Physiology 2

Front 1

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.

Back 1

brain, retina, gonads

Front 2

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.

Back 2

acids, lower

Front 3

Increased ECF glucose can cause severe cellular ________ by creating an osmotic gradient

Back 3

dehydration

Front 4

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.

Back 4

transport maximum

Front 5

This condition can damage blood vessel walls, retinas, kidneys, and neurons

Back 5

hyperglycemia

Front 6

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.

Back 6

1 - 2%, vascular

Front 7

Parasympathetic innervation _________ insulin release, whereas sympathetic innervation _________ insulin secretion.

Back 7

stimulates, inhibits

Front 8

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.

Back 8

beta-cells

Front 9

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.

Back 9

glucagon

Front 10

b-cells tend to occupy the ______ region of an islet, whereas the a-cells occupy the ______ rim.

Back 10

central, outer

Front 11

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.

Back 11

somatostatin

Front 12

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.

Back 12

proinsulin

Front 13

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.

Back 13

storage granules

Front 14

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.

Back 14

beta-cell

Front 15

Insulin is degraded by enzymes in the liver, kidney, _________ and other organs & has a plasma ½ life of about __ minutes.

Back 15

skeletal muscle, 10

Front 16

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.

Back 16

liver, 40

Front 17

The most important regulator of insulin secretion.

Back 17

glucose

Front 18

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).

Back 18

b-cells, GLUT-2

Front 19

________ 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 _________.

Back 19

amino acids, amino acids, gluconeogenesis

Front 20

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.

Back 20

parasympathetic, vagus

Front 21

Insulin secretion is virtually ___ ____ by epinephrine or norepinephrine delivered to b-cells by either the circulation or sympathetic neurons.

Back 21

shut off

Front 22

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.

Back 22

store, the liver, muscle and adipose tissue

Front 23

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.

Back 23

is not needed, is needed

Front 24

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.

Back 24

insulin, tyrosine kinase

Front 25

Activation of the tyrosine kinase occurs with _____________ and triggers a cascade of phosphorylations that lead to a physiological response by the target tissue.

Back 25

insulin binding

Front 26

Large doses of insulin cause internalization of a significant fraction of the plasma membrane receptors, leading to desensitization of the cell through _____________.

Back 26

down-regulation

Front 27

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.

Back 27

portal vein, 50

Front 28

This organ sees higher concentrations of insulin than the other insulin target organs, namely muscle and adipose tissue.

Back 28

liver

Front 29

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.

Back 29

glycogenesis, inactivates, increase

Front 30

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.

Back 30

fatty acids, fatty acids

Front 31

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.

Back 31

skeletal muscle, skeletal muscle, glycogen synthase

Front 32

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

Back 32

lipoprotein lipase, triglycerides

Front 33

In adipocytes, insulin increases glucose transport across the plasma membrane. This glucose is then converted into ________, which combines with fatty acids to form ____________.

Back 33

glycerol, triglycerides

Front 34

In adipocytes, insulin inhibits the action of ________________. Therefore, the release of fatty acids from the adipocytes into the bloodstream is inhibited by insulin.

Back 34

hormone-sensitive lipase (HSL).

Front 35

This is the enzyme that causes hydrolysis of the triglycerides already stored in adipocytes.

Back 35

hormone-sensitive lipase (HSL).

Front 36

Insulin-sensitive glucose transport into skeletal muscle cells and adipocytes is mediated by glucose transporters called ______.

Back 36

GLUT 4

Front 37

This does the opposite of lipoprotein lipase.???

Back 37

hormone-sensitive lipase

Front 38

This responds positively to glucagon and negatively to insulin:

Back 38

hormone-sensitvie lipase

Front 39

_______ 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

Back 39

hydrolysis

Front 40

_____________ is specifically found in endothelial cells lining the capillaries.

Back 40

lipoprotein lipase

Front 41

The chief enzyme responsible for the mobilization of FFA from adipose tissue, i.e., lipolysis, is thought to be ________________.

Back 41

hormone-sensitive lipase (HSL).

Front 42

____ is the insulin-regulated glucose transporter found in adipose tissues and striated muscle (skeletal and cardiac) that is responsible for insulin-regulated glucose disposal.

Back 42

GLUT4

Front 43

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.

Back 43

GLUT4, GLUT4, GLUT4

Front 44

In skeletal muscle cells and adipocytes, insulin _______ membrane transport of amino acids, ________ protein synthesis and _________ amino acid catabolism.

Back 44

increases, increases, decreases

Front 45

Insulin _______ (stimulates/inhibits) lipoprotein lipase which promotes triglyceride storage. It also _______ (stimulate/inhibits) hormone sensitive lipase.

Back 45

stimulates, inhibits

Front 46

What is the most important stimulus for glucagon?

Back 46

hypoglycemia

Front 47

In addition to hypoglycemia, what else stimulates glucagon?

Back 47

Epinephrine/Norepinephrine (SNS and adrenal medulla secretions)

Front 48

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

Back 48

inhibitory

Front 49

Glucagon activates ________ & _________. These two processes dramatically increase glucose output by the liver.

Back 49

glycogenolysis, gluconeogenesis

Front 50

__________ 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.

Back 50

glycogenolysis

Front 51

The hormones ______ and ______ stimulate glycogenolysis.

Back 51

glucagon, epinephrine

Front 52

___________ 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.

Back 52

Gluconeogenesis, gluconeogenesis

Front 53

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.

Back 53

glucagon

Front 54

___________ is a disorder of glucose metabolism in which the action of insulin on body cells is inadequate.

Back 54

Diabetes [siphon] mellitus [sweet]

Front 55

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

Back 55

20.8

Front 56

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.

Back 56

1,500,000, twice

Front 57

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 ___

Back 57

DM . . .

Front 58

DAIBETES MELLITUS:
Direct medical costs (hospitalizations, medical care, treatment supplies) – $__ billion
Indirect costs (disability, work loss, premature mortality) – $__ billion

Back 58

92, 40

Front 59

Accounts for 5-10% of all diagnosed cases of DM

Back 59

type 1 diabetes mellitus

Front 60

What are the two types of Type 1 diabetes mellitus?

Back 60

immune mediated
idiopathic

Front 61

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).

Back 61

destruction, destruction

Front 62

Islet cell autoantibodies (ICAs), autoantibodies to insulin (IAAs), and many others: these are markers for what?

Back 62

type 1 DM

Front 63

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.

Back 63

autoimmune, autoimmune

Front 64

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.

Back 64

type 1 DM, type 1 DM

Front 65

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) _________.

Back 65

type II DM, insulin resistance, insulin deficiency

Front 66

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

Back 66

type II DM

Front 67

Ketoacidosis (rarely/frequently)
occurs spontaneously in type 2 DM.

Back 67

rarely