hapter 12 - Hunger, Eating and Health Flashcards
Primary purpose of hunger
to increase the probability of eating
Primary purpose of eating
to supply the body with the molecular building block - hence, energy it needs to survive and function
Digestion
gastrointestinal process of breaking down foods and absorbing its constituents into the body
gut microbiome
the bacteria and other organisms that live inside our gastrointestinal tract
Energy is delivered to the body in three forms
- Lipids (fats)
- Amino acids (breakdown product of proteins)
- Glucose (simple sugar)
Energy is stored in three formats
- Fats
- Glycogen
- Proteins
Energy metabolism
the chemical changes by which energy is made available for an organism’s use
What are the three phases of energy metabolism?
- Cephalic phase
- Absorptive phase
- Fasting phase
Cephalic phase
- preparatory phase
- it often begins with sight, smell or even thought of food
- ends with when the food starts to be absorbed into the bloodstream
Absortive phase
period during which the energy absorbed into the bloodstream from the meal is meeting the body’s immedeate energy needs
Fasting phase
period during which all of the unstored energy from the previous meal have been used and the body is drawing energ from its reserves to meet its immediate energy requirements.
Flow of energy during the three phases of energy metabolism is controlled by two pancreatic hormones
- unsulin
- glucagon
Insulin does what three things?
- promotes use of glucose as primary source of energy by the body
- promotes the conversion of bloodborne fuels to forms that can be stored by glycogen and amino acid to proteins.
- promotes the storage of glycogen in liver and muscle, fat in adipose tissue and proteins in muscle.
Gluconeogenesis
conversion of protein to glucose.
What is the set-point assumption?
the assumption that hunger is typically triggered by a decline in the body’s energy resevered below their seit point.
All set-point systems have three components
- Set-point mechansims
- Detector mechanisms
- Effector mechanisms
Set-point mechanisms
defines the set-point
Detector mechanisms
detects deviations from the set-point
Effector mechanisms
acts to elimicate the deviations
What are negative feedback systems?
systems in which feedback from changes in one direction elicit compensatory effects in the opposite direction
Glucostatic theory
eating is regulated by a system designes to maintain a blood glucose set point
Lipostatic theory
theory that eating is controlled by deviations from hypothetical body set-point