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Chapter 4Chapter 4

Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Body BasicsBody Basics

Chapter 4Chapter 4

Chapter Learning Outcomes Chapter Learning Outcomes 1.1. Define key basic chemistry terms, including atom, Define key basic chemistry terms, including atom,

element, ion, chemical bond, solutions, solvent, solute, element, ion, chemical bond, solutions, solvent, solute, acid, base, and enzyme.acid, base, and enzyme.

2.2. Explain the basic function of an enzyme.Explain the basic function of an enzyme.3.3. Define tissue, organ, and organ system.Define tissue, organ, and organ system.4.4. Identify the organ systems, major organs or tissues in Identify the organ systems, major organs or tissues in

each system, and describe primary functions of each each system, and describe primary functions of each system.system.

5.5. Discuss the overall processes of digestion and Discuss the overall processes of digestion and absorption.absorption.

6.6. Identify some common gastrointestinal problems, and Identify some common gastrointestinal problems, and discuss preventive measures and treatments for these discuss preventive measures and treatments for these conditions.conditions.

Quiz YourselfQuiz Yourself True or FalseTrue or False

1.1. The atom is the smallest living unit in the body. The atom is the smallest living unit in the body. T FT F

2.2. The stomach produces hydrochloric acid (HCl). The stomach produces hydrochloric acid (HCl). T F T F

3. Taste buds can be found in the lining of your 3. Taste buds can be found in the lining of your mouth. T Fmouth. T F

4.4. The human intestinal tract cannot digest certain The human intestinal tract cannot digest certain combinations of foods, such as mixtures of combinations of foods, such as mixtures of simple carbohydrates and proteins. T Fsimple carbohydrates and proteins. T F

5.5. Undigested food rots in your stomach, causing Undigested food rots in your stomach, causing toxic materials to build up in your tissues. T Ftoxic materials to build up in your tissues. T F

How Did You Do?How Did You Do?

1.1. FalseFalse The atom is The atom is notnot the smallest living unit in the smallest living unit in the body.the body.

2.2. TrueTrue The stomach produces hydrochloric acid The stomach produces hydrochloric acid (HCl). (HCl).

3.3. TrueTrue Taste buds can be found in the lining of Taste buds can be found in the lining of your mouth. your mouth.

4.4. FalseFalse The human intestinal tract The human intestinal tract cancan digest digest combinations of foods, including mixtures of combinations of foods, including mixtures of simple carbohydrates and proteins. simple carbohydrates and proteins.

55. . FalseFalse Undigested food does Undigested food does notnot rot in your rot in your stomach, causing toxic materials to build up in stomach, causing toxic materials to build up in your tissues. your tissues.

Chemistry and PhysiologyChemistry and Physiology

ChemistryChemistryStudy of composition and characteristics of Study of composition and characteristics of mattermatter

Human physiologyHuman physiologyStudy of how the human body functionsStudy of how the human body functions

Principles of Principles of chemistrychemistry and and human physiologyhuman physiology formformthe the foundationfoundation for the scientific study of nutrition. for the scientific study of nutrition.

Basic Chemistry ConceptsBasic Chemistry Concepts

ChemicalsChemicals make up make up food food and other and other aspects of the environment.aspects of the environment.

Humans are complex collections of Humans are complex collections of chemicals…chemicals…mostly organized intomostly organized into living living unitsb unitsb —— cells.cells.

From Atoms to CompoundsFrom Atoms to Compounds

MatterMatter is made of is made of atomsatoms that contain: that contain:

Protons Protons — — PositivelyPositively--charged particles in the nucleus charged particles in the nucleus

Electrons Electrons — — NegativelyNegatively--charged particles that surround the charged particles that surround the nucleus in a “cloud”nucleus in a “cloud”

ElementElement - A substance that cannot be broken down into smaller components- A substance that cannot be broken down into smaller components

- Elements are the “building blocks” of matter- Elements are the “building blocks” of matter

Some elements are Some elements are essentialessential nutrients. nutrients.

Elements in the Human Body

• Insert Table 4.1

Molecules Molecules

• Insert Figure 4.2

MoleculeMolecule – Matter that forms when 2 or more – Matter that forms when 2 or more atoms interact and are held together by a atoms interact and are held together by a chemical bond (such as (such as H20 or or CC66HH1212OO66))

Chemical bondChemical bond – – Forms when atoms interact, Forms when atoms interact, share electrons, and rearrange themselvesshare electrons, and rearrange themselves

CompoundsCompounds

CompoundCompound – Molecule that contains 2 or more – Molecule that contains 2 or more different elementsdifferent elements

SolutionSolution – Evenly distributed mixture of 2 – Evenly distributed mixture of 2 compounds compounds

The 2 compounds in a solution are: The 2 compounds in a solution are:

SolventSolvent - the greater component - the greater component

SoluteSolute - lesser component - lesser component

WaterWater is the solvent for many solutions. is the solvent for many solutions.

Solubility Solubility

Describes Describes how easily a how easily a substance substance

dissolves in a dissolves in a liquidliquid

• Insert figure 4.3

IonsIons

• Insert Figure 4.4

IonIon – E – Electrically-charged atom or group of atoms. lectrically-charged atom or group of atoms. Ions form when the atom or group of atoms gains or Ions form when the atom or group of atoms gains or loses 1 or more electronsloses 1 or more electrons

Negative charge Negative charge - gain of - gain of an electron an electron

OHOH-- (hydroxide ion)

Positive charge Positive charge - loss of an - loss of an electron electron

HH++ (hydrogen ion)

What Are Acids and Bases?What Are Acids and Bases?

• Insert Figure 4.5

AcidsAcids – Donate hydrogen ions– Donate hydrogen ions

BasesBases – Accept hydrogen ions– Accept hydrogen ions

pHpH – Measure of acidity or alkalinity of a solution– Measure of acidity or alkalinity of a solution

What’s a Chemical Reaction?What’s a Chemical Reaction?

Chemical ReactionChemical Reaction

Process that changes atomic arrangement of Process that changes atomic arrangement of moleculesmolecules

DigestionDigestion

Process by whichProcess by which molecules in food are molecules in food are mechanically and chemically broken downmechanically and chemically broken down

MetabolismMetabolism

Chemical reactions occurring in living cellsChemical reactions occurring in living cells

EnzymesEnzymes

• Insert Figure 4.8

EnzymeEnzyme – – Protein that speeds up the rate of a Protein that speeds up the rate of a chemical reaction but is not altered during the chemical reaction but is not altered during the processprocess

Names ofNames of most enzymes end inmost enzymes end in “ “asease””

sucrsucrasease lactlactasease lip lipasease proteproteasease

Basic Physiology ConceptsBasic Physiology Concepts

AnatomyAnatomy

Study of cells and other body Study of cells and other body structuresstructures

PhysiologyPhysiology

Study of how cells and body structures Study of how cells and body structures functionfunction

The CellCell –– Smallest functional

structure in a living

organism

A human has ~ 100 A human has ~ 100 trilliontrillion cells. cells.

Organelles – Structures within cells that perform specialized functionsOrganelles include: nucleus, mitochondria, and ribosomes.

A Cell

• Insert Figure 4.9

What Are Tissues?

TissuesTissues – Collection of cells that perform – Collection of cells that perform specialized functionsspecialized functions

Epithelial tissueEpithelial tissue - Cells that form linings and coverings, - Cells that form linings and coverings, such as skinsuch as skin

Connective tissueConnective tissue - Cells that hold together, protect, and - Cells that hold together, protect, and support organssupport organs

From Cells to SystemsFrom Cells to SystemsOrganOrgan: Collection of various types of tissues with related

functions

SystemSystem: Collection of organs with related functions.

• Insert Figure 4.10

The Organ Systems of the Human BodyThe Organ Systems of the Human Body

Insert table 4.2

Respiratory Respiratory SystemSystem

LungsLungs enable body enable body to exchange gases, to exchange gases, mainly oxygen and mainly oxygen and

carbon dioxide.carbon dioxide.

• Insert Figure 4.12

Lymphatic Lymphatic SystemSystem

Helps maintain fluid Helps maintain fluid balance, absorb balance, absorb many fat-soluble many fat-soluble

nutrients, and nutrients, and defend the body defend the body against diseasesagainst diseases

• Insert Figure 4.13

Urinary SystemUrinary System

KidneysKidneys filter unneeded filter unneeded substances from blood substances from blood

and help maintain and help maintain proper fluid balance.proper fluid balance.

BladderBladder stores urine stores urine

until elimination.until elimination.

• Insert Figure 4.13

Muscular Muscular SystemSystem

MusclesMuscles enable the enable the body to move, and body to move, and

they provide support they provide support and protection. and protection.

• Insert Figure 4.15

Skeletal Skeletal SystemSystem

BonesBones pprovide rovide support, support,

movement, and movement, and protection. protection.

Bones also store certain Bones also store certain minerals and produce red minerals and produce red

blood cells.blood cells.

• Insert Figure 4.16

Nervous Nervous SystemSystem

Nervous systemNervous systemcells (cells (neuronsneurons) in ) in the brain, spinal the brain, spinal

cord, and cord, and throughout the body throughout the body transmit information transmit information and responses by and responses by

electrical and electrical and chemical signals. chemical signals.

• Insert Figure 4.17

Endocrine Endocrine SystemSystem

OOrgans and rgans and tissues that tissues that

produce produce hormoneshormones

• Insert Figure 4.18

Integumentary SystemIntegumentary System

• Comprised of Comprised of skinskin, , hairhair, and , and nailsnails

Reproductive System

• Main function to produce childrenMain function to produce children

Digestion Digestion and Absorptionand Absorption

GI TractMuscular tube that extends from mouth to anus

BioavailabilityBioavailabilityExtent to which digestive tract absorbs nutrients and how well body uses them

• Insert Figure 4.21

MouthMouthDigestionDigestion begins in thebegins in the mouth mouth

Mechanical digestionMechanical digestion – – Biting and grinding actions of teethBiting and grinding actions of teeth

breaks and mashes food into smaller breaks and mashes food into smaller pieces.pieces.

Chemical digestionChemical digestion – – SalivaSaliva mixes and lubricates food. mixes and lubricates food.

– – Salivary amylaseSalivary amylase and and lipaselipase begin begin

breakdown of starch and fat, respectively. breakdown of starch and fat, respectively.

Taste and Smell of FoodsTaste and Smell of Foods

Taste BudsTaste Buds – – Specialized sensory structures Specialized sensory structures on the tongue and in the lining of on the tongue and in the lining of mouth and throatmouth and throat

Five Tastes: Five Tastes: Sweet, sour, salty, Sweet, sour, salty, bitter, and umamibitter, and umami

SmellSmell – – Chemicals in food become Chemicals in food become airborne and stimulate nasal airborne and stimulate nasal passages, contributing to sense of passages, contributing to sense of tastetaste

• Insert photo of girl with ice cream page 96

From the Mouth to the From the Mouth to the Stomach Stomach

EsophagusEsophagus – Tube connecting pharynx to – Tube connecting pharynx to stomachstomach

EpiglottisEpiglottis – Flap that folds down over trachea – Flap that folds down over trachea (windpipe) when you swallow(windpipe) when you swallow

Gastroesophageal sphincterGastroesophageal sphincter – – LocatedLocated at the at the

end ofend of the esophagus; controls opening into the the esophagus; controls opening into the stomachstomach

What Happens When You Swallow?What Happens When You Swallow?

Insert Figure 4.22Insert Figure 4.22

PeristalsisPeristalsis

Muscular Muscular contractionscontractions

that move that move small amounts small amounts

of food and of food and beverages beverages

through through intestinal tractintestinal tract

Insert Figure 4.23Insert Figure 4.23

StomachStomach

• Large muscular sack that holds and churns foodLarge muscular sack that holds and churns food

• In stomach, food mixes with gastric juice, becoming In stomach, food mixes with gastric juice, becoming chymechyme

• Pyloric sphincterPyloric sphincter controls the rate that chyme is released controls the rate that chyme is released into the small intestineinto the small intestine

Insert Figure 4.24

Small IntestineSmall Intestine

Where most nutrients Where most nutrients are digested and are digested and absorbed absorbed • • DuodenumDuodenum

•• JejunumJejunum•• IleumIleum

• Insert Figure 4.26

Accessory Organs

PancreasPancreas –– produces and secretes many digestive enzymes

LiverLiver –– processes and

stores many nutrients • makes cholesterol

GallbladderGallbladder –– stores bilebile that the liver makes

• Insert figure 4.21

Absorbing Nutrients

Figure 4.26

VilliVilli Tiny projections that line the small intestine

Absorptive cellsAbsorptive cellsRemove nutrients from chyme and transfer them into intestinal blood or lymph

Water-soluble Water-soluble nutrients enter the nutrients enter the capillary of a villus, capillary of a villus, and travel to the liver and travel to the liver via via portal vein.portal vein.

Most fat-soluble Most fat-soluble compounds are compounds are formed into formed into chylomicronschylomicrons, that , that enter a enter a lacteal lacteal of the of the lymphatic system lymphatic system and eventually reach and eventually reach the bloodstream.the bloodstream.

• Figure 4.26

Cystic Fibrosis and Cystic Fibrosis and Inflammatory Bowel DiseaseInflammatory Bowel Disease

Cystic fibrosisCystic fibrosis – – An inherited, incurable diseaseAn inherited, incurable disease

– – Thick sticky mucus blocks passagewaysThick sticky mucus blocks passageways – – Mucus blocks pancreatic ducts, Mucus blocks pancreatic ducts, interfering interfering with nutrient digestion, with nutrient digestion, especially fatespecially fat

Inflammatory bowel diseaseInflammatory bowel disease – – Group of diseases that cause inflammation and Group of diseases that cause inflammation and swelling of the intestinesswelling of the intestines

– – Crohn’s diseaseCrohn’s disease and and ulcerative colitisulcerative colitis

Large Intestine

Absorption of water

and minerals

FecesFeces –– form aschyme becomessemisolid

RectumRectum –– lower part

of large intestine

where feces are stored

• Insert figure 4.21

Microbes in Your Digestive Tract

Bacteria

Vast numbers of bacteria reside in large intestine.

Intestinal bacteriaIntestinal bacteria:

Metabolize undigested food materialMake vitamin Kvitamin K and biotinbiotinProduce gas

Feces contain bacteria

Your Adaptable Digestive Tract

• Humans are omnivoresHumans are omnivores– Human digestive tract:

• Can handle combinations of foods, such as mixtures of animal and plant foods

• Can digest foods and absorb nutrients from wide variety of sources, including:

– Plants– Animals– Fungi– Bacteria

Chapter 4 HighlightGut Reaction

Common Intestinal ComplaintsCommon Intestinal Complaints– Constipation– Diarrhea– Vomiting– Heartburn– Peptic Ulcer– Irritable Bowel Syndrome

Gut Reaction: Constipation What is Constipation?What is Constipation?

• Difficult and infrequent bowel movements• CausesCauses:

– – Lack of fiber in diet

– – Inadequate water intake – – Anxiety or depression – – Changes in daily routine – – Ignoring need to defecate

Gut Reaction: Diarrhea

• Frequent, loose bowel movements

• Causes are often bacterial or viral

• Treatment:

– – OTC medication

– – Replacing fluid, sodium, and potassium to prevent dehydration

– – ImmediateImmediate treatment of severe diarrhea in infants or the elderly is crucial

Gut Reaction: Vomiting

Contraction of abdominal muscles to expel toxic stomach and duodenal contents

• CausesCauses: Ingestion of toxic substances, intense pain, head injury, motion

sickness, pregnancy, or touching back of throat

• TreatmentTreatment:- Avoid solid food until resolved- Sip water or non-carbonated beverages, if tolerated, to

prevent dehydration

WatchWatch for signs of dehydration. ContactContact physician if signs of dehydration are present and vomiting lasts longer than a few hours (children) or a day (adults).

Gut Reaction: Heartburn

Gnawing pain or burning in upper chest• Occasional heartburnOccasional heartburn affects about 50% of

U.S. adults

• Results when stomach acid enters esophagus

• CausesCauses: Pregnancy, smoking, excess body fat, alcohol, caffeine, citrus juice, onions,

chocolate, mints, fatty foods, spices, and eating too much at one time

Gut Reaction: Peptic Ulcer

• SoreSore in the lining of the stomach or duodenum• Symptoms:

– – Deep, dull upper abdominal painDeep, dull upper abdominal pain ~2 hrs afterafter eating

• Often caused by Helicobacter pyloriHelicobacter pylori infection• Treatment:

– – Antibiotics to eliminate Helicobacter pyloriHelicobacter pylori

– – Identification and avoidance of aggravating foods

Factors That Increase Risk of Peptic Ulcers

• Insert Table 4.B

Gut Reaction:Irritable Bowel Syndrome (IBS)

Affects ~10 to 30% of adults • Intestinal crampsIntestinal cramps and abnormal bowel functionabnormal bowel function (ranges

from diarrhea to constipation)

• Unknown causesUnknown causes — linked to stressstress

• TreatmentTreatment includes stress management• EliminationElimination of foods, such as milk and milk products, legumes,

and certain vegetables