Chapter 22 Metabolism and Energy Balance Flashcards
Distinguish between the feeding center and the satiety center. What factors contribute to the control of these hypothalamic centers?
The Feeding Center is tonically active and the Satiety Center stops food intake by inhibiting the feeding center
Leptin – Negative Feedback Signal protein hormone signal between adipose tissue and brain – as fat stores increase food intake decreases
Ghrelin – Secreted by stomach stimulates hunger when body is fasting
Neuropeptide Y – Brain neurotransmitter that stimulates for food intake (leptin inhibits NPY)
Contrast the glucostatic theory and the lipostatic theory
Glucostatic Theory – when blood glucose concentrations decrease, satiety is suppressed and feeding center is more dominant. When glucose metabolism is increased, satiety inhibits feeing center.
Lipostatic Theory- If fat stores increase, eating decreases. In times of starvation, eating increases.
Energy intake consists of ____________________.
What we eat, digest, and absorb
Energy output by the body takes one of two forms: _______________________________.
Work performed and energy returned to the environment as heat
List the three kinds of biological work and give an example of each.
Transport Work – molecules are moved from one side of the membrane to the other
Mechanical Work – Movement through the skeletal muscle contraction or movement of cytoplasmic vesicles and pumping heart
Chemical Work – used for growth, maintenance and storage of information and energy
List the metabolic energy content of 1 g of carbohydrate, 1 g of protein, and 1 g of fat.
1g of Carbohydrate = 4 kcal
1g of Protein = 4 kcal
1g of Fat = 9 kcal
List factors that influence metabolic rate.
- Age and Sex
- Amount of lean muscle mass
- Activity level
- Diet and diet-induced thermogenesis
- Hormones
- Genetics
Define diet-induced thermogenesis
The phenomenon that resting metabolic rate increases after a meal, depending on the type and amount of food ingested.
Fats cause little thermogenic
Proteins give off the most thermogenesis
Of the factors affecting metabolic rate, a person can voluntarily control only two. What are they?
Physical activity and energy intake
Compare the energy storage capacity of glycogen to that of fats. Which holds more energy? Which is easier to access?
Glucose has an energy content of 4 kcal/g. Fat has 9 kcal/g – but glucose is easier to access.
Where is glycogen stored in the body? About how much is in reserve in these locations?
Glycogen is stored in the liver (100g) and the skeleton (200g)
Define metabolism.
The sum of all chemical reactions in the body. The reactions making up these pathways:
- Extract energy from nutrients
- use energy for work
- Store excess energy so it can be used later
Distinguish between anabolic and catabolic pathways.
Anabolic pathways synthesize larger molecules from smaller ones (Fed State/Absorptive State)
Catabolic pathways break large molecules into smaller ones (Fasted State/Postabsorptive State)
What three possible fates do biomolecules meet in the body?
- Energy to do mechanical work
- Synthesis for growth and maintenance
- Storage as glycogen or fat
What are the three nutrient pools?
Free Fatty Acids Pool
Glucose Pool (brain prefers glucose)
Amino Acid Pool
What is the amino acid pool
used mainly for protein synthesis – but if out of glucose, gluconeogenesis can occur – turning amino acids into glucose
