Gastrointestinal Physiology Flashcards
(275 cards)
1
Q
What are the components of the digestive system?
A
- Alimentary canal (GI tract)
- Accessory organs
2
Q
The alimentary canal (GI tract) travels from ____ to ____
A
Mouth to anus
3
Q
The luminal contents within the alimentary canal are considered:
A
Outside the body
4
Q
How long is the alimentary canal?
A
30 feet in length
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
6
Q
______ are in place to keep digested food contents moving in one direction
A
Sphincters
7
Q
Sphincter located between the esophagus and stomach; failure leads to GERD
A
Lower esophageal sphincter
8
Q
Failure of the lower esophageal sphincter leads to:
A
Acid reflux
9
Q
Sphincter located between the stomach and small intestine:
A
Pyloric valve
10
Q
Sphincter located between the small intestine and colon:
A
Ileocecal valve
11
Q
Sphincter located at the end of the colon; made of smooth muscle & INVOLUNTARY:
A
Internal anal sphincter
12
Q
Sphincter located at the end of the colon; made of VOLUNTARY muscle
A
External anal sphincter
13
Q
Sphincter that controls the release of contents from the pancreas and liver into the small intestine
A
Sphincter of Oddi
14
Q
List the six functions of the GI system:
A
- Digestion
- Secretion
- Absorption
- Motility
- Excretion
- Defense
15
Q
Describe digestion:
A
Breakdown down of ingested macromolecules into their building blocks
16
Q
What are the two types of digestion?
A
- Mechanical
- Chemical
17
Q
Physically breaking down food into smaller pieces such as chewing:
A
Mechanical digestion
18
Q
Motility patterns of the digestive tract, particularly the ones in the stomach are designed for:
A
Mechanical digestion
19
Q
Breaking down food through the use of enzymes:
A
Chemical digestion
20
Q
What components are involved in GI secretion?
A
- digestive enzymes
- acid/base
- bile
21
Q
Involves the passive and active transport processes across an epithelial layer:
A
Absorption
22
Q
The absorption seen in the GI system moves substances from:
A
Lumen of gut to blood
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
24
Q
The contractile patterns of the GI system:
A
Motility
25
The motility aspect of the digestive system involves what three components:
1. Mixing
2. Mechanical digestion
3. Propulsion
26
Movement of material through the digestive tract:
Propulsion
27
Removal of metabolic waste from body:
Excretion
28
There is very little ____ in feces
true waste
29
any undigested products to be excreted from the body:
Metabolic waste
30
What gives the feces color?
Bile pigments
31
The defensive component of the GI tract involves:
Gut associated lymphoid tissue
32
What defensive organ monitors the entrance point of the digestive tract?
Tonsils
33
List the path of food travel through the GI tract:
1. Mouth
2. Esophagus
3. Stomach
4. Small intestine
5. Colon
6. Rectum
7. Anus
34
As food enters into the body it is stored in the _____, which will slowly release it into the ____
Stomach, small intestine
35
Describe the processes occurring in the stomach:
Not much absorption, mainly secretion (acid secretion)
36
What is the purpose of secretion of acid in the stomach?
To sterilize the meal
37
Describe the size of contents as if goes through the digestive tract:
Starts large, gets smaller and smaller until it reaches the colon where compaction occurs to re-solidify the material
38
Describe the processes that occur early on in the small intestine:
Massive amounts of secretion & absorption
39
Describe the processes that occur later on in the small intestine:
Still see absorption & secretion but much less than seen early on in the small intestine
40
The substances being absorbed in the small intestine are being absorbed by the:
Hepatic portal vein
41
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
Everything being absorbed from the small intestine will go to the liver before it gets dumped into general circulation
42
Under normal circumstance almost ALL of the meal is digested & absorbed by:
An exception to this is:
The first 25% of the small intestine
Exception= fats (take a bit longer)
43
Functions to compact the small fragments of material following digestion:
How does it do this?
Colon
Reabsorption of a lot of salt & water to concentrates the feces
44
List ingested substances that serve as nutrients: (7)
1. Carbs
2. Fats
3. Proteins
4. DNA/RNA
5. Water
6. Electrolytes
7. Vitamins
45
Amount of water & solids ingested per day:
1200 mL water/day
500-800 g solid/day
46
Amount of salivary secretions per day:
Amount of gastric secretions per day:
1500 mL
2000 mL
47
Amount of bile secreted by the liver per day:
Amount of pancreatic secretions per day:
500 mL bile
1500 mL pancreatic secretions
48
Amount of absorption into the blood from the small intestine per day:
6700 mL/day
49
Amount of intestinal secretions (primarily into the small intestine) per day:
1500 mL
50
Amount of absorption into the blood from the large intestine per day:
1400 mL
51
Amount of water & solid excreted into the feces per day:
(on average)
100 mL water
50 g solid
52
Movement of contents too quickly through the digestive tract will result in:
Diarrhea
53
Movement of contents too slowly through the digestive tract will result in:
Constipation
54
What four layers comprise the GI tract wall?
1. Mucosa
2. Submucosa
3. Muscularis externa
4. Serosa
55
What layer of the GI tract wall is being described:
- Simple columnar epithelium
- Lamina propria
- Muscular mucosa for the movement of villi
Mucosa
56
What layer of the GI tract wall is being described:
- Connective tissue layer
- Blood vessels & lymph
- Submucosal plexus
Submucosa
57
What layer of the GI tract wall is being described:
- Circulare muscle
- Longitudinal muscle
- Myenteric plexus
Muscularis externa
58
What layer of the GI tract wall is being described:
- Connective tissue covering
- Support GI tract in abdominal covering
Serosa
59
Describes the epithelium that comprises the mucosa layer of the GI tract wall:
Simple columnar epithlium; heterogeneous
60
What does it mean that the epithelium comprising the mucosa layer is "heterogeneous"
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
61
What is the innermost layer of the GI tract wall?
Mucosa
62
Located in the mucosa layer of the GI tract wall, just beneath the epithelial layer
Lamina propria
63
Blood & nerve supply come up through which portion of the mucosa layer of the GI tract wall?
Lamina propria
64
Innermost layer of the mucosa layer of the GI tract wall, functions to move villi:
Muscularis mucosa
65
Major blood & lymph vessels of the GI tract travel through the:
Submucosa layer
66
Network of neurons located within the submucosa:
Submucosal plexus
67
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
Myenteric plexus
68
Describe the muscular makeup of the muscularis externa layer of the GI tract wall:
- Made of smooth muscle
Arranged into circular muscle & longitudinal muscle
69
Muscle fibers arranged concentrically around the lumen; functions to change lumen diameter
Circular muscle
70
Contraction of concentric muscle=
Relaxation of concentric muscle=
Constrict lumen
Dilate lumen
71
Muscle fibers arranged along the long axis of the GI tube; allows for coordinated contraction of different areas of the tube to occur together
Longitudinal muscle
72
What does longitudinal muscle allow for:
Coordinated contraction of different areas along the tube
73
In between the circular & longitudinal muscle layers is the:
Myenteric plexus
74
The myenteric plexus is a network of neurons in the ______ that receives input from the ______
Muscularis externa; autonomic NS
75
The myenteric plexus has projections into the:
Submucosal plexus, circular muscle & longitudinal muscle
76
Submucosal & myenteric plexus "little brain"
Enteric nervous system
77
The digestive tract is the only organ in the body that has its own:
Brain
78
What types of cells are located within the epithelial layer of the GI tract?
1. Simple columnar (with microvilli)
2. Goblet cells
3. Enteroendocrine cells
4. Stem cells
79
The simple columnar cells found within the epithelial layer have:
Microvilli
80
Unicellular exocrine gland that secretes mucous within the epithelial layer:
Goblet cells
81
Why is it important to have mucous secretion by goblet cells within the epithelial layer?
Mucous protects the GI lining from the acidic environment
82
Enteroendocrine cells within the epithelial layer are located at the:
Base of the villi
83
Found within the epithelial layer, function to secrete hormone into the blood:
Enteroendocrine cells
84
Stem cells within the epithelial layer are located:
Within crypts
85
What components allow for the tremendous surface area available for the absorption of materials from the lumen?
1. Circular folds
2. Villi
3. Microvilli
86
Circular folds increase the surface area of the:
Intestinal lining
87
Vili are extensions off _____ and increase the surface area of the _____
Circular folds; circular folds
88
Another name for microvilli:
Brush border
89
Microvilli are located on the _____& increase the surface area of the ____
Apical membrane of the vili; apical membrane
90
Together, circular folds, villi, & microvilli increase the SA ____x over flat surface
600x
91
What two components are present inside the villus?
1. Lacteals (lymph vessels)
2. Capillary network
92
Substances absorbed across the epithelium will either enter _____ also known as ______ or will enter _____
lacteals also known as lymph vessels; capillary network
93
What moves the villus?
Muscularis mucosa
94
Venous drainage & lacteal movement can all be described as:
passive
95
Since venous drainage & lacteal movement are passive processes they require:
Skeletal muscle contractions & one-way valves
96
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:
Milking the villus
97
When looking at hormone levels within the GI system, changes in hormones are the response of changes in the ______ NOT the _____
Lumen; ECF
98
Control systems of the GI regulate systems in:
Lumen of tract
99
Control mechanisms are governed by ____ & ____ of luminal contents
Volume & luminal composition
100
When changes in the gut lumen initiate secretion of a hormone into the blood:
Endocrine secretion
101
When changes in the gut lime will cause paracrines to be secreted into the interstitial fluid & affect cells close by:
Paracrine secretion
102
Autonomic nerve function that will stimulate an endocrine gland to secrete a hormone into the blood:
Neurocrine secretion
103
When two cells actually have to make contact with eachother for secretion to occur:
Immune/Juxtacrine secretion
104
Name two examples of cells that displaying immune or juxtacrine secretion:
ECL cells & D cells
105
What do ECL cells secrete?
Histamine
106
What D-cells secrete?
Somatostatin
107
The gut innervation responsible for sensory:
Afferent neurons
108
The gut innervation responsible for secretomotor:
Efferent neurons
109
Reflex receptors that respond to stretch, inflammation, nutrients & endocrine factors:
Afferent sensory
110
Afferent sensory neurons respond to:
1. Stretch
2. Inflammation
3. Nutrients
4. Endocrine factors
111
Afferent sensory neurons form synapses in:
1. Enteric nervous system
2. Prevertebral ganglia
3. Spinal cord
4. Brainstem
112
Vagal nerves are mainly ______ to the brainstem
Afferent
113
Sensory info TO the brain stem is going to be carried by:
Vagal sensory neurons
114
When a vagal nerve carries the sensory information in & a vagal nerve caries the parasympathetic commands out:
Vagal-vagal reflex
115
What are the categories of efferent (secretomotor) control?
1. Somatic
2. Sympathetic
3. Parasympathetic
116
We have _____ control for muscles of the tongue, for muscles of chewing, and muscles of swallowing
Somatic motor control
117
Cranial nerve response for the following:
-Muscles of the tongue
-Muscles of chewing
-Muscles of swallowing
Tongue= CN 12
Chewing= CN 5
Swallowing= CN 9&10
118
The pudendal nerve is a ______ nerve that controls both the external urethral sphincter as well as the external anal sphincter
Somatic nerve
119
Both the external urethral sphincter & external anal sphincter can be described as:
Voluntary
120
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 _____
Smooth muscle; Autonomic nervous system
121
What is the majority of the autonomics that make up the middle of the digestive tract and why?
Mostly sympathetic post-ganglionic nerve fibers because they form in the pre-vertebral foramen & will extend to the digestive tract
122
The post-ganglionic nerve fibers that form in the pre-vertebral foramen & extend to the digestive tract will release _____ to _____
Norepinephrine; enteric nervous system, vasculature, ducts & cells of the tissue
123
The sympathetic nervous system is mostly ______ to digestion
Inhibitory
124
Digestion is dominated by ______ function
Parasympathetic
125
The parasympathetic motor neurons of the digestive tract:
1. Vagus nerve
2. Pelvic nerves
126
Parasympathetic nervous control can be stimulatory or inhibitory depending on:
The final neurotransmitter being released
127
Post-ganglionic fibers (NEpi) to enteric nervous system, vasculature, ducts, parenchyma; usually inhibitory
Sympathetic
128
ENS functions as post-ganglionic fibers, actions are stimulatory or inhibitory depending on final nerve transmitter receptor
Parasympathetic
129
Monitor the conditions of the lumen of the gut:
Sensory neurons
130
What are some things that a sensory neuron might monitor?
Stretch, nutrients, etc.
131
When a sensory neuron is stimulated, the sensory information can then go to the _______ OR the sensory information can go to the _________
Enteric nervous system; prevertebral ganglion, spinal cord, brain stem
132
Following the sensory neuron transmitting the stimuli to the appropriate area (ENS, Prevertebral ganglion, spinal cord or brainstem), we will then have:
Sympathetic and parasympathetic outflow from the brain
133
If the response to the stimulus is sympathetic outflow from the brain, it will be mostly ______ fibers that will secrete _____ as their NT
Post-ganglionic; Norepinephrine
134
Parasympathetic fibers are all going to be _____
Preglanglionic
135
Describe the length of the sympathetic post-ganglionic fibers:
Short
136
Describe the length of the parasympathetic pre-ganglionic fibers:
Long
137
The synapse between the pre-ganglionic & post-ganglionic nerve fibers occur in the:
Wall of the organ
138
Parasympathetic pre-ganglionic fibers release _____ and its going to influence the function of neurons in the____.
Acetylcholine; enteric nervous system
139
What neurotransmitter is released by the parasympathetic nerve fiber?
What does this influence?
Acetylcholine
Enteric nervous system
140
When the enteric nervous system is influenced by acetylcholine released from the parasympathetic nerve fibers, the response to the digestive system will be:
Either stimulatory or inhibitory
141
In general terms, the myenteric plexus is involved in:
Coordinated function all along the length of the digestive tract
142
The submucosal plexus and the myenteric plexus can both be stimulated by: (4)
1. Acetylcholine
2. Amines
3. Nitric oxide
4. Many peptides
143
When a sensory neuron is stimulated it can act on the _____ or travel up and act on the ____ or ____
1. Submucosal plexus
2. Myenteric plexus
3. Prevertebral ganglia, spinal cord & brainstem
144
Neurotransmitter for:
1. Sympathetic motor neurons:
2. Parasympathetic motor neurons:
1. Norepinephrine
2. Acetylcholine
145
Linear chain of neurons that extend the entire length of the GI tract:
Myenteric plexus
146
The myenteric plexus is a linear chain of neurons that extends:
The entire length of the GI tract
147
The myenteric plexus controls:
The muscle of the muscularis externa
148
What occurs when the myenteric plexus is 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 the gut
5. inhibition of sphincter contraction
149
Why is sphincter contraction inhibited when the myenteric plexus is stimulated?
The sphincter has to relax to move contents from one area to another
150
The enteric nervous system is considered:
"The Brain in the Gut"
151
Controls function of each minute segment of GI tract:
Submucosal plexus
152
What plexus is involved in local control?
Submucosal plexus
153
The control of the submucosal plexus involves control of:
1. intestinal secretions
2. absorption
3. contraction of mucosal muscle
154
Stimuli that can occur INSIDE the GI lumen include:
Changes in chemicals, osmolarity, or some sort of mechanical change like stretch
155
The stimulus sensed by sensory neurons will activate sensory receptors such as:
Chemoreceptors, osmoreceptors & mechanoreceptors
156
Describe the pathway of a short loop reflex:
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
Describe the pathways of a long loop reflex:
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
Describe the speed & CNS involvement in the long loop reflex:
Describe the speed & CNS involvment in the short loop reflex:
Long loop= Slower, involves CNS
Short loop= Rapid, No CNS involvement
159
In may instances, both short & long loop reflexes:
Occur at the same time
160
CNS stimulation can cause changes in the GI tract by stimnuli arising:
Outside of the GI tract
161
What are some examples of CNS stimulation outside of the GI tract?
-Site of food
-Smell of food
-Taste of food
- Emotional state
162
True or False:
Many of the neurons in the ENS also function as parasympathetic post-ganglionic fibers
True
163
True or False:
The submucosal plexus functions to inhibit sphincter contraction
False- Myenteric plexus does this
164
True or False:
Local control of the GI tract is mediated by the function of the submucosal plexus
True
165
True or False:
Vagal sensory neurons monitoring the gut are activated by changes in the GI lumen or wall
True
166
True or False:
Sensory information arising from the gut must be processes through the CNS
False- can have short loop reflex
167
Endocrine cells scattered in gut mucosa:
Unicellular endocrine glands
168
Unicellular endocrine glands are considered ____ cells with ____
Specialized cells; one hormone
169
Describe the secretion of hormones from specialized endocrine cells:
Usually secrete one hormone only
170
When looking at endocrine cells of the digestive system, specific cell types are:
Localized to regions of the gut
171
When & where do the unicellular endocrine glands secrete their hormone?
When they taste the luminal contents; into the blood
172
Hormones are secreted by the unicellular glands based on:
Responses to changes in the LUMEN
173
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
Basolateral surface
174
Paracrine factors are similar to endocrine, but instead of being released into the blood, they are released into the ______ where they _____
Interstitial fluid; Diffuse to target cells
175
Paracrine factors are released into the interstitial fluid, which diffuses to the target cell, but some of these factors may:
Overflow into the circulation
176
Two established paracrine factors include:
1. Histamine
2. Somatostatin
177
Histamine is released by ______ cells
Somatostatin is released by _____ cells
Histamine= ECL cells
Somatostatin= D cells
178
Paracrine secrete their substances across the _____ surface into the interstitial space
Basolateral surface
179
Histamine is mainly released by:
Gastrin
180
Somatostatin is mainly released by:
Luminal H+
181
Patterns of motility include:
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
Patterns of motility include:
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
Mixing of contents with the gastric juice to make a homogenous solution; to break things down
Trituration
184
One of the most complex reflexes the body has due to complete reversal of all motility
Vomiting
185
A protective reflex mediated by the brainstem
Vomiting
186
List the skeletal (voluntary, striated) gut musculature:
1. Mouth
2. Oropharynx
3. Upper esophageal sphincter
4. Upper 1/3 of esophagus
5. External anal sphincter
187
The mouth, oropharynx, upper esophageal sphincter, upper 1/3 of esophagus, & external anal sphincter can all be described as:
Skeletal, voluntary, striated muscle
188
List the smooth (involuntary) gut musculature:
1. Lower 2/3 of esophagus
2. Stomach
3. Small intestine
4. Large intestine
5. Gallbladder
6. Biliary & pancreatic ducts
189
The lower 2/3 of the esophagus, stomach, small & large intestine, gallbladder, & biliary and pancreatic ducts can all be described as:
Smooth, involuntary muscle
190
Collects all venous outflow from most GI organs:
Portal vein
191
All portal outflow goes to ___ before entering the _____
Liver; vena cava
192
Nutrients, hormones, drugs & toxins are scanned by the:
Liver
193
Describe the hypothalamic pituitary portal system:
Portal system between the hypothalamus & anterior pituitary
194
The hypothalamic pituitary portal system allows for:
Direct delivery of tropic hormones from hypothalamus to the anterior pituitary
195
The portal system of the digestive tract is found between:
The organs of digestion & the liver
196
Each organ in the digestive tract gets its own:
Blood supply
197
Everything along the digestive system that gets absorbed will first be absorbed into the:
Portal vein
198
After everything in the digestive system first gets absorbed into the portal vein, the portal vein will then carry that blood to the:
Liver
199
Types of saliva include:
1. Serous
2. Mucous
200
Serous saliva is a ____ secretion containing ____
Watery; ptyalin (alpha amylase)
201
Another name for ptyalin is:
Alpha amylase
202
What is the function of serous saliva?
Moisten & dissolve food
203
Alpha amylase is a digestive enzyme responsible for:
Small amount of chemical digestion of carbohydrates in the mouth
204
Describe mucous saliva:
Thick secretions containing mucin
205
Mucous saliva is responsible for:
Lubrication & protection of surfaces
206
List the types of salivary glands and their products:
1. Parotid= serous
2. Submandibular= mixed
3. Sublingual= mixed
4. Many tiny buccal glands= mucous
207
List the components that make up saliva:
1. Water
2. Bicarb
3. Mucins
4. Amylase
5. Lysozyme, Lactoferrin, IgA
6. Epidermal & nerve growth factors
208
Name the component of saliva being described:
Faciltates taste & dissolution of nutrients, aids in swallowing
Water
209
Name the component of saliva being described:
Neutralizes refluxed gastric acid
Bicarbonate
210
Name the component of saliva being described:
Lubrication
Mucins
211
Name the component of saliva being described:
Starch digestion
Amylase
212
Name the component of saliva being described:
Innate & acquired immunity
Lysozyme, Lactoferrin & IgA
213
Name the component of saliva being described:
Mucosal growth & protection
Epidermal & nerve growth factors
214
How much saliva do we produce per day?
1.5L/day
215
Describe the control of salivary secretion:
Secretion strictly under neural reflex
216
What is the predominant regulator of saliva production:
Parasympathetic nervous system
217
The parasympathetic nervous system is the predominant regulator of saliva production- it releases _____ & binds to _____
Acetylcholine; muscarinic receptors
218
Critical for the initiation of saliva secretion:
Parasympathetic NS
219
The parasympathetic nervous system is responsible for what aspects of saliva secretion?
1. For initiation of saliva secretion
2. Sustaining high levels of saliva secretion
3. Vasodilation of blood vessels supplying salivary glands
220
What is the parasympathetic nervous system's effect on the blood vessels supplying salivary glands?
Vasodilation
221
When the blood vessels supplying salivary glands are dilated via parasympathetic nervous system, there is up to a ____ increase in saliva production by _____
20x; acinar cells
222
As flow rate of saliva increases, the saliva: (3)
1. Less time for ductal modification
2. Saliva more closely resembles the plasma
3. Saliva becomes more basic
223
As flow rate of saliva increases, the amounts of what ions increase?
Na+, HCO3-, Cl-
224
Why does saliva more closely resemble plasma at high secretion rates?
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
What are the five modes of reflex activation of parasympathetic stimulated saliva production?
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
Why does nausea initiation reflex activation of parasympathetic saliva production?
The parotid glands secrete a basic solution that will prepare the esophagus & mouth for the upcoming vomit
227
The sympathetic nervous system's role in saliva secretion:
1. Minor role
2. Enhances parasympathetic nervous system's effects
228
For the minor control of saliva secretion the sympathetic nervous system secretes ____ which binds to _____
Norepinephrine; adrenergic receptors
229
In unstimulated salivary secretion:
_____% Submandibular glands
_____% Parotid glands
_____% Sublingual glands
69% submandibular
26% parotid
5% sublingual
230
In stimulated salivary secretion:
_____% Parotid glands
_____% Submandibular glands
_____% Sublingual glands
69% parotid
26% submandibular
5% sublingual
231
Saliva production is inhibited by: (4)
1. Fear
2. Sleep
3. Fatigue
4. Dehydration
232
Saliva production is stimulated by: (5)
1. Autonomic (primarily PNS)
2. Thinking/seeing/smelling food
3. Conditioned salivation
4. Chewing
5. Nausea
233
Thinking/seeing/smelling food which stimulates saliva production is in the _____ phase:
Cephalic
234
True or False:
Rates of saliva production are NOT dependent on age, flow rates remain constant in spite of acinar degeneration
True
235
Subjective feeling of dry mouth:
Xerostomia
236
What are the most common causes of xerostomia? (5)
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
Describe Sjorgen's syndrome:
-Autoimmune destruction of mucous membranes and moisture-secreting glands
-Decreased production of tears and saliva
-Dry eyes & mouth
238
What are the consequences of xerostomia? (7)
1. increased caries
2. Halitosis
3. Disrupted sleep
4. Difficulty lubricating & swallowing food
5. Dry mouth
6. Impaired taste
7. Heartburn
239
Why might someone with xerostomia have increased caries?
Due to reduced oral clearance of sugars, dietary acids & oral bacteria
240
In a patient with xerostomia what symptoms may be accompanied by the feeling of dry mouth?
-Feeling thirsty
-Dry cracked lips
-Burning mouth sensation
-Dry/sore oral mucosa
241
Why might someone with xerostomia experience heartburn?
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
What symptoms accompany the heartburn experienced by an individual with xerostomia:
1. Decreased buffering
2. Loss of protective growth factors in saliva
3. Lengthened healing time for ulcers
243
management of xerostomia includes: (4)
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
Two sialgogues commonly used in treatment of xerostomia include ____ & ____
How do these drugs work?
Pilocarpine & Cevimineline
They cholinergic agonists taken before meals to stimulate saliva production
245
Rhythmic opening & closing of mandible that is coordinated with tongue movements:
Mastication
246
There is a _______ so that chewing can be more automatic
Central pattern generator
247
What does the central pattern generator in chewing allow fo?
Chewing to be more automatic- Once chewing has begun, it will continue automatically until its voluntarily stopped
248
What are the two functions of mastication?
1. Prepare food bolus for swallowing
2. Initiate digestive and metabolic activities
249
In order to prepare a food bolus for swallowing ________ must occur to reduce the particle size
Mechanical digestion
250
What are the three goals of mechanical digestion in preparation of a food bolus for swallowing?
1. Break up cells
2. Break up indigestible cellulose
3. Increase surface area/decrease particle size for mixing with digestive enzymes
251
What will occur if you do not break up cellulose through mechanical digestion?
The contents will go undigested because we do not have enzymes to chemically digest cellulose
252
In addition to mechanical digestion, what also has to occur in preparation of a food bolus for swallowing?
Mix food with saliva
253
What type of saliva do we mix the food with in preparation of a food bolus for swallowing?
Serous & mucous
254
What four aspects does mixing the food with saliva function to aid in?
1. Chemical digestion (mainly carbohydrates)
2. Sufficient plasticity
3. Surface lubrication
4. Cohesive structure
255
After being mixed with saliva, the food bolus should have _____ & ______ and be a _______
Sufficient plasticity
Surface lubrication
Cohesive structure
256
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:
Sufficient plasticity
Surface lubrication
Cohesive structure
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How does mastication function to initiate digestive and metabolic activities?
By digesting carbohydrates starting in the mouth; Initiating reflexes to prepare digest tract for incoming food
258
Why does digestion of carbohydrates that is initiated in the mouth abruptly cease when the bolus hits the stomach:
Amylase (the enzyme responsible for the digestion of carbs in the mouth) is destroyed by the acidic environment of the stomach
259
Deglutination
Swallowing
260
What are the three stages of Deglutination:
1. Voluntary stage
2. Pharyngeal stage
3. Esophageal phase
261
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
Voluntary Stage
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How is the swallowing reflex initiated?
Voluntarily
263
Describe the Stage one (Voluntary) of the swallowing:
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
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:
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
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
Pharyngeal stage
266
What type of reflex occurs in the pharyngeal stage of swallowing, and how is this reflex mediated?
Involuntary reflex; mediated by contraction of skeletal muscles
267
The pharyngeal stage is mediated by ______ in the _____
Swallowing center; brainstem
268
Because an involuntary reflex is occuring, once the pharyngeal stage of swallowing is reached you:
Won't be able to stop it
269
The pharyngeal stage of swallowing is a _____ reflex mediated by contraction of ____ muscles
Involuntary; voluntary
270
Describe what happens to each of the following during the pharyngeal stage of swallowing:
1. Soft palate:
2. Epiglottis
3. Upper esophageal sphincter
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
The upper esophageal sphincter may also be called:
Pharyngoesophageal sphincter
272
What stage of swallowing is being described below:
-Coordinated muscles contractions to move bolus through esophagus into stomach (aborally)
-takes around 10 seconds
Esophageal stage
273
Describe the movement of the food bolus through the esophageal stage of swallowing:
Aborally
274
Describe what happens to each of the following during the esophageal stage of swallowing:
1. Soft palate:
2. Epiglottis:
3. Upper esophageal sphincter:
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
Describe respiration during each of the following stages of swallowing:
1. Voluntary Stage
2. Pharyngeal Stage
3. Esophageal Stage
1. Normal respiration
2. Respiration is inhibited for less than a couple of seconds
3. Airflow and respiration will occur again
