Lecture 79 Flashcards
Insulin, Glucagon, and Diabetes Mellitus.
1
Q
The pancreas secretes __
A
two important hormones: insulin and glucagon
2
Q
The pancreas secretes two important hormones:
A
(1) insulin
(2) glucagon
3
Q
The physiological anatomy of pancreas is composed of __ major types of cells
A
TWO major types of cells:
4
Q
The physiological anatomy of pancreas is composed of two major types of cells:
A
- Acini
- Islets of Langerhans
5
Q
Acini: The acini secrete __
A
digestive juices into the small intestine (duodenum)
6
Q
The islets of Langerhans (or just ‘islets’ for brevity), secrete
A
secrete insulin and glucagon into blood
7
Q
There are between __ islets in a pancreas
A
1 - 2 million
8
Q
The islets of
Langerhans were discovered in the year 1869 by a pathological anatomist
A
Paul Langerhans.
9
Q
Islets of langerhans are located
A
located around the small capillaries
10
Q
he islets of
Langerhans were discovered in the year 1869 by
A
a pathological anatomist Paul Langerhans
11
Q
size islets of langerhans
A
They are very small, only 0.3 mm in diameter
12
Q
The islets contain three major types of cells:
A
- Alpha (α) cells
- Beta (β) cells
- Delta (δ) cells
13
Q
The islets contain three major types of cells:
Alpha (α) cells compose what percentage?
A
25%
14
Q
Alpha (α) cells (25% of the islet) secrete:
A
glucagon
15
Q
The islets contain three major types of cells: beta cells percentage?
A
60%
16
Q
Beta (β) cells (60% of the islet) secrete:
A
insulin
17
Q
The islets contain three major types of cells: Delta (δ) cells represent what percentage of the islet?
A
10%
18
Q
Delta (δ) cells (10% of the islet) secrete:
A
somatostatin
19
Q
Delta cells secrete somatostatin: somatostatin is also known as
A
growth hormone-inhibiting hormone (GHIH)
20
Q
delta cells secrete: somatostatin is also known as growth hormone-inhibiting hormone (GHIH). It is the same hormone that controls the
A
somatotopes in the anterior pituitary
21
Q
- somatostatin is also known as growth hormone-inhibiting hormone (GHIH). It is the same hormone that controls the somatotopes in the anterior pituitary, however, where it is made in the islets, its job is to
A
regulate the alpha and beta cells.
22
Q
Delta (δ) cells: they are 10% of the islet, secrete* somatostatin. What is particular about their secretions?
A
Delta cells appear to secrete within the islets, not into the blood circulation
23
Q
The three hormones of the islets of langerhans can:
A
antagonize each other
24
Q
The three hormones of the islets of langerhans can antagonize each other:
(1) insulin inhibits __
(2) Glucagon inhibits __
(3) somatostatin inhibits __
A
(1) insulin inhibits glucagon secretion
(2) glucagon inhibits insulin secretion.
(2) somatostatin inhibits insulin and glucagon secretion
25
* insulin inhibits
glucagon secretion.
26
* glucagon inhibits
insulin secretion.
27
* somatostatin inhibits
insulin and glucagon secretion.
28
Chemistry of Insulin:
* Insulin is a (morphology)
a small protein, composed of two amino acid (aa) chains connected with two disulphide bonds (S bonds).
29
Chemistry of Insulin:
Insulin is what type of hormone (peptide, cholestoral,hydrophhobic,etc)
peptide/protein based
30
Chemistry of Insulin: Disulphide Bonds are important because:
when the sulphur bonds are insulin loses its functional activity.
31
insulin synthesized in β cells in the following steps:
Insulin RNA attaches to the endoplasmic reticulum (ER) to form a precursor, insulin PREPROHORMONE -> preprohormone cleaved in the ER to form PROINSULIN-> further cleaved in Golgi apparatus to form INSULIN, -> Insulin is packed into secretory granules -> secreted into blood when glucose levels are elevated.
32
Pharmacokinetics of Insulin:
* Plasma half-life of insulin is
short, only 5 - 6 minutes
33
Pharmacokinetics of Insulin
* Plasma half-life of insulin is short, only 5 - 6 minutes
o this means that
half of the peak levels are gone in 6 minutes
34
* Because of short half life, insulin function can be
rapidly turned off if glucose levels return to normal.
35
* Total clearance of insulin is about
10 - 15 minutes
36
* Total clearance of insulin is about 10 - 15 minutes. It is mainly cleared in the
liver.
37
* Total clearance of insulin is about 10 - 15 minutes. It is mainly cleared in the liver. This assumes that
insulin is not being synthesized and secreted
38
* Total clearance of insulin is about 10 - 15 minutes. It is mainly cleared in the liver. This assumes that insulin is not being synthesized and secreted.
o If insulin is continually secreted, it can
overcome the clearance rate and stay elevated for a long time. Can be problematic in diabetes.
39
The insulin receptor is
a protein with four subunits.
40
A subunit is
is a piece of protein that needs to form with other subunits to become functional
41
The insulin receptor is a protein with four subunits: alpha vs beta subunits?
There are two alpha (α) subunits that lie outside the cell membrane. There are two beta (β) subunits that cross the cell membrane into the cytoplasm.
42
Insulin enhances
glucose phosphorylation
43
Minutes after eating a meal or consuming nutrients, insulin __
rises
44
Minutes after eating a meal or consuming nutrients, insulin rises, which promotes
glucose uptake in tissues especially muscle, and allows storage of glucose in the liver.
45
The most important effects of insulin is to:
cause glucose to be absorbed by liver
46
Insulin enhances
glucose phosphorylation
47
Glucose phosphorylation is the process where
a phosphate group is added to glucose, converting it to glucose-6-phosphate (G6P), a key step in glycolysis and other metabolic pathways. This reaction, catalyzed by enzymes like hexokinase and glucokinase, traps glucose inside the cell and initiates its breakdown for energy.
48
The most important effects of insulin is to cause glucose to be absorbed by liver. Insulin enhances glucose phosphorylation by an enzyme called
glucokinase
49
Phosphorylation of glucose adds:
Phosphorylation of glucose adds a charged phosphate on the glucose unit: then glucose P can not escape the liver (it will be transformed into glycogen)
50
The following actions of insulin increase the glycogen in the liver (2): insulin activates/stimulate
(1) Insulin stimulates the enzyme glucokinase in liver -> enhances glucose phosphorylation -> enhances uptake of glucose from blood by the liver cell.
(2) Insulin activates enzyme glycogen synthase (synthetase) -> promotes glycogen synthesis (polymerization of glucose).
51
Hepatic Effects of Insulin on Carbohydrate Metabolism: insulin inactivates (2):
(1) glucose phosphatase (enzyme that removes phosphate)
(2) liver phosphorylase, preventing glycogen breakdown into glucose.
52
Insulin inactivates glucose phosphatase (enzyme that removes phosphate) which reduces (2):
the splitting of phosphate from the phosphorylated glucose -> reduces the release of the free glucose back into blood.
53
Insulin inactivates the liver phosphorylase (enzyme that causes the glycogen in the liver to split into glucose) which prevents:
the breakdown of glycogen into glucose in the liver.
54
Insulin stimulates/Activates (2):
(1) enzyme glucokinase in liver : enhances glucose phosphorylation and enhances uptake of glucose from blood by the liver cell
(2) enzyme glycogen synthase (synthetase) -> promotes glycogen synthesis (polymerization of glucose)
55
glucose phosphatase
enzyme that removes phosphate
56
liver phosphorylase
enzyme that causes the glycogen in the liver to split into glucose
57
Just after a meal, insulin also promotes glucose uptake by
other tissues in the body such as muscles.
58
Just after a meal, insulin also promotes glucose uptake by other tissues in the body such as muscles. The other tissues can now use the glucose for energy. In some tissues like muscle, they can even
store extra glucose as glycogen
59
2 hours after meal is over, the blood glucose concentration: blood glucose levels:
begins to fall to baseline levels, and then drops below baseline. This is due to effects of insulin, the blood glucose is lower
60
consequence of insulin's action on blood glucose from liver in between meals:drop in blood glucose cause decrease of
insulin secretion from islet,
61
consequence of insulin's action on blood glucose from liver in between meals? As insulin disappears, the following four effects occur in the liver:
(1) activates glycogen phosphorylase ( glycogen phosphorylase
causes glycogen to split into glucose-phosphate molecules )
(2) activates glucose phosphatase: glucose phosphotase causes phosphate to split away from glucose-phosphate (when phosphate is removed, the glucose is free to diffuse back into blood
(3) inhibits glycogen synthase (stops synthesis of glycogen)
(4) lack of insulin prevents the liver from taking glucose from the blood
62
Glucose metabolism in muscles: When muscle is at rest glucose required by muscles is
minimal
63
glucose metabolism in muscles: resting muscle: Muscle membrane is
only slightly permeable to glucose
64
glucose metabolism in muscles: muscle at rest: Insulin is
not absolutely required.
65
glucose metabolism in muscles: muscle at rest: energy mainly depends on:
fatty acids
66
glucose metabolism in muscles: When muscle is at rest, soon after a meal is eaten, Glucose concentration in the blood is __
higher
67
glucose metabolism in muscles: When muscle is at rest, soon after a meal is eaten, * Insulin release is
stimulated in islets
68
glucose metabolism in muscles: When muscle is at rest, soon after a meal is eaten, Glucose uptake into muscle cells is
enhanced by up to 15 fold
69
When muscle is at rest, soon after a meal is eaten, muscle can use __ or __
* Muscle can use glucose for energy
* Or, the extra glucose is stored as glycogen in the muscles
70
* When a muscle is being used, for example moderate or heavy exercise, the glucose needs are met by (3):
(1)insulin promotes glucose uptake, assuming the person has eaten a meal recently
(2) the increased blood flow promotes glucose uptake, regardless of insulin
(3) metabolic activity of the working muscle promotes glucose uptake, regardless of insulin
71
* When glucose enters a muscle it becomes __
phosphorylated by hexokinase
72
* When glucose enters a muscle it becomes phosphorylated by
hexokinase
73
* When glucose enters a muscle it becomes phosphorylated by hexokinase, then the glucose-phosphate
can not escape back into the blood.
74
phosphorylation of glucose is irreversible in
muscle.
75
Glucose is committed to energy production or storage within
the muscle
76
does a resting mucle require insulin to get glucose?
a resting muscle might require insulin to get glucose
77
When a muscle is being used it can obtain glucose
without insulin
78
when a muscle is being used it can obtain glucose without insulin. If a moving muscle also experiences insulin, it will
take up even more glucose.
79
Insulin is not required for glucose uptake in the (3):
(1) brain
(2) spinal cord
(3) peripheral nerves.
These tissues always get the glucose they need, since they are essential for life.
80
* It is essential that blood glucose levels are maintained at:
80 - 120 mg/dl ( 5 - 6 mmol/l )
81
what happens if blood glucose decreases less than 45 mg/dl ( < 2.5 mmol/l )?
severe hypoglycemia occurs leading to coma
82
If the blood glucose decreases less than 45 mg/dl ( < 2.5 mmol/l ), severe hypoglycemia occurs leading to
coma
83
If the blood glucose decreases less than 45 mg/dl ( < 2.5 mmol/l ), severe hypoglycemia occurs leading to coma. The coma is due to
to significant decline in brain activity due to relative lack of glucose.
84
effects of insulin on lipid metabolism: When insulin rises, it reduces:
fat utilization for energy
85
effects of insulin on lipid metabolism: Insulin promotes
synthesis of new fatty acids in the liver
86
Insulin promotes the synthesis of new fatty acids in the liver, which are then
then transported to the adipose tissue.
87
Describe synthesis pathway of new fatty acids in the liver promoted by insulin
Fatty acids are synthesized in the liver → become triglycerides in liver ➔
triglycerides are released from liver cells to blood in the lipoproteins ➔ insulin
activates lipoprotein lipase (enzyme) in the capillary walls of the adipose tissue
➔ lipase splits the triglycerides again into fatty acids to be absorbed into adipose
cells ➔ fatty acids in the cell are converted back to triglycerides for storage.
88
In what two ways does insulin promote the storage and synthesis of fat in ADIPOSE cell?
(1) Insulin promotes glucose uptake into the adipose cell ➔ glucose forms large
amount of α-glycerol phosphate which combines with fatty acids to form
triglycerides to be stored in adipose cell.
(1)Insulin inhibits the action of hormone-sensitive lipase (enzyme) ➔ this inhibits
the hydrolysis of triglycerides stored in adipose cell ➔ this inhibits the release
of fatty acids from adipose cell into blood.
89
Effects of insulin on lipid metabolism:
Insulin inhibits the action of:hormone-sensitive lipase (enzyme)
90
Hormone-sensitive lipase (HSL) is
an intracellular enzyme that plays a crucial role in mobilizing stored fats, primarily by hydrolyzing triglycerides into fatty acids, which are then released into the bloodstream for energy.
91
When insulin falls to low or absent levels, such as in between meals in a healthy person, or if
chronically low in type 1 diabetes, there are major impacts on fat metabolism
(1) The enzyme hormone-sensitive lipase in the adipose cell
becomes strongly activated ➔ hydrolysis of the stored triglycerides (TG) ➔ large
amount of fatty acids and glycerol are released into blood ➔ increase of free fatty
acids (FFA) in blood for energy utilization.
(2) Excess free fatty acids (FFA) in the plasma promote the conversion of fatty acids into
phospholipids and cholesterol (two major products of fat metabolism) in the liver,
(3) phospholipids, cholesterol and excess triglycerides are released into the blood in the
lipoproteins -> cause the concentration increase of these three substances to 300% during brief period of
insulin lack,
development
92
Chronic insulin deficiency can lead to a rapid development of:
atherosclerosis
93
Atherosclerosis is
buildup of fats, cholesterol and other substances in and on the artery wall
94
atherosclerosis
the buildup of fats, cholesterol and other substances in and on the artery walls
95
Prolonged fat utilization in the absence of insulin can lead to
ketosis and acidosis
96
chain reactiont that causes ketosis and acidosis
Acetyl-CoA Production: Increased fatty acids are transported into mitochondria in liver cells, leading to excessive acetyl-CoA production. (Page 9)
Acetoacetic Acid Formation: Acetyl-CoA is condensed to form acetoacetic acid, which is released into the blood. (Page 9)
Acidosis: Excess acetoacetic acid in the blood lowers the pH, leading to severe acidosis. (Page 9)
Ketone Body Formation: Acetoacetic acid is converted into β-hydroxybutyric acid and acetone, resulting in ketosis. (Page 9)
97
Ketone bodies are a combination of the three substances:
acetoacetic acid
β-hydroxybutyric acid acetone
98
acetoacetic acid, β-hydroxybutyric acid and acetone together make a
ketone body
99
acidosis is a general term for
low pH in the blood
100
__ is the specific situation that causes acidosis.
ketosis
101
, acidosis is a general term for low pH in the blood, ketosis is the specific situation
that causes acidosis. Thus, its better to say that the __ was due to __, or, the ketosis
caused __.
, acidosis is a general term for low pH in the blood, ketosis is the specific situation
that causes acidosis. Thus, its better to say that the acidosis was due to ketosis, or, the ketosis
caused acidosis.
102
Concept of Insulin in "Switching" Between Carbohydrate and Fat ( Lipid ) Metabolism: Insulin promotes the use of
___ for energy and depresses the use of __
* Insulin promotes the use of carbohydrates for energy and depresses the use of fats
103
In a healthy person, the use of fat for energy is important, however,
it should never reach
the point of causing acidosis due to ketosis because insulin will turn on again after the
next meal.
104
lack of insulin causes what in terms of utilization of energy?
promotes the use of fats and depresses the use of carbohydrates for energy
105
Concept of Insulin in "Switching" Between Carbohydrate and Fat ( Lipid ) Metabolism: __controls the switching mechanism:
blood glucose concentration
106
The blood glucose concentration controls the switching mechanism:
(1) Low glucose concentration -> suppression of insulin -> increase use of fat for energy ( except in the brain ) and suppress the use of glucose
(2) When glucose concentration is high-> stimulates insulin secretion -> increase of glucose utilization for energy.
107
effects of insulin on protein metabolism and growth: insulin has an __ effect to promote __
Insulin has an anabolic effect to promote proteins.
108
anabolism:
the synthesis of complex molecules in living organisms from simpler ones together with the storage of energy; constructive metabolism.
109
catabolism:
the breakdown of complex molecules in living organisms to form simpler ones, together with the release of energy; destructive metabolism
110
Insulin has an anabolic effect to promote proteins.
To do this, it :
(1) promotes amino acids uptake in the muscle cells
(2) insulin stimulates the DNA transcription ( in cell nucleus ) and ribosomes (in cytoplasm) to form new proteins
(3)Insulin inhibits proteolysis (catabolism of protein)
(4)insulin decrease the release rate of amino acid from cells (especially from muscle cells).
111
effects of insulin on protein metabolism and growth:Insulin suppresses
gluconeogenesis (formation of glucose from amino acids) by
inactivating the enzyme for gluconeogenesis ➔ more amino acids are available for
protein synthesis.
112
113
effects of insulin on protein metabolism and growth: Insulin suppresses gluconeogenesis (formation of glucose from amino acids) by :
inactivating the enzyme for gluconeogenesis --> more amino acids are available for protein synthesis
114
effects of insulin on protein metabolism and growth:
* The combined influence of growth hormone (GH) and insulin together leads to
to an accelerated rate of growth in babies.
115
What is the effect of a lack of insulin on protein metabolism (3)?
(1) protein catabolism increases
(2) protein synthesis stops
(3) amino acids increase dramatically in blood (gluconeogenesis can now occur)
116
gluconeogenesis
formation of glucose from amino acids
117
effects of insulin on protein metabolism and growth:when insulin is absent, __ can now occur in liver to create new glucose
gluconeogenesis (formation of glucose from amino acids)
118
effects of insulin on protein metabolism and growth:If insulin is chronically absent or dysfunctional, this is classic __ condition of accelerated ___ with resulting ___
If insulin is chronically absent or dysfunctional, this is classic diabetic condition of accelerated protein loss with resulting decrease in lean body mass.
119
Frederick Banting and J.J.R. Macleod;
nobel prize medicine for discovery of insuline
120
Frederick Sanger:
Nobel prize in chemistry for determining the structure of insulin
121
Dorothy Crowfoot Hodgkin
Nobel prize in chemistry for the development of crystallography (insulin structure)
122
Rosalyn Sussman Yalow:
Nobel prize in medicine for the development of the radioimmunoassay for insulin
123
paul langerhans
identifies some mysterious tissue clumps scattered throughout the pancreas
124
Oscar Minkowski / Joseph Von mering:
removed pancreas from a healthy dog --> uring became sweet
125
Frederick Banting and Charles best:
discovered insulin by purifying it from dog pancreas
126
Eli Lily
Made large quantities of insulin and began selling it for medicinal use (got the summer job on a coin toss)
127
* Secretion of insulin is primarily controlled by
blood glucose
128
* Secretion of insulin is primarily controlled by blood glucose
o Rapid increase in blood glucose leads to a
biphasic insulin response.
129
Secretion of insulin is primarily controlled by blood glucose: Resting blood glucose ( 80-90 mg/dl ) stimulates
approximately 25 ng/min/kg of insulin.
130
Secretion of insulin is primarily controlled by blood glucose: If the blood glucose concentration is increased to 2 to 3 times above normal level, insulin secretion increases in
two stages:
131
Secretion of insulin is primarily controlled by blood glucose: If the blood glucose concentration is increased to 2 to 3 times above normal level, insulin secretion increases in two stages:
(1) Within first 3 to 5 minutes insulin concentration increases almost 10-folds; then it decreases halfway back, because the increased transport of glucose into liver, muscle and other cells.
(2) At about 15 minutes insulin secretion rises a second time and reaches to a new plateau which is approximately 20 times normal level in 2 to 3 hours.
132
Secretion of insulin can also be controlled by (aside from blood glucose main mechanism):
some amino acids
133
insulin causes amino acids to
be transported into muscles, liver, and adipose tissue
134
Secretion of insulin can also be controlled by some amino acids. Recall that insulin causes amino acids to be transported into muscles, liver, and adipose tissue. The body can use this feature to
clear out excess amino acids
135
Arginine and lysine have the similar effects on
promoting insulin secretion.
136
Amino acids cause a __ when it is administered
a small increase in insulin secretion
this can occur without the rise of blood glucose
137
If amino acids and glucose both rise in blood, the secretion of insulin is
strongly promoted, it even doubles
138
in terms of insulin secretion, amino acids and glucose are
synergistic
139
in terms of insulin secretion, amino acids and glucose are synergistic, they do more than
just the simple sum of their individual effects.
140
Glucagon is a
small hormone secreted by alpha cells
141
Glucagon is a small hormone secreted by
by alpha cells of islet in pancreas
142
Glucagon is a small hormone secreted by alpha cells of islet in pancreas when
blood glucose concentration falls.
143
Glucagon is a polypeptide with
just 29 amino acids.
144
Glucagon has a powerful
hyperglycemic effect
145
Glucagon has a powerful hyperglycemic effect. Just 1 μg/kg of glucagon can
elevate blood glucose concentration 25% in 20 minutes!
146
How does glucagon have such a strong effect on glucose?
Glucagon increases the breakdown of liver glycogen into glucose (glycogenolysis).
147
glycogenolysis
breakdown of liver glycogen into glucose
148
Glucagon activates liver cell membrane and promotes degradation of glycogen into
glucose-1-phosphate
149
Glucagon activates liver cell membrane and promotes degradation of glycogen into glucose-1-phosphate -> glucose-1-phosphate is then:
dephosphorylated
150
Glucagon activates liver cell membrane and promotes degradation of glycogen into glucose-1-phosphate-> glucose-1-phosphate is dephosphorylated -> glucose is then:
released from the liver cells into blood.
151
Aside from increasing glycogenolysis, glucagon also increases:
gluconeogenesis in the liver.
152
Glucagon increases gluconeogenesis in the liver ; Glucagon activates
enzymes for promoting amino acids uptake by liver cells, and activates enzymes for conversion of amino acids to glucose by gluconeogenesis
153
Two actions of glucagon that serve to maintain or elevate blood glucose levels:
1)glycogenolysis (breakdown of liver glycogen into glucose
2)gluconeogenesis (activates enzymes for promoting amino acids uptake by liver cells, and
activates enzymes for conversion of amino acids to glucose by gluconeogenesis.)
154
effects of glucagon on lipid metabolism (2):
(1) Glucagon increase lipase activity in adipose cells -> increase fatty acids available to energy system.
2) Glucagon inhibits triglyceride storage in the liver.
155
glucagon opposes the effects of __ on __ and __
glucagon opposes the effects of insulin on carbohydrate and fat metabolism.
156
___ is the most potent factor that controls glucagon secretion
Low blood glucose concentration
157
The effect of blood glucose on glucagon secretion is exactly opposite to that of:
insulin secretion
158
___ stimulates glucagon release
o Low levels of blood glucose
159
__ inhibits glucagon release
High levels of blood glucose
160
An increase in amino acids (alanine and arginine) stimulates ___, promotes ___
An increase in amino acids (alanine and arginine) stimulates glucagon secretion, -.> promotes conversion of amino acids to glucose
161
an increase in amino acids might cause both
insulin and glucagon to rise
162
__ produced and secreted from delta cells of islet
Somatostatin (Growth hormone inhibitory hormone
163
Somatostatin (Growth hormone inhibitory hormone) is produced and secreted from
Somatostatin (Growth hormone inhibitory hormone) is produced and secreted from
164
somatostatin depresses both
insulin and glucagon secretion
165
Somatostatin depresses both insulin and glucagon secretion: what does this do?
decreases the use of the absorbed nutrients by tissues -> prevent rapid exhaustion of food -> making food available over a longer period of time.
166
How do insulin and glucagon work together to regulate blood glucose?
How do insulin and glucagon work together to regulate blood glucose?
167
The liver acts as a blood glucose __
buffer system
168
The liver acts as a blood glucose buffer system: When blood glucose concentration rise too high after a meal :
-> increase of insulin secretion -> increase of glucose storage in the liver as glycogen -> blood glucose decreases toward normal.
169
The liver acts as a blood glucose buffer system: When blood glucose concentration falls ( between meals ) :
stimulates secretion of glucagon -> glucose releases from liver back into blood.
170
___ feedback mechanism is much more important than the __ mechanism
Insulin feedback mechanism is much more important than the glucagon mechanism
171
Insulin feedback mechanism is much more important than the glucagon mechanism. But the glucagon mechanism becomes very valuable in the following conditions:
o Starvation,
o Excessive utilization of glucose during exercise,
o Other stressful situation.
172
In severe hypoglycemia, low blood glucose on __ stimulates __ and causes
in severe hypoglycemia, low blood glucose on hypothalamus stimulates the sympathetic nervous system -> causes secretion of epinephrine from adrenal medulla -> release of glucose from liver to protect against severe hypoglycemia
173
In severe and prolonged (chronic) hypoglycemia, both __ and _ are secreted which )) and help ___
in severe and prolonged (chronic) hypoglycemia, both growth hormone and cortisol are secreted -> decrease glucose utilization by most cells of the body -> help for returning blood glucose concentration toward normal.
174
What is the importance of good blood glucose regulation?
Glucose is the best nutrient for energy for brain, retina, and germinal epithelium of the gonads. Therefore it is important to maintain blood glucose concentration at a sufficiently high level to provide energy.
175
It is also important that the blood glucose concentration does not rise too high, because
glucose exerts large amount of osmotic pressure in the extracellular fluid
176
It is also important that the blood glucose concentration does not rise too high, because glucose exerts large amount of osmotic pressure in the extracellular fluid. If blood glucose concentration is too high it causes
considerable cellular dehydration.
177
Too high blood glucose causes loss of glucose in __ , which causes __ , which can ____
Too high blood glucose causes loss of glucose in urine -> causes osmotic diuresis by kidneys, which can deplete the body of its fluids and electrolytes.
178
Type I diabetes also known as:
Insulin-dependent diabetes mellitus, IDDM
179
Type I diabetes : The secretion of insulin from beta islet cells is:
significantly diminished
180
Type I diabetes usually due to:
to autoimmune disease destroying islet tissues
181
Type I diabetes requires
injections to regulate blood glucose and to maintain blood glucose to near-normal levels.
182
Type II diabetes also referred to as:
Non-insulin dependent diabetes mellitus; NIDDM
183
Type II diabete: insulin levels?
o Normal or high insulin levels associated with high blood glucose levels
184
Type II diabetes: Insulin receptor:
may be deficient or absent on target cell, ( obesity decreases insulin receptors )
o Receptors may not bind insulin properly
185
What is gestational diabetes
Elevated blood glucose levels during pregnancy only,
186
Gestational diabetes: Has high incidence of
type II diabetes for the mother in later life.
187
What is the general pathology of diabetes (5) ?
* Decreased utilization of glucose by body cell.
* Increased mobilization of fats from fat storage deposition of cholesterol in arterial walls ( atherosclerosis ).
* Decrease protein storage in tissues of the body
* Increase of urine production (polyuria) results in whole body dehydration (osmotic diuresis). This condition brings on a strong thirst to drink water (polydipsia).
* Energy use depends almost entirely on fat causes increased acidosis due to ketosis.
188
atherosclerosis
deposition of cholesterol in arterial walls
189
polyuria
Increase of urine production
190
whole body dehydration
osmotic diuresis
191
polydipsia
condition brings on a strong thirst to drink water
192
