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67 Cards in this Set

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These three tissues only use glucose as an energy substrate under normal conditions. It is important to maintain the blood glucose concentration so that these tissues can perform optimally.
brain, retina, gonads
The brain can use ketones in cases of emergency; one of the major problems with this however is the fact that ketones are _____ and can ____ ECF pH.
acids, lower
Increased ECF glucose can cause severe cellular ________ by creating an osmotic gradient
dehydration
If glucose levels are too high, glycosuria will develop as the kidneys reach a ______ in terms of reabsorption.
An osmotic diuresis within the kidney tubules will ensue.
transport maximum
This condition can damage blood vessel walls, retinas, kidneys, and neurons
hyperglycemia
The 1-2 million pancreatic islets of the human pancreas collectively comprise only ___% of the pancreatic mass. They are highly ______, with each cell seemingly in direct contact with a capillary.
1 - 2%, vascular
Parasympathetic innervation _________ insulin release, whereas sympathetic innervation _________ insulin secretion.
stimulates, inhibits
Histologically, the pancreatic islets consist of three or four cell types. The ________, which synthesize and secrete insulin, make up about 60-75% of a typical islet.
beta-cells
Histologically, the pancreatic islets consist of three or four cell types. The a-cells are the source of _________ and comprise approx. 20% of islet tissue.
glucagon
b-cells tend to occupy the ______ region of an islet, whereas the a-cells occupy the ______ rim.
central, outer
The delta cells, which are considerably less abundant, produce ________. An additional but rarer cell type, the PP or F cell, may also appear on the outer rim of an islet. These cells secrete pancreatic polypeptide.
somatostatin
Insulin is a protein derived from ________ by cleavage of a connecting peptide (the C-peptide) leaving the A (a) and B (b) chains joined by disulfide bonds necessary for activity of the molecule.
proinsulin
The conversion of proinsulin to insulin takes place within ____________, which contain the necessary enzyme. Consequently, the connecting peptide is released into the circulation whenever insulin is secreted.
storage granules
The connecting (C peptide)peptide has no known biological activity, but its presence in blood is useful for estimating __________ function in patients who are receiving injections of insulin.
beta-cell
Insulin is degraded by enzymes in the liver, kidney, _________ and other organs & has a plasma ½ life of about __ minutes.
skeletal muscle, 10
The ____ may inactivate as much as __% of the insulin that reaches it in hepatic portal blood and thus has the potential for regulating the amount of insulin that enters the systemic circulation.
liver, 40
The most important regulator of insulin secretion.
glucose
When the blood glucose level is high, glucose is taken up by _______ by a specific glucose transport molecule called ________ (which also transports glucose into hepatocytes).
b-cells, GLUT-2
________ are important stimuli for insulin secretion as well. The transient increase in plasma __________ after a protein-rich meal is accompanied by increased secretion of insulin. Arginine, lysine, and leucine are the most potent amino acid stimulators of insulin secretion. Insulin secreted at this time may facilitate storage of dietary amino acids as protein and prevents their diversion to _________.
amino acids, amino acids, gluconeogenesis
The secretion of insulin in response to food in the intestine is mediated by neural pathways. __________ fibers in the ____ nerve release acetylcholine which stimulates the b-cells to secrete insulin.
parasympathetic, vagus
Insulin secretion is virtually ___ ____ by epinephrine or norepinephrine delivered to b-cells by either the circulation or sympathetic neurons.
shut off
In a nutshell, insulin acts to _____ nutrients. It is the only hormone that does this and therefore a lack of insulin is fatal. It acts on three major organs, _________________________ to regulate the flux of three major classes of nutrients: carbohydrates, fats and protein.
store, the liver, muscle and adipose tissue
Insulin (is or is not needed) for glucose transport into the brain, red blood cells, liver hepatocytes and many kidney cells. It (is or is not needed) for glucose transport by all other tissues around the body.
is not needed, is needed
Insulin receptors have a complex structure; each one is a tetramer composed of two a and two b subunits held together by disulfide bonds. The a subunits bind ______, whereas the b subunits have inherent ____________ activity.
insulin, tyrosine kinase
Activation of the tyrosine kinase occurs with _____________ and triggers a cascade of phosphorylations that lead to a physiological response by the target tissue.
insulin binding
Large doses of insulin cause internalization of a significant fraction of the plasma membrane receptors, leading to desensitization of the cell through _____________.
down-regulation
It is important to remember that insulin is secreted into the _____ vein so that the first organ that sees insulin is the liver, which extracts about ___% of the insulin that passes through.
portal vein, 50
This organ sees higher concentrations of insulin than the other insulin target organs, namely muscle and adipose tissue.
liver
In liver hepatocytes, insulin increases __________ by activating glycogen synthase. At the same time, insulin also _____________ enzymes associated with glycogenolysis. The net effect is to _______ the amount of glycogen stored in the liver.
glycogenesis, inactivates, increase
In liver hepatocytes, insulin promotes the conversion of excess glucose into _________. The __________are then used to synthesize triglycerides which are then packaged into low density lipoproteins (LDL) and released into the bloodstream.
fatty acids, fatty acids
In resting __________ cells, insulin increases glucose transport across the plasma membrane. If ___________ cells are not exercising after a meal and glucose is being transported into the ICF, then most of the glucose will stored as muscle glycogen under the influence of insulin. Similar to hepatocytes, insulin stimulates the _______ enzyme.
skeletal muscle, skeletal muscle, glycogen synthase
In the capillary walls of adipose tissue, insulin activates ____________, which splits triglycerides again into fatty acids, a requirement for them to be absorbed into the adipocytes, where they are again converted to ___________ and stored
lipoprotein lipase, triglycerides
In adipocytes, insulin increases glucose transport across the plasma membrane. This glucose is then converted into ________, which combines with fatty acids to form ____________.
glycerol, triglycerides
In adipocytes, insulin inhibits the action of ________________. Therefore, the release of fatty acids from the adipocytes into the bloodstream is inhibited by insulin.
hormone-sensitive lipase (HSL).
This is the enzyme that causes hydrolysis of the triglycerides already stored in adipocytes.
hormone-sensitive lipase (HSL).
Insulin-sensitive glucose transport into skeletal muscle cells and adipocytes is mediated by glucose transporters called ______.
GLUT 4
This does the opposite of lipoprotein lipase.???
hormone-sensitive lipase
This responds positively to glucagon and negatively to insulin:
hormone-sensitvie lipase
_______ is a chemical reaction or process in which a chemical compound reacts with water.[1][2] This is the type of reaction that is used to break down polymers
hydrolysis
_____________ is specifically found in endothelial cells lining the capillaries.
lipoprotein lipase
The chief enzyme responsible for the mobilization of FFA from adipose tissue, i.e., lipolysis, is thought to be ________________.
hormone-sensitive lipase (HSL).
____ is the insulin-regulated glucose transporter found in adipose tissues and striated muscle (skeletal and cardiac) that is responsible for insulin-regulated glucose disposal.
GLUT4
In the absence of insulin, ____ is sequestered in the interior of muscle and fat cells.

Insulin induces the redistribution of ______ from intracellular storage sites to the plasma membrane.

Once at the cell surface, _____ facilitates the passive diffusion of circulating glucose down its concentration gradient into muscle and fat cells.

Once inside cells, glucose is rapidly phosphorylated by hexokinase to form glucose-6-phosphate, which then enters glycolysis.
GLUT4, GLUT4, GLUT4
In skeletal muscle cells and adipocytes, insulin _______ membrane transport of amino acids, ________ protein synthesis and _________ amino acid catabolism.
increases, increases, decreases
Insulin _______ (stimulates/inhibits) lipoprotein lipase which promotes triglyceride storage. It also _______ (stimulate/inhibits) hormone sensitive lipase.
stimulates, inhibits
What is the most important stimulus for glucagon?
hypoglycemia
In addition to hypoglycemia, what else stimulates glucagon?
Epinephrine/Norepinephrine (SNS and adrenal medulla secretions)
What effect do these have on glucagon?
-Hyperglycemia
-Insulin
-Increased concentration of plasma free fatty acids
-Increased concentration of plasma ketones
-It is not understood how the a-cells monitor blood glucose, free fatty acids & ketones and translate that information into an appropriate rate of glucagon secretion
inhibitory
Glucagon activates ________ & _________. These two processes dramatically increase glucose output by the liver.
glycogenolysis, gluconeogenesis
__________ is the catabolism of glycogen by removal of a glucose monomer and addition of phosphate to produce glucose-1-phosphate. This derivative of glucose is then converted to glucose-6-phosphate, an intermediate in glycolysis.
glycogenolysis
The hormones ______ and ______ stimulate glycogenolysis.
glucagon, epinephrine
___________ is the generation of glucose from non-sugar carbon substrates like pyruvate, lactate, glycerol, and glucogenic amino acids (primarily alanine and glutamine).

The vast majority of ____________ takes place in the liver and, to a smaller extent, in the cortex of kidney. This process occurs during periods of fasting, starvation, or intense exercise and is highly endergonic.
Gluconeogenesis, gluconeogenesis
Lipolysis and ketogenesis are also promoted by __________, increasing the supply of free fatty acids and ketone bodies for energy metabolism, primarily in muscle. These effects can be important to tissues like the brain which only use glucose. By increasing fatty acid and ketone availability, glucose can be somewhat "spared" by skeletal muscle and saved for the brain.
glucagon
___________ is a disorder of glucose metabolism in which the action of insulin on body cells is inadequate.
Diabetes [siphon] mellitus [sweet]
It is estimated that ___ million people in the U.S. (~7.0% of the population) have diabetes mellitus. Of that:
Diagnosed: 14.6 million
Undiagnosed: 6.2 million
20.8
New cases of diabetes mellitus diagnosed per year are over __________ and CLIMBING. Overall, the risk of death among people with diabetes is ______ that of people without diabetes.
1,500,000, twice
11.4% of all non-Hispanic blacks have __
8.2% of all Hispanic/Latino Americans have __
14.9% of American Indians and Alaska Natives have __
8.4% of all non-Hispanic whites have ___
DM . . .
DAIBETES MELLITUS:
Direct medical costs (hospitalizations, medical care, treatment supplies) – $__ billion
Indirect costs (disability, work loss, premature mortality) – $__ billion
92, 40
Accounts for 5-10% of all diagnosed cases of DM
type 1 diabetes mellitus
What are the two types of Type 1 diabetes mellitus?
immune mediated
idiopathic
Type 1 DM results from a cellular-mediated autoimmune ________ of the b-cells of the pancreas.
The rate of b-cell ______ is quite variable, being rapid in some individuals (mainly infants & children) and slow in others (mainly adults).
destruction, destruction
Islet cell autoantibodies (ICAs), autoantibodies to insulin (IAAs), and many others: these are markers for what?
type 1 DM
This type of destruction of b-cells has multiple genetic predispositions and is also related to environmental factors that are still poorly defined.
Immune mediated diabetics are also prone to other endocrine __________ disorders such as Graves' disease, Hashimoto's thyroiditis and Addison's disease.
autoimmune, autoimmune
No evidence of autoimmunity exists for this disorder. _________ is strongly inherited although a minority of patients with _______ fall into this category, most are of African and Asian origin.
type 1 DM, type 1 DM
Accounts for 90-95% of all diagnosed cases of DM
this form of diabetes, previously referred to as non-insulin-dependent diabetes mellitus (NIDDM), or adult onset diabetes, is a term used for individuals who have ____________ and usually have relative (rather than absolute) _________.
type II DM, insulin resistance, insulin deficiency
These individuals usually do not need insulin treatment to survive. Most patients with this form of diabetes are obese, and obesity itself causes some degree of insulin resistance
type II DM
Ketoacidosis (rarely/frequently)
occurs spontaneously in type 2 DM.
rarely