Ch. 4 "The Carbohydrates: Sugars, Starches, & Fiber" - 4.3 "Glucose in the Body"
Fasting Blood Glucose Range - Prediabetes:
100-125 mg/dL
How much of the body's total glycogen stores is in the liver?
25%
How many grams of carbs per day does the body need in order to spare body protein & prevent ketosis?
50-100 grams/day
Fasting Blood Glucose Range - Normal:
70-99 mg/dL
How much of the body's total glycogen stores is in muscle cells?
75%
Fasting Blood Glucose Range - Hypoglycemia:
<70 mg/dL
Fasting Blood Glucose Range - Diabetes:
>=126 mg/dL
The equilibrium in the body between acid & base concentrations
Acid-Base Balance
Metabolic disorder characterized by elevated blood glucose resulting from insufficient insulin, ineffective insulin, or both
Diabetes
A hormone of the adrenal gland that modulates the stress response
Epinephrine
A hormone secreted by special cells in the pancreas in response to low blood glucose concentration; Elicits release of glucose from liver glycogen stores
Glucagon
Glucagon or Insulin?: End Results - Glucagon secretion inhibited
Glucagon
Glucagon or Insulin?: End Results - Raised blood glucose
Glucagon
Glucagon or Insulin?: Stimulates the breakdown of glycogen from the liver
Glucagon
Glucagon or Insulin?: Stimulates the release of glucose into the blood
Glucagon
Hormone that brings glucose out of storage when needed
Glucagon
The making of glucose from a noncarbohydrate source such as amino acids or glycerol
Gluconeogenesis
___ fuels the work of most of the body's cells & is the preferred energy source for brain cells, other nerve cells, & developing red blood cells.
Glucose
___ plays the central role in carbohydrate metabolism.
Glucose
A method of classifying foods according to their potential for raising blood glucose
Glycemic Index
The extent to which a food raises the blood glucose concentration & elicits an insulin response
Glycemic Response
An abnormally low blood glucose concentration
Hypoglycemia
A hormone secreted by special cells in the pancreas in response to (among other things) elevated blood glucose concentration; Controls the transport of glucose from the bloodstream into the muscle & fat cells
Insulin
Glucagon or Insulin?: End Results - Insulin secretion inhibited
Insulin
Glucagon or Insulin?: End Results - Lower blood glucose
Insulin
Glucagon or Insulin?: Stimulate the uptake of glucose from the blood to the cells
Insulin
Glucagon or Insulin?: Stimulates the storage of glycogen in the liver & muscles
Insulin
Hormone that moves glucose from the blood into the cells
Insulin
___ moves glucose from the blood into the cells when levels are high; & ___ frees glucose from glycogen stores & releases it into the blood when levels are low.
Insulin; glucagon
Glucagon or Insulin?: Stimulates the conversion of excess glucose into fat for storage
Insuline
Acidic compounds produced by the liver during the breakdown of fat when carbohydrate is not available
Ketone Bodies
___ provide an alternative fuel source during starvation, but when their production exceeds their use, they accumulate in the blood.
Ketone bodies
An undesirably high concentration of ketone bodies in the blood & urine
Ketosis
Describe what liver cells do with excess glucose molecules after a meal.
Liver cells link excess glucose molecules by condensation reactions into long, branching chains of glycogen
When blood glucose levels are higher than normal but below the diagnosis of diabetes
Prediabetes
The action of carbohydrate (& fat) in providing energy that allows protein to be used for other purposes
Protein-Sparing Action
T/F: Glycogen holds water &, therefore, is rather bulky.
T
T/F: People can have dramatically different blood glucose responses to the same foods.
T
T/F: Unlike the liver cells, which can store only enough glycogen to meet about a day's energy needs, fat cells can store seemingly unlimited quantities of fat.
T
How do people who don't attend faithfully to their bodies' carb needs manage w.out glucose from dietary carbohydrate?
The draw energy from the other 2 energy-yielding nutrient, but not simply.
When glucose is abundant, energy metabolism shifts to use more glucose instead of fat. What happens if that isn't enough to restore glucose balance?
The liver breaks glucose into smaller molecules & puts them together into the more permanent energy-storage compound—fat.
What's the primary role of carbs in the body?
To supply the cells w. glucose for energy
Type I or Type II Diabetes: The pancreas fails to produce insulin
Type I Dabetes
The less common type of diabetes in which the pancreas produces little to no insulin; Usually results from autoimmune destruction of pancreatic beta cells
Type I Diabetes
Type I or Type II Diabetes: Less common
Type I Diabetes
Type I or Type II Diabetes: The exact cause is unclear, but some research suggests that in genetically susceptible people, certain viruses activate the immune system to attack & destroy insulin-producing cells in the pancreas as if they were foreign cells.
Type I Diabetes
The more common type of diabetes in which the cells fail to respond to insulin; Usually accompanies obesity & results from insulin resistance coupled with insufficient insulin secretion
Type II Diabetes
Type I or Type II Diabetes: More common
Type II Diabetes
Type I or Type II Diabetes: Tends to occur as a consequence of obesity
Type II Diabetes
Type I or Type II Diabetes: The cells fail to respond to insulin
Type II Diabetes
What do liver cells do w. glycogen when blood glucose falls?
When blood glucose falls, the liver cells break down glycogen by hydrolysis reactions into single molecules of glucose & release them into the bloodstream.
The liver can store enough glycogen to provide energy for how long?
about a day
Because most ketone bodies are acidic, ketosis disturbs the body's normal ___.
acid-base balance
Why might paying attention to the glycemic index may be unnecessary?
b.c current guidelines already suggest many low & moderate glycemic index choices: whole grains, legumes, vegetables, fruits, milk & milk products
Dietary carbohydrates provide glucose that can do 1 of 3 things:
be used immediately by the cells for energy; be stored by the liver & muscles as glycogen; be converted into fat if intakes exceed needs
When a person doesn't replenish glucose by eating carb, what is broken down to make glucose to fuel the brain & other nerve cells?
body protein, primarily from the liver & skeletal muscles
All of the body's cells depend on glucose; those of the ___ & ___ are espec. dependent on it.
brain; CNS
Which dietary intakes are factors that most influence fluctuations in blood glucose levels?
carbohydrate (quality & quantity); protein; fiber
Describe a low glycemic response.
desirable response: slow absorption, a modest rise in blood glucose, & a smooth return to normal
In some people, blood glucose regulation fails. When this happens, either of 2 conditions can result:
diabetes or hypoglycemia
Why might glycemic index values of a single food vary?
difference in the physical & chemical characteristics of foods, testing methods in labs, & digestive processes of individuals
Symptoms if a person's blood glucose falls below normal:
dizziness; weakness
Tips to slow down digestion & absorption of carbs so that glucose enters the blood gradually, thus balancing w.in the normal blood glucose range:
eat balanced meals w. abundant carbs, including fiber, & a little fat; eat at regular intervals
Where are fats deposited that are made from excess sugars?
either the liver or muscles
Another hormone that signals the liver cells to release glucose is the "fight-or-flight" hormone, ___.
epinephrine
Name the hormone that signals the liver cells to release glucose when a person experiences stress.
epinephrine
What else can the liver convert glucose to, other than glycogen?
fat
What are the 2 ultimate outcomes when carbohydrate intake is abundant?
fat is conserved (by using more carb in the fuel mix); fat is created (by using excess carb to make body fat)
Symptoms if a person's blood glucose rises above normal:
fatigue
Tips for managing type II diabetes & ensure blood glucose levels remain stable:
food portions & choices must be balanced; eat meals & snacks at regularly scheduled times & in similar amounts; eat nutritious foods that support healthy weight
What 2 factors does the maintenance of normal blood glucose depend on?
foods & hormones
Glucagon or Insulin?: Low blood glucose signals the pancreas to secrete ___ into the blood.
glucagon
All of the body's cells depend on ___.
glucose
In general, the amount of insulin released corresponds w. the rise in ___.
glucose
The body needs ___ primarily as an energy nutrient.
glucose
The cells of the brain & the rest of the nervous system depend almost exclusively on ___ for their energy.
glucose
When glucose is abundant, energy metabolism shifts to use more ___ instead of ___.
glucose; fat
Different foods elicit different glycemic responses; the ___ classifies foods accordingly.
glycemic index
The ___ refers to how quickly glucose is absorbed after a person eats, how high blood glucose rises, & how quickly it returns to normal.
glycemic response
Elevated blood glucose returns to normal levels as excess glucose is stored as ___ & ___.
glycogen; fat
What do muscles do with their glycogen stores?
hoard it for themselves, using it during exercise
After a meal, as blood glucose rises, special cells of the pancreas respond by secreting ___ into the blood.
insulin
In diabetes, blood glucose rises after a meal and remains above normal levels b.c ___ is either inadequate or ineffective.
insulin
Blood glucose regulation depends primarily on 2 pancreatic hormones:
insulin & glucagon
By which hormones is blood glucose homeostasis primarily regulated?
insulin & glucagon
Glucagon or Insulin?: High blood glucose signals the pancreas to secret ___ into the blood.
insuline
Ketone bodies provide an alternative fuel source during starvation, but when their production exceeds their use, they accumulate in the blood, causing ___.
ketosis
Describe a high glycemic response.
less desirable: a fast absorption, a surge in blood glucose, & an overreaction that plunges glucose below normal
When insulin reaches the body's cells, receptors respond by ushering glucose from the blood into the cells. most cells take only the glucose they can use right away, but the ___ & ___ cells can assemble the sm. glucose into long, branching chains of glycogen for storage.
liver; muscle
Some studies have shown that selecting foods with a (high/low) glycemic index is a practical way to improve glucose control and lower the risk of diabetes.
low
What's the best preventative measure when it comes to type II diabetes?
maintain a healthy body weight
Benefits of lowering the glycemic index of the diet:
may improve blood lipids, reduce inflammation, & lower the risk of heart diseases; may help w. appetite regulation & weight mgmt.; although research findings are mixed;
Which causes of hypoglycemia require medical intervention?
meds; pancreatic tumors; overuse of insulin; alcohol abuse; uncontrolled diabetes; other illnesses
Perhaps most relevant to real life, a food's glycemic effect differs depending on:
plant variety, food processing, cooking method, time of day, & whether it's eaten alone or w. other foods
What is hypoglycemia most often a result of?
poorly managed type I diabetes - too much insulin, strenuous physical activity, inadequate food intake, illness
Only adequate dietary carbohydrate can prevent the use of protein for energy (gluconeogenesis), & this role of carbohydrate is known as:
protein-sparing action.
What does blood glucose do after a meal?
rises
Sugars attached to a protein change the protein's ___ & ___.
shape; function
What happens when blood glucose levels fall (as occurs between meals)?
special cells of the pancreas respond by secreting glucagon into the blood; glucagon raises blood glucose by signaling liver to break down glycogen; glucose releases into blood for energy use by other cells
To maintain the continuously-needed supply of glucose, a steady stream of blood brings more glucose from either:
the small intestine (food) or the liver (via glycogen breakdown or gluconeogenesis)
When sugars bind to lipids in a cell's membrane, what happens?
the sugars alter the way cells recognize each other
Symptoms of hypoglycemia:
weakness, rapid heartbeat, sweating, anxiety, hunger, trembling
Does the brain store glycogen?
yes, just a small amount; it's though to provide an emergency reserve during times of severe glucose deprivation
