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Non-digestible carbohydrates that promote the growth of non-specific "beneficial" bacteria in the gut.
prebiotics
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specific strains of "beneficial" bacteria provided directly in a food product.
probiotics
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Fructooligosccharides in Iams dog food are an example of...
prebiotics
-
3 pathways of glucose utilization...
glycolysis, glycogen synthesis, hexose-monophosphate pathway
-
2 pathways of glucose production.
glycogen degradation, gluconeogensis
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Under conditions of rapid muscle contraction, the demand for _______ to generate ATP by ______________ exceeds the ____________.
O2; oxidative phosphorylaton; O2 supply to the muscles
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When the demand for ATP by oxidative phosphorylation exceeds the )2 supply to the muscles,...
the conversion of NADH to NAD+ in the mitochondria is blocked and pyruvate accumulates as lactate
-
Under anaerobic conditions, pyruvate is converted to ___________ by the _____________ reaction.
lactate; lactate dehydrogenase
-
Exercise intensity or level in which lactate is detectable in the blood.
lactate threshold
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Most dietary carbohydrate is in the form of _____, which are digested by _______, enzymes that digest __________.
starch; amylases; α-1,4 linkages
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Absorbed glucose enters the ________ to travel to the ________ and then to _______.
portal vein; pancreas, liver; systemic circulation
-
Glucose absorption occurs by...
glucose diffusing down its concentration gradient (ie. gut lumen to mucosal cell)
-
Glucose absorption is facilitated by a ______________.
specific transporter or carrier protein
-
Dietary glucose is mainly absorbed into the _____________ by _______.
jejunal mucosal cell; SGLT-1
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SGLT-1 is on the _________ of the _________ for glucose absorption.
luminal border; jejunal mucosal cells
-
Glucose exits the jejunal mucosal cell and enters the ______ via the _______ transporter.
portal blood; GLUT2
-
The GLUT5 transporter carries... (2)
fructose and a small amount of glucose
-
The two major functions of the pancreas in carbohydrate metabolism.
exocrine and endocrine pancreas
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The exocrine pancreas has function cells called ___________ that synthesize and secrete digestive enzymes into the pancreatic duct.
acinar cells
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Acinar cells of the exocrine pancreas secrete ________ into the pancreatic duct to...
α-amylase; digest dietary carbohydrates
-
Endocrine pancreas contains function cell types called ________________, which synthesize and secrete hormones that regulate blood glucose levels.
Islets of Langerhans
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Exocrine pancreas functions in...
the digestion of dietary carbohydrates
-
Endocrine pancreas functions in...
regulation of blood glucose levels
-
Alpha cells of the pancreas synthesize and secrete __________ in order to....
glucagon; increase blood glucose levels
-
Beat cells of the pancreas synthesize and secrete ______ in order to...
insulin; decrease blood glucose levels
-
The post-meal increase in blood glucose activates ___________, which lowers blood glucose by...
insulin release; increasing glucose uptake into the tissues
-
Glucose enters cells by _____________ with ____________.
facilitated diffusion; glucose transporters (GLUTs)
-
GLUT2 has ______ Km and ______ glucose affinity.
high; low
-
GLUT3 has _____ Km and _____ glucose affinity.
low; high
-
Two major cell types that express the GLUT2 transporter.
hepatocytes (liver cells) and β cells of the pancreas
-
Hepatocytes and β cells of the pancreas express GLUT2 because they...
have unique mechanisms for measuring and controlling blood glucose levels
-
The amount of glucose entering cells expressing GLUT2 is _______ over the normal (physiological) range of blood glucose levels.
linear (because it is low affinity)
-
GLUT3 transports ______ levels of glucose, even at _______ blood glucose concentration levels because it is expressed in cells of the ________.
high; low; nervous system
-
Enzymes with small values for Km will reach Vmax at...
lower substrate concentrations
-
Enzymes with high values for Km will reach Vmax at...
higher substrate concentrations.
-
Your brain doesn't know _____________, but the β cells in your pancreas do.
what your blood glucose levels are
-
-
After a meal, the linear relationship between glucose entering hepatocytes and pancreatic β cells and blood glucose levels allows...
the β cells to detect an increase in blood glucose and release insulin into the blood.
-
Increased uptake of glucose into β cells via __________ results in increased glucose metabolism by...
GLUT2; oxidation via glycolysis and the TCA cycle (thus increased ATP)
-
An increase in ATP due to increased glucose uptake by β cells initiates closing of __________, which leads to _____________.
K+ channels; membrane depolarization
-
Membrane depolarization due to increased ATP production (due t increased glucose uptake by β cells) is associated with the opening of ________________, allowing...
Ca++ channels; an increase in cellular Ca+ levels
-
Increased intracellular Ca+ levels induces...
translocation of insulin-containing vacuoles to the plasma membrane to be released into the blood stream by exocytosis
-
Class of drugs used to lower blood glucose.
Sulfonylureas
-
How do Sulfonylureas lower blood glucose?
they increase β cell insulin release by binding to and blocking the ATP-sensitive K+ channel, mimicking the increase in β cell ATP levels
-
What are the 3 ways that insulin lowers blood glucose?
- 1. increasing glucose uptake into "insulin responsive tissues"
- 2. increasing the activity of pathways of glucose utilization
- 3. decreasing the activity of pathways of glucose production
-
What are the 2 primary and 1 somewhat insulin responsive tissues?
muscle and adipose tissues; sometimes heart tissue
-
Insulin lowers blood glucose by driving glucose into...
muscle, adipose tissue, and sometimes heart tissue
-
Insulin mobilizes _________ to the plasma membranes of ________ and _______.
GLUT4; muscle; adipose tissue
-
In GLUT4 transports, insulin binds to the ________, inducing _______ and increased _______ activity.
insulin receptor; dimerization; RTK
-
The insulin receptor kinase activity phosphorylates and activates ___________.
Insulin receptor substrate (IRS)
-
Insulin receptor substrate activates _____.
PI3K
-
When PI3K s activated by insulin receptor substrate, ________ and _________ are activated.
αPKB and Atk/PKB
-
The combined signal from αPKC and Akt/PKB activates.....
translocation of GLUT4 to the plasma membrane
-
hen GLUT4 is translocated to the plasma membrane, ________________ is increased, subsequently...
glucose uptake; decreasing blood glucose levels, causing insulin levels to decrease and GLUT4 to be recycled
-
Endocrine disorder characterized by absolute or relative lack of insulin; persistently elevated glucose.
Diabetes mellitus
-
Describe the β cell function in Type I Diabetes and its treatment.
NO FUNCTIONAL β cells; daily insulin injections for life
-
Describe the β cell function of Type II Diabetes and its treatment.
Some variable β cell function; diet, weight loss, oral hypoglycemics
-
With a glucose tolerance test, the 4 steps are...
- 1. 12 hour fast
- 2. intravenous glucose infusion
- 3. assess blood glucose levels at 0,30,60,90,120 min after infusion
- 4. compare to general ranges of blood glucose
-
In healthy individuals, blood glucose levels are...
maintained within a VERY TIGHT range
-
On the glucose tolerance test, a healthy individual had a _______ fasting blood glucose level and a _________ in response to glucose infusion; subsequently, their blood glucose level __________.
low; moderate rise; returned to normal
-
On the glucose tolerance test, a diabetes type I individual had _______ fasting blood glucose level and ________ blood insulin; subsequently, their blood glucose level __________.
an elevated; no detectable; does not decline
-
On the glucose tolerance test, a diabetes type II individual had _______ fasting blood glucose level and a _________ in response to glucose infusion; subsequently, their blood glucose level __________.
elevated; modest induction of blood insulin; does not significantly decline
-
On the glucose tolerance test, an obese individual had _______ fasting blood glucose level and _________ in response to glucose infusion; subsequently, their blood glucose level __________.
elevated; extremely high insulin levels; does not decline
-
Obese individuals have insulin but their glucose levels cannot return to normal; this is _____________.
peripheral insulin resistance
-
___________, which is non-digestible, reduces the caloric density of feed.
Fiber
-
Fiber reduces caloric density of feed by....
slowing glucose uptake from the gut
-
Peripheral insulin resistance (from obesity) is due to the fact that adipocytes produce ________, which bind and activate signaling pathway that interfere with ______, and ultimately....
adipokines; insulin receptor signaling; reduce insulin dependent glucose uptake in fat and muscle cells.
-
Glycogen is stored in...
the muscle and liver
-
_______ is the body's source of glucose during a fast.
Liver glycogen
-
_________ is the body' source of glucose for contraction within a cell.
Muscle glycogen
-
Although glycogen stores are a relatively small percent of total body energy,...
glycogen storage diseases are fatal, usually in the early postnatal period
-
Insulin activates ________ vis _______.
glycogen synthase; protein phosphatase 1
-
Following a meal, increased blood glucose levels cause _____________, which then bind to...
increased insulin release from the pancreas; liver cell insulin receptors.
-
Insulin receptor mediated signaling in the liver activates ___________, which in turn ________ and activates __________.
protein phosphatase; dephosphorylates; glycogen synthase
-
In addition to activating glycogen synthesis, protein phosphatase...
dephosphorylates and deactivates glycogen phosphorylase, the enzyme that degrades glycogen
-
Glycogen branching enzyme deficiency is a ______ disorder in Quarter Horses and always...
autosomal recessive; results in death
-
The first line of defense in maintaining blood glucose levels is the _________.
breakdown of liver glycogen
-
The fall in blood glucose is detected by __________, which release ________.
α cells of the pancreas; glucagon
-
The function of the hormone glucagon is to...
increase blood glucose levels by mobilizing glucose stored in the liver as glycogen.
-
The second line of defense in maintaining blood glucose levels during a long-term fast is ________.
gluconeogenesis
-
The primary target tissue of the hormone glucagon is _______.
liver
-
Glucagon's main mechanism of action is activation of ________________ of __________ and release of ______.
GPR-mediated activation of protein kinase A (PKA); Ca+
-
Glucagon binds to _______ and activates _______, which phosphorylates and activates _______, which degrades glycogen.
liver cell glucagon receptor; phosphorylase kinase; glycogen phosphorylase
-
Glucose-6-phosphate, produced by glycogen phosphorylase, is converted to "free" glucose by ___________.
glucose-6-phosphatase
-
Glucose-6-phosphatase is only expressed in ________.
the liver
-
In glycogen storage disease Ia, a genetic alteration results in glucose-6-phosphatase; therefore,...
you cannot access glycogen in the liver because you can't mobilize glycogen during a fast......G-6-P never becomes "free" glucose
-
Epinephrine is synthesized by the _________ in response to ______.
adrenal medulla; stress
-
The epinephrine mechanism of action in muscle is mediated by activation of ___________ via ________ and _________.
muscle glycogen degradation; protein kinase A (PKA); phosphorylase kinase (PK)
-
During rigorous exercise, _______ levels increase.
epinephrine
-
Epinephrine binds to ___________ and activates _______, which converts ATP to cAMP.
muscle cell epinephrine receptor; adenyl cyclase
-
Epinephrine receptor mediated signaling activates _________, which phosphorylates and activates ___________, which degrades glycogen.
phosphorylase kinase; glycogen phosphorylase
-
Glucose-6-phosphate is oxidized via the ___________ and the ________ to generate ATP for muscle contraction.
glycolytic pathway and TCA cycle
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