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Physiology > Gastrointestinal Physiology > Flashcards

Gastrointestinal Physiology Flashcards

1
Q

What are the components of the digestive system?

A
  1. Alimentary canal (GI tract)
  2. Accessory organs
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2
Q

The alimentary canal (GI tract) travels from ____ to ____

A

Mouth to anus

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3
Q

The luminal contents within the alimentary canal are considered:

A

Outside the body

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4
Q

How long is the alimentary canal?

A

30 feet in length

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5
Q

When are substances within the alimentary canal when are they considered inside the body?

A

After they have been absorbed across the epithelial layer that lines the GI tract

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6
Q

______ are in place to keep digested food contents moving in one direction

A

Sphincters

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7
Q

Sphincter located between the esophagus and stomach; failure leads to GERD

A

Lower esophageal sphincter

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8
Q

Failure of the lower esophageal sphincter leads to:

A

Acid reflux

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9
Q

Sphincter located between the stomach and small intestine:

A

Pyloric valve

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10
Q

Sphincter located between the small intestine and colon:

A

Ileocecal valve

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11
Q

Sphincter located at the end of the colon; made of smooth muscle & INVOLUNTARY:

A

Internal anal sphincter

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12
Q

Sphincter located at the end of the colon; made of VOLUNTARY muscle

A

External anal sphincter

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13
Q

Sphincter that controls the release of contents from the pancreas and liver into the small intestine

A

Sphincter of Oddi

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14
Q

List the six functions of the GI system:

A
  1. Digestion
  2. Secretion
  3. Absorption
  4. Motility
  5. Excretion
  6. Defense
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15
Q

Describe digestion:

A

Breakdown down of ingested macromolecules into their building blocks

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16
Q

What are the two types of digestion?

A
  1. Mechanical
  2. Chemical
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17
Q

Physically breaking down food into smaller pieces such as chewing:

A

Mechanical digestion

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18
Q

Motility patterns of the digestive tract, particularly the ones in the stomach are designed for:

A

Mechanical digestion

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19
Q

Breaking down food through the use of enzymes:

A

Chemical digestion

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20
Q

What components are involved in GI secretion?

A
  1. digestive enzymes
  2. acid/base
  3. bile
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21
Q

Involves the passive and active transport processes across an epithelial layer:

A

Absorption

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22
Q

The absorption seen in the GI system moves substances from:

A

Lumen of gut to blood

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23
Q

Looking at the starling forces governing capillary exchange outside of the small intestine, overall we have ______ along the entire of the capillary

A

Net absorption

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24
Q

The contractile patterns of the GI system:

A

Motility

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25
Q

The motility aspect of the digestive system involves what three components:

A
  1. Mixing
  2. Mechanical digestion
  3. Propulsion
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26
Q

Movement of material through the digestive tract:

A

Propulsion

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27
Q

Removal of metabolic waste from body:

A

Excretion

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28
Q

There is very little ____ in feces

A

true waste

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29
Q

any undigested products to be excreted from the body:

A

Metabolic waste

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30
Q

What gives the feces color?

A

Bile pigments

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31
Q

The defensive component of the GI tract involves:

A

Gut associated lymphoid tissue

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32
Q

What defensive organ monitors the entrance point of the digestive tract?

A

Tonsils

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33
Q

List the path of food travel through the GI tract:

A
  1. Mouth
  2. Esophagus
  3. Stomach
  4. Small intestine
  5. Colon
  6. Rectum
  7. Anus
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34
Q

As food enters into the body it is stored in the _____, which will slowly release it into the ____

A

Stomach, small intestine

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35
Q

Describe the processes occurring in the stomach:

A

Not much absorption, mainly secretion (acid secretion)

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36
Q

What is the purpose of secretion of acid in the stomach?

A

To sterilize the meal

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37
Q

Describe the size of contents as if goes through the digestive tract:

A

Starts large, gets smaller and smaller until it reaches the colon where compaction occurs to re-solidify the material

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38
Q

Describe the processes that occur early on in the small intestine:

A

Massive amounts of secretion & absorption

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39
Q

Describe the processes that occur later on in the small intestine:

A

Still see absorption & secretion but much less than seen early on in the small intestine

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40
Q

The substances being absorbed in the small intestine are being absorbed by the:

A

Hepatic portal vein

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41
Q

Because the hepatic portal vein is the location of where the absorbed substances from the small intestine go, describe what happens to these absorbed substances: T

A

Everything being absorbed from the small intestine will go to the liver before it gets dumped into general circulation

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42
Q

Under normal circumstance almost ALL of the meal is digested & absorbed by:

An exception to this is:

A

The first 25% of the small intestine

Exception= fats (take a bit longer)

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43
Q

Functions to compact the small fragments of material following digestion:

How does it do this?

A

Colon

Reabsorption of a lot of salt & water to concentrates the feces

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44
Q

List ingested substances that serve as nutrients: (7)

A
  1. Carbs
  2. Fats
  3. Proteins
  4. DNA/RNA
  5. Water
  6. Electrolytes
  7. Vitamins
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45
Q

Amount of water & solids ingested per day:

A

1200 mL water/day
500-800 g solid/day

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46
Q

Amount of salivary secretions per day:

Amount of gastric secretions per day:

A

1500 mL

2000 mL

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47
Q

Amount of bile secreted by the liver per day:

Amount of pancreatic secretions per day:

A

500 mL bile

1500 mL pancreatic secretions

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48
Q

Amount of absorption into the blood from the small intestine per day:

A

6700 mL/day

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49
Q

Amount of intestinal secretions (primarily into the small intestine) per day:

A

1500 mL

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50
Q

Amount of absorption into the blood from the large intestine per day:

A

1400 mL

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51
Q

Amount of water & solid excreted into the feces per day:
(on average)

A

100 mL water
50 g solid

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52
Q

Movement of contents too quickly through the digestive tract will result in:

A

Diarrhea

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53
Q

Movement of contents too slowly through the digestive tract will result in:

A

Constipation

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54
Q

What four layers comprise the GI tract wall?

A
  1. Mucosa
  2. Submucosa
  3. Muscularis externa
  4. Serosa
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55
Q

What layer of the GI tract wall is being described:

  • Simple columnar epithelium
  • Lamina propria
  • Muscular mucosa for the movement of villi
A

Mucosa

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56
Q

What layer of the GI tract wall is being described:

  • Connective tissue layer
  • Blood vessels & lymph
  • Submucosal plexus
A

Submucosa

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57
Q

What layer of the GI tract wall is being described:

  • Circulare muscle
  • Longitudinal muscle
  • Myenteric plexus
A

Muscularis externa

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58
Q

What layer of the GI tract wall is being described:

  • Connective tissue covering
  • Support GI tract in abdominal covering
A

Serosa

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59
Q

Describes the epithelium that comprises the mucosa layer of the GI tract wall:

A

Simple columnar epithlium; heterogeneous

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60
Q

What does it mean that the epithelium comprising the mucosa layer is “heterogeneous”

A

Some of the cells of the epithelium actively absorb nutrients of the lumen, some of the cells actively secrete hormones into the blood and some of these cells may be stem cells that are dividing and replacing

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61
Q

What is the innermost layer of the GI tract wall?

A

Mucosa

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62
Q

Located in the mucosa layer of the GI tract wall, just beneath the epithelial layer

A

Lamina propria

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63
Q

Blood & nerve supply come up through which portion of the mucosa layer of the GI tract wall?

A

Lamina propria

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64
Q

Innermost layer of the mucosa layer of the GI tract wall, functions to move villi:

A

Muscularis mucosa

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65
Q

Major blood & lymph vessels of the GI tract travel through the:

A

Submucosa layer

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66
Q

Network of neurons located within the submucosa:

A

Submucosal plexus

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67
Q

The submucosal plexus is receiving input from another nervous system plexus that is deeper in the wall, called the ______, & the submucosal plexus will also send info to this plexus

A

Myenteric plexus

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68
Q

Describe the muscular makeup of the muscularis externa layer of the GI tract wall:

A
  • Made of smooth muscle

Arranged into circular muscle & longitudinal muscle

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69
Q

Muscle fibers arranged concentrically around the lumen; functions to change lumen diameter

A

Circular muscle

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70
Q

Contraction of concentric muscle=

Relaxation of concentric muscle=

A

Constrict lumen
Dilate lumen

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71
Q

Muscle fibers arranged along the long axis of the GI tube; allows for coordinated contraction of different areas of the tube to occur together

A

Longitudinal muscle

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72
Q

What does longitudinal muscle allow for:

A

Coordinated contraction of different areas along the tube

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73
Q

In between the circular & longitudinal muscle layers is the:

A

Myenteric plexus

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74
Q

The myenteric plexus is a network of neurons in the ______ that receives input from the ______

A

Muscularis externa; autonomic NS

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75
Q

The myenteric plexus has projections into the:

A

Submucosal plexus, circular muscle & longitudinal muscle

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76
Q

Submucosal & myenteric plexus “little brain”

A

Enteric nervous system

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77
Q

The digestive tract is the only organ in the body that has its own:

A

Brain

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78
Q

What types of cells are located within the epithelial layer of the GI tract?

A
  1. Simple columnar (with microvilli)
  2. Goblet cells
  3. Enteroendocrine cells
  4. Stem cells
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79
Q

The simple columnar cells found within the epithelial layer have:

A

Microvilli

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80
Q

Unicellular exocrine gland that secretes mucous within the epithelial layer:

A

Goblet cells

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81
Q

Why is it important to have mucous secretion by goblet cells within the epithelial layer?

A

Mucous protects the GI lining from the acidic environment

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82
Q

Enteroendocrine cells within the epithelial layer are located at the:

A

Base of the villi

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83
Q

Found within the epithelial layer, function to secrete hormone into the blood:

A

Enteroendocrine cells

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84
Q

Stem cells within the epithelial layer are located:

A

Within crypts

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85
Q

What components allow for the tremendous surface area available for the absorption of materials from the lumen?

A
  1. Circular folds
  2. Villi
  3. Microvilli
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86
Q

Circular folds increase the surface area of the:

A

Intestinal lining

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87
Q

Vili are extensions off _____ and increase the surface area of the _____

A

Circular folds; circular folds

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88
Q

Another name for microvilli:

A

Brush border

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89
Q

Microvilli are located on the _____& increase the surface area of the ____

A

Apical membrane of the vili; apical membrane

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90
Q

Together, circular folds, villi, & microvilli increase the SA ____x over flat surface

A

600x

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91
Q

What two components are present inside the villus?

A
  1. Lacteals (lymph vessels)
  2. Capillary network
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92
Q

Substances absorbed across the epithelium will either enter _____ also known as ______ or will enter _____

A

lacteals also known as lymph vessels; capillary network

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93
Q

What moves the villus?

A

Muscularis mucosa

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94
Q

Venous drainage & lacteal movement can all be described as:

A

passive

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95
Q

Since venous drainage & lacteal movement are passive processes they require:

A

Skeletal muscle contractions & one-way valves

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96
Q

The process of muscularis mucosa contraction, causing the villus to move up and down & allowing for the absorbed digestates to move through the capillaries, through the veins, and then back to the general circulation:

A

Milking the villus

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97
Q

When looking at hormone levels within the GI system, changes in hormones are the response of changes in the ______ NOT the _____

A

Lumen; ECF

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98
Q

Control systems of the GI regulate systems in:

A

Lumen of tract

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99
Q

Control mechanisms are governed by ____ & ____ of luminal contents

A

Volume & luminal composition

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100
Q

When changes in the gut lumen initiate secretion of a hormone into the blood:

A

Endocrine secretion

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101
Q

When changes in the gut lime will cause paracrines to be secreted into the interstitial fluid & affect cells close by:

A

Paracrine secretion

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102
Q

Autonomic nerve function that will stimulate an endocrine gland to secrete a hormone into the blood:

A

Neurocrine secretion

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103
Q

When two cells actually have to make contact with eachother for secretion to occur:

A

Immune/Juxtacrine secretion

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104
Q

Name two examples of cells that displaying immune or juxtacrine secretion:

A

ECL cells & D cells

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105
Q

What do ECL cells secrete?

A

Histamine

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106
Q

What D-cells secrete?

A

Somatostatin

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107
Q

The gut innervation responsible for sensory:

A

Afferent neurons

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108
Q

The gut innervation responsible for secretomotor:

A

Efferent neurons

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109
Q

Reflex receptors that respond to stretch, inflammation, nutrients & endocrine factors:

A

Afferent sensory

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110
Q

Afferent sensory neurons respond to:

A
  1. Stretch
  2. Inflammation
  3. Nutrients
  4. Endocrine factors
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111
Q

Afferent sensory neurons form synapses in:

A
  1. Enteric nervous system
  2. Prevertebral ganglia
  3. Spinal cord
  4. Brainstem
112
Q

Vagal nerves are mainly ______ to the brainstem

113
Q

Sensory info TO the brain stem is going to be carried by:

A

Vagal sensory neurons

114
Q

When a vagal nerve carries the sensory information in & a vagal nerve caries the parasympathetic commands out:

A

Vagal-vagal reflex

115
Q

What are the categories of efferent (secretomotor) control?

A
  1. Somatic
  2. Sympathetic
  3. Parasympathetic
116
Q

We have _____ control for muscles of the tongue, for muscles of chewing, and muscles of swallowing

A

Somatic motor control

117
Q

Cranial nerve response for the following:

-Muscles of the tongue
-Muscles of chewing
-Muscles of swallowing

A

Tongue= CN 12
Chewing= CN 5
Swallowing= CN 9&10

118
Q

The pudendal nerve is a ______ nerve that controls both the external urethral sphincter as well as the external anal sphincter

A

Somatic nerve

119
Q

Both the external urethral sphincter & external anal sphincter can be described as:

120
Q

We have voluntary muscle at the start of the digestive tract & voluntary muscle at the digestive tract but _______ muscle in between that is controlled by _____

A

Smooth muscle; Autonomic nervous system

121
Q

What is the majority of the autonomics that make up the middle of the digestive tract and why?

A

Mostly sympathetic post-ganglionic nerve fibers because they form in the pre-vertebral foramen & will extend to the digestive tract

122
Q

The post-ganglionic nerve fibers that form in the pre-vertebral foramen & extend to the digestive tract will release _____ to _____

A

Norepinephrine; enteric nervous system, vasculature, ducts & cells of the tissue

123
Q

The sympathetic nervous system is mostly ______ to digestion

A

Inhibitory

124
Q

Digestion is dominated by ______ function

A

Parasympathetic

125
Q

The parasympathetic motor neurons of the digestive tract:

A
  1. Vagus nerve
  2. Pelvic nerves
126
Q

Parasympathetic nervous control can be stimulatory or inhibitory depending on:

A

The final neurotransmitter being released

127
Q

Post-ganglionic fibers (NEpi) to enteric nervous system, vasculature, ducts, parenchyma; usually inhibitory

A

Sympathetic

128
Q

ENS functions as post-ganglionic fibers, actions are stimulatory or inhibitory depending on final nerve transmitter receptor

A

Parasympathetic

129
Q

Monitor the conditions of the lumen of the gut:

A

Sensory neurons

130
Q

What are some things that a sensory neuron might monitor?

A

Stretch, nutrients, etc.

131
Q

When a sensory neuron is stimulated, the sensory information can then go to the _______ OR the sensory information can go to the _________

A

Enteric nervous system; prevertebral ganglion, spinal cord, brain stem

132
Q

Following the sensory neuron transmitting the stimuli to the appropriate area (ENS, Prevertebral ganglion, spinal cord or brainstem), we will then have:

A

Sympathetic and parasympathetic outflow from the brain

133
Q

If the response to the stimulus is sympathetic outflow from the brain, it will be mostly ______ fibers that will secrete _____ as their NT

A

Post-ganglionic; Norepinephrine

134
Q

Parasympathetic fibers are all going to be _____

A

Preglanglionic

135
Q

Describe the length of the sympathetic post-ganglionic fibers:

136
Q

Describe the length of the parasympathetic pre-ganglionic fibers:

137
Q

The synapse between the pre-ganglionic & post-ganglionic nerve fibers occur in the:

A

Wall of the organ

138
Q

Parasympathetic pre-ganglionic fibers release _____ and its going to influence the function of neurons in the____.

A

Acetylcholine; enteric nervous system

139
Q

What neurotransmitter is released by the parasympathetic nerve fiber?

What does this influence?

A

Acetylcholine

Enteric nervous system

140
Q

When the enteric nervous system is influenced by acetylcholine released from the parasympathetic nerve fibers, the response to the digestive system will be:

A

Either stimulatory or inhibitory

141
Q

In general terms, the myenteric plexus is involved in:

A

Coordinated function all along the length of the digestive tract

142
Q

The submucosal plexus and the myenteric plexus can both be stimulated by: (4)

A
  1. Acetylcholine
  2. Amines
  3. Nitric oxide
  4. Many peptides
143
Q

When a sensory neuron is stimulated it can act on the _____ or travel up and act on the ____ or ____

A
  1. Submucosal plexus
  2. Myenteric plexus
  3. Prevertebral ganglia, spinal cord & brainstem
144
Q

Neurotransmitter for:

  1. Sympathetic motor neurons:
  2. Parasympathetic motor neurons:
A
  1. Norepinephrine
  2. Acetylcholine
145
Q

Linear chain of neurons that extend the entire length of the GI tract:

A

Myenteric plexus

146
Q

The myenteric plexus is a linear chain of neurons that extends:

A

The entire length of the GI tract

147
Q

The myenteric plexus controls:

A

The muscle of the muscularis externa

148
Q

What occurs when the myenteric plexus is stimulated?

A
  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 the gut
  5. inhibition of sphincter contraction
149
Q

Why is sphincter contraction inhibited when the myenteric plexus is stimulated?

A

The sphincter has to relax to move contents from one area to another

150
Q

The enteric nervous system is considered:

A

“The Brain in the Gut”

151
Q

Controls function of each minute segment of GI tract:

A

Submucosal plexus

152
Q

What plexus is involved in local control?

A

Submucosal plexus

153
Q

The control of the submucosal plexus involves control of:

A
  1. intestinal secretions
  2. absorption
  3. contraction of mucosal muscle
154
Q

Stimuli that can occur INSIDE the GI lumen include:

A

Changes in chemicals, osmolarity, or some sort of mechanical change like stretch

155
Q

The stimulus sensed by sensory neurons will activate sensory receptors such as:

A

Chemoreceptors, osmoreceptors & mechanoreceptors

156
Q

Describe the pathway of a short loop reflex:

A
  1. Stimulus
  2. Chemoreceptors, osmoreceptors, or mechanoreceptors in GI wall
  3. ^^ these receptors stimulate the enteric NS inside the GI wall
  4. The enteric NS activates smooth muscles & glands
  5. Response in the GI lumen
157
Q

Describe the pathways of a long loop reflex:

A
  1. Stimulus
  2. Chemoreceptors, osmoreceptors, or mechanoreceptors
  3. Afferent neurons to CNS
  4. Vagal efferent neurons
  5. Enteric nervous system
  6. Smooth muscle or gland action activation
  7. GI response
158
Q

Describe the speed & CNS involvement in the long loop reflex:

Describe the speed & CNS involvment in the short loop reflex:

A

Long loop= Slower, involves CNS

Short loop= Rapid, No CNS involvement

159
Q

In may instances, both short & long loop reflexes:

A

Occur at the same time

160
Q

CNS stimulation can cause changes in the GI tract by stimnuli arising:

A

Outside of the GI tract

161
Q

What are some examples of CNS stimulation outside of the GI tract?

A

-Site of food
-Smell of food
-Taste of food
- Emotional state

162
Q

True or False:

Many of the neurons in the ENS also function as parasympathetic post-ganglionic fibers

163
Q

True or False:

The submucosal plexus functions to inhibit sphincter contraction

A

False- Myenteric plexus does this

164
Q

True or False:

Local control of the GI tract is mediated by the function of the submucosal plexus

165
Q

True or False:

Vagal sensory neurons monitoring the gut are activated by changes in the GI lumen or wall

166
Q

True or False:

Sensory information arising from the gut must be processes through the CNS

A

False- can have short loop reflex

167
Q

Endocrine cells scattered in gut mucosa:

A

Unicellular endocrine glands

168
Q

Unicellular endocrine glands are considered ____ cells with ____

A

Specialized cells; one hormone

169
Q

Describe the secretion of hormones from specialized endocrine cells:

A

Usually secrete one hormone only

170
Q

When looking at endocrine cells of the digestive system, specific cell types are:

A

Localized to regions of the gut

171
Q

When & where do the unicellular endocrine glands secrete their hormone?

A

When they taste the luminal contents; into the blood

172
Q

Hormones are secreted by the unicellular glands based on:

A

Responses to changes in the LUMEN

173
Q

The secretory products of the endocrine cells will be secreted out of the _____where the blood supply is & will be secreted in response to changes in the lumen

A

Basolateral surface

174
Q

Paracrine factors are similar to endocrine, but instead of being released into the blood, they are released into the ______ where they _____

A

Interstitial fluid; Diffuse to target cells

175
Q

Paracrine factors are released into the interstitial fluid, which diffuses to the target cell, but some of these factors may:

A

Overflow into the circulation

176
Q

Two established paracrine factors include:

A
  1. Histamine
  2. Somatostatin
177
Q

Histamine is released by ______ cells

Somatostatin is released by _____ cells

A

Histamine= ECL cells

Somatostatin= D cells

178
Q

Paracrine secrete their substances across the _____ surface into the interstitial space

A

Basolateral surface

179
Q

Histamine is mainly released by:

180
Q

Somatostatin is mainly released by:

A

Luminal H+

181
Q

Patterns of motility include:

A
  1. Chewing
  2. Swallowing
  3. Esophageal transport
  4. Gastric storage, trituration, emptying
  5. Vomiting
  6. Gallbladder storage, emptying
  7. Small intestinal mixing & transport
  8. Colonic storage, defication
182
Q

Patterns of motility include:

A
  1. Chewing
  2. Swallowing
  3. Esophageal transport
  4. Gastric storage, trituration, emptying
  5. Vomiting
  6. Gallbladder storage, emptying
  7. Small intestinal mixing & transport
  8. Colonic storage, defecation
183
Q

Mixing of contents with the gastric juice to make a homogenous solution; to break things down

A

Trituration

184
Q

One of the most complex reflexes the body has due to complete reversal of all motility

185
Q

A protective reflex mediated by the brainstem

186
Q

List the skeletal (voluntary, striated) gut musculature:

A
  1. Mouth
  2. Oropharynx
  3. Upper esophageal sphincter
  4. Upper 1/3 of esophagus
  5. External anal sphincter
187
Q

The mouth, oropharynx, upper esophageal sphincter, upper 1/3 of esophagus, & external anal sphincter can all be described as:

A

Skeletal, voluntary, striated muscle

188
Q

List the smooth (involuntary) gut musculature:

A
  1. Lower 2/3 of esophagus
  2. Stomach
  3. Small intestine
  4. Large intestine
  5. Gallbladder
  6. Biliary & pancreatic ducts
189
Q

The lower 2/3 of the esophagus, stomach, small & large intestine, gallbladder, & biliary and pancreatic ducts can all be described as:

A

Smooth, involuntary muscle

190
Q

Collects all venous outflow from most GI organs:

A

Portal vein

191
Q

All portal outflow goes to ___ before entering the _____

A

Liver; vena cava

192
Q

Nutrients, hormones, drugs & toxins are scanned by the:

193
Q

Describe the hypothalamic pituitary portal system:

A

Portal system between the hypothalamus & anterior pituitary

194
Q

The hypothalamic pituitary portal system allows for:

A

Direct delivery of tropic hormones from hypothalamus to the anterior pituitary

195
Q

The portal system of the digestive tract is found between:

A

The organs of digestion & the liver

196
Q

Each organ in the digestive tract gets its own:

A

Blood supply

197
Q

Everything along the digestive system that gets absorbed will first be absorbed into the:

A

Portal vein

198
Q

After everything in the digestive system first gets absorbed into the portal vein, the portal vein will then carry that blood to the:

199
Q

Types of saliva include:

A
  1. Serous
  2. Mucous
200
Q

Serous saliva is a ____ secretion containing ____

A

Watery; ptyalin (alpha amylase)

201
Q

Another name for ptyalin is:

A

Alpha amylase

202
Q

What is the function of serous saliva?

A

Moisten & dissolve food

203
Q

Alpha amylase is a digestive enzyme responsible for:

A

Small amount of chemical digestion of carbohydrates in the mouth

204
Q

Describe mucous saliva:

A

Thick secretions containing mucin

205
Q

Mucous saliva is responsible for:

A

Lubrication & protection of surfaces

206
Q

List the types of salivary glands and their products:

A
  1. Parotid= serous
  2. Submandibular= mixed
  3. Sublingual= mixed
  4. Many tiny buccal glands= mucous
207
Q

List the components that make up saliva:

A
  1. Water
  2. Bicarb
  3. Mucins
  4. Amylase
  5. Lysozyme, Lactoferrin, IgA
  6. Epidermal & nerve growth factors
208
Q

Name the component of saliva being described:

Faciltates taste & dissolution of nutrients, aids in swallowing

209
Q

Name the component of saliva being described:

Neutralizes refluxed gastric acid

A

Bicarbonate

210
Q

Name the component of saliva being described:

Lubrication

211
Q

Name the component of saliva being described:

Starch digestion

212
Q

Name the component of saliva being described:

Innate & acquired immunity

A

Lysozyme, Lactoferrin & IgA

213
Q

Name the component of saliva being described:

Mucosal growth & protection

A

Epidermal & nerve growth factors

214
Q

How much saliva do we produce per day?

215
Q

Describe the control of salivary secretion:

A

Secretion strictly under neural reflex

216
Q

What is the predominant regulator of saliva production:

A

Parasympathetic nervous system

217
Q

The parasympathetic nervous system is the predominant regulator of saliva production- it releases _____ & binds to _____

A

Acetylcholine; muscarinic receptors

218
Q

Critical for the initiation of saliva secretion:

A

Parasympathetic NS

219
Q

The parasympathetic nervous system is responsible for what aspects of saliva secretion?

A
  1. For initiation of saliva secretion
  2. Sustaining high levels of saliva secretion
  3. Vasodilation of blood vessels supplying salivary glands
220
Q

What is the parasympathetic nervous system’s effect on the blood vessels supplying salivary glands?

A

Vasodilation

221
Q

When the blood vessels supplying salivary glands are dilated via parasympathetic nervous system, there is up to a ____ increase in saliva production by _____

A

20x; acinar cells

222
Q

As flow rate of saliva increases, the saliva: (3)

A
  1. Less time for ductal modification
  2. Saliva more closely resembles the plasma
  3. Saliva becomes more basic
223
Q

As flow rate of saliva increases, the amounts of what ions increase?

A

Na+, HCO3-, Cl-

224
Q

Why does saliva more closely resemble plasma at high secretion rates?

A

Because the ductal cells are responsible for reabsorbing salt, water & bicarb but at high flow rates this does not allow enough time for these processes to take place

(less reabsorption occurs)

225
Q

What are the five modes of reflex activation of parasympathetic stimulated saliva production?

A
  1. Taste (especially sour)
  2. Tactile stimuli (presence of smooth objects on tongue)
  3. Smell of food (especially disliked food)
  4. Ingestion of irritating foods
  5. Nausea
226
Q

Why does nausea initiation reflex activation of parasympathetic saliva production?

A

The parotid glands secrete a basic solution that will prepare the esophagus & mouth for the upcoming vomit

227
Q

The sympathetic nervous system’s role in saliva secretion:

A
  1. Minor role
  2. Enhances parasympathetic nervous system’s effects
228
Q

For the minor control of saliva secretion the sympathetic nervous system secretes ____ which binds to _____

A

Norepinephrine; adrenergic receptors

229
Q

In unstimulated salivary secretion:

_____% Submandibular glands
_____% Parotid glands
_____% Sublingual glands

A

69% submandibular
26% parotid
5% sublingual

230
Q

In stimulated salivary secretion:

_____% Parotid glands
_____% Submandibular glands
_____% Sublingual glands

A

69% parotid
26% submandibular
5% sublingual

231
Q

Saliva production is inhibited by: (4)

A
  1. Fear
  2. Sleep
  3. Fatigue
  4. Dehydration
232
Q

Saliva production is stimulated by: (5)

A
  1. Autonomic (primarily PNS)
  2. Thinking/seeing/smelling food
  3. Conditioned salivation
  4. Chewing
  5. Nausea
233
Q

Thinking/seeing/smelling food which stimulates saliva production is in the _____ phase:

234
Q

True or False:

Rates of saliva production are NOT dependent on age, flow rates remain constant in spite of acinar degeneration

235
Q

Subjective feeling of dry mouth:

A

Xerostomia

236
Q

What are the most common causes of xerostomia? (5)

A
  1. Polypharmacy (>4 drugs/day)
  2. Anxiety & depression (& meds used to treat these conditions)
  3. Insufficient hydration
  4. Head/neck radiation
  5. Sjogren syndrome
237
Q

Describe Sjorgen’s syndrome:

A

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

238
Q

What are the consequences of xerostomia? (7)

A
  1. increased caries
  2. Halitosis
  3. Disrupted sleep
  4. Difficulty lubricating & swallowing food
  5. Dry mouth
  6. Impaired taste
  7. Heartburn
239
Q

Why might someone with xerostomia have increased caries?

A

Due to reduced oral clearance of sugars, dietary acids & oral bacteria

240
Q

In a patient with xerostomia what symptoms may be accompanied by the feeling of dry mouth?

A

-Feeling thirsty
-Dry cracked lips
-Burning mouth sensation
-Dry/sore oral mucosa

241
Q

Why might someone with xerostomia experience heartburn?

A

Saliva is supposed to buffer any gastric acid that gets up into the esophagus, and if you don’t have enough saliva the acid does not get buffered

242
Q

What symptoms accompany the heartburn experienced by an individual with xerostomia:

A
  1. Decreased buffering
  2. Loss of protective growth factors in saliva
  3. Lengthened healing time for ulcers
243
Q

management of xerostomia includes: (4)

A
  1. Avoid acidic, spicy, crunchy & coarse foods
  2. Alcohol-free toothpastes & rinses
  3. Oral moisturizers (sips of water, sugarless chewing gum)
  4. Sialogogues such as pilocarpine & cevimeline before meals
244
Q

Two sialgogues commonly used in treatment of xerostomia include ____ & ____

How do these drugs work?

A

Pilocarpine & Cevimineline

They cholinergic agonists taken before meals to stimulate saliva production

245
Q

Rhythmic opening & closing of mandible that is coordinated with tongue movements:

A

Mastication

246
Q

There is a _______ so that chewing can be more automatic

A

Central pattern generator

247
Q

What does the central pattern generator in chewing allow fo?

A

Chewing to be more automatic- Once chewing has begun, it will continue automatically until its voluntarily stopped

248
Q

What are the two functions of mastication?

A
  1. Prepare food bolus for swallowing
  2. Initiate digestive and metabolic activities
249
Q

In order to prepare a food bolus for swallowing ________ must occur to reduce the particle size

A

Mechanical digestion

250
Q

What are the three goals of mechanical digestion in preparation of a food bolus for swallowing?

A
  1. Break up cells
  2. Break up indigestible cellulose
  3. Increase surface area/decrease particle size for mixing with digestive enzymes
251
Q

What will occur if you do not break up cellulose through mechanical digestion?

A

The contents will go undigested because we do not have enzymes to chemically digest cellulose

252
Q

In addition to mechanical digestion, what also has to occur in preparation of a food bolus for swallowing?

A

Mix food with saliva

253
Q

What type of saliva do we mix the food with in preparation of a food bolus for swallowing?

A

Serous & mucous

254
Q

What four aspects does mixing the food with saliva function to aid in?

A
  1. Chemical digestion (mainly carbohydrates)
  2. Sufficient plasticity
  3. Surface lubrication
  4. Cohesive structure
255
Q

After being mixed with saliva, the food bolus should have _____ & ______ and be a _______

A

Sufficient plasticity
Surface lubrication
Cohesive structure

256
Q

As the food bolus squeezes through the esophagus, you want it to stay together and NOT fall apart, this describes:

It is ideal for the food bolus to slip through the pharynx and esophagus and into stomach, without sticking to surfaces along the way, this describes:

We want the food bolus to stay together until it hits the stomach, this describes:

A

Sufficient plasticity

Surface lubrication

Cohesive structure

257
Q

How does mastication function to initiate digestive and metabolic activities?

A

By digesting carbohydrates starting in the mouth; Initiating reflexes to prepare digest tract for incoming food

258
Q

Why does digestion of carbohydrates that is initiated in the mouth abruptly cease when the bolus hits the stomach:

A

Amylase (the enzyme responsible for the digestion of carbs in the mouth) is destroyed by the acidic environment of the stomach

259
Q

Deglutination

A

Swallowing

260
Q

What are the three stages of Deglutination:

A
  1. Voluntary stage
  2. Pharyngeal stage
  3. Esophageal phase
261
Q

What stage of swallowing is being described below:

  • Initiates swallowing reflex
  • Bolus of food is moved into the pharynx by the tongue
  • Stimulates epithelial swallowing receptor area
A

Voluntary Stage

262
Q

How is the swallowing reflex initiated?

A

Voluntarily

263
Q

Describe the Stage one (Voluntary) of the swallowing:

A

As we chew food and feel that is ready for swallowing, the tongue pushes the bolus of food back towards the pharynx.

The bolus will the come through the oropharynx which will activate stretch receptors to initiate the pharyngeal phase of swallowing

264
Q

Describe what happens to each of the following during the voluntary phase of swallowing:

  1. Soft palate:
  2. Nasopharynx:
  3. Epiglottis:
  4. Upper esophageal sphincter:
A
  1. Soft palate is RELAXED & DOWN
  2. Nasopharynx is OPEN
  3. Epiglottis is UP (allows for tracheal opening to be available for air flow)
  4. Upper esophageal sphincter is CONTRACTED
265
Q

What stage of swallowing is being described below:

-Involuntary reflex mediated by contraction of skeletal muscles
-Mediated by swallowing center in brainstem
-Soft palate pulled upward and closes off nasopharynx
-Epiglottis closes off trachea
-Upper esophageal sphincter relaxes

A

Pharyngeal stage

266
Q

What type of reflex occurs in the pharyngeal stage of swallowing, and how is this reflex mediated?

A

Involuntary reflex; mediated by contraction of skeletal muscles

267
Q

The pharyngeal stage is mediated by ______ in the _____

A

Swallowing center; brainstem

268
Q

Because an involuntary reflex is occuring, once the pharyngeal stage of swallowing is reached you:

A

Won’t be able to stop it

269
Q

The pharyngeal stage of swallowing is a _____ reflex mediated by contraction of ____ muscles

A

Involuntary; voluntary

270
Q

Describe what happens to each of the following during the pharyngeal stage of swallowing:

  1. Soft palate:
  2. Epiglottis
  3. Upper esophageal sphincter
A
  1. Soft palate MOVES UP to close off nasopharynx preventing food from & fluid from getting into nasal cavity
  2. Epiglottis LOWERS & closes off tracheal opening preventing food from entering trachea
  3. Upper esophageal sphincter relaxes allowing food to enter esophagus
271
Q

The upper esophageal sphincter may also be called:

A

Pharyngoesophageal sphincter

272
Q

What stage of swallowing is being described below:

-Coordinated muscles contractions to move bolus through esophagus into stomach (aborally)
-takes around 10 seconds

A

Esophageal stage

273
Q

Describe the movement of the food bolus through the esophageal stage of swallowing:

274
Q

Describe what happens to each of the following during the esophageal stage of swallowing:

  1. Soft palate:
  2. Epiglottis:
  3. Upper esophageal sphincter:
A
  1. Soft palate LOWERS & opens up the nasopharynx so airflow can begin again
  2. The epiglottis will LIFT opening the tracheal opening so we can have airflow into the lungs
  3. Upper esophageal sphincter will CONTRACT to prevent the food bolus from coming back up into the mouth
275
Q

Describe respiration during each of the following stages of swallowing:

  1. Voluntary Stage
  2. Pharyngeal Stage
  3. Esophageal Stage
A
  1. Normal respiration
  2. Respiration is inhibited for less than a couple of seconds
  3. Airflow and respiration will occur again

Physiology (11 decks)

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