BioPsychology Exam 3 Study Guide:

Explain How Digestion works

The purpose of digestion → Provide the body with Molecular building blocks and energy

·  Breaking down food and absorbing its constituents

Starts with the mouth and is expelled through the anus. One long pathway and track interconnected, when we look at the different organs and components of digestion we start with the salivary glands and the Parotid gland.

Salivary Gland – near the jaw, provide lubrication and lubricate the food so it can easily work its way down the esophagus (tube that connects to the stomach) 

Parotid gland – by the ear (sudden twitching after eating a lemon) Secreting chemicals that start to break down starch

Pyloric Sphincter – How quickly is food going to move out and how quickly. If opened completely the food can move quickly and a lot at one time. Regulating how much and how quickly food is going to be moving out of the stomach and through the intestines.

Duodenum – most of the absorption of the nutrients we need is happening here (sugars, acids, etc.) Additionally, things are being mixed in to help further break down the food that is being put in. Other chemicals that break down proteins, starch, simple sugars, and amino acids. The wall is penetrable to glucose, amino acids, and simple sugars. Fats that now have to pass through channels within the duodenum and make it into the bloodstream. As the food is working it’s way through

Jejunum – Nutrients make its way into the jejunum and absorption continues for whatever sugar, amino acids, or fats are left over from the duodenum.

Ileum- A lot less important nutrients remain but vitamins, minerals, and WATER it absorb a lot of these leftover minerals and vitamins along with water AND electrolytes.

Explain how energy is delivered and stored

Lipids and Fatty Acids -

Animo Acids – being absorbed by all the proteins we consume. They get recreated as proteins for long-term storage and are stored in our muscle tissue which enables us to have protein available for when we need an energy resource. About 14% will be made up of proteins in the muscles.

Glucose – Simple sugar. Access glucose will be converted into triglyceride and them Glycogen. To get extra Glucose.

 

-   Absorption is going to enable us to use what we need at the time. The body is going to first use in terms of what it needs in Fatty acids/lipids, amino acids, and Glucose. Energy is going to be stored for later use when you will need it based on your activity level.

 

-   Whatever is left over from your momentary energy needs is going to be stored and put away for later.

 

Triglyceride – about 85% of our stored energy is made up of these (under our skin. It is made up of leftover Lipids/Fatty acids, Amino Acids, and Glucose that did not get used. Takes multiple steps to convert down into fatty acids and glucose. Once you have started to use these up, you will start breaking down proteins into amino acids and start to provide energy to your body. Can happen when people are losing weight too quickly, the shift occurs to start breaking down muscles and proteins. (Ozempic -> because they are so quickly losing weight and burning triglycerides they are losing muscle tone and not eating a normal amount. Burning Triglercides at a much faster rate. Big push to make sure people taking this drug are drinking more protein shakes or eating more protein to stop the breakdown of their muscles for fuel.)

 

Glycogen – 0.5% Stored in the liver and the muscle tissue. A type of sugar that is easily converted into glucose. Glycogen is the first conversion that will happen. Glycogen will convert in order to make Glucose to help maintain your needs. A non-efficient energy source, one gram of fat is equal to 2 grams of Glycogen which means in storage terms the energy you get out of Glycogen you are going to need to have a larger supply. It absorbs water meaning our bodies will carry a lot of water. We would need a lot more Glycogen and our bodies would likely be water boarded.

List and explain the 3 phases of energy metabolism.

1. cephalic phase – Phase before (consuming food) eating, often thought of as the preparatory phase. It can be triggered by seeing food, thinking about food, or smelling food; if we think it terms of human history, our ancestors weren’t around food the way we are today. Food was not readily available; this is a carryover from our ancestors that now, every time we see images of food, etc., this phase will be initiated. Triggers the digestive process in the anticipation of food. The pancreas is going to release insulin into the bloodstream. It is going to produce changes like momentarily dizzy or weak due to the sudden rush of energy into the bloodstream. Responsible for helping to release and break down Lysogen into glucose. Proteins from the muscles turn into amino acids, it is a chemical that is necessary to start converting stored energy into something we can use. If you don’t eat food the feelings will pass and your insulin levels will go back to normal. (If you don’t eat for hours on end you will enter the Fasting phase.)

 

2. absorptive phase – When you do eat once food hits your stomach. You’re going to be trying to put extra nutrients into storage and keep it away from breaking down. We don’t need the glucagon because insulin is going to help us use the energy that is coming in. Insulin is important for the cells of our body to utilize. The peripheral nervous system are in essence, starving. People with diabetes, without insulin, are consuming food but their bodies cannot us the nutrients or the glucose. Any extra that we have available in terms of nutrients will be converted into storage. Insulin helps to create long storage components, we are not tapping into our storage and pulling energy out.

 

3. fasting phase – No longer absorbing nutrients, we have to rely on our storage for energy needs at this moment. (The phase that we switch in from the cephalic phase if you do NOT eat.) Insulin levels are low but not non-existent the pancreas is releasing insulin at a baseline level enough that you will be able to use the glucose coming out of long-term storage. The levels are lower because you are getting whatever glucose you need, you don’t need a lot of it because you are not trying to put glucose back into storage. Breaking down glycogen into Glucose and eventually, if needed, breaking down protein into amino acids. The Glucagon helps to break things down at a steady speed. The utilization of the body decreases in comparison to the brain. Slow down how quickly it burns energy in order to conserve the brain.

What are the 5 Influential Factors?

1.) Biologically based

2.) The Idea that we learn from others (modeling of food preference)

3.) Vitamins and Minerals

4.) Pre-Meal Hunger

5.) Conditioning of Hunger

Explain the “Biologically based” Influential factor on what we eat.

-   Some theories propose that we have evolved (Evolution of taste.) Typically prefer sweet, fatty, and salty foods. In nature sweet and fatty foods tend to be higher in “nutrient value” and energy, than less sweet/fatty food. If you are thinking about historically when food was scarce when they found berries and fruits, they preferred them, they preferred animal fat. We evolved from ancestors who needed these foods in order to survive. Need salty foods for electrolyte balance, if they came across foods that had higher sodium content they would eat more of it. Bitter tastes are typically not favored because they are generally associated with toxins and spoilage, learned by exposure. Children typically do not like the same bitter foods as adults it’s a biological adaptation.

Explain the idea that we learn from others (modeling of food preference) Influential factor on what we eat.

Prefer flavors found in mother milk and on the breath of others. In cultures where the food that everyone is consuming is spicy and aromatic, the kids will love them vs. kids whose mothers only eat bland food, those children will choose foods that have those tastes and flavors. The idea is that when you’re exposed to people and talk to them in conversation talking by the aromatics will carry through the air and you can pick up those scents. Adaptive evolutionary mechanism, somewhere in our brain we detect and pick up those aromatics and decide to try those foods because if someone else is eating it, it must be okay. (Animals checking our other animals to see what they’ve eaten -> Barbs cats’ line up on the stairs and they all would lean in and whiskers wiggle and then walk away and they would all do it individually to sniff her mouth and walk away and noticed that they would do it together.) Also watching what people eat and choose, makes us more likely to try other foods. Asking other people what they order on the menu – trying your friends food if it looks really good. Neophobia – scared of trying new foods but try a little bit at a time, watching based on what other people are choosing and eating.

Explain the Vitamins and Minerals Influential factor on what we eat.

-   prefer foods that are good sources of vitamins & minerals, especially when there is a deficiency. When deficiency occurs, animals eat more of that specific food and keep choosing it over other foods. Barb’s husband would occasionally suffer from low iron because his mother would occasionally make liver and onions for herself she began noticing that he would start asking for liver and onion at 8 years old. The doctor found out he was anemic and he got medication his iron labels were stabilized and he never ate liver and onions ever again. When we are deficient in some mineral or vitamin we start to crave certain specific foods, etc.

Explain Pre-meal huger when we eat through influential factors.

we often see that the time of day seems to correlate with when people feel hungry (dependent on regular schedules). Realizing its noon and starting to feel hungry. If we are eating on a regular schedule, then we find that our body anticipates based on how much time has passed to trigger the Cephalic phase. People who eat very regularly and stick to a particular schedule as it gets close to the normal time they eat they start to get hungry. They have noticed this in animals, like dogs. Barb’s cats are fed on a very regular schedule, but she will start to get bothered by them at 4:00 because their body is telling them that it’s time to eat. Only seems to work when on a very regular schedule.

Explain the Conditioning of Hunger when we eat through influential factors.

Cues associated with food can trigger the Cephalic phase. What you consistently around when you eat. (Always on iPad when eating breakfast/dinner or watching a show or a video you shouldn’t be hungry but you start watching a video and want to start snacking.) Being around certain people, certain environments, people that eat in bed if you’re sitting on your bed studying and eating that bed is going to become a signal for food. When you encounter that place you are going to initiate the cephalic phase, you can wait it off and stabilize the cephalic phase. Diet plans target the idea of conditioned hunger, they do behavioral training and figure out hunger triggers. Look for cues that are associated with food and advise people to set up one place where they eat and that is the one place that they eat. Help people get rid of triggers and their attachments to food making them less likely to trigger the cephalic phase when they’re actually really not that hungry.

Explain the Cephalic Phase of Energy Metabolism

The phase (before) consuming food and eating, often thought of as the “preparatory phase.

• It can be triggered by seeing food, thinking about food, or smelling food; if we think in terms of human history, our ancestors weren’t around food the way we are today. Food was not readily available; this phase will be initiated. Triggers the digestive process in the anticipation of food. The pancreas is going to release insulin into the bloodstream. It is going to produce changes like momentarily dizzy or weak due to the sudden rush of energy into the bloodstream. It is going to produce changes like momentarily dizzy or weak due to the sudden rush of energy into the bloodstream. Responsible for helping to release and break down Lysogen into Glucose. Proteins from the muscles turn into amino acids, it is a chemical that is necessary to start converting stored energy into something we can use. If you don’t eat food, the feelings will pass and you insulin levels will go back to normal (If you don’t eat for hours on end, you will enter the fasting phase.)

Explain the absorptive phase of energy metabolism

When you do eat once food hits your stomach.

• You’re going to be trying to put extra nutrients into storage and keep it away from breaking down. We don’t need glucagon because insulin is going to help us use the energy that is coming in. Insulin is important for the cells of our body to utilize. The peripheral nervous system is in essence, starving. People with diabetes, without insulin, are consuming food but their bodies cannot use the nutrients or glucose. Any extra that we have available in terms of nutrients will be converted into storage. Insulin helps to create long storage components, we are not tapping into our storage and pulling energy out.

Explain the Fasting Phase of energy metabolism

No longer absorbing nutrients, we have to rely on storage for energy at this moment. (The phase that we switch in from the cephalic phase if you do NOT eat.)

• Insulin levels are low but not non-existent from the pancreas is releasing insulin at a baseline level, enough that you will be able to use the glucose coming out of long-term storage. The levels are lower because you are getting whatever glucose you need, you don’t need a lot of it because you are not trying to put glucose back into storage. Breaking down glycogen into glucose and eventually if needed, breaking down protein into amino acids. The Glucagon helps to break things down at a steady speed. The utilization of the body decreases in comparison to the brain. Slow down how quickly it burns energy in order to conserve the brain.

Explain what Satiety SIgnals are and how they work.

generated by social factors/peptides as to what is going to determine how much food we consume, motivational state by which we are stopping eating at a point where there is still food available, you’re choosing not to eat and are pushing food away and not eating everything that is available to you at that exact moment.

What happens when food is in the gut?

Once food hits your duodenum your hunger and appetite start to decrease at this time.

Explain glucose in the blood

-   because you are absorbing sugars the level of glucose rising will trigger a release of Satiety Signals. Less activation of hunger signals but cells are going to be responding by triggering and releasing Satiety Signals.

When glucose blood levels rise – more satiety and less hunger

Explain the volume of Food (Explain Cannon and Washburn 1912 experiment)

Proposed that the amount of food you consume is what is driving your hunger and satiety. Washburn learned how to swallow a balloon with a tube until the balloon got into his stomach and lay on a table while Cannon would blow up and deflate the balloon. What they were trying to measure through the balloon was, how did the wall of the stomach contract during this time. Every 7-9 minutes there is a stomach contraction that occurs, they wondered if you allowed the stomach to contract how it would/did correlate with hunger. When the balloon was over-inflated the monitor could not detect feeling hungry when the balloon was full but as the balloon would slowly be deflated and the muscle contractions of the stomach started happening he would verbalize being hungry.

Proposal: When your stomach contracts you get hungry and when it doesn’t, you aren’t hungry. (it’s actually not that simple.)

What was the proposal of the Cannon and Washburn experiment?

When your stomach contracts you get hungry and when it doesn’t, you aren’t hungry. (actually not this simple.)

Explain the Nutritive Density of Food

People given food lower in calories, sugar, and fat will claim to be hungrier faster People will eat less foods on a high fat, high sugar diet but more on a low fat, low sugar diet.

• In situations where rats can choose how much they want to eat when given as much food as they possibly could eat, rats tend to only eat 13-15 grams everyday. One group of rats was given a higher fat and higher sugar diet than what they were originally give, the rats started to eat less and consistently ate the lower amount. They are getting all the nutrients they need so they don’t have to eat a lot of the food. The other group was given less sugar and less fat diet food and they were eating much more than usual.

At some point if they lowered the nutrient level below 50% the rats stopped eating altogether. (Barb’s cat started to gain a lot of weight)

Explain Cognitive Factors

With humans, we’re more complex → a lot of cognitive factors that play a role in both, hunger and satiety. How much we eat is dependent on the habits we have formed. Sometimes people have a hard time stopping and can’t push the food away because of their background (etc.) We also have factors that influence the memories we have of the food, we tend to eat food that we really enjoyed in the past. The expectation of how fulfilling the food is can also effect satiety → trigger satiety in a way that is related to past experience (not in the moment) if you know a burger and fries is filling, you might eat less of it from known past experience.

Explain how Appetizers Effect Satiety

If you have a small bit of food there is a tendency to trigger more hunger which leads to people ordering more food, it is shown that people will also eat more of their food. Eating just a little bit is thought to trigger a hunger response, what happens here is by putting a small amount of food into your stomach (which gets into your duodenum) your blood sugar levels will rise very quickly and trigger more insulin release which will lead to a very fast depletion.

• When you go to a restaurant the staff always asks if you want an appetizer first , and usually come back right after you take a few bites to ask what you’d like to eat. When people order an appetizer they usually order more and eat more.

Explain Social Factors and Satiety

Being around other people tends to increase our appetite and behavior, when eating socially we tend to eat more. Studies have shown that when people eat in groups, people will eat 60% more food when they’re eating with other people, than when they’re eating alone. Having others around may influence our eating behavior. Triggered from ancestors constantly competing and being in competition for food, all biologically driven.

Explain Sensory Specific Satiety

Biological phenomenon that seems to be affecting how much we consume, has to do with the taste and flavors of food. After you taste a food with a particular flavor profile you decrease that positive incentive value of the food. If you’re eating the same food with the same sensory profile you are going to lose that positive incentive profile. (Eating pizza 3 days in a row, are you really craving it, or do you just want something else?)

• In the long run, helps us to understand