Module 38: Hunger Motivation Flashcards
What are the physiological effects of hunger?
Stomach Contractions
- L. Washburn swallowed device with a balloon. Inflated to fill his stomach the balloon transmitted his stomach contractions. Washburn pressed a key each time he felt a pang of hunger
Can hunger exist without stomach contractions?
Some hunger similarly persists in humans whose ulcerated or cancerous stomachs have been removed.
Glucose
The form of sugar that circulates in the blood and provides the major source of energy for the body tissues
*when its level is low, we feel hunger
Glucose and Hunger
Your brain is automatically monitoring your blood chemistry and your body’s internal state, will trigger hunger
How does blood glucose impact hunger?
Appetite hormones released from your hypothalamus, stomach, intestines, pancreas, and liver all signal your brain to motivate eating or not to motivate eating
Orexin
A hunger-triggering hormones produced by the hypothalamus
Ghrelin
Hormones secreted by empty stomach sends “I’m hungry” signals to the brain
Insulin
Hormones secreted by pancreas; controls blood glucose
Leptin
Protein hormone secreted by fat cells; when abundant, cause brain to increase metabolism and decrease hunger
PYY (Peptide Tyrosine Tyrosine)
Digestive tract hormone sends “I’m not hungry” signals to the brain
How does the arcuate nucleus impact hunger?
A small structure in the base of the hypothalamus, the arcuate nucleus plays a key role in the regulation of appetite and body weight by signaling the release of leptin or ghrelin
What role does the hypothalamus play in hunger?
The hypothalamus performs various body maintenance functions, including control of hunger. Blood vessels supply the hypothalamus, enabling it to respond to our current blood chemistry as well as to incoming neural information about the body’s state
Set Point
The point (weight) at which your “weight thermostat” may be set (fixed).
When your body falls below this weight, increased hunger and a lowered metabolic rate may combine to restore lost weight
Basal Metabolic Rate
The resting rate of energy expenditure for maintaining basic body functions
How do our bodies regulate weight?
Our bodies regulate weight through the control of food intake, energy output, and basal metabolic rate.
Social/Cultural influences on hunger
- Cultural preferences for or aversions to certain foods
- portion sizes offered
- eating & socializing
What are some of the risk associated with obesity?
Diabetes, high blood pressure, heart disease, gallstones, arthritis, certain types of cancer
Obesity
A disorder involving excessive body fat that increases the risk of health problems
Body Mass Index (BMI)
A measurement of your body fat based on your weight in relation to your height
*does not take into account muscle mass, bone density, overall body composition, and racial and sex differences
Why is storing fat adaptive?
This ideal form of stored energy carried our ancestors through periods of famine (evolutionary perspective)
People in impoverished places still find heavier bodies attractive, as plumpness signals affluence and status
How do set point and metabolism contribute to obesity?
Fat (lower metabolic rate than muscle) requires less food intake to maintain than it did to gain
If weight drops below a set point/settling point, the brain triggers hunger and metabolism
Body perceives Starvation; adapts by burning fewer calories. Most dieters in the long run regain what they lose on weight-loss programs
Does sleep loss contribute to obesity?
yes
Sleep deprivation increase the release of ghrelin which stimulates the appetite and decrease the release of leptin which reports body fat to the brain
If we are eating more and not alerting the brain to fat accumulation, we are going to gain weight
Unit Bias
The tendency to eat more if given more food (eat more when the portion is bigger). This occurs mindlessly
Food Variety
Stemming from evolutional benefits, people eat more when there are varied and plentiful amounts of food. This is because the different foods provide different types of vitamins and minerals
Genetic Factors
There is a genetic influence on body weight. This is evident through studies where adoptive siblings do not have similar body weights regardless of shared family meals
Food & Activity
People who experience sleep loss are more vulnerable to obesity because their levels of leptin drop while their levels of ghrelin increase (leptin signals body fat to the brain and ghrelin is the appetite-stimulating hormone). Another factor is the decrease in the daily activity since changes in technology and work doesn’t require physical activity as much as it used to
True or False: A person is more likely to become obese if their friend is, especially if they are a close friend.
True
True or False: Obesity does not contribute to depression.
False
Obesity contributes to depression and brings about more obesity
