GI - pt 2 Hormones etc Flashcards

1
Q

Zollinger-Ellison Syndrome

  • Non [] cell tumors of the pancrease or duodenum
    • Continually produce [] gastrin [] of the stomach
    • Not controlled by [] regulation
  • If left untreated
    • Diarrehea –> [] acid causes inactive digestive enzymes
    • Steatorrhea –> Excess [] in stool
  • Can cause [] which leads to a [] of parietal cells in the [] glands and G cell.
A
  • Non beta cell tumors of the pancrease or duodenum
    • Continually produce unregulated gastrin outside of the stomach
    • Not controlled by somatostatin regulation
  • If left untreated
    • Diarrehea –> increased acid causes inactive digestive enzymes
    • Steatorrhea –> Excess fat in stool
  • Can cause hypergastinemia which leads to a growth of parietal cells in the Oxynitic glands and G cell.
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2
Q

Cholecystokinin (CCK)

  • Structure is similar to []
  • Released from []-cells in the [] and jejunum
  • Released in response to [] from
    • peptides, amino acids, fatty acids, acids
  • Stimulates:
    • Gall bladder []
    • [] of Sphincter of Oddi
    • potent stimulator of [] [] secretion
    • Inhibits [] emptying
    • trophic action of [] pancreas, and mucosa of [] []
A

Cholecystokinin (CCK)

  • Structure is similar to gastrin
  • Released from I-cells in the duodenum and jejunum
  • Released in response to chemoreception from
    • peptides, amino acids, fatty acids, acids
  • Stimulates:
    • Gall bladder contraction
    • Relaxation of Sphincter of Oddi
    • potent stimulator of pancreatic enzyme secretion
    • Inhibits gastric emptying
    • trophic action of exocrine pancreas, and mucosa of gall bladder
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3
Q

Secretin

  • Chemically homologous to []
  • Released from []-cells of the duodenum
    • most important stimulus is [] (and [] [] to a lesser extent)
  • Stimulates
    • intestinal []and [] secretion
    • [] secretion from the stomach
  • Inhibits
    • [] [] secretion by parietal cells
A
  • Chemically homologous to Glucagon
  • Released from S-cells of the duodenum
    • most important stimulus is acid (and fatty acids to a lesser extent)
  • Stimulates
    • intestinal HCO3- and H2O secretion
    • Pepsinogen secretion from the stomach
  • Inhibits
    • gastric acid secretion by parietal cells
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4
Q

Secretin serves to [] the acid content of the intestine

A

reduce

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5
Q

Glucose-Dependent Insulinotropic Peptide (Gastric inhibitory Peptide, GIP)

  • Member of the []/[] family
  • Released from mucosal []-cells of the duodenum and [] []
  • Released in response to [] [] in the [] lumen
  • Stimulates pancreatic []-cell relese of [] in response to glucose and is the reaosn [] glucose is cleared form blood faster than [] glucose.
A

Glucose-Dependent Insulinotropic Peptide (Gastric inhibitory Peptide, GIP)

  • Member of the secretin/Glucagon family
  • Released from mucosal K-cells of the duodenum and proximal jejunum
  • Released in response to oral glucose in the duodenal lumen
  • Stimulates pancreatic Beta-cell release of insulin in response to glucose and is the reaosn oral glucose is cleared from blood faster than intravenous glucose.
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6
Q

Motilin:

  • Secreted by crypt []-cells found in the duodenum and Jejunum
  • Relese mechanism is []
  • Stimulates:
    • [] []
      • Clears the small intestine of [] in anticipation of the next meal
    • Alakalin pH - [] gastic motor functions
    • Acidic pH - [] gastric motor functions
A
  • Secreted by crypt M-cells found in the duodenum and Jejunum
  • Relese mechanism is unknown
  • Stimulates:
    • Migrating myoelectric Complex (interdigestive myoelctric complex)
      • Clears the small intestine of food in anticipation of the next meal
    • Alakalin pH - stimulates gastic motor functions
    • Acidic pH - inhibits gastric motor functions
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7
Q

Pancreatic Polypeptide

  • released from the []-cells of the [] pancreas
  • Released in response to [], [], and [] that are delivered through the []
  • Acts to inhibit:
    • All [] enzyme release
    • [] secretion
A
  • released from the PP-cells of the endocrine pancreas
  • Released in response to proteins, fats, carbohydrates that are delivered through the blood
  • Acts to inhibit:
    • All pancreatic enzyme release
    • HCO3- secretion
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8
Q

Enteroglucagon

  • released from the mucosa of the [] [] and []
  • released in response to [] (primarily) and
  • Stimulates [] [] flow
  • Inhibits:
    • [] secretion and []
    • [] flow rate in order to [] the amount of absorption that can take place.
    • This is done because [] should not be this far into the large intestine.
A
  • released from the mucosa of the distal ileum and colon
  • released in response to glucose (primarily) and fat (secondarily)
  • Stimulates hepatic bile flow
  • Inhibits:
    • acid secretion and motility
    • Decreases flow rate in order to increase the amount of absorption that can take place.
    • This is done because glucose should not be this far into the large intestine.
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9
Q

Histamine

  • synthesized in [] []-[] (ECLs) of the stomach
  • released by [] gland of the mucosa
  • Diffuses to []-[] Receptors on the nearby parietal cells.
  • Stimulates [] [] secretion
  • May be the most potent [] of gastric HCl…but so may gastrin.
A
  • synthesized in enterchromaffin-like cells (ECLs) of the stomach
  • released by Oxyntic gland of the mucosa
  • Diffuses to H2-Type Receptors on the nearby parietal cells.
  • Stimulates gastic acid secretion
  • May be the most potent stimulator of gastric HCl…but so may gastrin.
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10
Q

Vasoactive Intestinal Polypeptide

  • Chemically similar to []/[] family
  • released from nerve [] (half life 2-3 minutes)
  • Acts as a []
  • Mediates relaxation of:
    • [] smooth muscle
    • [] smooth muscle
  • Stimulates intestinal mucosa to release:
    • [] fluid, [] and [].
  • Inhibits gastrin-stimulated [] secretion
A
  • Chemically similar to secretin/Glucagon family
  • released from nerve varicosities (half life 2-3 minutes)
  • Acts as a vasodilator
  • Mediates relaxation of:
    • GI smooth muscle
    • Vascular smooth muscle
  • Stimulates intestinal mucosa to release:
    • Pancreatic fluid, HCO3- and H2O.
  • Inhibits gastrin-stimulated gastric acid secretion
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11
Q

Nitric Oxide

  • N-NOS, [] [] [] [], forms NO for release in [] endings
  • released in the [] mucosa and [] [] []
  • [] visceral smooth muscle and vasuclar smooth muscle
    • []would constrict the LES
A
  • N-NOS, or neuronal nitric oxide synthase, forms NO for release in nerve endings
  • released in the GI mucosa and Lower esophageal sphincter
  • Relaxes visceral smooth muscle and vasuclar smooth muscle
    • Ach would constrict the LES
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12
Q

The muscles that are involved in jaw closing:

A

Masseter (most important)

Medial Ptergoid

Temporalis Muscles

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13
Q

The muscles that are involved in the jaw opening:

A

Lateral pterygoid

Digastric Muscles

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14
Q

Mouth mastication is innervated by the []

A

Trigeminal Nerve (V)

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15
Q

Chewing Reflex:

  • Occurs when a bolus of food touches the lining of the []
  • Causes [] of the []jaw muscles
  • the jaw []
  • []stretch reflexes are activated which causes a rebound [].
A
  • Occurs when a bolus of food touches the lining of the mouth
  • Causes relaxation of the striated jaw muscles
  • the jaw opens
  • Monosynaptic stretch reflexes are activated which causes a rebound contraction.
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16
Q

Chewing rhythm is generated by [] stimuli to the [] center from the [] receptors. This caues a cycle of about [] duration.

A

Chewing rhythm is generated by afferent stimuli to the chewing center from the pressure receptors. This caues a cycle of about 1 second duration.

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17
Q

Deglutition ([])

  • May be initiated []
  • After the oral phase, exclusively []
  • Swallowing is a reflex triggered by [] [] receptors.
    • this reflex includes a component to inhibit [] and prevent []
A

Deglutition (swallowing)

  • May be initiated voluntarily
  • After the oral phase, exclusively reflexive
  • Swallowing is a reflex triggered by pharyngeal pressure receptors.
    • this reflex includes a component to inhibit inspiration and prevent aspiration
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18
Q

What are the 3 phases of swallowing?

A

Buccal Phase

Pharyngeal Phase

Esophageal Phase

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19
Q

Buccal Phase of Swallowing

  • initiated by [] receptors in the back of the mouth
  • The tongue lifts the bolus against the [] [] and propells it backwards.
  • Afferent Pressure Receptors
    • V - []
    • VII - []
    • IX - []
    • X - []
  • Efferents
    • V - []
    • VII - []
    • IX - []
    • X - []
    • XII - []
A
  • initiated by tactile receptors in the back of the mouth
  • The tongue lifts the bolus against the hard palate and propells it backwards.
  • Afferent Pressure Receptors
    • V - Trigeminal Nerve
    • VII - Facial Nerve
    • IX - Glossopharyngeal Nerve
    • X - Vagus Nerve
  • Efferents
    • V - Trigeminal Nerve
    • VII - Facial Nerve
    • IX - Glossopharyngeal Nerve
    • X - Vagus Nerve
    • XII - Hypoglossal Nerve
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20
Q

Pharyngeal Phase of Swallowing

  • [] palate and [] are pulled up and [] [] close to prevent nasal reflex
  • Pharyngeal muscles [] around the bolus
  • Vocal cords [] to close the glottis
  • [] covers the Trachea and respiration is []
  • UES [] and peristaltic wave begins
  • UES [] once bolus passes by
  • [] [] propels the bolus.
A
  • Soft palate and uvula are pulled up and palatopharyngeal folds close to prevent nasal reflex
  • Pharyngeal muscles accomodate around the bolus
  • Vocal cords contract to close the glottis
  • Epiglottis covers the Trachea and respiration is inhibited
  • UES relaxes and peristaltic wave begins
  • UES contracts once bolus passes by
  • Peristaltic stripping propels the bolus.
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21
Q

Esophageal Phase of Swallowing

  • Primary [] occurs
  • respiration resumes after [] of UES
  • Lower Esophageal Sphincter relaxes [] of and prior to the arrival of the [] []
  • LES is located in the [] region of the stomach
  • LES is made of [] [] muscle.
A
  • Primary peristalsis occurs
  • respiration resumes after contraction of UES
  • Lower Esophageal Sphincter relaxes independent of and prior to the arrival of the peristaltic wave
  • LES is located in the cardiac region of the stomach
  • LES is made of visceral smooth muscle.
22
Q

The upper esophageal sphincter is made of [] [] muscle and is normally [].

The lower esophageal sphincter is made of [] [] muscle and is normally [] (a lot of times due to the low energy [] state)

A

The upper esophageal sphincter is made of striated skeletal muscle and is normally relaxed.

The lower esophageal sphincter is made of visceral smooth muscle and is normally constricted (a lot of times due to the low energy latch state)

23
Q

[] [] occurs when a bolus gets stuck in the esophagus. It does not involve a [] phase of swallowing.

A

Secondary peristalsis occurs when a bolus gets stuck in the esophagus. It does not involve a pharyngeal phase of swallowing.

24
Q

Dysphagia

  • Difficulty in [], usually caused by LES not maintaining complete []
    • Can lead to [] and []
A
  • Difficulty in swallowing, usually caused by LES not maintaining complete closure
    • Can lead to esophagitis and heartburn
25
Q

Achalasia

  • Occurs when the LES does not [], usually due to problems with the myenteric plexus
  • [] [] neurotransmitter seems to be impaired, which causes the malfunction in LES.
  • food accumulates in the esophagus and causes [] [].
  • Treated by [] [] of the LES
  • Can cause [] in venous return –> [] in blood pressure
A
  • Occurs when the LES does not relax, usually due to problems with the myenteric plexus
  • Nitric Oxide neurotransmitter seems to be impaired, which causes the malfunction in LES.
  • food accumulates in the esophagus and causes secondary peristalsis.
  • Treated by balloon stretching of the LES
  • Can cause decrease in venous return –> decrease in blood pressure
26
Q

Stomach Motor functions:

  • Internal [] layer of smooth muscle helps [] out stomach during emptying
  • Extrinsic innervation from [] nerve and [] Ganglia (= [] innervation)
  • Gastric receptors - like []receptors that generate feelings of [].
A
  • Internal oblique layer of smooth muscle helps wring out stomach during emptying
  • Extrinsic innervation from Vagus nerve and Celiac Ganglia (= sympathetic innervation)
  • Gastric receptors - like pain receptors that generate feelings of satiation.
27
Q

Antral Pyloric Systole

  • BER increases in [] at the antrum starts to cause [] which lead to muscle contraction during feeding
    • mixes [] with gastric secretions
    • mixing is due to []
  • Regulates the [] of the stomach
A
  • BER increases in amplitude at the antrum and starts to cause action potentials which lead to muscle contraction during feeding
    • mixes chyme with gastric secretions
    • mixing is due to retropulsion
  • Regulates the emptying of the stomach
28
Q

Gastric Emptying

  • Rate is slowed by
    • [] volume of meal
    • high [] pressure
    • high [] and [] concentration
A
  • Rate is slowed by
    • Small volume of meal
    • high osmotic pressure
    • high fat and protein concentration
29
Q

Mechanism of Gastric Emptying:

  • 2 Rules
    • Greater stomach [] = greater emptying
    • Greater energy []= less emptying
      • fat>protein>carbs
A
  • 2 Rules
    • Greater stomach volume = greater emptying
    • Greater energy density = less emptying
      • fat>protein>carbs
30
Q

What 3 things decrease Gastric motility?

A

Gastric Inhibitory Peptide (GIP)

Cholecystokinin (CCK)

Sympathetic Nervous System (SNS

31
Q

Gastric motility is increased by…

  • []- increases release of [] from G-cells
  • [] [] [] from vagovagal reflexes
A
  • distention - increases release of gastrin from G-cells
  • Parasympathetic Nervous System (PNS) from vagovagal reflexes
32
Q

What are the 3 phases of Digestion?

A

Cephalic Phase

Gastric Phase

Intestinal Phase

33
Q

Cephalic digestion is controlled via the [] comprised of [] input and [] l input. Basically…its controlled [] the shoulders.

A

Cephalic digestion is controlled via the vagus comprised of hypothalamic input and cortical input. Basically…its controlled “above” the shoulders.

34
Q

Gastric digestion

  • Involves [] reflexes like distenstion leading to increased motility.
  • Stimuli comes from the []
    • neural stimuli is []
    • hormonal stimuli is []
A
  • Involves vago-vagal reflexes like distenstion leading to increased motility.
  • Stimuli comes from the stomach
    • neural stimuli is distention
    • hormonal stimuli is gastrin.
35
Q

Intestinal Digestion:

  • Inhibits stomach [] and stomach activity
  • Controlled by:
    • [] pH
    • osmolarity [] gastric emptying
    • []
    • Gastric [] Peptide
A
  • Inhibits stomach motility and stomach activity
  • Controlled by:
    • duodenal pH
    • osmolarity decrease gastric emptying
    • Secretin
    • Gastric Inhibitory Peptide
36
Q

[] is a protective reflex providing a mechanism to empty gastric and dueodenal contents.

A

Emesis

37
Q

Retching:

  • Reverse []
  • LES [], but UES remains []
  • Product of [] [] dominant signals
A
  • Reverse peristalsis
  • LES relaxes, but UES remains closed
  • Product of peripheral afferent dominant signals
38
Q

Central Afferents and Vomitting:

  • [] [] [] (CTZ) is though to reside in the area postrema in the medulla
  • [] []or the Nucleus Tractus Solitarius (NTS)
  • Anti-[] suppress both CTZ and NTS
  • Projectile vomitting is can be indicitive of []damage
A
  • Chemoreceptor Trigger Zone (CTZ) is though to reside in the area postrema in the medulla
  • Vomitting Center or the Nucleus Tractus Solitarius (NTS)
  • Anti-emetic suppress both CTZ and NTS
  • Projectile vomitting is can be indicitive of NTS damage
39
Q

Vomitting leads to a loss of [] and possibly metabolic []

A

Vomitting leads to a loss of H+​ and possibly metabolic Alkalosis

40
Q

Gall Bladder Motility

  • [] acids and [] acids in dueodenum casue release of []
  • CCK initiates [] of the Gall bladder and [] of the Sphincter of Oddi
A
  • Fatty acids and amino acids in dueodenum casue release of CCK
  • CCK initiates contractions of the Gall bladder and relaxation of the Sphincter of Oddi
41
Q

[] in the intestines helps “crush” food, mix chyme, and increase opportunity for food to contact enterocytes.

A

Segmentation in the intestines helps “crush” food, mix chyme, and increase opportunity for food to contact enterocytes.

42
Q

3 types of GastroIntestinal Reflexes:…

A
  1. Enteric Nervous System moediate dwith the Gut wall
  2. Prevertebral Ganglia - Sympathetic NS Reflexes
  3. Brain Stem (PNS) mediated reflexes
43
Q

Enteric NS within the gut wall Reflex:

  • [] Gastrointestinal reflex
  • Mechanisms to control [], []
  • Inhibited by over [] of the intestines
    • Inhibits [] activity for protection
A
  • Fastest Gastrointestinal reflex
  • Mechanisms to control mixing, peristalsis
  • Inhibited by over distention of the intestines
    • Inhibits contractile activity for protection
44
Q

Prevertebral Ganglia - Sympathetic NS reflexes to the Gut

  • [] Fast
  • Examples:
    • GastoIleal Reflex
      • distention of the stomch [] the [] of the ileum & [] of Ileaocecal Sphincter
    • GastroCholic Reflex
      • Distention of stomach causes and [] in the motility of the Colon…clears [] from the large intestine
    • Colonoileal Reflex
      • distention of the colon causes [] of ileum emptying.
A
  • MODESTLY Fast
  • Examples:
    • GastoIleal Reflex
      • distention of the stomch increases the motility of the ileum & relaxtion of Ileaocecal Sphincter
    • GastroCholic Reflex
      • Distention of stomach causes and increase in the motility of the Colon…clears chyme from the large intestine
    • Colonoileal Reflex
      • distention of the colon causes inhibition of ileum emptying.
45
Q

Brain Stem reflexes in the Gut

  • [] gut reflex
  • Has to travel al the way to the brain stem and wait for []response to the gut
  • Examples:
    • regulation of [] motor activity
    • regulation of [] activity
    • [] reflexes
    • [] reflexes
A
  • Slowest gut reflex
  • Has to travel al the way to the brain stem and wait for PNS response to the gut
  • Examples:
    • regulation of gastric motor activity
    • regulation of secretory activity
    • Pain reflexes
    • Defecation reflexes
46
Q

Villi Movements

  • Muscularis mucosa contracts irregularly at about []/[]
  • contraction thought to aid [] flow
A
  • Muscularis mucosa contracts irregularly at about 3/min
  • contraction thought to aid lymph flow
47
Q

List the 6 sections of the colon.

A

Ascending

Transverse

Descending

Sigmoid

Rectum

Anus

48
Q

Colonic Innervation:

  • Vagus Nerve (PNS) - [] the transverse colon
  • Pelvic Nerve (PNS) - [] the transverse colon
  • [] and [] Mesenteric Ganglia (SNS)
  • Hypogastric Ganglia (SNS) for [] and []
  • [] Nerve (voluntary) - External Anal Sphincter
A
  • Vagus Nerve (PNS) - above the transverse colon
  • Pelvic Nerve (PNS) - below the transverse colon
  • Superior and Inferior Mesenteric Ganglia (SNS)
  • Hypogastric Ganglia (SNS) for Rectum and anus
  • Pudendal Nerve (voluntary) - External Anal Sphincter
49
Q

Defecation:

  1. [] [] causes filling of rectum
  2. Rectal distention causes [] reflex relaxtion of []
  3. Reflex [] of EAS, through [] Nerve
  4. Voluntary action is necessary to [] EAS
  5. If one ignores defecation urge, feces are moved back into [] and [] passes
A
  1. Mass movement causes filling of rectum
  2. Rectal distention causes autonomic reflex relaxtion of IAS
  3. Reflex contraction of EAS, through pudendal Nerve
  4. Voluntary action is necessary to relax EAS
  5. If one ignores defecation urge, feces are moved back into colon and anxiety passes
50
Q
  • Interal Anal Sphincter
    • [] [] muscle
    • Always [], normally []
  • External Anal Sphincter
    • [] muscle innervated by the [] Nerve
    • Voluntary and [] control, normally []
  • Angle between the rectum and anus is maintained by the [] Muscle
A
  • Interal Anal Sphincter
    • circular smooth muscle
    • Always toned, normally closed
  • External Anal Sphincter
    • Striated muscle innervated by the Pudendal Nerve
    • Voluntary and reflex control, normally relaxed
  • Angle between the rectum and anus is maintained by the Puborectalis Muscle
51
Q

Haustrations

  • Bulging of [] muscle in the colon
  • SM [] to squeeze fecal material and propel the matter towards next haustra
  • 1-3 times/day we have a [] [] - which is a slow long lasting peristaltic contraction
A
  • Bulging of smooth muscle in the colon
  • SM contracts to squeeze fecal material and propel the matter towards next haustra
  • 1-3 times/day we have a Mass movement - which is a slow long lasting peristaltic contraction