GI 1 Flashcards

1
Q

Mouth to anus
Lumen Contents considered outside body
30 feet in length

A

Alimentary Canal (GI Tract)

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2
Q
Not part of GI tract
Produce substances secreted into tract
  –Salivary glands
  –Exocrine pancreas
  –Liver and Gall Bladder
A

Accessory organs

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3
Q
Function of GI:
Breakdown ingested molecules into building blocks
Two Types
  A. Mechanical
  B. Chemical
A

Digestion

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4
Q

Function of GI:
Digestive enzymes
Acid/Base
Bile

A

Secretion

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5
Q

Function of GI:
Passive and Active transport processes
Moves substances from lumen of gut to blood

A

Absorption

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6
Q

Function of GI:
Mixing
Mechanical Digestion
Move material through tract

A

Motility

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7
Q

Function of GI:
Removal of Metabolic waste
Very little true waste in Feces (Bile pigments)

A

Excretion

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8
Q

Function of GI:

Gut Associated Lymphoid Tissue

A

Defense

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9
Q

What are the 4 layers of structure of GI tract wall from outermost to innermost?

A

Mucosa
Submucosa
Muscularis externa
Serosa

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10
Q

Simple Columnar Epithelium
Lamina Propria
Muscularis Mucosa
-Movement of Villi

A

Mucosa

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11
Q

CT Layer
Blood and lymph vessels
Submucosal Plexus
-Network of neurons-Projections to luminal surface cells, muscularis mucosa, and to Myenteric plexus

A

Submucosa

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12
Q

-Network of neurons-Projections to luminal surface cells, muscularis mucosa, and to Myenteric plexus

A

Submucosal Plexus

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13
Q

Circular Muscle-Contraction narrows lumen
Longitudinal muscle-Contraction shortens tube
Myenteric Plexus
-Network of neurons-Input from Autonomic NS-
Projections to Submucosal Plexus, Circular, and
Longitudinal muscle

A

Muscularis Externa

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14
Q
  • Network of neurons
  • Input from Autonomic NS
  • Projections to Submucosal Plexus, Circular, and Longitudinal muscle
A

Myenteric Plexus

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15
Q

CT covering

Support GI tract in abdominal cavity

A

Serosa

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16
Q

What 2 things make up the enteric NS?

A

Submucosal and Myenteric Plexus

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17
Q
\_\_\_\_\_\_ layer:
Simple Columnar (microvilli)
Goblet Cells
Enteroendocrine cells (base of villi)
Stem cells
A

Epithelial

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18
Q

Tremendous surface area available for absorption of materials from lumen via what 3 things?

A
  1. Circular Folds
  2. Villi
  3. Microvilli (Brush Border)
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19
Q

Circular Folds, Villi, and Microvilli (Brush Border)Increases SA ____ times over flat surface

A

600x

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20
Q

The following are Inside the ______:
Lacteals (lymph vessels)
Capillary network

A

Villus

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21
Q

Control Systems regulate conditions in ____ of tract

A

lumen

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22
Q

Control mechanisms are governed by ______ and ______ of luminal contents

A

volume and composition

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23
Q

ECL cells in the GI system secrete ______

A

histamine

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24
Q

D cells in the GI system secrete ______

A

Somatostatin

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25
Q

_____ innervation:
Responds to stretch, inflammation, nutrients, endocrine factors.
Synapses in enteric nervous system, prevertebral ganglia, spinal cord, brainstem.
Vagal nerves mainly afferent to brainstem.

A

Afferent (sensory)

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26
Q

_____ innervation– CN XII (tongue), V (chewing), IX, X (swallowing); Pudendal n. – ext. anal sphincter

A

Somatic

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27
Q

_____innervation post-ganglionicfibers (NEpi) to enteric nervous system, vasculature, ducts, parenchyma; usually inhibitory.

A

Sympathetic –

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28
Q

_____ innervation: ENS functions as post-ganglionic fibers, actions are stimulatory or inhibitory, depending on final neurotransmitter receptor.

A

Parasympathetic (vagus, pelvic)

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29
Q

____ is the neurotransmitter that is released from symp postganglionic neurons

A

NE

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30
Q

____ is the neurotransmitter that is released from parasymp preganglionic neurons

A

ACh

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31
Q

Linear chain of neurons that extend the entire length of GI Tract
Control muscle of muscularis externa
When stimulated
1.Increase tone of gut wall
2.Increase intensity of rhythmic contractions
3.Slight increase in rate of rhythmic contractions
4.Increase conduction velocity of electrical waves along gut wall
5.Inhibition of sphincter contraction

A

Enteric nervous system (ENS)

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32
Q
\_\_\_\_\_\_\_:
Controls function of each minute segment of tract
Local control of 
-Intestinal secretions
-Absorption
-Contraction of mucosal muscle
A

Enteric Nervous System (ENS)

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33
Q

What are the 3 receptors that respond to GI lumen stimulus?

A

Chemoreceptors, osmoreceptors, and mechanoreceptors

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34
Q

Are there long or short feedback loops in GI?

A

Both

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35
Q

____ cells are scattered in gut mucosa

A

Endocrine cells

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36
Q

Specialized cells: one cell – one hormone (mostly).
Specific cell types localized to regions of gut.
Cells “taste” luminal contents.

A

Endocrine regulation of digestive function

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37
Q

Cells similar to endocrine.
Released into interstitial fluid, diffuses to target (may “overflow” into the circulation).
Two established gut paracrine factors: histamine (ECL cell), somatostatin (D cell).

A

Paracrine factors

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38
Q

____ is mainly released by gastrin

A

Histamine

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39
Q

_____ is mainly released by luminal H+

A

Somatostatin

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40
Q
Patterns of \_\_\_\_\_\_ include: 
Chewing
Swallowing
Esophageal transport
Gastric storage, trituration, emptying
Vomiting
Gallbladder storage, emptying
Small intestinal mixing & transport
Colonic storage, defecation
A

Motility

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41
Q

_____ muscle of the GI tract:

-mouth, oropharynx, upper esophageal sphincter, upper 1/3 of esophagus, external anal sphincter.

A

Skeletal (voluntary, striated) –

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42
Q

_____ muscle of the GI tract:

- lower 2/3 of esophagus, stomach, small intestine, large intestine, gallbladder, biliary and pancreatic ducts.

A

Smooth (involuntary)

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43
Q

Collects all venous outflow from most GI organs.

A

Portal vein

44
Q

All portal outflow goes to ____ before entering vena cava.

A

liver

45
Q

Nutrients, hormones, drugs, toxins are “scanned” by _____ before going to IVC.

A

liver

46
Q

_______ saliva:
Watery secretion containing ptyalin (α amylase)
Moisten and dissolve food
Small amount of chemical digestion

A

Serous saliva

47
Q

______ saliva:
Thick secretions containing mucin
Lubrication and protection of surfaces

A

Mucous saliva

48
Q

What type of saliva is secreted by parotid?

A

Serous

49
Q

What type of saliva is secreted by submandibular?

A

Mixed

50
Q

What type of saliva is secreted by sublingual?

A

Mixed

51
Q

What type of saliva is secreted by the many tiny buccal salivary glands?

A

Mucous

52
Q

_____ is made up of the following things:

  • Water
  • Bicarb
  • Mucins
  • Amylase
  • Lysozyme, Lactoferrin, and IgA
  • Epidermal and nerve growth factors
A

Saliva

53
Q

Up to _____ L/day of saliva is produced

A

1.5 L/day

54
Q

Secretion of saliva is strictly under ______ reflex control

A

Neural reflex control

55
Q

_____ (constituent of saliva):

-Facilitates taste and dissolution of nutrients, aids in swallowing

A

Water

56
Q

_____ (constituent of saliva): Neutralizes refluxed gastric acid

A

Bicarbonate

57
Q

_____ (constituent of saliva): Lubrication

A

Mucins

58
Q

_____ (constituent of saliva):Starch Digestion

A

Amylase

59
Q

_____ (constituent of saliva): Innate and acquired immunity

A

Lysozyme, Lactoferrin, IgA

60
Q

_____ (constituent of saliva): ? Mucosal growth and protection

A

Epidermal and nerve growth factors

61
Q

Does parasymp activity or symp activity increase saliva?

A

Parasymp

62
Q

Predominate regulator of saliva production
Critical for initiation of saliva secretion
Critical for sustaining high levels of saliva secretion
Vasodilation of blood vessels supplying salivary glands22
Causes:-Up to 20x increase in saliva production by acinar cells

A

Parasymp NS

63
Q

What neurotransmitter binds to what receptors for the parasymp NS?

A

Ach/Muscarinic

64
Q

As flow rate increases, the saliva becomes more closely resembles the ______

A

Plasma

65
Q

As flow rate increases, the saliva becomes more basic or acidic?

A

Basic

66
Q

As flow rate increases, the saliva becomes less hyper or hypotonic?

A

Hypotonic

67
Q

Reflex Activation of ______ Stimulated Saliva Production:
Taste (especially sour) and tactile stimuli (presence of smooth objects) on tongue surface
Smell of food (especially if it is a food that is not liked)
Ingestion of irritating foods
Nausea

A

Parasympathetic

68
Q

_____ NS plays a minor role in control of saliva and potentiates parasympathetic effects

A

SNS

69
Q

What neurotransmitters bind to what receptors for SNS?

A

NE/adrenergic

70
Q

At low flow rates, saliva is ______

A

hypotonic

71
Q

What percentage of saliva in unstimulated salivation is secreted by parotid gland?

A

69%

72
Q

What percentage of saliva in unstimulated salivation is secreted by submandibular gland?

A

26%

73
Q

What percentage of saliva in unstimulated salivation is secreted by sublingual gland?

A

5%

74
Q

What percentage of saliva in stimulated salivation is secreted by parotid gland?

A

26%

75
Q

What percentage of saliva in stimulated salivation is secreted by submandibular gland?

A

69%

76
Q

What percentage of saliva in stimulated salivation is secreted by sublingual gland?

A

5%

77
Q

______ salivation is inhibited by the following:

  1. Fear
  2. Sleep
  3. Fatigue
  4. Dehydration
A

Unstimulated salivation

78
Q

_____ salivation is stimulated by the following:

  1. Autonomic (primarily parasympathetic)
  2. Thinking/seeing/smelling food
  3. Conditioned salivation
  4. Chewing
  5. Nausea
A

Stimulated salivation

79
Q

T/F: Rates of saliva production are not dependent on age, flow rates remain constant in spite of acinar degeneration.

A

True

80
Q
Subjective feeling of a dry mouth.
Most common causes
-Polypharmacy (>4 drugs/day)
-Anxiety and depression (and medications used for treatment)
-Insufficient hydration
-Radiation to the head and neck
-Sjogren syndrome
A

Xerostomia

81
Q

What are the 5 common causes of xerostomia?

A
  • Polypharmacy (>4 drugs/day)
  • Anxiety and depression (and medications used for treatment)
  • Insufficient hydration
  • Radiation to the head and neck
  • Sjogren syndrome
82
Q

Autoimmune destruction of mucous membranes and moisture-secreting glands
Decreased production of tears and saliva
Dry eyes and mouth

A

Sjogren’s syndrome

83
Q

Consequences of _______:
Increased caries due to reduced oral clearance of sugars, dietary acids, oral bacteria
Halitosis
Disrupted sleep due to dry mouth; wake up to sip water and moisten mouth
Difficulty lubricating and swallowing food
Dry mouth (feel thirsty, dry, cracked lips)
–Burning mouth sensation
–Dry/sore oral mucosa
Impaired sense of tastes
Heartburn
–Low saliva; decreased buffering
–Loss of protective growth factors in saliva
–Lengthened healing time for ulcers

A

Xerostomia

84
Q

Management of ______:
•Avoid acidic, spicy, crunchy and coarse foods.
•Alcohol-free toothpastes and rinses.
•Oral moisturizers, sips of water, sugarless chewing gum.
•Sialogogues such as pilocarpine and cevimeline before meals (cholinergic agonists)

A

Xerostomia

85
Q

Rhythmic opening and closing of mandible that is coordinated with tongue movements

A

Mastication

86
Q

Functions of ______ include:
1. Prepare food bolus for swallowing
Mechanical digestion – Reduce particle size
-Break up cells
-Break up indigestible cellulose
-Increase surface area/decrease particle size for
mixing with digestive enzymes
Mix food with saliva (serous and mucous)
-Chemical digestion (mainly carbohydrates)
-Sufficient plasticity-Surface lubrication
-Cohesive structure
2. Initiate digestive and metabolic activities
Digestion of carbohydrates in mouth
Initiate reflexes to prepare digestive tract for
incoming food

A

Mastication

87
Q

What are the 3 stages of deglutition?

A

Voluntary stage
Pharyngeal stage
Esophageal stage

88
Q

_____ stage of deglutition:
Initiate swallowing process
Bolus of food moved into pharynx by tongue
Stimulates epithelial swallowing receptor area

A

Voluntary Stage

89
Q

_____ stage of deglutition:
Involuntary
Mediated by swallowing center in brainstemSoft palate pulled upward and closes off nasopharynx
Epiglottis closes off trachea (Respiration inhibited for < 2 sec.)
Upper Esophageal Sphincter (UES; Pharyngoesophageal Sphincter) relaxes

A

Pharyngeal Stage

90
Q

_____ stage of deglutition:
Coordinated muscle contractions to move bolus through esophagus into stomach (aborally).
≈ 10 sec.

A

Esophageal Stage

91
Q

What are the 3 functions of the esophagus?

A
  1. Transport of solids and liquids from Pharynx to stomach
  2. Prevents air intake - UES
  3. Prevents reflux (stomach to esophagus) -LES
92
Q

Which esophageal sphincter prevents air intake?

A

UES

93
Q

Which esophageal sphincter prevents reflux?

A

LES

94
Q

wave of contraction that moves bolus through esophagus

A

Peristalsis =

95
Q

_____ peristalsis:

-continuation of peristaltic wave initiated during pharyngeal phase of swallowing (8-10 sec)

A

A. Primary Peristalsis

96
Q

_____ peristalsis:

-activated by esophageal distension from retained food in esophagus

A

Secondary Peristalsis

97
Q

Is the upper portion or lower portion of esophagus under voluntary control?

A

Upper

98
Q

_____ peristalsis occurs as a wave of relaxation in front of bolus and a wave of contraction behind bolus

A

Primary peristalsis

99
Q

_____ is the term used for the wave of relaxation in front of bolus

A

Caudad

100
Q

_____ is the term used for the wave of contraction behind bolus

A

Orad

101
Q

Which neurotransmitter carries out orad?

A

Ach

102
Q

Which neurotransmitter carries out caudad?

A

NO

103
Q

______ peristalsis Function
Clearing a bolus that was not wholly expelled by primary wave
Removing any gastric contents that reflux back into the lower esophagus

A

Secondary peristalsis

104
Q

Upper and lower esophageal sphincters remain _______ between swallows

A

closed

105
Q

________ sphincter relaxes during swallow.

A

Upper esophageal sphincter

106
Q

______ sphincter relaxes as peristaltic wave approaches.

A

Lower esophageal sphincter

107
Q

Reflux of gastric contents into esophagus
Common and potentially disabling
Treated by inhibiting gastric acid secretion

A

Gastro-Esophageal Reflux Disease