Anatomy & PhysiologyDr. Assad Mujtaba, MD MBA RNAchieveWeek 1

FOCUS AREAa. The Human Body 5% Week 1

b. Chemical Basics of Life 5% Week 1

c. Dynamics of Support & Motion 12% Week 2-5 (Tissue, Bone & Muscle)

d. Integration and Regulation Mechanism 23% Week 6(CNS, Endocrine, Special Senses)

e. Maintenance of Human Body 33% Week 7,8,9(Blood, Heart, Respiratory, Digestive)

f. Urinary System 10% week 9

g. Reproductive & Developmental 7% week 10

THE HUMAN BODY: AN ORIENTATIONPART I

Overview of Anatomy and Overview of Anatomy and PhysiologyPhysiology• Anatomy – the study of the structure of body parts and their

relationships to one another• Gross or macroscopic• Microscopic• Developmental

• Physiology – the study of the function of the body’s structural machinery

Gross AnatomyGross Anatomy• Regional – all structures in one part of the body

(such as the abdomen or leg)• Systemic – gross anatomy of the body studied by system• Surface – study of internal structures as they relate to the

overlying skin

Microscopic AnatomyMicroscopic Anatomy• Cytology – study of the cell• Histology – study of tissues

Developmental AnatomyDevelopmental Anatomy• Traces structural changes throughout life• Embryology – study of developmental changes of the body

before birth

Specialized Branches of Specialized Branches of AnatomyAnatomy• Pathological anatomy – study of structural changes caused by

disease• Radiographic anatomy – study of internal structures visualized

by specialized scanning procedures such as X-ray, MRI, and CT scans

• Molecular biology – study of anatomical structures at a subcellular level

PhysiologyPhysiology• Considers the operation of specific organ systems• Renal – kidney function• Neurophysiology – workings of the nervous system• Cardiovascular – operation of the heart and blood vessels

• Focuses on the functions of the body, often at the cellular or molecular level

PhysiologyPhysiology• Understanding physiology also requires a knowledge of

physics, which explains • electrical currents• blood pressure• the way muscle uses bone for movement

Principle of ComplementarityPrinciple of Complementarity• Function always reflects structure• What a structure can do depends on its specific form

Levels of Structural Levels of Structural OrganizationOrganization• Chemical – atoms combined to form

molecules• Cellular – cells are made of molecules• Tissue – consists of similar types of cells• Organ – made up of different types of tissues• Organ system – consists of different organs

that work closely together• Organismal – made up of the organ systems

1

2

4

5

6

3

Smooth muscle cellMolecules

Atoms

Smoothmuscletissue

Epithelialtissue

Heart

Bloodvessels

Smoothmuscletissue

Connectivetissue

Bloodvessel(organ)

Cardiovascularsystem

Cellular levelCells are made up ofmolecules.

Tissue levelTissues consist ofsimilar types of cells.

Organ levelOrgans are made upof different typesof tissues.

Organ system levelOrgan systems consist ofdifferent organs thatwork together closely.

Organismal levelThe human organismis made up of manyorgan systems.

Chemical levelAtoms combine toform molecules.

Levels of Structural Levels of Structural OrganizationOrganization

Integumentary SystemIntegumentary System

• Forms the external body covering• Composed of the skin, sweat glands, oil

glands, hair, and nails• Protects deep tissues from injury and

synthesizes vitamin D

Skeletal SystemSkeletal System• Composed of bone, cartilage, and

ligaments• Protects and supports body organs• Provides the framework for muscles• Site of blood cell formation• Stores minerals

Muscular SystemMuscular System• Composed of muscles and tendons• Allows manipulation of the environment,

locomotion, and facial expression• Maintains posture• Produces heat

Nervous SystemNervous System• Composed of the brain, spinal column,

and nerves• Is the fast-acting control system of the

body• Responds to stimuli by activating

muscles and glands

Cardiovascular SystemCardiovascular System• Composed of the heart and blood

vessels• The heart pumps blood• The blood vessels transport blood

throughout the body

Lymphatic SystemLymphatic SystemComposed of red bone marrow, thymus,

spleen, lymph nodes, and lymphatic vessels

Picks up fluid leaked from blood vessels and returns it to blood

Disposes of debris in the lymphatic stream

Houses white blood cells involved with immunity

Respiratory SystemRespiratory System

• Composed of the nasal cavity, pharynx, trachea, bronchi, and lungs

• Keeps blood supplied with oxygen and removes carbon dioxide

Digestive SystemDigestive System

Composed of the oral cavity, esophagus, stomach, small intestine, large intestine, rectum, anus, and liver

Breaks down food into absorbable units that enter the blood

Eliminates indigestible foodstuffs as feces

Urinary SystemUrinary System

• Composed of kidneys, ureters, urinary bladder, and urethra

• Eliminates nitrogenous wastes from the body

• Regulates water, electrolyte, and pH balance of the blood

Male Reproductive SystemMale Reproductive System• Composed of prostate gland, penis,

testes, scrotum, and ductus deferens• Main function is the production of

offspring• Testes produce sperm and male sex

hormones• Ducts and glands deliver sperm to the

female reproductive tract

Female Reproductive SystemFemale Reproductive System

Composed of mammary glands, ovaries, uterine tubes, uterus, and vagina

Main function is the production of offspring

Ovaries produce eggs and female sex hormones

Remaining structures serve as sites for fertilization and development of the fetus

Mammary glands produce milk to nourish the newborn

Organ Systems InterrelationshipsOrgan Systems Interrelationships

• The integumentary system protects the body from the external environment

• Digestive and respiratory systems, in contact with the external environment, take in nutrients and oxygen

Organ Systems InterrelationshipsOrgan Systems Interrelationships

• Nutrients and oxygen are distributed by the blood

• Metabolic wastes are eliminated by the urinary and respiratory systems

Necessary Life FunctionsNecessary Life Functions• Maintaining boundaries – the internal environment remains distinct

from the external environment• Cellular level – accomplished by plasma membranes• Organismal level – accomplished by the skin

• Movement – locomotion, propulsion (peristalsis), and contractility

Necessary Life FunctionsNecessary Life Functions• Responsiveness – ability to sense changes in the environment and

respond to them• Digestion – breakdown of ingested foodstuffs• Metabolism – all the chemical reactions that occur in the body• Excretion – removal of wastes from the body

Necessary Life FunctionsNecessary Life Functions• Reproduction – cellular and organismal levels• Cellular – an original cell divides and produces two identical daughter

cells• Organismal – sperm and egg unite to make a whole new person

• Growth – increase in size of a body part or of the organism

Survival NeedsSurvival Needs• Nutrients – needed for energy and cell building• Oxygen – necessary for metabolic reactions• Water – provides the necessary environment for chemical reactions• Normal body temperature – necessary for chemical reactions to

occur at life-sustaining rates • Atmospheric pressure – required for proper breathing and gas

exchange in the lungs

HomeostasisHomeostasis• Homeostasis – ability to maintain a relatively stable internal

environment in an ever-changing outside world• The internal environment of the body is in a dynamic state of

equilibrium• Chemical, thermal, and neural factors interact to maintain

homeostasis

Homeostatic Control MechanismsHomeostatic Control Mechanisms

• Variables produce a change in the body• The three interdependent components of control

mechanisms:• Receptor – monitors the environments and responds to changes

(stimuli)• Control center – determines the set point at which the variable

is maintained• Effector – provides the means to respond to stimuli

Homeostatic Control MechanismsHomeostatic Control Mechanisms

Change detected by receptor

Stimulus: Produces changein variable

Input:Informationsent along afferentpathway to

Receptor (sensor) Effector

Controlcenter

Variable (in homeostasis)

Response ofeffector feedsback toinfluencemagnitude ofstimulus andreturns variableto homeostasis

Output:Information sentalong efferentpathway to

Imbalance

Imbalance

2

34

5

1

Negative FeedbackNegative Feedback• In negative feedback systems, the output shuts off the original

stimulus• Example: Regulation of room temperature

Positive FeedbackPositive Feedback• In positive feedback

systems, the output enhances or exaggerates the original stimulus

• Example: Regulation of blood clotting

Homeostatic ImbalanceHomeostatic Imbalance• Disturbance of homeostasis or the body’s normal equilibrium• Overwhelming the usual negative feedback mechanisms allows

destructive positive feedback mechanisms to take over

THE HUMAN BODY: AN ORIENTATIONPART II

Anatomical PositionAnatomical Position• Body erect, feet slightly apart, palms

facing forward, thumbs point away from body

Directional TermsDirectional Terms• Superior and inferior – toward and away from the head,

respectively• Anterior and posterior – toward the front and back of the

body• Medial, lateral, and intermediate – toward the midline, away

from the midline, and between a more medial and lateral structure

Directional TermsDirectional Terms• Proximal and distal – closer to and farther from the origin of

the body part• Superficial and deep – toward and away from the body surface

Directional TermsDirectional Terms

Directional TermsDirectional Terms

Regional Terms: Anterior ViewRegional Terms: Anterior ViewNasal (nose)

Oral (mouth)

Cervical (neck)

Acromial(point of shoulder)

Axillary (armpit)

Brachial (arm)

Antecubital(front of elbow)

Abdominal(abdomen)

Pelvic (pelvis)

Antebrachial(forearm)

Carpal (wrist)

Palmar(palm)

Pollex(thumb)

Digital(fingers)

Pubic (genital region)

Patellar(anterior knee)

Crural (leg)

Tarsal (ankle)

Inguinal(groin)

Coxal(hip)

Femoral(thigh)

Fibular, orperoneal(side of leg)

Hallux (great toe)

Mammary(breast)

Frontal (forehead)

Orbital (eye)

Buccal (cheek)

Sternal(breastbone)

Thoracic(chest)

Mental (chin)

Umbilical(navel)

Regional Terms: Posterior Regional Terms: Posterior ViewView

Brachial (arm)

Otic (ear)

Occipital (back ofhead or base of skull)

Acromial(point of shoulder)

Vertebral(spinal column)

Scapular(shoulder blade)

Dorsum or dorsal(back)

Olecranal(back of elbow)

Lumbar (loin)Sacral(between hips)

Gluteal (buttock)

Perineal(region betweenthe anus and external genitalia)

Femoral (thigh)

Popliteal(back of knee)

Sural (calf)

Calcaneal (heel)

Plantar (sole)

Manus(hand)

Upperextremity

Cephalic(head)

Lowerextremity

Body PlanesBody Planes• Sagittal – divides the body into right and left parts• Midsagittal or medial – sagittal plane that lies on the midline• Frontal or coronal – divides the body into anterior and

posterior parts• Transverse or horizontal (cross section) – divides the body

into superior and inferior parts• Oblique section – cuts made diagonally

Body PlanesBody Planes

Anatomical VariabilityAnatomical Variability• Humans vary slightly in both external and internal anatomy• Over 90% of all anatomical structures match textbook

descriptions, but:• Nerves or blood vessels may be somewhat out of place• Small muscles may be missing

• Extreme anatomical variations are seldom seen

Body CavitiesBody Cavities

• Dorsal cavity protects the nervous system, and is divided into two subdivisions• Cranial cavity – within the skull; encases the brain• Vertebral cavity – runs within the vertebral

column; encases the spinal cord• Ventral cavity houses the internal organs

(viscera), and is divided into two subdivisions• Thoracic• Abdominopelvic

TERM• Visceral Peritoneum: serous membranous lining around the

organ• Parietal Peritoneum: The outer layer, called the parietal

peritoneum, is attached to the abdominal wall

Body CavitiesBody CavitiesCranial cavity(contains brain)

Dorsalbodycavity

Diaphragm

Abdominal cavity(contains digestiveviscera)

Pelvic cavity(contains bladder,reproductive organs,and rectum)

Vertebral cavity(contains spinal cord)

Key:

Dorsal body cavity

Ventral body cavity

Thoraciccavity(containsheartand lungs)

(a) Lateral view

Body CavitiesBody Cavities

Ventral body cavity(thoracic and abdomino-pelviccavities)

Abdomino-pelviccavity

Superiormediastinum Pleuralcavity

Cranialcavity

Vertebralcavity

Pericardialcavity withinthe mediastinum

Diaphragm

Abdominal cavity(contains digestiveviscera)

Pelvic cavity(contains bladder,reproductive organs,and rectum)

Thoraciccavity(containsheartand lungs)

(b) Anterior view

Key:

Dorsal body cavity

Ventral body cavity

Body CavitiesBody Cavities• Thoracic cavity is subdivided into two pleural cavities, the

mediastinum, and the pericardial cavity• Pleural cavities – each houses a lung• Mediastinum – contains the pericardial cavity; surrounds the

remaining thoracic organs• Pericardial cavity – encloses the heart

Body CavitiesBody Cavities• The abdominopelvic cavity is separated from the superior

thoracic cavity by the dome-shaped diaphragm• It is composed of two subdivisions

• Abdominal cavity – contains the stomach, intestines, spleen, liver, and other organs

• Pelvic cavity – lies within the pelvis and contains the bladder, reproductive organs, and rectum

Ventral Body Cavity Ventral Body Cavity MembranesMembranes• Parietal serosa lines internal body walls• Visceral serosa covers the internal organs• Serous fluid separates the serosae

>>>REMEMBER: POUT

Serous Membrane RelationshipSerous Membrane Relationship

Heart SerosaeHeart Serosae

Other Body CavitiesOther Body Cavities• Oral and digestive – mouth and cavities of the digestive organs• Nasal –located within and posterior to the nose• Orbital – house the eyes• Middle ear – contains bones (ossicles) that transmit sound

vibrations• Synovial – joint cavities

Other Body CavitiesOther Body Cavities

Abdominopelvic RegionsAbdominopelvic Regions

Organs of the Abdominopelvic Organs of the Abdominopelvic RegionsRegions

Abdominopelvic QuadrantsAbdominopelvic Quadrants• Right upper• Left upper• Right lower• Left lower

Human Body Question 1Which halves would be the result of a midsagittal section of the head?

a)Right and left halves

b)Anterior and posterior halves.

c)Superior and inferior halves.

d)Ventral and dorsal

Correct Answer: •right and left halves •*1) A midsaggital section runs along the midline of the body, dividing it into right and left. •2) A frontal section divides the body into anterior and posterior halves. 3) A transverse section creates superior and inferior halves. •4) Ventral and dorsal are alternative terms for anterior and posterior, the results of a frontal section.

CHEMISTRY COMES ALIVEPART 1

BiochemistryBiochemistry• Organic compounds

• Contain carbon, are covalently bonded, and are often large

• Inorganic compounds• Do not contain carbon• Water, salts, and many acids and bases

Properties of WaterProperties of Water• High heat capacity – absorbs and releases large amounts of

heat before changing temperature• High heat of vaporization – changing from a liquid to a gas

requires large amounts of heat• Polar solvent properties – dissolves ionic substances, forms

hydration layers around large charged molecules, and serves as the body’s major transport medium

Properties of WaterProperties of Water• Reactivity – is an important part of hydrolysis and dehydration

synthesis reactions• Cushioning – resilient cushion around certain body organs

SaltsSalts• Inorganic compounds• Contain cations other than H+ and anions other than OH–

• Are electrolytes; they conduct electrical currents

Acids and BasesAcids and Bases• Acids release H+ and are therefore proton donors

HCl → H+ + Cl –

• Bases release OH– and are proton acceptorsNaOH → Na+ + OH–

Acid-Base Concentration (pH)Acid-Base Concentration (pH)• Acidic solutions have higher H+ concentration and therefore a

lower pH• Alkaline solutions have lower H+ concentration and therefore

a higher pH• Neutral solutions have equal H+ and OH– concentrations

Acid-Base Concentration (pH)Acid-Base Concentration (pH)• Acidic: pH 0–6.99 • Basic: pH 7.01–14• Neutral: pH 7.00

Organic CompoundsOrganic Compounds• Molecules unique to living systems contain carbon and hence

are organic compounds• They include:

• Carbohydrates• Lipids• Proteins• Nucleic Acids

CarbohydratesCarbohydrates• Contain carbon, hydrogen, and oxygen• Their major function is to supply a source of cellular food• Examples:

• Monosaccharides or simple sugars

CarbohydratesCarbohydrates• Disaccharides or double sugars

LipidsLipids• Contain C, H, and O, but the proportion of oxygen in lipids is

less than in carbohydrates• Examples:

• Neutral fats or triglycerides• Phospholipids• Steroids• Eicosanoids

Neutral Fats (Triglycerides)Neutral Fats (Triglycerides)• Composed of three fatty acids bonded to a glycerol molecule

Other LipidsOther Lipids• Steroids – flat molecules with four interlocking hydrocarbon

rings• Eicosanoids – 20-carbon fatty acids found in cell membranes

Representative Lipids Found in the BodyRepresentative Lipids Found in the Body

• Neutral fats – found in subcutaneous tissue and around organs• Phospholipids – chief component of cell membranes• Steroids – cholesterol, bile salts, vitamin D, sex hormones,

and adrenal cortical hormones

Representative Lipids Found in the BodyRepresentative Lipids Found in the Body

• Fat-soluble vitamins – vitamins A, E, and K• Eicosanoids – prostaglandins, leukotrienes, and thromboxanes• Lipoproteins – transport fatty acids and cholesterol in the

bloodstream

Amino AcidsAmino Acids• Building blocks of protein, containing an amino group and a

carboxyl group• Amino group NH2

• Carboxyl groups COOH

Amino AcidsAmino Acids

ProteinProtein• Macromolecules composed of combinations of 20 types of

amino acids bound together with peptide bonds

Figure 2.17

Amino acid Amino acid

+N

H

H

C

R

H

O

N

H

H

C

R

CC

H

O

OH OH

ProteinProtein• Macromolecules composed of combinations of 20 types of

amino acids bound together with peptide bonds

Figure 2.17

Amino acid Amino acid

Dehydrationsynthesis

+N

H

H

C

R

H

O

N

H

H

C

R

CC

H

O H2O

OH OH

ProteinProtein• Macromolecules composed of combinations of 20 types of

amino acids bound together with peptide bonds

Figure 2.17

Amino acid Amino acid

Dehydrationsynthesis

Dipeptide

Peptide bond

+N

H

H

C

R

H

O

N

H

H

C

R

CC

H

O H2O

N

H

H

C

R

C

H

O

N

H

C

R

C

H

O

OH OH OH

ProteinProtein• Macromolecules composed of combinations of 20 types of

amino acids bound together with peptide bonds

Figure 2.17

Amino acid Amino acid

Dehydrationsynthesis

HydrolysisDipeptide

Peptide bond

+N

H

H

C

R

H

O

N

H

H

C

R

CC

H

O H2O

H2O

N

H

H

C

R

C

H

O

N

H

C

R

C

H

O

OH OH OH

Structural Levels of ProteinsStructural Levels of Proteins• Primary – amino acid sequence• Secondary – alpha helices or beta pleated sheets

Structural Levels of ProteinsStructural Levels of Proteins• Tertiary – superimposed folding of secondary structures• Quaternary – polypeptide chains linked together in a specific

manner

Structural Levels of ProteinsStructural Levels of Proteins

Structural Levels of ProteinsStructural Levels of Proteins

Fibrous and Globular ProteinsFibrous and Globular Proteins• Fibrous proteins• Extended and strand-like proteins • Examples: keratin, elastin, collagen, and certain contractile fibers

Fibrous and Globular ProteinsFibrous and Globular Proteins• Globular proteins • Compact, spherical proteins with tertiary and quaternary

structures• Examples: antibodies, hormones, and enzymes

Protein DenuaturationProtein Denuaturation• Reversible unfolding of proteins due to drops in pH and/or

increased temperature

Protein DenuaturationProtein Denuaturation• Irreversibly denatured proteins cannot refold and are formed

by extreme pH or temperature changes

Molecular Chaperones Molecular Chaperones (Chaperonins)(Chaperonins)• Help other proteins to achieve their functional three-

dimensional shape• Maintain folding integrity• Assist in translocation of proteins across membranes• Promote the breakdown of damaged or denatured proteins

Characteristics of EnzymesCharacteristics of Enzymes

• Most are globular proteins that act as biological catalysts• Holoenzymes consist of an apoenzyme (protein) and a

cofactor (usually an ion)• Enzymes are chemically specific

Characteristics of EnzymesCharacteristics of Enzymes

• Frequently named for the type of reaction they catalyze• Enzyme names usually end in -ase• Lower activation energy

Mechanism of Enzyme ActionMechanism of Enzyme Action• Enzyme binds with substrate• Product is formed at a lower activation energy• Product is released

Nucleic AcidsNucleic Acids• Composed of carbon, oxygen, hydrogen, nitrogen, and

phosphorus• Their structural unit, the nucleotide, is composed of N-

containing base, a pentose sugar, and a phosphate group

Nucleic AcidsNucleic Acids• Five nitrogen bases contribute to nucleotide structure –

adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U)

• Two major classes – DNA and RNA• AT• GC• AU

Deoxyribonucleic Acid (DNA)Deoxyribonucleic Acid (DNA)• Double-stranded helical molecule found in the nucleus of the

cell• Replicates itself before the cell divides, ensuring genetic

continuity• Provides instructions for protein synthesis

Structure of DNAStructure of DNA

Structure of DNAStructure of DNA

Ribonucleic Acid (RNA)Ribonucleic Acid (RNA)• Single-stranded molecule found in both the nucleus and the

cytoplasm of a cell• Uses the nitrogenous base uracil instead of thymine• Three varieties of RNA: messenger RNA, transfer RNA, and

ribosomal RNA

Adenosine Triphosphate (ATP)Adenosine Triphosphate (ATP)• Source of immediately usable energy for the cell• Adenine-containing RNA nucleotide with three phosphate

groups

Adenosine Triphosphate (ATP)Adenosine Triphosphate (ATP)

DNA• Deoxyribonucleic acid (DNA) is a molecule that encodes the

genetic instructions used in the development and functioning of all known living organisms and many viruses.

• Within cells, DNA is organized into long structures called chromosomes. During cell division these chromosomes are duplicated in the process of DNA replication, providing each cell its own complete set of chromosomes. • Eukaryotic organisms (animals, plants, fungi, and protists) store

most of their DNA inside the cell nucleus and some of their DNA in organelles, such as mitochondria or chloroplasts

• Prokaryotes (bacteria and archaea) store their DNA only in the cytoplasm.

DNA Cont.• Purines and pyrimidines make up the two groups of

nitrogenous bases, including the two groups of nucleotide bases. Two of the four deoxyribonucleotides and two of the four ribonucleotides, the respective building-blocks of DNA and RNA, are purines.

• Two of the five bases in nucleic acids, adenine and guanine are purines. In DNA, these bases form hydrogen bonds with their complementary pyrimidines thymine and cytosine, respectively. This is called complementary base pairing. In RNA, the complement of adenine is uracil instead of thymine.

• Adenine goes with?• Cytosine goes with• Uracil goes with?

CHEMISTRY COMES ALIVEPART 2

MatterMatter• The “stuff” of the universe• Anything that has mass and takes up space• States of matter• Solid – has definite shape and volume• Liquid – has definite volume, changeable shape• Gas – has changeable shape and volume

EnergyEnergy• The capacity to do work (put matter into motion)• Types of energy• Kinetic – energy in action• Potential – energy of position; stored (inactive) energy

Forms of EnergyForms of Energy• Chemical – stored in the bonds of chemical substances • Electrical – results from the movement of charged particles• Mechanical – directly involved in moving matter• Radiant or electromagnetic – energy traveling in waves (i.e.,

visible light, ultraviolet light, and X-rays)

Energy Form ConversionsEnergy Form Conversions• Energy is easily converted from one form to another• During conversion, some energy is “lost” as heat

Composition of MatterComposition of Matter• Elements – unique substances that cannot be broken down by

ordinary chemical means• Atoms – more-or-less identical building blocks for each

element• Atomic symbol – one- or two-letter chemical shorthand for

each element

Properties of ElementsProperties of Elements• Each element has unique physical and chemical properties• Physical properties – those detected with our senses• Chemical properties – pertain to the way atoms interact with

one another

Major Elements of the Human BodyMajor Elements of the Human Body

• Oxygen (O)• Carbon (C)• Hydrogen (H)• Nitrogen (N)

Lesser and Trace Elements of the Lesser and Trace Elements of the Human BodyHuman Body• Lesser elements make up 3.9% of the body and include:• Calcium (Ca), phosphorus (P), potassium (K), sulfur (S), sodium

(Na), chlorine (Cl), magnesium (Mg), iodine (I), and iron (Fe)

• Trace elements make up less than 0.01% of the body• They are required in minute amounts, and are found as part of

enzymes

Atomic StructureAtomic Structure• The nucleus consists of neutrons and protons• Neutrons – have no charge and a mass of one atomic mass unit

(amu)• Protons – have a positive charge and a mass of

1 amu

• Electrons are found orbiting the nucleus• Electrons – have a negative charge and 1/2000 the mass of a

proton (0 amu)

Models of the AtomModels of the Atom• Planetary Model – electrons move around the nucleus in fixed,

circular orbits• Orbital Model – regions around the nucleus in which

electrons are most likely to be found

Identification of ElementsIdentification of Elements• Atomic number – equal to the number of protons• Mass number – equal to the mass of the protons and neutrons• Atomic weight – average of the mass numbers of all isotopes

Identification of ElementsIdentification of Elements• Isotope – atoms with same number of protons but a different

number of neutrons• Radioisotopes – atoms that undergo spontaneous decay called

radioactivity

Identification of Elements: Atomic Identification of Elements: Atomic StructureStructure

Identification of Elements: Isotopes of Identification of Elements: Isotopes of HydrogenHydrogen

Molecules and CompoundsMolecules and Compounds• Molecule – two or more atoms held together by chemical

bonds• Compound – two or more different kinds of atoms chemically

bonded together

Mixtures and SolutionsMixtures and Solutions• Mixtures – two or more components physically intermixed

(not chemically bonded)• Solutions – homogeneous mixtures of components• Solvent – substance present in greatest amount• Solute – substance(s) present in smaller amounts

Concentration of SolutionsConcentration of Solutions• Percent, or parts per 100 parts• Molarity, or moles per liter (M)• A mole of an element or compound is equal to its atomic or

molecular weight (sum of atomic weights) in grams

Colloids and SuspensionsColloids and Suspensions• Colloids (emulsions) – heterogeneous mixtures whose solutes

do not settle out• Suspensions – heterogeneous mixtures with visible solutes

that tend to settle out

Mixtures Compared with Mixtures Compared with CompoundsCompounds• No chemical bonding takes place in mixtures• Most mixtures can be separated by physical means• Mixtures can be heterogeneous or homogeneous• Compounds cannot be separated by physical means• All compounds are homogeneous

Chemical BondsChemical Bonds• Electron shells, or energy levels, surround the nucleus of an

atom• Bonds are formed using the electrons in the outermost

energy level• Valence shell – outermost energy level containing chemically

active electrons• Octet rule – except for the first shell which is full with two

electrons, atoms interact in a manner to have eight electrons in their valence shell

Chemically Inert ElementsChemically Inert Elements• Inert elements have their outermost energy level fully

occupied by electrons

Chemically Reactive ElementsChemically Reactive Elements• Reactive elements

do not have their outermost energy level fully occupied by electrons

Types of Chemical BondsTypes of Chemical Bonds• Ionic • Covalent • Hydrogen

Ionic BondsIonic Bonds• Ions are charged atoms resulting from the gain or loss of

electrons• Anions have gained one or more electrons• Cations have lost one or more electrons

Formation of an Ionic BondFormation of an Ionic Bond• Ionic bonds form between atoms by the transfer of one or

more electrons • Ionic compounds form crystals instead of individual molecules • Example: NaCl (sodium chloride)

Formation of an Ionic BondFormation of an Ionic Bond

Formation of an Ionic BondFormation of an Ionic Bond

Covalent BondsCovalent Bonds• Covalent bonds are formed by the sharing of two or more

electrons • Electron sharing produces molecules

Single Covalent BondsSingle Covalent Bonds

Double Covalent BondsDouble Covalent Bonds

Triple Covalent BondsTriple Covalent Bonds

Polar and Nonpolar MoleculesPolar and Nonpolar Molecules• Electrons shared equally between atoms produce nonpolar

molecules• Unequal sharing of electrons produces polar molecules• Atoms with six or seven valence shell electrons are

electronegative• Atoms with one or two valence shell electrons are

electropositive

Hydrogen BondsHydrogen Bonds• Too weak to bind atoms together• Common in dipoles such as water• Responsible for surface tension in water• Important as intramolecular bonds, giving the molecule a

three-dimensional shape

Hydrogen BondsHydrogen Bonds

Chemical ReactionsChemical Reactions• Occur when chemical bonds are formed, rearranged, or

broken• Written in symbolic form using chemical equations• Chemical equations contain:• Number and type of reacting substances, and products produced• Relative amounts of reactants and products

Examples of Chemical Examples of Chemical ReactionsReactions

Patterns of Chemical ReactionsPatterns of Chemical Reactions• Combination reactions: Synthesis reactions which always

involve bond formation

A + B → AB

Patterns of Chemical ReactionsPatterns of Chemical Reactions• Decomposition reactions: Molecules are broken down into

smaller molecules AB → A + B

Patterns of Chemical ReactionsPatterns of Chemical Reactions• Exchange reactions: Bonds are both made and broken

AB + C → AC + B

Oxidation-Reduction (Redox) Oxidation-Reduction (Redox) ReactionsReactions• Reactants losing electrons are electron donors and are

oxidized• Reactants taking up electrons are electron acceptors and

become reduced

Energy Flow in Chemical Energy Flow in Chemical ReactionsReactions• Exergonic reactions – reactions that release energy• Endergonic reactions – reactions whose products contain

more potential energy than did its reactants

Reversibility in Chemical Reversibility in Chemical ReactionsReactions• All chemical reactions are theoretically reversible

A + B → AB

AB → A + B

• If neither a forward nor reverse reaction is dominant, chemical equilibrium is reached

Factors Influencing Rate of Chemical Factors Influencing Rate of Chemical ReactionsReactions• Temperature – chemical reactions proceed quicker at higher

temperatures• Particle size – the smaller the particle the faster the chemical

reaction• Concentration – higher reacting particle concentrations

produce faster reactions

Factors Influencing Rate of Factors Influencing Rate of Chemical ReactionsChemical Reactions• Catalysts – increase the rate of a reaction without being

chemically changed• Enzymes – biological catalysts