Final Exam Flashcards
What are the two types of energy reservoirs?
Short-term and long-term
What is a short-term energy reservoir?
involves the liver and muscles; the small amount of energy that is stored from food consumption in the form of glycogen.
What is a long-term energy reservoir?
- involves adipose tissue
- it is the most efficient form of energy
- it is made up of fats
What is the difference between saturated and unsaturated fats?
saturated fats are usually solid at room temperature and can be good in moderation, whereas unsaturated fats are liquid and the omega 3 varieties are good but not the omega 6s
When we store fat, do the number of fat cells increase or does the size of the fat cells increase?
the size
What are the 3 pathways of energy storage and mobilization?
- hormone release from the pancreas
- insulin is released to store glucose and glucagon is released to mobilize glucose - Adrenal gland activity
- glucocorticoids release glucose from storage when adrenal gland is active - Neuronal activation of fat tissue
- the brain can tell fat cells to release fat tissue or it can also reduce communication with fat cells
What part of the body uses 20% of the body glucose levels?
the brain
If you were in a fasting state, how would your body use glucose?
your body will spare glucose to be used in the brain, your liver, muscles, etc. wouldn’t be able to take in excess glucose without insulin
What are the two phases of metabolism?
Absorptive and Fasting
What happens in the absorptive phase of metabolism?
you eat, the food is separated into glucose, fats, and amino acids. Glucose is distributed throughout the body, fats are stored directly into fat cells, and amino acids are delivered to the muscles and fat cells.
what happens in the fasting phase of metabolism?
liver releases short term energy, but without insulin the energy is transported to the brain. Triglycerides or fat cells release fat tissue. Over prolonged fasting catabolism occurs where muscles break down due the lack of nutrients
what is the difference between ketosis and ketoacidosis?
Ketosis occurs when the body doesn’t have enough glycogen, whereas ketoacidosis occurs in undiagnosed Type 1 diabetics. They will eat and drink a lot, pee a lot but gain no weight. Ketones will be the body’s primary source of energy, but they are highly acidic and it has major side effects.
What are the factors involved in hunger and satiety?
Gastric (stomach) factors, Adipose (fat), Intestinal factors, Liver factors, and Pancreas factors
What are the gastric factors of satiety and hunger?
the stomach conveys satiety by sensing nutrients and the stretching of the stomach.
It conveys hunger by releasing the “hunger hormone” ghrelin
What is the hunger hormone in the stomach?
Ghrelin
What are the Adipose (fat) factors of satiety?
Adipose will release leptin (a satiety hormone) to the brain and other areas to convey satiety.
What is the largest endocrine gland?
Adipose
What is the difference between an Ob and Db mouse?
An Ob mouse has the omission or absence of leptin (no leptin to work with)
A Db mouse has a damaged leptin receptor (has leptin but doesn’t respond to it)
What are the intestinal factors of satiety?
The upper intestine will release the CCK hormone to convey satiety by inhibiting the emptying of the stomach. Peptide YY (PYY) is also released from the small intestine
What would happen if we injected animals with the satiety hormone CCK?
the animal would decrease or stop its eating behavior
What are the liver factors of satiety?
Liver monitors the levels of glucose and lipids, telling the brain to slow down the eating behavior
What are the pancreas factors of satiety and hunger?
The pancreas monitors the insulin and glucagon production to determine if food is needed or not
Is insulin a hunger or satiety hormone?
BOTH!
Why should we be cautious of artificial sweeteners?
sweeteners indicate to the brain that we are taking in glucose, but there is no calories coming in so the body cannot store anything with the insulin it has released
How does the area postrema affect hunger?
it senses toxicity in the blood and activates vomiting or gagging behavior in response to these toxins
What would happen if we lesioned the ventromedial hypothalamus (VMH)?
no “stop” signal would be activated, causing the inability to stop eating and extreme obesity
What would happen if we lesioned or stimulated the lateral hypothalamus (LH)?
if lesioned: no “start” signal would be activated, the animal would experience extreme weight loss because they wouldn’t eat.
if stimulated: the rat would start eating and continue until the stimulus stops
What are the two hormones of the lateral hypothalamus?
Melanin Concentrating Hormone (MCH) and Orexin
Orexin is also involved in wakefulness
If we increased MCH and Orexin would hunger increase or decrease?
increase
what are the two types of orexegins?
MCH and Orexin
What brain areas are involved in hunger and satiety?
Cerebral cortex, thalamus, PAG, RF, and locus coeruleus
What are the two excitatory neurotransmitters in the arcuate nucleus?
NPY (hunger stimulating) and AGRP (agouti related)
What would an orexin agonist do?
stimulate hunger or eating behavior