Physiology1. Ingestion

Food enters mouth

2. Propulsion Food moves from one organ to next

Swallowing Peristalsis – involuntary muscle contraction

Physiology3. Food Breakdown

Mechanical – chewing (teeth), churning (stomach)

Chemical Large molecules are broken into smaller building

blocks Proteins -- amino acids Carbs simple sugars (monosaccharides)

Physiology4. Absorption

Enzymes from liver and pancreas help digest food

Nutrients are absorbed into the bloodstream by active and passive transport

5. DefecationElimination of feces from body

AnatomyTongue – swallowSalivary glands – moisten food and begin

digestionsEsophagus – brings food from mouth to

stomach (uses peristalsis)Stomach – produces acids to breakdown food,

mixes and churns

AnatomySmall Intestine – uses enzymes from liver and

pancreas to digest foodNutrients absorbed into blood

Large Intestine – absorbs waterRectum – stores fecesAnus – releases feces

Accessory OrgansLiver

Makes bile that helps in fat digestionGall bladder – stores bile

PancreasMakes enzymes that digest proteins, carbs and

fat

Flow of foodMouthesophagusstomachsmall

intestinelarge intestinerectumanus

Nutrition and MetabolismNutrient

A substance in food that is used by the body to promote normal growth, maintenance and repair

ATPChemical energy needed by cells to do their

activities

Major NutrientsCarbohydratesLipidsProteins

Nutrition and MetabolismOther nutrients

Needed in minute (small) amounts but still very important Vitamins Minerals

Carbohydrates – sugars and starchesMade of carbon, hydrogen and oxygenAlmost all come from plants except lactose

and glycogenBroken down to make ATP through the

process of cellular respiration (in mitochondria)

Excess stored as fat or glycogen

CarbohydratesMonosaccharides – single sugars

Examples – glucose and fructose

Disaccharides – double sugarsExamples – sucrose (table sugar), lactose, maltose

Polysaccharides – many sugars – good for storageExamples – starch (plants store sugar this way),

glycogen (animals store sugar this way)

Lipids - fatsMade of glycerol and fatty acidsMost abundant source of usable energyUsed for

Insulation, protectionBuild cell membrancesFuel to make ATP

Broken down in the liver (use bile)

Lipids - fatsSaturated fats – all single bonds – most from

animalsExamples – meat, dairy, some plants (coconut)

Unsaturated fats – some double or triple bondsExample – seeds, nuts, vegetable oils

Cholesterol – steroid – found in cell membranesExample – animal products – meat, eggs, cheese

ProteinsOver 50% of organic material in bodyMade of amino acidsEssential amino acids come only from the dietUsed for

Collagen – bones, cartilage, tendonsKeratin – hair, nails (waterproofing)Antibodies – immunityHormones – growth and developmentEnzymes – regulate chemical reactions

VitaminsOrganic nutrients that the body needs in

small amountsObtained through a balanced dietUsed for many things in body (see pgs 543-

544)

VitaminsA – healthy eyes, skin and bonesD – absorption of calcium and phosphorus (bones

and teethE – prevents cell membrane damageK – helps make certain proteins, especially blood

clottingB1, Riboflavin, Niacin – help in metabolismB12/Folate – help in making DNA and RNA –

important for early pregnancyC – makes collagen, helps in detoxification, helps

absorb iron

MineralsInorganic substances that the body needs in

small amountsCalcium – strong bones, teeth, blood clotting,

muscles movement, nerve signalsPhosphorus – bone and teethSulfur – part of tendons, cartilage, proteinsSodium /potassium– nerve impulses, muscle

contractionIron – helps make hemoglobinIodine – helps thyroid work

MetabolismAll the chemical reactions necessary to

maintain lifeCatabolism – breaking down big substances

into smaller substancesAnabolism – building larger molecules from

smaller building blocksEnergy intake = total energy output (heat +

work +storage)If energy intake and energy outflow are

balanced, weight remains stable

BMR – basal metabolic rateAmount of energy used by the body at restUsed for essential activities – breathing, eating,

heartbeat, kidney funct. EtcAffected by

-surface area – large surface area in relation to volume = increased BMR (thin people)

Gender – BMR is higher in males than femalesThyroxine production

Increased thyroxine = higher BMRAge – Young growing = higher BMR

Elderly = lower BMRStrong emotions = higher BMR

Total Metabolic RateTMR – total amount of kilocalories the body must

consume to fuel ALL ongoing activities (including exercise, digestion, physical activities)

If calories eaten = TMR your body maintains stable weight

If you eat more than your TMR requires – excess calories are stored as fat

If you eat less than your TMR requires – break down fat

Determining your BMR/TMRTake your weight in poundsDivide by 2.2 to get weight in kilogramsMultiply by .9 to get calories per hourMultiple by 24 to get calories per day

This number is your BMR

Determining your BMR/TMRTo find your TMR – it is based on activity levelIf you are sedentary (little or no exercise)

Multiply your BMR by 0.15 and add this number to your BMRIf you are lightly active (light exercise like walking, most

days of week)Multiply your BMR by 0.50 and add this number to your BMR

If you are moderately active (vigorous exercise at least 30 min per day)Multiply your BMR by 0.70 and add this number to your BMR

If you are very active (vigorous exercise at least 60 min per day)Multiply your BMR by 0.80 and add this number to your BMR