Exam 4: GI 6-10 Flashcards
(150 cards)
1
Q
What are the 2 control systems of the GI tract?
A
- intrinsic control sys.
2. Extrinsic control sys
2
Q
Component of the autonomc nervous system, located w/i the GI wall and enables autonomic regulation of GI functions
A
enteric nervous system
3
Q
What are the 2 plexuses of the enteric nervous system
A
- plexus submucosus
2. Plexus myentericus
4
Q
plexus of the enteric NS located b/t submucosa and circular muscullature.
A
plexus submucosus
5
Q
Plexus of the enteric NS located in the muscularis externa, between longitudinal and circular musculature.
A
Plexus myentericus
6
Q
Which Plexus of the ENS regulates mucus secretion and food absorption?
A
Plexus submucosus
7
Q
Which plexus of the ENS controls the muscular activity
A
Plexus myentericus
8
Q
Unlike typical neurons, enteric neurons secrete their neuroT from ______, or bulge like structures located on axonal collaterals or branches
A
varicosities
9
Q
What is imortant about enteric neurons varicosities
A
can spread effect to wide area
10
Q
What are the 3 types of enteric neurons?
A
- dogiel type 1
- dogiel type 2
- dogiel type 3
11
Q
What are dogiel type 1 neurons?
A
have a small cell body with short dendrites and are motor neurons
12
Q
what are dogiel type 2 neurons
A
have large cell bodies with one or two long dendrites and are sensory
13
Q
what are dogiel type 3 neurons
A
show multiple shapes and functions
14
Q
What are the 3 types of neurons based on function?
A
- sensory nerve cells
- interneurons
- motoneurons
15
Q
detect changes/stimuli and are used to regulate funtion
A
Sensory nerve cells
16
Q
What are the 2 types of sensory nerve cells?
A
- mechanosensitive cells
2. chemosensitive cells
17
Q
Sensory nerve cells that recognize stretching of intestinal wall or volume changes
A
mechanosensitive cells
18
Q
sensory nerve cells that detect the presence of nutrients in the GI lumen, changes in osmolarity, and changes in Ph
A
chemosensitive cells
19
Q
Process signals coming from other cells or from the CNS and propagate them to other neurons
A
interneurons
20
Q
induce a change in the GI tract as an answer to stimulus
A
motor neurons
21
Q
What are the 3 types of motor neurons?
A
- muscle MN
- Secreto MN
- Vaso MN
22
Q
MN primarily located in the plexus myentericus
A
Muscle MN
23
Q
MN primarily located in plexus submucosus
A
Secreto MN
24
Q
MN in both the mhyentericus and submucosus
A
Vaso MN
25
What are 3 examples of NANC substances?
1. NO
2. VIP
3. Substance P
26
What is NANC?
Non-noradrenergic, non-cholinergic substances
substances, alnong with conventional transmitters, that are released by enteric neurons
27
Sympathetic nervous system uses noradrenaline which has an _stim/inhib_ effect on the GI tract.
Inhibitory
28
What are the two basic types of electrical waves in the gI tract
1. slow waves
| 2. spikes
29
What are the slow waves of the GI tract?
rhythmical GI contractions
30
electrical pacemakers for smooth muscle cells
Interstitial cells of Cajal (ICC)
31
True AP of the GI tract that occur automatically when the resting membrane potential of the GI smooth muscle becomes more positive than -40mV
Spike potentials
32
concerning GI smooth muscle cells which one is true?
a. their contraction cannot be extrinsically influenced
b. spike potential do not conduce to a contraction
c. they show spontaneous undulations in the membrane potential
c.
33
What are the 3 types of GI reflexes essential to GI control.
1. reflexes integrated within the gut wall
2. reflexes from the gut to the prevertebral sympathetic canglia and back
3. reflexes from the gut to the spinal cord/brain stem and back
34
What are the 3 types of the Reflexes from the gut to the ganglia and back?
1. gastrocolic reflex
2. enterogastric reflex
3. colonoileal reflex
35
signal from the stomach that causes evacuation of the colon
Gastrocolic reflex
36
signal from the colon and SI to inhibit stomach motility and stomach secretion
enterogastric reflex
37
Signal from the colon to inhibit emptying of ileal contents into colon
colonoileal reflex
38
Which reflex is responsible for controling GI secretions , peristalsis, mixing contractions, and local inhibitory effects?
reflexes integrated within gut wall
39
Which reflex is responsible for transmitting signals long distances to other areas of the GI tract
reflexes from the gut to prevertebral sympathetic ganglia and back
40
Which reflex is responsible for controlling gastric motor and secretory activity
from gut to spinal cord
41
which reflex is responsible for pain
from gut to spinal cord
42
which reflex is responsible for defecation reflex?
gut to spinal cord
43
Stretching of the intestinal wall during the passage of a bolus triggers this reflex to constrict the lumen behind the bolus and dilate in front
peristaltic reflex
44
In order to move bolus through GI, areas proximal to the bolus are stimulated by _____ causing _____
excitatatory MN, Smooth muscle contraction
45
In order to move bolus through GI, areas distal to the bolus are stimulated by _____ causing ______.
inhibitory motor neurons, smooth muscle relaxation
46
Which kinds of sensory neurons will be stimulated during the peristaltic reflex?
a. chemosensitive neurons
b. mechanosensitive neurons
b. mechanosensative neurons
47
GI tract reflex circuts where afferent and efferent fibers of the vagus n. coordinate responses to gut stimuli via the dorsal vagal complex in the brain
vagovagal reflex
48
This reflex controls contraction of the GI m. layers in response to distension of the tract by the chyme
vagovagal reflex
49
the vagovagal reflex is active during _______ of the stomach in response to mastication of food.
Receptive relaxation
50
What does the vagovagal reflex do to the stomach
active relaxation
51
What are the 3 parts of the stomach based on function?
1. gastric store- tonix relaxation and contraction
2. gastric pump- peristaltic wave
3. grinder- mixing and breaking down
52
inflow into the gastric pump happens due to the following sequences:
1. tonic contraction of fundus
2. peristaltic waave in corpus
3. passage into grinder then pylorus
4. emptying into duodenum
53
What are the 3 relaxation signals of the stomach?
1. receptive relaxation
b. adaptive relaxation
c. feed-back relaxation
54
What reflex control receptive relaxation of the stomach?
vagovagal reflex
55
Which reflex controls adaptive relaxation of the stomach?
gastro-gastric reflexes
56
What are the 3 purposes of intestinal motility?
1. mixing of food with GI juices
2. inc. contact b/t food and walls
3. peristalsis
57
What are the 2 distinct phases of SI motility?
1. digestive period
| 2. interdigestive period
58
Which phase of SI motility occurs when food is present in the stomach?
digestive period
59
Which phase of SI motility occurs when little food is present in the gut?
interdigestive period
60
Which phase of SI motility occurs when little food is present in the gut?
interdigestive period
61
What are the two contraction patterns of the SI?
1. Propulsive pattern
| 2. non-propulsive pattern
62
Motility pattern of SI during interdigestive period.
migrating motoric complex (MMC)
63
What are the two function of MMC in the SI during the interdigestive period
1. helps pushing undigested material out of the intestine
| 2. controls bacterial pop.
64
What are the 3 phases of the MMC of the sI during the interdigestive period.
Phase 1- no contractions Phase 2- intermitent contractions
| Phase 3- strong peristaltic contractions starting from the stomach and moving distally
65
What are the 2 motility patterns of the large intestine?
1. peristaltic waves
| 2. antiperistaltic waves
66
Motility pattern of the LI that impedes the movement of ingesta, causing a more intense mixing
antiperistaltic waves
67
Giant contractions
pathologic contractions
68
What are 2 exapmles of pathologic contractions
1. vomiting
| 2. diarrhea
69
Where is vomiting coordinated in the body?
brainstem
70
T/F. vomiting contains only ingesta of gastric origin.
F
71
An inc. in frequency of defecation or fecal volume
Diarrhea
72
what are 3 reasons for water in the gut?
1. ingested water
2. water secreted by glands
3. water secreted or lost directly through the mucosal epithelium
73
Diarrhea occurs when there is a mismatch between ____ and ____.
secretion and absorption
74
What are the 2 types of Diarrhea
1. malabsorptive
| 2 secretory
75
D that occurs when absorption is inadequate to recover all secreted water
malabsorptive diarrhea
76
D that occurs when rate of intestinal secretion increases and overwhelms the absorptive capacity
secretory diarrhea
77
What Type of diarrhea is caused by viral, bacterial, or protozoal infections?
malabsorptive
78
In which type of diarrhea would you see shortened villi?
malabsorptive
79
in which type of D would you see opening of the Cl channels?
secretory
80
Is the internal sphincter sympathetic or parasympathetic?
both
81
sympathetic stimulation causes _contraction/relaxation_ of the sphincter.
constriction
82
Parasympathetic stimulation causes _constriction/relaxation_ of the sphincter
relaxation
83
the _internal/external_ sphincter is normally tonically contracted
internal
84
What is the retrosphincteric reflex?
When poo accumulates in the rectum, peristaltic movement of poo into the rectum and relaxation of internal anal sphincter, urge to defecate
85
What are the 2 suborders of ruminants?
1. ruminantia
| 2. tylopoda
86
digestion that occurs in specialized compartments localized before the stomach or after the stomach an SI
fermentative digestion
87
3 microbes that are responsible for fermentation?
1. bacteria
2. fungi
3. protozoa
88
What side of the animal is the abomasum located on?
Right
89
The ______ is the largest compartment of the newborn's stomach
abomasum
90
most protozoa in the rumen belong to the genus ____ or ____
isotricha or entodinium
91
what is the ph of the ruminants stomach?
5.5-7
92
carbohydrates, proteins, and lipids in the ruminants stomach is digested by microbes to become ______.
VFA
93
propionate in the rumen goes to the _____ to procuce _____
liver, glucose
94
Acetate in the rumen goes to the ______ to procuce ____
all tissues, energy
| adipose tissue, fatty acid
95
Butyrate in the rumen goes to the ______ to produce ____
all tissues, energy
96
Indigestible plant component
lignin
97
what are the 3 primary VFAs
1. acetic acid
2. propionic acid
3. butyric acid
98
product of microbes that form short chain peptides as end products which are absorbed in to the microbial cell bodies
endopeptidases
99
AA contribute to what 2 things?
1. synthesis of microbial protein
| 2. metabolized to VFA and ammonia
100
To enter the VFA pathway an AA must first be ______
deaminated
101
what happens in deamination?
NH3 group removed, carbon skeleton remains
102
What are the exception to the deamination rule
Branch chain AA
(BCAA)
carbon skeleton cannot be used
103
nitrogen waste product of prtotein catabolism
urea
104
What are the 2 sources of urea?
1. urea from deamination of AA
| 2. nitrogen absorbed as ammonia from the rumen
105
What are the 4 types of fats and lipids?
1. triglycerides
2. glycolipids
3. phospholipids
4. free fatty acids
106
major lipid type found in cereal grains, oilseeds, animal fats, and byproduct of feeds, also in milk
triglycerides
107
major lipid type found in forages
glycolipids
108
minor compnent of most feeds, forms the cell memb. of all animal cells, and the surface of milk fat globules
phospholipids
109
Lipid that is important in fat digestion in the SI of cows
phospholipids
110
minor component of dairy feeds, but major component of certain fat supplements
free fatty acids
111
microorganism that digests triglycerids
A. lipolytica
112
microorganism that digests phospho and glycolipids
B. fibrisolvens
113
ruminants eating high forage will have a acetic/propionic/butyric ratio of:
70:20:10
114
Ruminants eating high grain diets will have an acetic/propionic/butyric ratio of:
60:30:10
115
What 3 vitamins do microbs synthesize?
1. vit. C
2. vit. K
3. Vit. B (B1 and B12)
116
Vitamin B1
Thyamin
117
Bitamin B12
Cobalamin
118
When do you see a vit. B1 deficiency
sudden change of feed from roughage to concentrate
119
When do you see a vit B12 deficiency
cobalt poor soils or diets with too much grain
120
What are the 2 main mechanisms for absorption of VFA in rumen epithelium?
1. ionized VFA- need carrier
| 2. non-ionized VFA- lipophilic- diffuse through apical memb
121
how does rumen acidosis occur?
fast-fermentable carbohydrates lead to an inc. in VFA production
ph in rumen dec.
122
what is the pK of VFA?
4.8
123
What are the 3 ways sodium is absorbed in the rumen
1. Na channel
2. Na/H exchanger
3. basolat. Na/K ATPase
124
What 2 ways are Cl absorbed in the rumen
1. Cl/HCO3 exchanger
| 2. basolateral channel
125
what is the highest mineral found in the rumen?
Na
126
what are the 2 buffers found in the rumen?
H2PO4-
| HCO3-
127
What 2 ways is potassium absorbed in the rumen?
apical and basolateral channels
128
how is magnesium absorbed in the rumen?
```
Mg channel
(affected by high K)
```
129
what are the clinical signs of pasture grass tetany?
irritability, muscle twitching, incoordination staggers, collapse
130
What two ways are Ca absorbed in rumen?
1. Ca/H exchanger
| 2. basolat. Na/Ca exchanger and Ca ATPase
131
compartment of the stomach with muscular folds that project into the lumen, the canal connects reticulum to abomasum
omasum
132
What are the 3 functions of the omasum?
1. concentration of ingestia (absorption of H2o)
2. SCFA absorption
3. Na Cl absorption
4. HCO3 reabsorption
133
What are the two motility patterns in the rumen?
1. mixing (primary contractions)
| 2. erucation (secondary contractions)
134
The two major motility patterns observed in the rumen are:
a. Peristaltic and antiperistaltic waves
b. Segmentation andpropulsive contractions
c. Mixing and erucation contractions
c.
135
T/F. Deglutition, eructation, and regurgitation can be observed on the left side of a cow?
T
136
What is the function of primary contractions?
reduce particle size
137
What is the function of secondary contractions
force gas toward cranial part of rumen
138
What are the main compnents of the gas produced in the rumen?
carbon dioxide and methane
139
where is the eructation center located?
medulla
140
bloating that occurs in cattle when the eructation mechanism fails
tympanism
141
When cattle feed on lush, rapidly growing alfalfa or clover pastures, gas becomes trapped in tiny bubbles and normal gas bubble cannot accumulate on top of dorsal sac
legume bloat
142
occurs most frequently in high producing dairy cows
ruminant ketosis
143
Where is the control center for reticulorumen motility located
brainstem
144
a gutterlike infagination transversing the wall of the reticulum from the cardia to the reticulo-omasal orfice
esophageal groove/ reticular groove
145
What is the importance of the reticular groove?
diverts milk away from the rumen to the abomasum
146
all of the glucose available to ruminants originates from _______.
gluconeogenesis
147
The most important precrsor of glucose in ruminants is the VFA ______
propionate
148
Bloat in cattle is caused by
a. inc. in the volume of cas produced
b. failure of the erucation lmechanism
b.
149
proprionate enters the krebs cycle as ____
succinate
150
succinate leads to the formation of ______ which is the entry metabolite for gluconeogenesis.
oxyloacetate
