W7 - Exercise & Hunger Flashcards
Difference between appetite + hunger?
Appetite = Desire to eat
Hunger = Internal drive to eat
Where is appetite derived from?
External + psych factors
Where is hunger derived from?
Hypothalamus + vagus nerve (central)
Blood glucose + hormones (peripheral)
From what external factors can appetite be derived from?
Smell
Sight
Temp
Humidity
Learned
Situation
What effect does the CCK hormone have on food?
Decreases food intake
What effect does the pancreatic polypeptide (PP) hormone have on food?
Decreases food intake
What is the pancreatic polypeptide (PP) hormone released in response to?
Ingestion of food
What effect does the peptide YY (PYY) hormone have on the intake of food?
Decreases it
What effect does the Glucagon like peptide 1 (GLP-1) hormone have on the intake of food?
Decreases it
What effect does the Excess glucocorticoids hormone have on the intake of food?
Increases it
What effect does the Leptin hormone have on the intake of food?
Decreases it
What effect does the ghrelin hormone have on the intake of food?
Increases it
Where is ghrelin released from?
Stomach + duodenum
What does Orexigenic mean?
Substance that stimulates appetite.
What is the only orexigenic out of the brain?
Ghrelin
When do levels of ghrelin increase?
Between meals + when stomach is empty
What does central administration of a substance mean?
Injecting it into CNS
What is the active form of ghrelin called?
Acylated form of ghrelin
Mechanism of action for ghrelin
Released from stomach when empty
Travels in blood to hypothalamus
Neuropeptide Y is released = ⬆️ food intake
Eating surpasses release of ghrelin
Which hormone is the opposite to ghrelin?
Leptin
Where is leptin produced?
In the white adipose tissue
What does leptin do?
Stimulates release of melanocyte - stimulating hormone (MSH)
Controls level of stored body fat
What does it mean if there’s more triacylglycerides in your adipocytes?
More leptin released
What happens to the levels of leptin released in a starvation state?
Less leptin released
What does leptin suppress?
Release of Neuropeptide Y
What does melanocyte - stimulating hormone (MSH) do?
Surpresses hunger
What can happen to obese individuals in regards to leptin?
Can become resistant to it
What type of hormone is CCK?
Neuropeptide
Where is CCK released from?
Small intestine
Within how long after starting a meal will levels of CCK increase?
15 mins
What does the increase in CCK release cause for the gall bladder?
Causes it to release bile
What does peripherally administered CCK cause?
⬇️ size + meal duration
Where is Pancreatic polypeptide (PP) released from?
Pancreas
Where does Pancreatic polypeptide (PP) act?
Hypothalamus
What would infusing the Pancreatic polypeptide (PP) hormone into someone do?
⬇️ their food intake
Where is the polypeptide YY (PYY) hormone secreted from?
Ileum + colon
What can polypeptide YY (PYY) hormone do?
Suppress appetite for a long period of time
What does the amount of polypeptide YY (PYY) hormone released depend on?
Energy in meal
Composition of meal
Where is GLP-1 released from?
Small intestine + colon
What is the release of the GLP-1 hormone proportional to?
Energy intake
What does GLP-1 hormone promote when administered centrally or peripherally?
Weight loss
What is oxytomodulin co released with?
GLP-1
What is the release of the oxytomodulin hormone proportional to?
Energy intake
What type of hormone is adiponectin?
Adipocyte derived hormone
What is adiponectin involved with?
What happens to levels of adiponectin with obesity?
Involved in regulating glucose levels + FA breakdown
Decreases w/ obesity
What happens to levels of adiponectin with weight loss?
Increases
What helps with the release of leptin?
Insulin
Where are glucocorticoids derived from?
Adrenal glands
Meaning… Adrenal gland failure = anorexia
What does excess amounts of glucocorticoids lead to?
Hyperphagia
What is hyperphagia?
Abnormally great desire for food; excessive eating.
What does short exposure to normobaric hypoxia whilst performing exercise cause?
⬇️ appetite
What does the Benedicts test test for?
Reducing sugars
What does the biuret test test for?
Protein
Blue –> Purple if present
If peptides present = pink
What does the ethanol test test for?
Fat
What in reducing sugars is the reducing agent?
The aldehyde functional group
Reducing sugars have 1 of 2 groups, what are they?
Aldehyde functional group
Ketone group (can be converted into an aldehyde)
What does the aldehyde group in a reducing sugar do?
Reduces the soluble copper (II) ions in copper (II) sulphate
TO insoluble copper (I) ions in copper (I) oxide.
What sugars are classified as reducing sugars?
Simple sugars (mono + most di-saccharides)
How do you prepare a test solution for the Benedicts test?
Crush food
+ mod. amount of distilled H20
Decant suspension to remove large particles
Use decanted liquid as test solution
Procedure for Benedicts test
+ 1ml of sample solution to test tube
+ 2ml of Benedicts solution to test tube + swirl mixture
Leave in a boiling H20 bath for ~5 minsk
Observe colour changes during time + as final colour
OBSERVATIONS FOR BENEDICTS TEST
No change (blue)
No reducing sugars present
OBSERVATIONS FOR BENEDICTS TEST
Green
Trace amounts of reducing sugars present
OBSERVATIONS FOR BENEDICTS TEST
Yellow
Low amounts of reducing sugars present
OBSERVATIONS FOR BENEDICTS TEST
Orange
Mod amounts of reducing sugars present
OBSERVATIONS FOR BENEDICTS TEST
Brick-red
Large amounts of reducing sugars present
Procedure for biuret test
+ 2ml of liquid food sample to test tube
+2ml of biuret reagent
Shake
Stand for 5 mins
Observe colour change
What other tests are there besides ethanol test for testing for lipids in food?
Grease spot test
Sudan stain test
Procedure for solid sample in ethanol test
Crush food sample
Place in dry test tube
+ ethanol to about 2ml above level of sample
Shake
Allow solid to settle (~3mins) to allow lipid to be extracted
Decant ethanol into another test tube
+2ml of de-ionised H20 to 2nd test tube
Make observations
Procedure for liquid sample in ethanol test
+ few drops of liquid food sample to dry test tube
+ 2ml ethanol
Shake
+ 2ml of deionised H20
Make observations
Why did granulated sugar not change colour when it was heated with the benedicts solution?
Because there’s no reducing sugar present
Which hormone most commonly increases satiety?
GLP-1
What do low levels of insulin + leptin in the body do?
Stimulate hunger + appetite for high calorie foods
Which hormone is elevated post bariatric surgery
Polypeptide yy
What happens to food intake after exercise in the cold + why?
Increased due to more CHO intake
What will ingesting CHO in the hours before exercise do to the plasma?
Raise plasma insulin = suppressing fat oxidation by ~35%
– This effect may last up to 6-8hrs meaning the highest fat oxidation rates can be achieved after an overnight fast.
It has been suggested that CHO intake DURING exercise may interfere w/ training adaptations.
What is this notion based on?
Observation that CHO intake during exercise can ⬇️ the expression of the mRNA of certain proteins after exercise, i.e the CPT1 mRNA.
What would happen to liver glycogen and muscle glycogen after an overnight fast?
Liver glycogen may be low
Muscle glycogen wouldn’t be affected.
Which BCAA particularly stimulates muscles signalling pathways?
Leucine
What are low energy dense foods?
Foods high in H20 +/or fibre
What do low energy dense foods do?
How?
Promote satiety
Because they expand the stomach + intestines to a greater extent than lighter-weight foods
Give examples of lighter-weight foods
Oils + snack foods
What in the small intestine is thought to help promote satiety?
Nutrient receptors
What is the obesity gene?
ob gene
What does the ob gene code for?
Synthesis of leptin
What happens when the ob gene is functioning normally?
Leptin is made + signals satiety.
What happens when there’s a mutation in the ob gene + leptin isn’t made in sufficient quantities?
Desire to eat ⬆️ dramatically
Metabolic rate ⬇️
weight gain.
What is the process of satiety?
Flavour of food
Knowing a meal has been eaten
Influence of stomach + intestinal expansion + activity
Influence of nutrient use in liver + related communication w. hypothalamus
Conscious thinking in brains cortex + can overcome hunger or satiety signals.
