24 Nutrition, Metabolism, and Body Temperature Regulation

24 Nutrition, Metabolism, and Body Temperature Regulation

substances in food used by the body to promote normal growth, maintenance and repair

*essential nutrients - cannot be made fast enough to meet the body's needs and so must be provided by the diet

*calorie (kilocalorie) - amount of energy needed to raise the temperature of 1 kilogram of water by 1 C

Table 24.1 - Dietary Sources

6 Major Nutrients - Main Cellular Uses

*often good sources of fiber, too!

Uses in the body - pg. 912

Saturated vs. Unsaturated Fats

*straightens out chain

Uses in the body - pg. 914

24 Nutrition, Metabolism, and Body Temperature Regulation

*complete - meet the body's amino acid requirements for tissue maintenance and growth

*incomplete - missing one or more essential amino acid

beans peasnuts

Uses in the body - pg. 914-915

meat

*nitrogen balance - protein synthesis is equal to rate of protein breakdown and loss

tissue building

broken down for energy

*children, pregnant women, repairs

tissue building

broken down for energy

*physical or emotional stress, poor diet

*potent organic compounds needed in minute amounts for growth and good health

*absorbed along with water from the gastrointestinal tract

*bind to ingested lipids and are absorbed along with their digestion products

Table 24.2

*coenzymes

*blood clots, ETC

*antioxidant, protects cell membranes

*acts like hormone, promotes bone growth

*vision, protects cell membranes, antioxidant

*antioxidant, improves iron absorption, detox, collagen synthesis

Minerals - Table 24.3

*energy balance means intake equals output

more intake = weight gain more output = weight loss*lost as heat, used to do work, stored as fat

Regulation of Food Intake - It's COMPLICATED... here's what you need to know

leptin, hunger*same with increasing

levels of insulin and CCK

ghrelin, hunger*same with increasing levels of

glucagon and epinephrine

24 Nutrition, Metabolism, and Body Temperature Regulation

Basal Metabolic Rate (BMR) - energy the body needs to perform only its most essential activities (i.e. breathing, resting levels of organ function)

Affected By: body surface

area (increases heat loss, increasing

metabolic rate to replace lost

heat), age, gender, stress, and hormones

(increased thyroxine, increased

metabolism)

"energy cost of living" Total Metabolic Rate (TMR) - BMR + all ongoing activities

TMR

Regulating Body Temperatureorgans in skull, chest,

and abdomen

skin

Mechanisms of Heat Exchange - Heat Loss

loss of thermal energy

conduction - transfer of heat from warmer to cooler

convection - hot air rises, cold air sinks

heat absorbed by water

Body Temperature Regulationpg. 948-949