Exchange of Exchange of materials. materials. Intensity of Intensity of metabolic metabolic processes in processes in the bodythe body

ProteinProtein

• Foods such as meat, eggs, and beans consist of large molecules of protein that must be digested by enzymes before they can be used to build and repair body tissues.

Digestibility of common Digestibility of common

proteins foodsproteins foods

Food source Protein digestibility (%)

Egg 97

Milk and cheese 97

Mixed US diet 96

Peanut butter 95

Meat and fish 94

Whole wheat 86

Oatmeal 86

Soybeans 78

Rice 76

BV of some BV of some common common proteinsproteins

• Table 2 presents the BV of some common proteins.

• Considering the high protein intakes of most strength athletes (2.0 g/kg or higher) it is hard to see how BV will play a meaningful role in rating proteins in this population. In all likelihood, any decent quality protein will be as good as any other at these types of protein intakes.

Protein BV

whey 100

egg 100

milk 93

rice 86

casein, fish and beef

75

corn 72

peanut flour

56

wheat gluten

44

Extracting Energy Extracting Energy from Glucosefrom Glucose

• Two different pathways are involved in the metabolism of glucose: one anaerobic and one aerobic.

• The anaerobic process occurs in the cytoplasm and is only moderately efficient.

• The aerobic cycle takes place in the mitochondria and is results in the greatest release of energy. As the name implies, though, it requires oxygen.

Aerobic Aerobic MetabolismMetabolism

• Pyruvate is the starting molecule for oxidative phosphorylation via the Krebb's or citric acid cycle.

• In this process, all of the C-C and C-H bonds of the pyruvate will be transferred to oxygen.

Summary of Summary of metabolism of metabolism of

glucoseglucose• Basically, the pyruvate is

oxidized to acetyl coenzyme A, which can then bind with the four carbon oxaloacetate to generate a six carbon citrate.

• Carbons and hydrogens are gradually cleaved from this citrate until all that remains is the four carbon oxaloacetate we started with. In the process, four NADHs, one FADH and one GTP are generated for each starting pyruvate.

Anaerobic

Consumed: 2 ATP

Produced: 8 ATP

Net: 6 ATP

Aerobic

Consumed: 0 ATP

Produced: 2x 15 ATP

Net: 30 ATP

FatsFats

• Fat molecules are a rich source of energy for the body. The first step in digestion of a fat is to dissolve it into the watery content of the intestinal cavity.

Notion about Notion about basal metabolismbasal metabolism

Poikilothermic Poikilothermic and and

homeothermic homeothermic organismsorganisms

• Invertebrates generally cannot adjust their body temperatures and so are at the mercy of the environment. In vertebrates, mechanisms for maintaining body temperature by adjusting heat production and heat loss have evolved. These species are called "cold-blooded" (poikilothermic) because their body temperature fluctuates over a considerable range.

• In birds and mammals , the ' 'warm-blooded ' ' (homeothermic) animals, a group of reflex responses that are primarily integrated in the hypothalamus operate to maintain body temperature within a narrow range in spite of wide fluctuations in environmental temperature.

Temperature Temperature balancebalance

• The balance between heat production and heat loss is continuously being disturbed, either by changes in metabolic rate (exercise being the most powerful influence) or by changes in the external environment that alter heat loss or gain.

• The resulting changes in body temperature are detected by thermoreceptors, which initiate reflexes that change the output of various effectors so that heat production and/or loss are changed and body temperature is restored toward normal.

Sensory Nerve Endings in the Skin

Heat Exchange in the Skin

Scheme of reflex arc

Head ThermogramHead Thermogram

• Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. The name means "below red" (from the Latin infra, "below"), red being the color of visible light of longest wavelength. Infrared radiation spans three orders of magnitude and has wavelengths between approximately 750 nm and 1 mm

Infrared thermographyInfrared thermography

• Infrared thermography is a non-contact, non-destructive test method that utilizes a thermal imager to detect, display and record thermal patterns and temperatures across the surface of an object.

Thermography in medical Thermography in medical practicepractice

• Right breast cancer

ClothingClothing and body and body temperaturetemperature

• Clothing is important not only at low temperatures but also at very high temperatures. When the environmental temperature is greater than body temperature, conduction favors heat gain rather than heat loss.

• Heat gain also occurs by radiation during exposure to the sun. People therefore insulate themselves in such situations by wearing clothes. The clothing, however, must be loose so as to allow adequate movement of air to permit evaporation. White clothing is cooler since it reflects more radiant energy, which dark colors absorb. Loose-fitting, light-colored clothes are far more cooling than going nude in a hot environment and during direct exposure to the sun.

Summary of Effector Summary of Effector Mechanisms in Temperature Mechanisms in Temperature

RegulationRegulation