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MSCI-M 131: EXAM 3
What causes weight gain?
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Energy intake > energy expenditure
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Energy intake |
kcalories in food
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Energy expenditure |
kilocalories used in metabolism
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Factors affecting energy expenditure
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Basal metabolic rate
Physical Activity - the less activity the less calories expended and vice versa - this is the most important
Thyroid hormone levels
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Control of appetite |
Multiple and complex inputs from the brain and body --> Central appetite control center in the brain --> appetite and energy intake
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Central appetite control center
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located in the hypothalamus, in the limbic system
All sensory input and all other information is integrated in the hypothalamus, with the result being apetite
Sensory Input: taste, smell, anticipation of food
other information: bood sugar [glucose] levels
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Hypothalamus
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location of the central appetite control center and all sensory information including smell and taste that deal with appetite
Damage to the hypothalamus can cause gross abnormalities in appetite
(1) Prader-Willi Syndrome
(2) Certain Hypothalamic lesions can cause anorexia and severe weight loss
(3)No known hypothalamic defect in anorexia nervosa
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Prader - Willi Syndrome |
Chromosome damage causing children to not stop eating --> congenital defect (birth defect)
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Hypothalamic lesions |
causes someone to lose hunger
anorexia and severe weight loss
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What are the changes in hypothalamic activity mediated through? |
Hypothalamic activity changes are mediated through changes in the neurotransmitter activity
manipulation of apetite can involve drugs that alter the hypothalamic neurotransmitter levels and activity
Some current drugs act (inadvertently) directly on the hypothalamus to cause weight gains; a few cause weight loss
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Specific Neurotransmitters within the brain/hypothalamus: Neuropeptide Y |
When this is increased, the apetite is increased
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What does "Anandamide" neurotransmitter within the brain/hypothalamus do?
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mimicked by the active chemical in weed (THC)
CANNABINOID AGONISE = increases appetite --> Block Anandamide = decrease in appetite
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Peripheral inputs to the appetite control center (outside of the brain) |
Blood glucose and insulin:
eat carbs --> blood glucose goes up and insulin goes up --> insulin moves glucose into the cells, blood glucose goes down, --> when the blood glucose goes down, appetite goes up
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Distention of the stomach or small bowel |
with food, watery food is fine, but it should be more than water. |
What hormone is released from the gastrointestinal tract during eating? |
CCK - cholecystokinin is released from the gastrointestinal tract during eating
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What hormones are released from fat cells (adipocytes)? |
Leptin is released from adipocytes.
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What hormone is released from the stomach wall during fasting? |
Grhelin is released from the stomach wall during fasting.
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What are some environmental influences on food intake? |
Palatability
Portion size
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Environmental influences on food intake: palatability |
increased palatability: increased food intake
If the change in Palatability is .5 between foods, then intake of the more palatable food will be 400 kcal more at a meal
-->increased hunger as feeding continues, hunger will only decline after several hundred kcals
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What defines palatability? |
Taste
Smell
(Orosensory Stimuli): fat and sugar
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Influence on appetite control by neurotransmitters (brain reward area) |
Similar to a heroine addiction, the brain pathways are shared between that addiction and an addiction to sweet substances.
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Environmental Influences on food intake: Portion Size |
Example - larger pop corn size = 30% increased intake even if stale
The larger the portion the larger size of intake
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Obesity |
increasing to epidemic levels in the developing world, much more prevalent
Only 13% in the 1960s were considered obese, today 34%
Since 1990, average american adult gains .98lbs/year every year
300,000 preventable deaths occur each year, taken over the #1 cause of tobacco
Increases all diseases associated with metabolic syndrome, 47 million have metabolic syndrome
increasing in all ages
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Obesity: Metabolic Syndrome
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Diabetes (type 2)
Atherosclerosis
Coronary artery disease --> heart attack (myocardial infraction)
Hypertension (high blood pressure)
Stroke
age 20 = 7%
age 70 = 42%
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Abdominal Obesity |
carries GREATEST risk!
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Environmental Influences on food intake: Increased competition among food companies
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Lower food prices: food used to be much more expensive
Increased advertising
Great food availability
Increased food palatability: tasty food that you can buy anywhere --> high fat, high sugar processed foods --> example in class was the candy bars that you could buy at Staples
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Three General Methods for treating Obesity
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Change the culture, make it less "obesogenic"
At a population level, promote "eating less and moving more"
At an individual level, use drugs or surgery to reduce calorie intake or increase calorie expenditure
This causes no self motivation to better oneself, it has
health risks and can be expensive.
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Drugs to Reduce Caloric Intake |
orlistat (Xenical, Alli)
These are fat absorption blockers and produce very small weight loss. --block gastral intestine fat absorption meaning less calories come in, side affects cause diarrhea
phenetermine + toprimate: (Qnexa)= amphetamine and lorcaserin: (Lorqess) = manipulates the hypothalamus and seritonin levels
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Weight Loss Intervention: Bariatric Surgery
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Roux-en-Y gastric bypass
Expensive, risky, and best option for morbidly obese people.
After surgery, much less stomach.
Frequency: more frequent that any other bypass surgery
Effectiveness: very good, 70% see positive results. -- it resolves sleep apnea and hypertension as well.
Some risks could be weight loss that happens to quickly or death on the table.
Stomach doesn't aid in digestion, food skips straight to the intestines, enzymes from the stomach still secreted but broke down in intestine.
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Weight Loss Intervention: Laparoscopic adjustable gastric banding surgery
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Frequency - less often than gastric bypass
effectiveness - 50% have dramatic weight loss and recover from conditions
Risk: can be ineffective, too effective or damaging -- but is is safer than bypass
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Weight Loss Intervention: Gastric Sleeve Surgery |
slice off majority of the stomach -- this one was not in the notes, side note that the professor discussed.
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Diabetes Mellitus:
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"sweet urine", due to excessive amounts of glucose (any kind of sugar) in the blood, which then spill into the urine
Diabetes is a disease of ABSOLUTE or RELATIVE lack of INSULIN
Insulin is the hormone needed to put glucose into cells.
The "endocrine" pancreas is the normal source of insulin.
5% of the pancreas makes the molecule
which put glucose into the cells (BETA CELLS)
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Normal Glucose Control
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Food intake (carbs) elevate the blood glucose
Insulin moves the glucose to other areas of the body -- adipose tissue and skeletal muscle, lowering the blood glucose
EAT -- GLUCOSE INCREASES -- INSULIN INCREASES -- GLUCOSE DECREASES
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Other Sources of Blood Glucose |
liver (stored glycogen) or convert protein into glucose
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Other hormones controlling blood glucose |
insulin and cortisol lower the blood glucose
epinephrine (adrenal)
growth hormone
glucagon raise blood glucose
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Type I Diabetes |
"insulin-dependent" diabetes mellitus - accounts for the majority of diabetes cases in childhood and adolescence.
It is characterized by an absolute lack of insulin.
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What is the blood glucose response to a normal meal in a person with untreated type I diabetes?
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blood glucose just continues to rise with nothing stopping it.
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Simple Diagnostic tests for Type I diabetes |
finger prick and check for insulin after eating and blood glucose levels
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Three Classic Symptoms of untreated Type I diabetes
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constantly urinating - polyuria
constantly drinking - dehydrated
constant eating and still losing weight
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Type I diabetes age of onset |
Starts in youth, one must maintain it all through life.
very serious condition that can be fatal.
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What causes Type I Diabetes? come back to this card and add why? page 126
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Genetic Vulnerability, but the ultimate triggers are not known.
80% of new type I diabetes patients have islet-cell antibodies
-- antibodies are NOT the direct cause
-- "Killer" T cells (CD4 and CD8) direct an attack at only
those cells that make insulin; all other cells in the
pancreas remain unharmed
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hyperglycemia |
blood glucose too high
high levels of blood sugar
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hypoglycemia |
level of blood glucose too low
low level of blood sugar
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What year was insulin introduced? |
1922
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What are the blood glucose levels of someone with untreated Type I diabetes? |
too high, keeps climbing without stopping, can reach levels in the 1000s
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What are the blood glucose levels of something with 'too little insulin after a high carb meal'? |
glucose will raise too high without enough of an insulin response
you must match the amount of insulin to the meal
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What are the blood glucose levels of someone who gets 'too much insulin after a low carb meal'? |
blood glucose drops too LOW
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Accidental Insulin Overdose |
Blood glucose will drop too low
This is a very serious condition that can be potentially fatal.
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How does exercise affect the blood glucose levels and need for insulin? |
If someone were to add two strenuous hours of exercise a day, they would need less insulin and more carbs.
Exercise acts much like insulin in that it moves the glucose into the cells, and therefore one needs less insulin when they exercise.
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Problems with 'hypoglycemia' in Type I Diabetes
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never happens in untreated diabetes
The brain relies on glucose for energy.
Insulin is not needed as glucose moves into the brain directly
without it.
Low blood glucose--> low brain glucose --> low brain energy supply --> confusion, dizziness, faintness, unconsciousness, coma
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Problems with 'hyperglycemia' in Type I diabetes |
Three classic symptoms: constantly --
urinating
thirsty
hungry
Diabetes ketoacidosis
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Diabetes Ketoacidosis |
cells totally deprived of glucose, begin to rely heavily on fat
ketoacidosis are biproducts of using fat for metabolism
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What common condition causes healthy young adults to experience acidosis in the blood? |
lactic acid build up during exercise
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What are symptoms of lactic acid build up? |
cramping, headache, vomiting, nausea, burning muscles
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What are some reasons that acidosis or alkalosis are so difficult for the body to tolerate? |
decreases enzyme activity
all enzymes work a specific acidity -- this can be fatal
If you are adding H+ to the blood, then you screw with the bonding
of enzymes in the blood to promote vital functions in the body.
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What does chronic hyperglycemia cause? |
small blood vessel damage -- such as in the eye, noticeable effects of chronic hyperglycemia are visible in the retina.
Hemorrhages in eyes are small bleeds in the eye. When these are burnt to close them up, small blind spots are made in the eye eventually causing one to go blind.
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What does chronic hyperglycemia cause? |
kidney damage -- leaks proteins
neuropathy -- damaged nerves
small blood vessel damgage especially in eyes
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What was insulin original derived from? |
Pigs
The problem with this was that people started to have the same imune responses to diseases that pigs would, however the insulin allowed those with diabetes to live normal lives.
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Synthetic Human Insulin |
matches exactly what the body makes in a healthy person with healthy beta cells
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ORGANIZE PAGE 130 |
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Type II Diabetes |
characterized by a relative lack of insulin and insulin action: there is some insulin but not enough insulin, and the ability of cells to respond to that insulin is inadequate
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Percentage of total Type II Diabetes? |
90% more common than type I diabetes
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What causes Type II diabetes?
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Obesity
adult onset vs. childhood onset in Type I diabetes
ethnicity
Pima Indians - 70% have disease; African Americans also
more likely than others
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organize and make card for diagram on page 131 |
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What are some factors that contribute to the association of decreases physical activity with increased risk for type 2 diabetes?
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weight gain, harder to exercise
exercise demands insulin use & makes it more potent
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What are the pros and cons of daily exercise for patients with type 1 and type 2 diabetes? |
ADD LATER
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Treatments for Type 2 diabetes
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weight loss and increased physical activity
oral anti-hyperglycemic drugs
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Treatments for Type 2 Diabetes: Oral Anti-Hyperglycemic Drugs
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Sulfonylureas
Metformin (Glucaphage)
a - Glucosidase inhibitors (e.g. Precose)
Thiazolidinediones (Avandia)
Exenatide (Byette)
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Treatment - Type 2 Diabetes: Sulfonylureas |
bring down glucose without using insulin -- this is designed to make the pancreas secrete more insulin
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Treatment - Type 2 Diabetes: Metformin (Glucaphage) |
reduce livers production of glucose
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Treatment - Type 2 Diabetes: a Glucosidase inhibitors (Precose) |
effectively reduces glucose absorption in GI trac
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Treatment - Type 2 Diabetes: Thiazolidinediones (Avandia) |
Raises sensitivity of adipose tissue and skeletal muscle encouraging it to go back to normal --- check this with someone else, answer does not make complete sense
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Treatment - Type 2 Diabetes Exentatide (Byetta) |
tells pancreas in advance here comes a meal. Insulin is then produced before the food gets there and the blood glucose goes up.
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Cholesterol |
present in the diet, made in many cells, primarily the liver and the intestine
Essential for membranes of all cells
used to produce many hormones (estrogen, testosterone, Vit D)
Used to make bile acids
Only need small amount of cholesterol to meet needs.
increased or decreased levels of certain forms of transported cholesterol in the blood are associated with increased risk for the vascular disease called atherosclerosis.
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Cholesterol Transport |
= fat soluble
lipoproteins - fat laden particles that move cholesterol.
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Lipoproteins - 2 functions the protein portion serves
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solubilize fats and cholesterol
target specific cells
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Low Density Lipoproteins |
Primary form of cholesterol storage and transportation.
90- 110 (70) = normal LDL
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