Chapter 3 The Cells: The Raw Materials and Building Blocks

Anatomy, Physiology, & Disease

Anatomy, Physiology, & Disease

An Interactive Journey for Health Professionals

Copyright ©2009 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Anatomy, Physiology, and Disease: An Interactive Journey for Health ProfessionalsBruce J. Colbert, Jeff E. Ankney, and Karen T. Lee

Chapter 3The Cells: The Raw Materials

and Building Blocks




Multimedia DirectoryMultimedia Directory

Slide 12Cell Structure VideoSlide 93Cytology VideoSlide 105Handwashing and Gloving Techniques VideoSlide 125Lab Technician Video




IntroductionIntroduction

•Cells are basic building blocks of human body•Cells come in different sizes, shapes, and types•Blood cells, skin cells, and nerve cells all differ from

one another, but form basis of the system•There are many components that perform specific

functions to keep cells alive•Cells of similar type form tissues that function to

work together in an organ, while organs perform special functions to create a system

•Systems work together to form functioning human body




Learning ObjectivesLearning Objectives

• List and describe the various parts of a cell and explain their function and pathology

•Explain the process of cellular mitosis•Describe cancer growth and staging•Describe the types of active and passive transport

within cells •Explain cellular respiration and enzyme function and

dysfunction •Differentiate between bacteria, viruses, fungi, and

protozoa and understand how these pathogens cause disease




Pronunciation GuidePronunciation Guide

BenignCapsidCentriolesCentrosomesChromatinCiliaCytoplasmDeoxyribonucleic acidDiabetes Mellitus Endocytosis

(bee NINE)(CAP sid)(SEN tree oles)(SEN tre soams)(CROW ma tin)(SILL ee ah)(SIGH tow plazm)(dee OK see RYE bow new clee ick a sid)(DIE ah bee teez Mel LITE us) (en Doe Sigh TOE sis)

Click on the megaphone icon before each item to hear the pronunciation.




Pronunciation Guide Pronunciation Guide (cont’d)(cont’d)

Endoplasmic reticulumExocytosisFlagellaFungiGolgi apparatusHypercholesterolemia LysosomesMalignantMetastasisMitochondriaMycelia

(EN doh PLAZ mic ri TIH cue lum)(EX oh sigh TOE sis)(flah GELL ah)(FUN jie)(GOAL jee app ah RA tuss)(HI per koh LESS tur ul ee me ah) (LIE she soams)(mah LIG nant)(meh TASS tah siss)(my the CAHN dree ah)(my SEE lee ah)





Pronunciation Guide Pronunciation Guide (cont’d)(cont’d)

OrganellesOrganismOsmosisPhagocytosisPhenylketonuria PinocytosisProtozoaRibonucleic acidRibosomesVesicle

(ore ga NELLS)(OR gan iz em)(ahz MOE sis)(FAG oh sigh TOH sis)(FIN ill KEE toe new ree ah) (pin oh se TOH sis)(pro tow ZOE ah)(rie bow new KLEE ic)(RIE beh Soams)(VESS ih kle)





Overview of CellsOverview of Cells

•Cells are formed from chemicals and structures

•Cells are found in all living things•Some nerve cells can be 2 feet long or

longer•Cells can be flat, round, thread like, or

irregularly shaped•7.5 trillion cells found in body work together

to allow for proper functioning of body




Figure 3-1 Various types of cells within the human body.




Cell StructureCell Structure

•Certain common traits that almost all cells share:–Nucleus–Organelles–Cytoplasm–Cell membrane




Figure 3-2 Cellular components.




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Cell MembraneCell Membrane

•Defined boundary that possesses a definite shape and actually holds cell contents together, acting as protective covering

•Allows material in and out of cell•Selectively permeable because they

choose what gets in or out




Cell Membrane Cell Membrane (cont’d)(cont’d)

•Has identification markers that identify it as coming from a certain person

•3/10,000,000 of an inch thick




Figure 3-3 The cell membrane.




Transport MethodsTransport Methods

•Moving things in and out of cell can be done in two broad ways:– Passive transport: requires no extra form of

energy to complete– Active transport: requires some addition of

energy to make it happen




Transport Methods Transport Methods (cont’d)(cont’d)

•Passive transport can be divided into four types:– Diffusion– Osmosis – Filtration– Facilitated diffusion




DiffusionDiffusion

•Most common form of passive transport in which substance of higher concentration travels to area of lesser concentration

•Examples:– Adding packet of powdered drink mix to pitcher of

water– Smell of classmate’s perfume filling room

•Necessary to move oxygen from lungs to blood stream, or carbon dioxide from blood stream to lungs




Figure 3-4 Two examples of diffusion.




OsmosisOsmosis

•Another form of diffusion in which water travels through selectively permeable membrane to equalize concentrations of a substance

•Dissolved substance called a solute




Osmosis Osmosis (cont’d)(cont’d)

•Water tends to travel across a membrane to equalize concentrations of a solute; ability of substance to pull water toward area of higher concentration called osmotic pressure

•The greater concentration of solute, the greater osmotic pressure, or pull, it exerts to bring in water




Figure 3-5 Osmosis: Water moves from an area of lower concentrated solute to an area of higher concentrated solute.




FiltrationFiltration

•Differs from osmosis in that pressure is applied to force water and its dissolved materials across membrane

•Similar to crush of people pushing through turnstile during rush hour

•Major supplier for forces in body is pumping of heart, which forces blood flow into kidneys, where filtration takes place




Figure 3-6 The process of filtration in the kidneys, where smaller solutes such as the electrolytes sodium and potassium pass through the membrane, while the larger blood protein and cells normally do not.




Facilitated DiffusionFacilitated Diffusion

•Facilitated diffusion is a variation of diffusion in which a substance is helped in moving across the membrane, similar to an usher helping you to your seat

•Glucose is the substance that is often passed into our bodies

• It can be imagined as moving into an already revolving door – once it steps into the door it is pushed along




Figure 3-7 Facilitated diffusion.




Pathology Connection: Cystic FibrosisPathology Connection: Cystic Fibrosis

•Incurable, fatal genetic disease affecting 1/3000 Caucasian babies




Pathology Connection: Cystic Fibrosis Pathology Connection: Cystic Fibrosis (cont’d)(cont’d)

•Caused by malformation in membrane channels for chloride and sodium ions–Sodium and chloride do not diffuse across cell

membrane as they normally would–Fluid around cells becomes extremely salty

due to excess sodium and chloride–Results in excessively thick mucus in

respiratory, digestive, and reproductive systems; mucus can cause clogging in organs





•Symptoms may include–Difficulty breathing–Nutritional deficits due to decreased

absorption of nutrients–Increased risk of respiratory infection–Diabetes–Infertility (especially in males)





•Treatment–No cure; treatments help extend and improve

quality of life –Nutritional supplements–Antibiotics to prevent pneumonia–Mucus thinning drugs–With treatment today, average life span of

patient is 35 years





•Diagnosis –Prenatal genetic testing –Postnatal genetic testing–Testing pulmonary function–Testing amount of sodium in sweat




Pathology Connection: Diabetes MellitusPathology Connection: Diabetes Mellitus

•Common medical problem; main symptom (high blood sugar) caused by problem with facilitated diffusion–Glucose transported into cells via facilitated

diffusion–Hormone insulin must be present in order for

transport of glucose to occur–Insulin is either absent, or cells insensitive to

insulin–Results in glucose not getting to cells like it

should




Pathology Connection: Diabetes Mellitus Pathology Connection: Diabetes Mellitus (cont’d)(cont’d)

•Lack of glucose transport into cells causes several problems –Lots of glucose hangs around in bloodstream,

causing big osmotic problems for cells–Cells can’t make as much energy as they

need when glucose can’t be transported




Active TransportActive Transport

•Can be broken down further to three different types:–Active transport pumps–Endocytosis–Exocytosis




Active Transport PumpsActive Transport Pumps

•Require addition of energy in form of ATP to move substance

•Energy needed because cell is trying to move substance into area that already has high concentration of substance

•Example: need to transport potassium into our cells, where high concentration already exists; it must be “pushed” in




EndocytosisEndocytosis

•Used by cells for intake of liquid and food when substance too large to diffuse across membrane




Endocytosis Endocytosis (cont’d)(cont’d)

•Substance is surrounded by small portion of cell membrane, forming chamber or vesicle which then separates from rest of membrane and moves into cell– Phagocytosis: name for process if solid

particle being transported– Pinocytosis: name for process if water being

transported




ExocytosisExocytosis

•Transport of things out of cell•Some cells produce substance needed outside cell–Once substance is made, it is surrounded by

membrane, forming a vesicle, and moves to cell membrane

–Vesicle becomes part of cell membrane and expels its load out of cell




Figure 3-8 Types of active transport in and out of cells.




Table 3-1 Methods of Cellular Transportation




Pathology Connection: Familial Pathology Connection: Familial Hypercholesterolemia Hypercholesterolemia

•Condition in which blood cholesterol too high; caused by poor diet and exercise or inherited

•Normally low density lipoprotein (LDL or “bad cholesterol”) binds to cholesterol, and allows it to be carried into cells via endocytosis; once inside, cholesterol used to make other lipids




Pathology Connection: Familial Pathology Connection: Familial Hypercholesterolemia Hypercholesterolemia

•In familial hypercholesterolemia, LDL doesn’t move into cells, and stays in blood; causes two problems–Too little cholesterol gets into cells, and cells

must make more cholesterol–LDL that cannot get into cells hangs around in

blood; causes plaques in blood vessels which can lead to blood clots, strokes, and heart attacks




Pathology Connection: Familial Pathology Connection: Familial Hypercholesterolemia Hypercholesterolemia (cont’d)(cont’d)

•Severe form– Patients often have heart attacks or strokes

as children– Often fatal in children or teenagers– Has no effective treatment




Pathology Connection: Familial Pathology Connection: Familial Hypercholesterolemia Hypercholesterolemia (cont’d)(cont’d)

•Moderate form– Leads to heart attacks and strokes, but

usually not until mid-life– Can be treated with diet modifications and

cholesterol lowering drugs– 1/500 Americans have moderate form




CytoplasmCytoplasm

•Gel-like substance composed of water, nutrients, and electrolytes, which looks a lot like white of raw egg

•Required by cells for their internal environment in order for parts of cell, known as organelles, to thrive and function




NucleusNucleus

•“Brains” of cell•Dictates activities of other organelles in

cell•Has double walled nuclear membrane with

large pores allowing certain materials to pass in and out, while preventing other materials from entering




Nucleus Nucleus (cont’d)(cont’d)

•Chromatin–Material found in nucleus that contains

deoxyribonucleic acid (DNA); DNA contains blueprints, or specifications, for creation of new cells

–Will eventually form chromosomes, which contain genes

–Genes determine our inherited characteristics




Nucleus Nucleus (cont’d)(cont’d)

•Nucleolus–Spherical body made up of dense fibers found

within cell nucleus–Major function is to synthesize ribonucleic acid

(RNA) that forms ribosomes




Figure 3-9 The cell membrane, cytoplasm, nucleus, and nucleolus.




RibosomesRibosomes

•Organelles found on endoplasmic reticulum or found floating around in cytoplasm

•Made of ribonucleic acid (RNA) and assist in production of enzymes and other protein substances needed for cell repair and reproduction

•Can be considered “remodeler” of cell, taking existing structure and maintaining and repairing it




CentrosomesCentrosomes

•Act as building contractor, building new structures as need arises

•Contain centrioles that are involved in division of cell

•Centrioles are tubular shaped and usually found in pairs




Figure 3-10 The cell membrane, cytoplasm, nucleus, nucleolus, ribosomes, centrosomes, and mitochondria.




MitochondriaMitochondria

•Tiny bean-shaped organelles, act as power plant to provide up to 95% of bodies’ energy needs for cellular repair, movement, and reproduction

•If cell needs more power, it increases number of mitochondria in cell

•Liver cells, which are quite active, have up to 2,000 mitochondria in each cell




MitochondriaMitochondria

•Contain special enzymes that help to take in oxygen for use in producing energy

•Energy produced is in form of ATP (adenosine triphosphate) created by mitochondria




Endoplasmic ReticulumEndoplasmic Reticulum

•Series of channels set up in cytoplasm that are formed from folded membranes

•Has two distinct forms:–One has sandpaper-like surface, with

ribosomes on it, called rough endoplasmic reticulum; responsible for synthesis of protein

–Second form has no ribosomes and appears smooth, called smooth endoplasmic reticulum; synthesizes lipids and steroids




Figure 3-11 The cell membrane, cytoplasm, nucleus, nucleolus, ribosomes, centrosomes, mitochondria, endoplasmic reticulum, Golgi apparatus, and lysosomes.




Golgi ApparatusGolgi Apparatus

•Looks like a bunch of flattened membranous sacs

•Once protein from the endoplasmic reticulum is received, it further processes and stores it

•Takes processed protein to cell membrane where it is released




Golgi Apparatus Golgi Apparatus (cont’d)(cont’d)

•Salivary glands and pancreatic glands have higher numbers of Golgi apparati because they have higher level of secretion or storage




LysosomesLysosomes

•Organelles containing powerful enzymes that take care of cleaning up intercellular debris and other waste

•Lysosomes help keep us healthy; they destroy unwanted bacteria by participating in process of phagocytosis




Other Interesting PartsOther Interesting Parts

•Vesicles: can be thought of as little vans; they can be loaded up with substances and travel to other sites within cell

•Cytoskeleton: network of microtubules and interconnected filaments that provide shape to cell and allow cell and its contents to be mobile




Other Interesting PartsOther Interesting Parts

•Flagella: whip-shaped tails that move some cells, like sperm, to other locations

•Cilia: short, microscopic, hair-like projections located on outer surface of some cells; move particles using wavelike motion




Pathology Connection: Organelle Pathology Connection: Organelle DisordersDisorders

•Lysosomal storage disorder –Occur when lysosomes missing one of their

enzymes–Results in some molecules not breaking down

and accumulating in cells–Many kinds of lysosomal storage disorders

All are genetic Most lack effective therapies




Pathology Connection: Organelle Pathology Connection: Organelle Disorders Disorders (cont’d)(cont’d)

•Tay Sachs–Enzyme missing in lysosomes of nervous

system cells –As result, glycoproteins accumulate in cells in

nervous system–Build up causes inflammation and eventual

cellular destruction–Symptoms include mental regression,

dementia and paralysis appearing within first year of patient’s life





•Tay Sachs–Diagnosis: appearance of cherry red spot on

back of patient’s eyes; abnormalities in startle reflex

–No treatment; disease generally fatal within two or three years of onset

–Availability of genetic test has decreased incidence in recent years





•Cigarettes and paralyzed cilia–Smoking causes cilia in respiratory tract to

become paralyzed–As a result, cannot keep lungs clean–Over time, can lead to chronic obstructive

pulmonary disease (COPD) and other smoking-related lung problems

–Passive smoking (second hand smoke exposure) also increases risk of lung problems




Cellular ProcessesCellular Processes

•Cell energy and ATP: energy molecule–Digestion breaks food down, releasing energy– In order for cells to use energy, nutrients must be

converted to ATP, an energy transfer molecule ATP made up of base, sugar, and three phosphate

groups Phosphate groups held together by high-energy bonds Energy released each time bond is broken, turning

ATP to ADP (two phosphate groups) ADP can then pick up another bond, storing more

energy, so process can begin again




Cellular Processes Cellular Processes (cont’d)(cont’d)

•Cells produce ATP through process called cellular respiration–In cellular respiration, glucose (from food) is

combined with oxygen–Chemical reaction results in production of ATP

in mitochondria




Cellular Processes Cellular Processes (cont’d)(cont’d)

•Cells produce ATP through process called cellular respiration–Also produces two waste products: water and

carbon dioxide–Breathing (exchange of oxygen and carbon

dioxide) provides necessary materials for cellular respiration

Oxygen breathed in to be combined with glucose (from food) to produce ATP

Carbon dioxide breathed out to rid body of chemical waste product generated by ATP production




Chemical Energy EquationChemical Energy Equation




Pathology Connection:Pathology Connection:Diabetes Mellitus Diabetes Mellitus

•Relationship to membrane transport previously discussed; also relates to cellular respiration

•Glucose from food that doesn’t get into cells effectively; results in cells looking for other substances to be used to make ATP–Body begins to break down tissues like

muscle in order to get energy from alternate sources such as fats and proteins; causes abnormal body chemistry





•Excess glucose in blood causes problems –Abnormal concentration gradient develops

between inside and outside of cells–Body tries to rid extra glucose by filtering extra

blood through kidneys–Kidneys produce excessive amounts of urine,

leads to water loss and possible dehydration





•Lack of cellular glucose uptake and body’s attempts to compensate for high blood sugar lead to classic symptoms– Weight loss: cells cannot effectively use glucose

from food patient eats– Excessive urination: body increases blood flow

to kidneys in attempt to normalize excessively high blood sugar

– Excessive thirst: patient dehydrates from excessive urination





•May cause development of long-term problems, such as heart disease and kidney failure





•Two types– Type 1 diabetes (formerly IDDM – insulin

dependent diabetes mellitus); auto-immune disorder Immune system attacks and destroys cells in

pancreas that make insulin resulting in cessation of insulin production





•Two types– Type 2 diabetes (formerly NIDDM – non-

insulin dependent diabetes mellitus) Develops when cells stop responding (insulin

resistance); insulin still produced by pancreas, but tissues don’t respond

Usually related to obesity; associated with high cholesterol, high lipids and high blood pressure





•Treatment depends on type of diabetes–Type-1 diabetes: not curable

Can be treated with daily insulin injections Patients must adhere to strict diet

–Type-2 diabetes: can sometimes be reversible First step of treatment includes adoption of healthy

diet & exercise habits and weight loss Medications affecting pancreas or tissues can

improve blood sugars Some patients eventually require supplemental

insulin




EnzymesEnzymes

•Facilitate important chemical reactions in body –One way is by speeding up reactions –Not used up by reactions that they facilitate;

instead, act like carrier molecules–Very specific; each only facilitates (catalyzes)

certain reactions




Pathology Connection: Phenylketonuria Pathology Connection: Phenylketonuria (PKU)(PKU)

•Genetic condition; enzyme disorder•Most common in Caucasians of Irish,

Scottish, or Scandinavian descent •Patients missing enzyme: phenylalanine

hydroxylase–Without enzyme, amino acid phenylalanine

builds up in cells–Build up affects nervous system; causes

progressive mental retardation if not treated




Pathology Connection: Phenylketonuria Pathology Connection: Phenylketonuria (PKU) (PKU) (cont’d)(cont’d)

•Other signs include–Light pigmentation of skin, hair and eyes–Abnormalities of posture and gait–Epilepsy





•Treatment: low phenylalanine diet includes avoidance of high protein foods and products sweetened with aspartame (NutraSweet™)– Consequences of going “off diet”

Children: cognitive defects Adults: depression, anxiety, or other neurological

changes





•Diagnosis– Blood tests & genetic tests– Every newborn in US routinely screened




MitosisMitosis

•Cellular reproduction: process of making new cell; also called cell division

•Asexual reproduction: cells make identical copies of themselves without involvement of another cell–Most cells (including animal cells, plant cells &

bacteria) able to reproduce asexually




Mitosis Mitosis (cont’d)(cont’d)

•Mechanism by which asexual reproduction occurs depends on type of cell; two main types–Prokaryotes: do not have nucleus or

organelles; example: bacteria–Eukaryotes: have nucleus and organelles;

example: human cells





•Prokaryotic cell division is simpler; cell need only: copy its DNA, divide up cytoplasm, and split in half; process called binary fission

•Process of sorting chromosomes is called mitosis; only way eukaryotic cells can reproduce asexually





•Eukaryotic cell division is more complicated, since structure of cell is more complicated–DNA (stored in chromosomes in this kind of

cell) must be copied; all 46 chromosomes must be copied

–Chromosomes must be sorted, so that each new cell gets complete set of chromosomes

–Organelles must be sorted, so that each new cell gets right organelles




The Cell CycleThe Cell Cycle

•Two major phases of cell’s life known as cell cycle

•Most of the time cell is in interphase where it is NOT dividing and is performing normal function

•When cell needs to reproduce, enters mitotic phase

•Mitotic phase divided into two major portions: mitosis and cytokinesis




The Cell Cycle The Cell Cycle (cont’d)(cont’d)

•Mitosis: sorting and division of genetic material; has 4 phases (prophase, metaphase, anaphase, and telophase)

•Cytokinesis: division of cytoplasm




The Cell Cycle The Cell Cycle (cont’d)(cont’d)

•Several places in cell cycle are checkpoints where cells must wait for signal to tell them to keep dividing – If something is wrong with cell or there is

some reason cell should not reproduce, cell will not get signal and will stop dividing

– If timing is good, cell will get go ahead signal and divide without interruption




Figure 3-12 Flow chart of the cell cycle.




Phases of MitosisPhases of Mitosis

•Prophase (pro = before): nucleus disappears, chromosomes become visible, set of chromosomal anchor lines or guide wires, spindle, forms

•Metaphase (meta = between): chromosomes line up in center of cells

•Anaphase (an = without): chromosomes split and spindles pull them apart

•Telophase (telo = the end): chromosomes go to far ends of cell, spindle disappears, and nuclei reappear




CytokinesisCytokinesis

•During or directly after telophase, cytokinesis happens and cell divides in half

•Original cell was mother cell that has now formed into two new identical daughter cells

•Thus mitosis (asexual reproduction), results in two new daughter cells identical to original mother cell




Figure 3-13 Phases of mitosis.




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Cellular Reproduction in the BodyCellular Reproduction in the Body

•Purpose of mitosis–Growth; example: bone–Tissue replacement; example: red blood cells




Cellular Reproduction in the BodyCellular Reproduction in the Body

•Meiosis: sexual reproduction in which two different cells unite to form new cell–Used to make sperm and egg cells for sexual

reproduction–Each parent cell produces four new cells that

are not identical to parent cell and has only half normal number of chromosomes; other half of chromosomes contributed when sperm fuses with egg in sexual reproduction




Pathology Connection: CancerPathology Connection: Cancer

•When body is healthy, cells grow in orderly fashion; control system prevents cells from reproducing too fast

•Sometimes conditions are altered that trigger changes in way cells reproduce; this wild, uncontrolled reproduction can lead to too many cells being produced, creating a lump, or tumor

•Tumors can generally be either benign or malignant




Pathology Connection: Cancer Pathology Connection: Cancer (cont’d)(cont’d)

•Benign tumors – Slow growth – Tend to push healthy cells out of the way– Generally non–life threatening





•Malignant tumors – Rapid growth– Tend to invade healthy tissues– Can enter blood or lymphatic system and start

new tumors in other parts of body; this kind of spread called metastasis





•Prognosis often determined by stage at diagnosis; two basic strategies for staging cancers–Staging based on amount of metastasis

Stage I: no cancer spread Stage II: spread to nearby tissues Stage III: spread to the lymphatic system Stage IV: spread to distant organs

–TNM classification of stages Tumor characteristic or extent (T) Number of lymph nodes invaded (N) Any tumor metastasis (M)





•Diagnosis of cancer–Imaging techniques (MRI, CAT, X-ray, etc.)–Blood tests–Biopsy (surgical examination of abnormal

tissue)





•Treatment of cancer; four main types; typically more than one type used to attack cancer–Chemotherapy: uses chemicals to kill rapidly

dividing cells–Radiation therapy: uses energy to target

cancer cells–Surgery: removes cancer cells from body–Biological or immunotherapy: trains body’s

natural defenses to fight cancer cells




MicroorganismsMicroorganisms

•Four primary microorganisms to be discussed, including:–Bacteria–Viruses–Fungi–Protozoa




BacteriaBacteria

•Bacteria can be harmful, as in case of pathogens, or can be harmless and essential for life

•Harmless bacteria sometimes called normal flora–Certain bacteria in intestines help to digest food–Some help to synthesize vitamin K, needed for

blood clotting




Figure 3-14 Types of bacteria.




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VirusesViruses

•Infectious particles that have core containing genetic material surrounded by protective protein coat called a capsid

•Cannot grow, eat, or reproduce by themselves; must enter another cell and use that cell for energy to grow and reproduce

•Do not respond to antibiotics; can stay dormant in body and become active later in life




Figure 3-15 A virus.




FungiFungi

•Plural form of fungus; can be one-celled or multi-celled organism; plant-like organisms with tiny filaments, called mycelia, that travel out from cell to find and then absorb nutrients

•Good fungi, like edible mushrooms, are harmless; others can cause disease

•Fungi spread through release of spores•Examples of fungal infections include

athlete’s foot, thrush, or candidiasis




Figure 3-16 Types of fungi and a fungal infection of the tongue. (Photo Source: Courtesy of Jason L. Smith, MD.)




ProtozoaProtozoa

•One-celled, animal-like organisms that can be found in water and soil

•Diseases caused by these microorganisms can result from swallowing them or from being bitten by insects that carry them in their bodies




Figure 3-17 Protozoa.




Pathology Connection: How Pathology Connection: How Microorganisms Cause Disease Microorganisms Cause Disease

•Bacteria–Destroy body tissues–Destroy blood cells–Inhibit ribosomes–Cause fluid loss–Cause high fever–Cause decreased blood pressure–Increase blood clotting–Cause fluid in the lungs–Cause paralysis




•Signs and symptoms of bacterial infection–High fever–Rapid pulse–Rapid breathing–Abnormal, often foul-smelling discharge from

infected area–Pain at infection site–Swelling at infection site

Pathology Connection: How Pathology Connection: How Microorganisms Cause Disease Microorganisms Cause Disease (cont’d)(cont’d)




•Antibiotics used to treat bacterial infections–Chemicals kill prokaryotic bacteria without

harming eukaryotic cells–Most antibiotics produced naturally by other

microorganisms





Table 3-2 Common Bacterial Pathogens and Associated Diseases




•Viruses cause disease by–Shutting down cell–Causing cell to rupture and release viruses–Making good environment for secondary

bacterial infection–Example: influenza can result in secondary

bacterial pneumonia





•Signs and symptoms of viral infection–Low grade fever (although sometimes can be

high)–Muscle aches–General fatigue–Some have no symptoms





•Some may be latent (hidden without symptoms) for many years, only to activate and cause symptoms later

•Some may become chronic, causing low level symptoms for weeks, months, or even years





•Few treatments for viral infections–Antibiotics do not kill viruses–Treatment for most is rest, fluids, and

treatment of symptoms to keep patient comfortable

–Some antiviral drugs, but because viruses use host cell’s machinery, drugs commonly affect host cell as well, causing side effects





Table 3-3 Viral Pathogens and their Diseases




•Fungal infections–Spores are inhaled–Spores enter body through open wounds

•Spores: tiny bodies resistant to environmental changes (able to stay dormant until conditions are just right)

•Most fungal spores do not cause disease in otherwise healthy individuals; exception is fungal infections of skin (such as athlete’s foot and jock itch)






•Many fungal infections opportunistic (only infect people with compromised immune systems or other underlying disease)

•Symptoms of fungal infection vary depending on location of infection

•Treatment of fungal infections is difficult–Most anti-fungal drugs are highly toxic–Many fungal infections are resistant to

treatment




•Most protozoan infections caused by–Ingestion of contaminated water–Insect bites

•Many protozoans are parasites





•Symptoms vary depending on type of protozoan–Many are serious disease causing long term

debilitating illness; example: malaria, which is transmitted by mosquitoes

–Some are relatively mild illnesses; example: “beaver fever” caused by Giardia, protozoan that lives in streams and water supplies contaminated by fecal matter





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Snapshots from the JourneySnapshots from the Journey

•All living organisms made of one or more cells

•Even though cells are fundamental units, they are composed of variety of parts necessary for proper cellular function; these small parts called organelles




Snapshots from the Journey Snapshots from the Journey (cont’d)(cont’d)

•Substances can cross cell membrane via active or passive transport

•Passive transport can occur through diffusion, facilitative diffusion, osmosis, or filtration





•Active transport can occur through active transport pumps, endocytosis, and exocytosis

•Problems with transport across cell membranes can cause serious disorders such as cystic fibrosis and diabetes





•One form of cellular movement is through use of flagella

•Cilia found in lungs aid in removal of foreign particles in airways through rhythmic movement





•When organelles do not work properly, serious problems result, often in every cell of body

•Cells must have energy molecule, ATP in order to power cell; ATP made in mitochondria by process called cellular respiration; in order to make ATP cells must have glucose and oxygen





•Diabetes mellitus results when glucose cannot get into cells; cells cannot make energy and excess glucose builds up in blood, causing many problems





•Most chemical reactions in body could not happen without help of proteins called enzymes; missing enzymes usually cause major problems

•Cells and tissues grow, are replaced, and are repaired by asexual reproduction; cells make identical copies of themselves; this takes place all over body whenever tissues grow or are repaired





•Some tissues, like epidermis, blood, and bone replace themselves continually, always by asexual reproduction

•The life of a cell is depicted as a cycle; 10% of the cell cycle is to mitosis; the rest is in interphase, preparing to divide and carrying on day-to-day cellular activities





•Asexual reproduction in eukaryotic cells is accomplished by relatively complex processes called mitosis and cytokinesis

•Mitosis (division of genetic material) takes place in four phases: prophase, metaphase, anaphase and telophase; it produces two daughter cells, identical to each other

•Cytokinesis is the division of the cytoplasm and organelles





•Meiosis is sexual reproduction of cells•If an organism is going to reproduce

sexually, it must use specialized cells called gametes with only half typical number of chromosomes for that organism

•Chief difference between mitosis and meiosis is that mitosis is asexual and produces exact number of chromosomes while meiosis is sexual and combines two cells with half of needed chromosomes





•Cancer results when mitosis is not regulated and cells divide out of control, spreading to other tissues

•Not all bacteria are bad; bacteria needed to survive

•A virus is not a one-celled organism; it needs one to replicate





•Fungi can be single-celled or multi-celled organisms and can cause infection; spores can be immune to harsh environment, thus allowing fungi to spread

•Protozoa are one-celled and can cause disease through ingestion or through insect bites





•Many microorganisms cause disease; each has unique characteristics and treatments; antibiotics can be used ONLY to treat illnesses cause by bacteria




Case StudyCase Study

•Given the following mini-scenarios, identify what type microorganism may be the causative agent– Two young boys complain of stomach ache

and severe diarrhea after drinking pond water– Julia is a 13-year-old with a compromised

immune system due to an inherited disease. Two days after returning home from a school field trip to a mushroom factory, Julia complains of shortness of breath and is diagnosed with a respiratory infection




Case Study Case Study (cont'd)(cont'd)

•Given the following mini-scenarios, identify what type microorganism may be the causative agent– Bob has had a stubborn cold for three days

and is given an antibacterial agent. However, he doesn’t respond to the treatment and the cold persists




Case Questions Maria’s StoryCase Questions Maria’s Story

•List and explain two problems the lack of insulin causes for cells

•In what future system chapters will you expect to see Maria discussed?

Documents

Chapter 3 The Cells: The Raw Materials and Building Blocks