Exchange of matters, energies Exchange of matters, energies

and termoregulation.and termoregulation.

Types of exchangeTypes of exchange

1. Exchange between the organism and 1. Exchange between the organism and the environment, the environment, in examplein example circulation circulation of substances in nature.of substances in nature.

2. Metabolism within the body: changing 2. Metabolism within the body: changing substances from the time theysubstances from the time they pass pass through the digestive canal to the through the digestive canal to the withdrawal outside. withdrawal outside.

ProteinProtein

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

Digestibility of common Digestibility of common

proteins foodsproteins foods

Food sourceFood source Protein digestibility (%)Protein digestibility (%)

EggEgg 9797

Milk and cheeseMilk and cheese 9797

Mixed US dietMixed US diet 9696

Peanut butterPeanut butter 9595

Meat and fishMeat and fish 9494

Whole wheatWhole wheat 8686

OatmealOatmeal 8686

SoybeansSoybeans 7878

RiceRice 7676

BV of some BV of some common common proteinsproteins

Table 2 presents the BV of Table 2 presents the BV of some common proteins.some common proteins.

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

ProteinProtein BVBV

wheywhey 100100

eggegg 100100

milkmilk 9393

ricerice 8686

casein, casein, fish and fish and beefbeef

7575

corncorn 7272

peanut peanut flourflour

5656

wheat wheat glutengluten

4444

Extracting Energy Extracting Energy from Glucosefrom Glucose

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

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

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

Aerobic Aerobic MetabolismMetabolism

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

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

Summary of Summary of metabolism of metabolism of

glucoseglucose Basically, the pyruvate is Basically, the pyruvate is

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

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

AnaerobicAnaerobic

ConsumedConsumed::

2 ATP2 ATP

Produced:Produced: 8 ATP8 ATP

Net:Net: 6 ATP6 ATP

AerobicAerobic

ConsumeConsumed:d: 0 ATP0 ATP

Produced:Produced: 2x 15 ATP2x 15 ATP

Net:Net: 30 ATP30 ATP

FatsFats

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

Nervous regulationNervous regulation

- changechangess the intensity of endocrine the intensity of endocrine glands function glands function

- direcdirectlytly activat activates es enzymes.enzymes.- central nervous system, acting on central nervous system, acting on

cellular and humoral mechanisms of cellular and humoral mechanisms of regulation, adequateregulation, adequatelyly chang changeses metabolism processes inmetabolism processes in cells cells

Humoral regulation of enzyme Humoral regulation of enzyme activityactivity

MeansMeans the action of hormones on the action of hormones on enzymesenzymes, which , which cancan enhance or inhibit enhance or inhibit the activity of the enzyme.the activity of the enzyme.  Some hormones directly regulate the   Some hormones directly regulate the synthesis or breakdown of enzymes and synthesis or breakdown of enzymes and the permeability of cell membranes, the permeability of cell membranes, altering the cell content of substrate, altering the cell content of substrate, cofactor and ion composition. cofactor and ion composition.

Notion about basal Notion about basal metabolismmetabolism

Poikilothermic Poikilothermic and and

homeothermic homeothermic organismsorganisms

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

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

Temperature Temperature balancebalance

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

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

Sensory Nerve Endings in the Sensory Nerve Endings in the SkinSkin

Heat Exchange in the SkinHeat Exchange in the Skin

Scheme of reflex arcScheme of reflex arc

Head ThermogramHead Thermogram InfraredInfrared ( (IRIR) radiation ) radiation

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

Infrared thermographyInfrared thermography

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

Thermography in medical practiceThermography in medical practice

Right breast Right breast cancercancer

ClothingClothing and body and body temperaturetemperature

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

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

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

RegulationRegulation

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