GI physiology and the endocrine pancreas Flashcards
(239 cards)
1
Q
what are the functions of the GIT
A
transport food digest food absorb food components into the blood secrete saliva and digestive fluids regulate water and electrolyte balance immune system thermoregulation
2
Q
hind gut fermenters
A
horses
3
Q
what do carnivores use for food intake
A
teeth and forelimbs
4
Q
what do horses use when grazing? when at manger?
A
grazing - lips retracted, incissors
manger - lips
5
Q
use tongue as a spoon
A
carnivores
6
Q
drink water via suction/inspiration
A
herbivores
7
Q
masticate sparsely and have vertical mandible movements
A
carnivores
8
Q
frequent mastication and horizontal mandible movements
A
herbivores
9
Q
first motility pattern of the GIT
A
deglutition
10
Q
is the oral phase of deglutition voluntary or involuntary
A
voluntary
11
Q
what is the oral phase of deglutition
A
food is molded into a bolus by the tongue and pushed back into the pharynx
12
Q
what initiates the involuntary phase of deglutition
A
sensory nerve endings activated when food enters the pharynx
13
Q
what elevates to close the pharyngeal opening to the nasopharynx
A
soft palate
14
Q
T/F
breathing stops during the involuntary (swallow reflex) phase of deglutition
A
TRUE
15
Q
what closes the oral opening in the swallow reflex
A
the tongue against the hard palate
16
Q
what blocks the laryngeal opening in the swallow reflex
A
epiglottis
17
Q
regulatory center for energy homeostasis
A
hypothalamus
18
Q
hypothalamic hunger center is comprised of..
A
nucleus paraventricularis
lateral fields
19
Q
hypothalamic satiety center is comprised of..
A
nucleus ventromedialis
20
Q
neuropeptide hormones that stimulate hunger
A
NPY
orexin
21
Q
neuropeptide hormones that inhibit hunger
A
MSH
22
Q
non-hypothalamic hunger stimulating hormone
A
ghrelin
23
Q
non-hypothalamic hunger inhibiting hormone
A
cck
pyy
leptin
insulin
24
Q
which hormone inhibits NPY and stimulates MSH
A
leptin (from fat cells)
25
list the major salivary glands
parotid
mandibular
sublingual
26
which salivary glands produce 90% of the saliva
parotid and mandibular
sublingaul does 5%
27
which salivary gland does serous secretions
parotid
28
which salivary glands have seromucous secretions
sublingual and mandibular
29
primary functions of saliva
protect buccal mucosa and teeth
facilitate deglutition
initiate enzymatic carb digestion (amylase in pigs/humans)
ph regulation
30
secondary functions of saliva
immune
protection
thermoregulation
31
what is primary saliva
the saliva from the acinus glands -- contains Na, Cl, H2O
32
Parasympathetic regulation of saliva
acts on M3 receptors - increase diluted saliva
SNS: on alpha-1 receptors = small amounts of mucus saliva
33
T/F
| in carnivores, high saliva production leads to an increase in electrolyte concentration
TRUE
34
in the salivary ducts, what is secreted and what is reabsorbed?
secreted: HCO3-
reabsorbed: Cl-
35
ENDOCRINE PANCREAS organization and percent of the pancreas
2-3%
islets of langerhan
36
T/F
the endocrine pancreas is richly innervated by both vagal parasympathetic system and splanchnic
sympathetic fibers
TRUE
37
T/F
| all hormones of the endocrine pancreas are involved in glucose metabolism
TRUE
38
what percent of the islet cells are alpha cells and what do they secrete
20%
| glucagon
39
what percent of the islet cells are beta cells and what do they secrete
70%
insulin
40
what percent of the islet cells are delta cells and what do they secrete
5%
| somatostatin
41
what percent of the islet cells are F cells and what do they secrete
5%
| pancreatic polypeptide
42
a polypeptide hormone produced by beta cells in response to hyperglycemia
insulin
43
what is insulin released in response to
hyperglycemia
44
insulin structure
a polypeptide with an alpha and a beta chain connected by a disulfide bridge
45
canine insulin and porcine insulin are _____
the SAME
46
bovine and feline insulin are ____
1 amino acid different
47
in omnivores what governs the release of insulin
GLUCOSE
48
in carnivores what governs the release of insulin
PROTEIN -- amino acids
49
what does acetylcholine do to insulin secretion
STIMULATES
50
what do GI hormones (gastrin, secretin, GIP) do to insulin secretion
stimulates
51
list 4 hormones that inhibit insulin secretion
1. GLUCAGON
2. SOMATOSTATIN
3. EPINEPHRINE
4. NOREPINEPHRINE
52
glucose transporter in the membrane of beta cells that allows glucose to diffuse freely into the cell
GLUT2
53
T/F
| Extracellular fluid glucose concentration directly affects glucose concentration inside of the beta cell
TRUE
54
if blood glucose concentration increases, what will happen to insulin
it will be secreted and synthesized
55
the acute phase of insulin secretion involves...
Involves the release of preformed insulin
56
the chronic phase of insulin secretion involves
the synthesis of protein
57
After release, insulin binds to a specific membrane
| receptor on target tissues called....
receptor tyrosine kinase
58
list three insulin-sensitive tissues (meaning they have the insulin target receptors)
liver
muscle
fat
59
The net effect of insulin is...
The net effect of insulin is to lower blood concentration of
| glucose , fatty acids and amino acids
60
what is the only insulin sensitive transporter
GLUT4
61
Insulin facilitates glucose entry into cells by increasing the number of ....
specific GLUCOSE TRANSPORTERS (GLUT 4) in the
| cell membrane
62
what does insulin do to glycogen in the liver
increases glycogen synthesis
63
T/F
| in the liver, insulin increases lipolysis
TRUE
64
T/F
| in the liver, insulin increases gluconeogenesis
FALSE -- decreases gluconeogenesis
65
what is the action of insulin on smooth, striated, and cardiac muscle?
1. stimulated glycogen synthesis enzymes (promotes the storage of glucose as glycogen)
2. promotes glucose as a fuel source
3. enhances aa uptake which promotes muscle growth
66
In the absence of insulin muscles rely on what for a fuel source
fatty acids
67
T/F
| insulin stimulates lipolysis in adipose tissue
FALSE -- inhibits lipolysis and promotes fat deposition
68
Glucose provided to adipocytes promotes:
1. glycogen synthesis
2. Glycerol formation - combines with fatty acids delivered to adipose
tissue to form triglycerides
69
T/F
| Insulin promotes fatty acid synthesis in hepatocytes
TRUE
70
T/F
| Insulin stimulates glycogen synthesis in the liver
TRUEEE
71
what two organs is insulin mainly metabolized by
kidney and liver
| -specific enzymes reduce the disulfide bridges and the chains are subject to protease activity
72
whats the half life of insulin
10 minutes
73
______ will be the main source of energy for all cells and excess will be stored as ___ and fat
CARBOHYDRATES
glycogen
74
half life of glucagon
5 minutes
75
T/F
| insulin stimulates amino acid uptake in muscles which promotes muscle growth
TRUE
76
what hormone is a major inhibitor of lipolysis
insulin
77
what is released when glucose levels exceed 110mg/dL
insulin
78
what is released when glucose levels are below 60 mg/dl
glucagon/epinephrine
79
two hormones that stimulate the use of glycogen for glucose
epinephrine and glucagon
80
T/F
| if we don't eat any meals, in 24 hours we will use up all of our glycogen
TRUE
81
Hepatic glycogenolysis stimulates the release of what hormones
cortisol and GH
82
a process that produces glucose from glycerol, amino acids, and lactate
gluconeogenesis
83
what two hormones can directly stimulate gluconeogenesis
cortisol and GH
84
what there is no glucose, what can be used as energy everywhere in the body except for in the brain
FAT
85
hormone that acts in the liver to greatly enhances glucose availability to other organs in the body
glucagon
86
T/F
| under normal conditions, kidneys do gluconeogenesis
FALSE
BUT they pick up 40% in liver failure
87
What does glucagon do to glycogen synthesis
LOWERS it
| --stimulates glycogenolysis
88
what does glucagon do to gluconeogenesis in the liver
increases
89
what stimulates glucagon synthesis
a decreased glucose concentration
90
what is required for glucose to be taken up into alpha cells
insulin
91
is glucagon high or low when insulin is deficient
HIGH
92
hormone that inhibits secretion of pancreatic enzymes and contraction of the gall bladder
pancreatic somatostatin
93
absolute insulin deficient
lack of insulin -- type 1 diabetes
94
relative insulin deficient
insulin is either not working or there is resistance
| type 2 diabetes -- common in cats and people
95
insulin deficiency will cause the blood glucose concentrations to ______
increase
96
insulin deficiency will cause the blood lipid levels to _____
increase (due to lipolysis of storage fat and the release of FFA)
97
insulin deficiency causes the plasma protein level to _______
increase -- amino acids will be in the blood/protein catabolism, synthesis stops
98
amino acids in the blood can be used for what
1. direct energy sources in the liver
| 2. substrate for gluconeogenesis -- hyperglycemia
99
in diabetes, what substrates becomes so excessive that the krebs cycle and triglyceride synthesis become too overwhelmed and ketone bodies are made
acetyl CoA
100
why are some diabetic patients so skinny
there is no insulin so there is no glucose uptake into the satiety center -- polyphagia, they eat a ton BUT the proteins are in a state of catabolism so huge weight loss
101
most common long term complication in dogs of type 1 diabetes mellitus
cataracts
102
impaired insulin action in the liver, muscle, and adipose tissue -- also beta cell failure
type 2 diabetes -- relative deficiency
103
top two potential factors that can lead to type 2 diabetes mellitus
obesity
| islet amyloidosis
104
polypeptide produced by beta cells with insulin to increase satiety and lower glucagon production
amylin
105
what is islet amyloidosis
when amyloid deposits in the islets/aggregates and becomes toxic to beta cells and they fail to produce insulin
106
what organ compensates producing insulin when there starts to be insulin resistance
pancreas
107
when the beta cells lost their ability to compensate glucose will not be maintained to the normal range and what will occur...
glucose intolerance
108
list some common causes of insulin resistance in cats
```
obesity
progestins
glucocorticoids
acromegaly
cushings
hyperthyroidism
pancreatitis
```
109
why is progesterone a cause of insulin resistance
it stimulates GH production which is a counterregulatory hormone and lowers insulin levels
110
T/F
| amyliodosis is reversible
FALSE
111
T/F
| glucotoxicity is reversible
TRUE
112
What is diabetic neuropathy and who gets it
cats and people
it is when hyperglycemia leads to nerve damage
- ataxia
- muscle atrophy
- plantigrade posture
- limb weakness
113
derived by oxidation of FFA by the liver and used as an energy source in glucose deficiency
ketone bodies
114
the condition when ketone bodies build up in excess
ketosis
115
what two things happen for ketone body synthesis
1. increased mobilization of FFA from the triglycerides stored in the adipose tissue
2. a shift in hepatic metabolism from fat synthesis to fat oxidation
116
insulin _____ will promote an increased release of FFAs which in turn promotes _______ in the liver
deficiency
ketogenesis
117
most influential ketogenic hormone
glucagon
118
hormone that will inhibit glucose uptake in muscles and stimulate glucose production in the liver
glucagon (epinephrine)
***leads to insulin resistance
119
enhance lipolysis in insulin deficiency
cortisol and GH
120
block insulin action in peripheral tissues
cortisol and GH
121
potentiate glucagon on hepatic glucose output
cortisol and GH
122
low insulin = what with proteins
PROTEIN CATABOLISM = amino acids being made to liver
123
protein catabolism will stimulate what processes in the liver
gluconeogenesis and glycogenolysis to make glucose
124
list coexisting disorders increase the secretion of counterregulatory hormones
1. pancreatitis
2. infection
3. CKD
4. hormonal disorders
125
T/F
counter regulatory hormones worsen hyperglycemia and ketonemia, provoking acidosis, fluid depletion and
hypotension
TRUE
126
excess accumulation of ketones in the blood ..
acidosis
overwhelms the body's buffer systems
kidneys fail to compensate/bicarb is lost
127
Insulin ________ renal sodium reabsorption in the distal portion of the nephron
enhances
128
Insulin ______ increases sodium wasting
deficiency
129
during ketoacidosis what happens to the body sodium levels
DEFICIT
* Excessive urinary loss caused by osmotic diuresis
* Glucagon, vomiting and diarrhea also contributes
130
explain the deficit in total body potassium during diabetic ketoacidosis
Increase in plasma and ECF tonicity in DKA leads to a shift of water out of the cells, potassium follows the water out of the cells
acidosis shifts K+ out of cells
• Potassium shift is enhaced by the presence of acidosis and the breakdown of
intracellular protein secondary to insulin deficiency
• Entry of potassium into cells is also impaired in the presence of insulinopenia
• Osmotic diuresis causes marked urinary losses of potassium
• Secondary hyperaldosteroneism augment the potassium deficit
131
how does insulin keep K+ levels in the cells
insulin gets glucose into the cells and K+ follows glucose
132
T/F
| Osmotic diuresis also leads to enhanced urinary phosphate loss
TRUE
133
layer of the adrenal gland that is Mesodermal in origin
Cortex
134
outermost layer of the adrenal gland
cortex
135
layer of the adrenal gland that is Ectodermal in origin
adrenal medulla
136
what are the 3 zones of the adrenal cortex
1. granulosa
2. fasiculata
3. reticularis
137
Adrenal cortex produces _____ hormones
steroid
138
zone of the cortex that produces glucocorticoids
fasiculata
139
zone of the cortex that produces sex steroids
reticularis
140
layer of the adrenal gland that produces CATECHOLAMINES
medulla
141
zone of the cortex that produces mineralocorticoids
glomerulosa
142
all steroid hormones are derived from
cholesterol
143
first step for all steroid biosynthesis classic pathways
cholesterol is turned into PREGNENOLONE in the mitochondria
144
pregnenolone formation is regulated by what hormone from the adeno hypophysis
ACTH
145
T/F
| ACTH regulates the rate of synthesis of all adrenocortical hormones
TRUE
146
adrenal cortex hormones are hydro____ and lipo____
Hydrophobic
lipophilic
147
where are steroid hormone receptors located
intracellularly
- cytosol
- cytoplasm
- nucleus
148
T/F
| the activity of glucocorticoids and mineralocorticoids do not overlap
FALSE
149
T/F
| steroid/adrenal cortex hormones can freely cross cell membranes
TRUE
150
T/F
| steroid hormones need a protein to carry them in the plasma
TRUE -- specific binding globulins
151
what do the adrenal cortex hormones bind to to be carried in the plasma
corticosteroid binding globulin -- Transcortin
| 75% bind to this
152
half life of cortisol
60 min
153
half life of aldosterone
20 min
154
adrenocortical hormones are metabolized in the
liver
155
most important mineralocorticoid
aldosterone
156
most important glucocorticoid
cortisol
157
T/F
| the zona glomerulosa is the outermost layer of the cortex
true
158
hormone that acts in the distal tubules of the kidneys ro regulate electrolyte balance and blood pressure by absorbing more water and sodium and excreting K+
aldosterone
159
nonspecific competitive antagonist drug for aldosterone
spironolactone
160
what stimulates the RAAS
low ECF
| low plasma Na concentration
161
aldosterone is linked with what other hormone
ADH
162
what zone will produce the aldosterone and what is the trigger
fasiculata -- angiotensin II
163
an increase in potassium will directly stimulate what zone
zona glomerulosa -- for regulation and secretion of mineralocorticoids
**independent of the RAAS
164
disease in cats with excessive aldosterone production
hyperaldosteroneism
**also causes weakness, hypokalemia, retinal lesions
165
hyperaldosteroneism is caused by what occurring in the zona glomerulosa
hyperplasia / neoplasia
166
Which glucose transporter is important for
| the glucose entrance in the beta cell?
GLUT 2
167
T/F
The acute phase of insulin secretion involves
the synthesis of new insulin by beta cells
FALSE
168
hormone
| released immediately after hypoglycemia
catecholamine
169
Under insulin action, the liver will
decrease gluconeogenesis
170
Which enzyme is responsible for the release of
| FFAs and glycerol in the blood during diabetes?
hormone sensitive lipase
171
T/F
| ketone bodies are a source of energy for the brain
true
172
Why do we see hyperventilation in a DKA patient
they are trying to decrease pCO2
173
most ketogenic hormone
glucagon
174
The increase in ketone bodies without
| interference in the blood pH is called
ketosis
175
T/F
For the synthesis of ketone bodies to be enhanced,
there must be an increased mobilization of FFAs
TRUE
176
major hormone from zona fasiculata
cortisol
177
T/F
| ACTH is also called a corticotrophin
TRUE
178
what regulates ACTH
corticotrophin releasing factor from the hypothalamus
179
what receptor does ACTH bind to
G-coupling receptor on the adrenal cortex
**this stimulates the intracellular pathway of cortisol production and secretion
180
what does cortisol do to carbohydrate metabolism
stimulates the synthesis of enzymes involved in gluconeogenesis -- the main substrate is the amino acids from muscles
181
how does cortisol decrease the utilization of glucose by cells
decreases the GLUT4 transporters in skeletal muscle -- can lead to insulin resistance
182
How does cortisol cause diabetes mellitus
increases gluconeogenesis
| lowers glucose utilization
183
what does cortisol do to protein metabolism
lowers protein synthesis
| increased protein catabolism of already present proteins
184
what does cortisol do to fat metabolism
increases mobilization of fatty acids from adipose tissue
**shifts metabolism from glucose to fat utilization
**can cause obesity
185
what are some of the immunosuppressive and anti-inflammatory effects of cortisol
stabilizes lysosomal membranes and lowers proteolytic enzymes
lowers prostaglandins and leukotriene production
lowers histamine from mast cells
lowers phagocytosis and suppresses Ab formation
186
what clinical signs would you see with hyperadrenocorticism
```
high glucocorticoids
polyphagia
alopecia
hepatomegaly
glycogen deposition
panting -- heat produced bc ADH is blocked telling it to drink/urinate
```
187
primary catecholamine produced by the adrenal medulla
epinephrine
188
what cells produce the epinephrine in the medulla
chromaffin cells from the amino acid Tyrosine
189
How does the adrenal medulla secrete its hormones
like a postsynaptic ganglia of the SNS -- secretes neurotransmitters into the blood
190
action of catecholamines
fight or flight response
191
the thyroid gland is composed of follicle cells filled with
colloid -- a viscous protein rich fluid
192
T/F
| colloid stores the thyroid hormones
TRUE
193
what are the cells located outside of the thyroid follicular cells
parafollicular or C cells
194
what do the parafollicular cells secrete
calcitonin -- regulates Calcium metabolism
195
what are the 2 molecules involved in thyroid hormone synthesis
tyrosine
| iodine
196
where does iodine come from
diet
197
T/F
| extracellular iodine > intracellular iodine
FALSE
198
drug that inhibits TPO
Methimazole
199
first step of thyroid hormone synthesis
oxidation of iodide to iodine done by Thyroid Peroxidase (TPO) in the apical membrane
200
what is the major hormone made by the follicular cells
THYROXINE (T4)
201
what is the TPO coupling equation to form T4
DIT + DIT = T4
202
what is the TPO coupling equation to form T3
MIT + DIT = T3 (Thiiodothyronine)
203
what is the inactive form of T3
the reversed form
204
where does the majority of T3 come from
the deiodination of the free T4 in the cell
205
How do T3 and T4 get into the membrane
they pass freely because they are lipophilic
206
how are thyroid hormones transported in the plasma
attached to liver proteins
- albumin
- thyroxine binding globulin
207
list some actions of the thyroid hormones
1. bind to nucleus receptors to initiate transcription of mRNA
2. increased mitochondria and ATP
3. increased basal metabolic rate
4. stimulate carbohydrate metabolism
5. fat metabolism -- plasma and liver fat decreased
6. high heart rate/blood flow/vasodilation at tissues/cardiac output
208
main organ involved in the Calcium and Phosphate metabolism
parathyroid hormone
209
% phosphate in bone
| % calcium in bone
85 Phosphate
| 99 Ca
210
% phosphate in ICF
| % calcium in ICF
14% Phosphate
| <1% calcium
211
% phosphate ECF
| % calcium ECF
1% phosphate
| 0.1% calcium
212
percent of blood calcium that is ionized
50%
213
biologically active form of calcium
ionized
214
percent of calcium bound to albumin in the blood
40%
215
important ion molecule for muscle contraction
calcium
216
The regulation of calcium levels involves control of the
| movement of calcium between the ECF and 3 organs
Bone
GIT
Kidney
217
3 hormones involved in calcium / phosphate metabolism
1. PTH
2. vitamin D
3. calcitonin
218
2 types of parathyroid in the glandular tissue
1. active = chief cells
| 2. inactive = oxyphil cells
219
cells that produce PTH
chief cells
220
Parathyroid cells are very sensitive to a ______ in iCa
decline
* *a drop in iCa activates the membrane receptors to start producing PTH
* *normal Ca levels = inactive receptors
221
where is PTH metabolized
liver
| kidney
222
half life of PTH
5-10 minutes
223
PTH has a direct effect on what?
| indirect effect on?
```
direct = bone and kidney metabolism
indirect = GIT metabolism
```
224
PTH action on ca/phosphate levels
inceases Ca and lowers phosphate in the ECF
225
PTH directly effects bone how
• Binds to its receptors on osteocytes and stimulates osteocytic-osteolysis
- Binds to receptors on bone osteoblast cells and stimulates the
production of osteoclast-activating factor
226
PTH direct effect on kidney--
acts on the distal convoluted tubules to increase Ca reabsorption and also lower Proximal tubule phosphate absorption
227
T/F
| PTH can activate vitamin D in the kidney
TRUE
| **only way vitamin D becomes active
228
stimulates the active transport of dietary calcium across the intestinal epithelium
calcitriol
**Without calcitriol most animals are unable to aquire enough calcium from the
diet to support normal bone structure
229
T/F
| hindgut fermenters need calcitriol
false -- rabbits and horses dont need because always can reabsorb calcium -- urinary loss regulation
230
_________ in iCa stimulates PTH secretion
decrease
231
PTH is mainly regulated by
free ionized calcium concentration in the blood
232
produced by parafolicullar cell or C cell in the thyroid gland
calcitonin -- counterbalance of PTH
233
an increase in calcium will stimulate calcitonin to do what in the bone, kidney, GIT
bone -- increase Ca storage
kidney -- increase Ca excretion
GIT -- increase Ca excretion
234
T/F
| GI hormones also stimulates the secretion of calcitonin
TRUE
235
T/F
Steroid hormones are made from cholesterol, transported by proteins in the blood and bind to nuclear receptors in the target tissues.
TRUE
236
effects of aldosterone
Na reabsorbed
Cl reabsorbed
Water reabsorbed
**increases blood vol
237
Which of the following is a direct regulator of
| aldosterone release?
potassium
238
what hormones stimulates
| zona fasiculata and glomerulosa respectively
ACTH and Angiotensin II
239
T/F
epinephrine causes Vasodilation of visceral
organs
FALSE
