Serves as a protective coating for stomach and lubricant and barrier between cells and ingested material
Mucus
37
Is soluble mucous present in resting stomach?
No
38
What type of stomach mucous is secreted by mucous neck cells ?
Soluble form
39
What type of stomach mucous is secreted by surface mucous cells
Insoluble/visible form
40
Is insoluble mucous secreted in the resting stomach ?
Yes. In response to chemical or physical irritation
41
Receptive relaxation is controlled by _______ signaling
Vagovagal
42
Parietal cells secrete ____ into lumen of stomach and _______ into the bloodstream
HCL HCO3-
43
At low basal rates, gastric juice is primarily _____ from nonparietal secretion
NaCl
44
At high stimulated gastric rates, gastric juice is primarily _______ from parietal secretion
HCl
45
[K] in gastric juice are always _______ than in plasma
Higher
46
The blood near the stomach having high pH due to the high activity of the Cl - HCO3- pumps is called
The alkaline tide
47
During production of. Acid, H+ enters the lumen in exchange for which ion?
K+
48
Acid secretion initiated by though, sight, taste, or smell of food
Cephalic phase
49
Region in the fourth ventricle of the brain that initiates vomiting
Chemoreceptor trigger zone
50
Substance that causes vomiting
Emetic
51
Acid secretion initiated by entry of food into the stomach
Gastric phase
52
Acid secretion initiated by the presence of protein digestion products in the duodenum
Intestinal phase
53
Release of acid by the parietal cell after initiation by multiple stimulants; The amount is greater than the sum of release by each individual stimulant
Potentiation
54
What are stimulants of acid secretion?
ACh Histamine Gastrin Ca and cAMP (by increasing concentration of H, K atpases and Cl channels)
55
How does Acetylcholine (ACh) cause stimulation of acid secretion ?
Acetylcholine binds to muscarinic receptors on the membrane of parietal cells; this activates phospholipase C which catalyzes the formation of IP3 which releases Ca++. Ca++ causes secretion of H+ by. Increasing concentration of H/K atpases and Cl- channels
56
How do Ca and cAMP cause stimulation of H+ secretion ?
By increased the concentration of H-K atpases and Cl- channels in the apical membrane
57
How does histamine cause stimulation of H+ secretion ?
Histamine binds to H2 receptors on the parietal cell membrane. H2 then activates adenylate cyclase to form cAMP
58
How does gastrin cause an increase of H+ secretion in parietal cells?
Gastrin binds to gastrin/CCK-B receptors in the parietal cell membrane. This causes the activation of phospholipase C which then catalyzes the formation of IP3 IP3 then causes the release of Ca++ ions
59
________ potentiates the actions of gastrin and ACh
Histamine
60
_______ potentiates the actions of histamine and gastrin
ACh
61
_______ stimulates the release and synthesis of histamine and the proliferation of enterochromaffin-like cells
Gastrin
62
______ stimulates the release and synthesis of histamine but not as much as gastrin
ACh
63
ECL cells has receptors for ____- and _____
Gastrin and acetylcholine
64
Explain how acid production and stomach pH cycles in relation to meals
At baseline, stomach acidic. You eat food, pH rises, causing release of gastric acid. Food is digested and leaves the stomach. Then pH drops in stomach. When it drops to below 3.0 gastrin release is inhibitted by the release of somatostatin which inhibits acid secretion by parietal cells and gastrin secretion by G cells. Maintaining baseline pH
65
What are inhibitors of acid secretion ?
Chyme in duodenum Low pH in stomach
66
How does chyme in the duodenum affect acid secretion in the stomach ?
Chyme in the duodenum inhibits acid secretion in the stomach by both hormonal and neural methods. There are responses to acidity, osmolarity, and fat content in the chyme that trigger these responses. The responses mechanism is to inhibit gastrin release by G cells and/or acid secretion by the parietal cells
67
When are the basal rates of acid secretion the highest ?
The evening
68
What are 2 ways in which the vagus nerve stimulates acid secretion in the cephalic phase of acid secretion ?
ACh directly acts on muscarinic receptors of parietal cells ACh causes release of GRP
69
________ is the only major nutrient that stimulates gastric secretion. And works by causing direct chemical release of gastrin from G cells
Proteins (must be broken down to peptides and amino acids)
70
Caffeine causes a ______ in acid secretion by the stomach
Increase
71
What are stimulants of acid production in the gastric phase?
Stomach distention PH increased Proteins
72
Caused when protective barrier of stomach breaks down, leading to injury of gastric mucosa by acid and pepsin. Most commonly in distal stomach H+ secretion into stomach reduced because some acid leaks into gastric mucosa
Gastric ulcers
73
3 major causes of peptic ulcers
Infections (helicobacter pylori) NSAID’s Alcohol
74
How does helicobacter pylori contribute to peptic ulcers ?
In stomach, breaks down gastric epithelial barrier In duodenum, inhibits secretion of somatostatin, allowing increased gastrin release and acid produciton
75
What are treatments for peptic ulcer disease
Antibiotics Proton pump inhibitor (blocks H-K-ATPase)
76
What leads to increased salivation, sweating, rapid breathing, and irregular heartbeat that occurs before and during emesis
General discharge of the autonomic nervous system
77
The vomiting center is located in the ?
Medulla
78
What are some afferent stimulations that can cause vomiting (from the vomiting center in the medulla)
Sight/smells Intense pain Motion sickness Tickling back of throat (pulling the trigger) Distention of the stomach/duodenu
79
Direct activation of the vomiting center causes what ?
Vomiting w/o nausea or retching
80
What are 3 places of vomiting control
Medulla (vomiting center) Chemoreceptor trigger zone (area postrema) Receptors present in stomach and duodenum
81
What are the effects of prolonged vomiting ?
Metabolic alkalosis Hypokalemia (loss of K and decreased reuptake) Hyponatremia (lost Na in vomit) Dehydration