9.4 - the search for better health

8/20/2019 9.4 - The Search for Better Health

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HSC - Stage 6 2 Unit Biology

9.4 – The Search for Better Health:

1. What is a healthy organism?

• Discuss the difficulties in defining the terms ‘health’ and ‘disease’:

– ‘Health’ is difficult to define as health has many components, such as physical,

mental, and social, some of which ae !ey su"#ecti!e

– ‘$isease’ is also difficult to define, as it also has many components% Because it is

desci"ing a state of impaied functioning, it depends on an oganism’s nomal

le!el of functioning, and what they e&pect thei 'uality of life to "e%

– $efinitions(

Health: ) state of complete physical, mental and social health, and not meely

the a"sence of disease o infimity%

Disease: ) state of impaied functioning of an oganism, including impaied

physical, social and mental functioning%

• Outline how the function of genes, mitosis, cell differentiation and

specialisation assist in the maintenance of health:

– Genes:

*enes contol the poduction of poteins in the "ody +needed fo pope

functioning and so healthy genes ensue the coect poteins ae made%

hough poduction of poteins +especially en.ymes, genes ensue the coect

cell pocesses occu, maintaining meta"olism and homeostasis%

– Mitosis:

/itosis is the pocess that ena"les genetic mateial to "e copied e&actly,

ensuing the genes ae coect and a"le to maintain health in thei own way

/itosis is also the pocess that oganisms use to gow, and maintain and epai

"ody cells, maintaining health

– ell Differentiation an! S"ecialisation:

hese 2 pocesses esult in cells which ae specialised fo specific functions in

the "ody, such as ed "lood cells, etc%

Copyight 0 2116 )hmad Shah 3dil




ogethe, all the specialised "ody cells wo4 togethe in a coodinated way to

maintain the health and pope functioning of the oganism%

• Use available evidence to analyse the links between gene expression and

maintenance and repair of body tissues:

– ) healthy oganism is the esult of(

he coect functioning of genes

he poduction of pefect copies of genetic mateial "y mitosis

he e&pession of genes in cell specialisation and diffeentiation

– he "ody’s cells ae always "eing eplaced all the time, so the coect specialised

cells must "e poduced to eplace them%

– his is done though mitosis, followed "y gene e&pession%

– Healthy cells ha!e thei cell cycle egulated "y poteins that ae poduced "y

diffeent types of genes

– D#$ re"air genes ensue that the $5) is accuately copied

– 2 genes that egulate the cell cycle ae(

%roto&oncogenes: hese poduce poteins that stimulate di!ision

T'mo'r s'""ressor genes: hese poduce poteins that stop di!ision

– 3n healthy cells, these two ae "alanced – 3n unhealthy cells(

/utated poto-oncogenes ae called oncogenes and cause uncontolled cell

di!ision +cances

/utated tumou suppesso genes lose thei a"ility to contol cell di!ision%

he ate of cell di!ision inceases and uncontolled gowth occus – this also

leads to cances%





(. )*er +,,, years ago the hinese an! He-res ere a!*ocating

cleanliness in foo!/ ater an! "ersonal hygiene:

• Distinguish between infectious and noninfectious disease:

– 3nfectious $isease(

Caused "y an in!asion of the "ody "y )H7*85S%

) "athogen is an infectious agent that causes disease

he disease can "e tansfeed fom one oganism to anothe

athogens can "e micoscopic o macoscopic

8%g% !iuses +influen.a, "acteia +tonsillitis, poto.oans +malaia, pions

+C9$, fungi +tinea%

– 5on-infectious $isease(

3n!ol!es no pathogens

hee is no tansfe of the disease fom one oganism to anothe

8g(

0nherite! +genetic disease( $own’s Syndome, haemophilia

#'tritional disease( scu!y, "ei"ei, 4washio4o

n*ironmental disease( s4in cance, as"estosis

• !xplain why cleanliness in food, water and personal hygiene practices

assist in control of disease:

– "leanliness in #ood:

Contaminated food is a souce of pathogens +such as salmonella, and can

!ey eadily spead diseases

But mico"es in food only "ecome a health is4 when they ae allowed to

multiply and each lage num"es

/oden methods to educe the num"es of mico"es in food include(

Heating( 8%g% coo4ing food to 4ill mico"es, pasteuisation

Cooling( :efigeation of foods slows down the gowth of mico"es

$ying: $ehydating foods, such as fuit o !egeta"les, and smo4ing meat,

4ills mico"es, ma4ing them last longe





)ll these methods ae used to educe the num"e of mico"es and to contol

the spead of disease

– "leanliness in $ater:

;ac4 of clean wate, such as in de!eloping counties with no wate puification o sewage systems, is a lage facto in speading disease%

he ma#o cause of disease ae the pathogens that oiginate fom faeces

<ate will always contain mico"es, "ut educing the num"es though

teatment contols the spead of disease

eatment of wate, in pocesses such chloination, educes the is4 of disease

– %ersonal &ygiene(

esonal hygiene is the pocess of 4eeping ou "odies clean in ode tomaintain health%

Sanitation efes to the maintenance of conditions that pomote health,

including emo!al of wastes

:educing pathogen num"es in moden times in!ol!es(

Steili.ation( his is the complete emo!al of all taces of mico"es% his

is e'uied in situations whee pathogens ae paticulaly dangeous, eg

sugical ooms%

$isinfecting( his in!ol!es educing mico"es to a safe le!el, such as

washing clothes o dishes with disinfectant%

• 'dentify the conditions under which an organism is described as a

pathogen:

– 7ganisms ae called pathogens when they cause disease%

– 3f an pathogen is to cause disease, it must(

Ha!e virulence( that is, "e pesent in sufficient num"es to cause the disease

8nte the host though a cetain pat of the "ody o su!i!e on the "ody

without "eing destoyed "y the "ody’s natual defences

8scape fom one host to anothe

Su!i!e tansmission fom one host to anothe





• Describe ways in which drinking water can be treated and use available

evidence to explain how these methods reduce the risk of infection from

pathogens:

– <ates fom lage undistu"ed catchment aeas need little teatment, as the

pocess of sedimentation ta4es place natually +li4e in a dam

– Howe!e, wate fom i!es that lead fom industial sites, fams, o waste aeas

e'uies e&tensi!e teatment%

– he teatment of wate usually has = stages%

– imay eatment(

Screening out lage de"is using "as and sceens

Degritting – the emo!al of lage git paticles

2locc'lation – mi&ing of the wate with chemicals to fom suspended

paticles that contain many microbes

Se!imentation of suspended microbefull paticles to the "ottom of tan4s

Sl'!ge "rocessing – collection and pocessing of sediment fom tan4s

– Seconday eatment(

2iltration – this emo!es nealy all the emaining mico"es and othe paticles

"y passing the wate though sand "eds o chacoal%

– etiay eatment(

hlorination – adding chloine to the wate 4ills of the emaining hamful

mico"es

7the chemicals ae added hee, such as fluoides, depending on the location





+. D'ring the secon! half of the nineteenth cent'ry/ the or3 of %aste'r

an! och an! other scientists stim'late! the search for micro-es as the

ca'se of !isease:

• Describe the contribution of %asteur and (och to our understanding of

infectious diseases:

– Until the mid >?th Centuy people thought that li!ing things wee poduced "y

spontaneous geneation( that they came into e&istence diectly fom non-li!ing

matte

– @o e&ample, the )ncient *ee4s thought that ats came fom ga"age

– 5o'is %aste'r 617(8 – 1798:

asteu disco!eed that infectious diseases ae caused "y mico-oganisms

his is 4nown as his ‘*em heoy of $isease’

asteu’s 8&peiment(

He sought to dispo!e the theoy of spontaneous geneation

He hypothesised that mico"es wee in the ai e!eywhee, and food spoils

when these mico"es land thee and "ecome acti!e

asteu poued nutient "oth into 2 identical swan-nec4ed flas4s, and

"oiled "oth of them to 4ill off all mico"es

hen he "o4e one of the ‘nec4s’ and left "oth flas4s out in the open ai

)s he pedicted, the flas4 with the "oth open to the ai de!eloped cloudy

"acteial gowths, while the flas4 with the swan-nec4 stayed clea

his po!ed that the mico"es that spoil food come fom the ai, and

dispo!ed spontaneous geneation%

asteu’s <o4 with )ntha& and Aaccination(

asteu demonstated that antha& was caused "y a od-shaped "acteium

He de!eloped a wea4ened stain of the "acteium, and using this, poduced

the fist !accine%

He too4 1 sheep, and inoculated 2 of them with the wea4ened stain%

)fte they eco!eed, he in#ected all the sheep with the nomal antha&





he 2 that wee inoculated su!i!ed, while the othe 2 died

asteu and @ementation(

asteu e&amined samples of fementing wines unde the micoscope

He o"se!ed 8)SS, which wee con!eting the sugas to alcohol

He also o"se!ed B)C8:3), which wee con!eting sugas to lactic

acid%

he "acteia wee also o"se!ed in sou mil4 and wee the cause of food

spoilage%

asteu showed that heating the wine o mil4 to DC fo a few minutes

4ills the mico"es that spoil them% his pocess is called pasteuisation

– o-ert och 6174+ – 191,:

Eoch also studied the antha& disease

)ntha& is a "acteial disease that affects "oth sheep and humans

he pocess of his in!estigation was(

>% He o"tained infected matte fom a sheep suffeing fom antha&

2% He placed it on a slide, o"se!ed it unde a micoscope and saw acti!e od-

shaped cells and inacti!e, domant spoes

=% He esta"lished that the "lood of animals with the disease always containedthese mico-oganisms, while the "lood of healthy animals did not

F% He found that if "lood fom an infected animal was in#ected into a healthy

animal, it would cause disease%

% He gew cultues of the od-shaped "acteia to infect mice – they

de!eloped the disease% his po!ed that it was the "acteia, and not any

othe "lood component that caused disease%

Eoch’s ostulates +fo esta"lishing a cetain mico"e causes a disease(

he mico-oganism must "e pesent in e!ey oganism with the disease

he mico-oganism must "e isolated fom the host and cultued

) potential host, when inoculated with the cultued mico-oganism, must

de!elop the same symptoms as the oiginal host





he mico-oganism must "e a"le to "e isolated fom the second host and

"e identified as the same species as the oiginal cultue%

• Distinguish between prions, viruses, bacteria, proto)oans, fungi and macro

parasites and name one example of a disease caused by each type of

pathogen:

– :375S(

hey ae non-cellula infectious agents that cause disease in mammals

)e a"nomal poteins that ae alteed fom nomal shape +no $5) o :5)

hey can also con!et nomal poteins to a"nomal poteins

Can "e passed fom one animal to anothe +usually "y "ain o spinal tissue

8*( Bo!ine spongifom encephalopathy, Ceut.feld 9aco"s disease%

– A3:US8S(

5on-cellula pathogens, simply a potein coat aound genetic mateial

)e found in eu4ayotic and pocayotic cells

Can only epoduce inside othe cells +host cells, 4illing them%

5o cue fo !ial diseases – !accinations can educe pe!alence

8*( )3$S, smallpo&, influen.a

– B)C8:3)(

Unicellula, pocayotic cells% Cell wall suounding cell%

5o mem"ane "ound oganelles

7nly some ae pathogenic and cause disease many ae useful

/ost li!e feely, "ut some ae paasites

8*( etanus, pneumonia, antha&

– :77G7)5S(

Unicellula eucayotic, animal-li4e oganisms no cell wall

@ee-li!ing, o paasitic%

8*( Sleeping sic4ness, giadiasis, amoe"ic dysentey

– @U5*3(

8ucayotic oganisms ha!e a cell wall made of chitin +not cellulose





Some ae unicellula +eg yeast, most ae multicellula

hey play an impotant ole in decomposition of oganic molecules, togethe

with "acteia

8*( :ingwom, tinea

– /)C:7):)S38S(

;age disease causing oganisms that can "e seen with the na4ed eye

8&tenal paasites ae called ectopaasites, intenal ae called endopaasites

8*( :ingwom, tic4s, fleas, oundwoms

• 'dentify the role of antibiotics in the management of infectious diseases:

– )nti"iotics ae su"stances that ae capa"le of destoying o inhi"iting the gowth

of "acteia that cause disease%

– hey ae chemicals that act selecti!ely they attac4 the "acteia "ut not the host

– )nti"iotics wo4 at the cellula le!el they destoy the cells of the "acteia

– Howad @loey and )le&ande @leming disco!eed the fist anti"iotic( penicillin

– Some anti"iotics affect the stuctue of the "acteia – penicillin destoys cell walls

and amphoteicin destoys cell mem"anes

– Boad-spectum anti"iotics affect a wide ange of "acteia, naow-spectum act

on only one o two%• *race the historical development of our understanding of the cause and

prevention of malaria:

– F BC( *ee4s thought that the symptoms of malaia wee caused "y eithe

"eathing in mash !apous o "ites of insects that li!e in mashes

– >1( 5a*eran o"se!ed mico-oganisms in fesh "lood fom malaial patients

and suggested that malaia was caused "y this mico-oganisms

– >6( Golgi o"se!ed ase&ual epoduction of mico"e in "lood of patients – >?F( atic4 Manson poposed that malaia is tansmitted "y mos'uitoes

– >?( Grassi disco!eed that malaia was tansmitted "y the +nopheles mos'uito%

– >?I->??( onal! oss esta"lished that the poto.oan lasmodium was the

cause of malaia, winning the 5o"el i.e%





– 8aly 21th( eatments of malaia wee de!eloped, including anti-malaial dugs

such as 'uinine% 8ffots to stop the spead of malaia include using $$ to 4ill the

disease !ecto – the mos'uito%

– oday( :esistance to 'uinine and othe dugs "y the lasmodium, as well as $$esistance "y the mos'uitoes has "ecome a po"lem% $e!elopment of a malaial

!accine is the main diection eseach is going%

• Describe one named infectious disease in terms of its: - "ause .-

*ransmission /- &ost 0esponse 1- 2a3or 4ymptoms 5- *reatment 6-

%revention 7- "ontrol:

– Disease: /alaia

– a'se: F species of the poto.oan, %lasmodium – Transmission: he +nopheles mos'uitoes ae the hosts that tansmit the disease

to humans duing the "lood-suc4ing pocess%

– Sym"toms: he diffeent stages in the life cycle of the poto.oan cause the

diffeent symptoms of the disease(

<hen the pathogen fist entes the "lood, it ta!els to the ;3A8: C8;;S,

whee it hides fom the immune system% hee, it multiplies apidly, poducing

do.ens of cells called meo.oites

he meo.oites then ta!el "ac4 into the "lood, whee they infect :8$

B;77$ C8;;S, again, multiplying ase&ually poducing many cells%

he meo.oites "ust out of the ed "lood cells e!ey F-I2 hous, and as they

elease to&ins in this pocess, this causes the symptoms%

he to&ins cause ecuing attac4s of shi!eing, fe!e, headaches, nausea,

sweating and lethagy% he destuction of many ed "lood cells causes

anaemia%

– Host es"onse: )t each stage of the paasite’s life cycle, it poduces a diffeent

set of antigens +they stimulate the immune esponse% he host poduces

anti"odies to fight the pathogens, "ut the antigens continually change, so the

immune esponse is not effecti!e% he meo.oites in the li!e escape detection





– Treatment: 5atual esistance can de!elop, "ut only !ey slowly% eatment of

suffees includes using anti-malaial dugs such as 'uinine +effecti!e against

paasites in ed "lood cells, and pima'uine phosphate +wo4s in "oth "lood and

li!e cells% Some stains of plasmodium ae esistant howe!e% – %re*ention: otecti!e clothing, insect epellent, mos'uito nets%

– ontrol: )ims to 4eep incidence of disease to a minimum in population% $ugs to

destoy !ecto, and paasite% $estoying !ecto’s ha"itat% Aaccines against

plasmodium% *enetic engineeing of mos'uitoes to esist paasite%

• Discuss problems relating to antibiotic resistance JCase StudyK(

– 2 Stains of dug-esistant "acteia(

4treptococcus %neumonia and 4taphylococcus +ureus8

– hey cause meningitis and pneumonia

– hey cannot "e teated with common anti"iotics they ae esistant

– 7ne stain of 48 +ureus has added a new gene, ena"ling it to spead though s4in

contact and e!en infect healthy people%

– he ‘supe-"ugs’ ae moe common o!eseas than in )ustalia

– hey ae "lamed fo thousands of meningitis and othe infections e!ey yea%

– esent tends suggest that "y mid 211F, a"out F1L of 48 %neumonia "acteium

will "e esistant to the two most common anti"iotics +penicillin and

eythomycin%

– o o!ecome these po"lems, steps must "e ta4en to limit the use of anti"iotics as

the geate the use, the geate the is4 of a mutation gi!ing "acteia esistance%





4. )ften e recognise an infection -y the sym"toms it ca'ses. The imm'ne

res"onse is not so o-*io's 'ntil e reco*er:

• 'dentify defence barriers to prevent entry of pathogens in humans such as

skin, mucous membranes, cilia, chemical barriers, and other bodily

secretions:

– @3:S ;358 7@ $8@85C8

– esent fom "ith%

– hese physical "aies, e%g% s4in, potect the "ody at possi"le enty points

– he potection po!ided is non-specific – it potects against all mico"es

– S3in:

@oms a tough oute "aie that suounds the "ody

7ute layes contain E8:)35, which mico"es cannot penetate, unless the

s4in is "o4en – e%g% a cut

S4in has its own population of hamless "acteia% hese 4eep the num"es of

in!ading pathogens low – stops them multiplying +competition

Se"aceous glands +oil glands secete se"um +oil% he lipids in the se"um ae

"o4en down "y the s4in’s "acteia into acids which inhi"it "acteial and

fungal gowth

3f the s4in is "o4en, a seal +clot is 'uic4ly fomed "y the "lood-clotting

mechanism to pe!ent pathogen enty%

– M'co's Mem-ranes:

he digesti!e, espiatoy, epoducti!e and uinay tacts ae lined with thic4

mucus – it is stic4y and taps dust paticles and pathogens%

/ucus also contains an anti"ody – 3g) which eacts with potential pathogens

@luids such as sali!a, teas and nasal secetions wash o!e mucus mem"anesand contain lyso)yme – this "ea4s down "acteia cell walls%

– ilia:

Cilia ae minute hais that po#ect fom cells lining the nose, tachea and

"onchial tu"es





Cilia "eat and sweep mucus +containing dust and pathogens towads the nose

o thoat opening whee it is coughed out o swallowed

– hemical Barriers:

hese ceate conditions which ma4es the sufaces inhospita"le fo the potential pathogens%

8%*% 3n the digesti!e system(

he acidic en!ionment in the stomach

he al4aline en!ionment in the small intestine

– )ther Bo!ily Secretions:

opulations of hamless "acteia in the !agina act on dead "ody cells to ceate

acidic conditions – these pe!ent "acteial and fungal gowth Uine is steile and acidic – it flushes out the uetes, "ladde and uetha,

pe!enting mico"ial gowth%

• 'dentify antigens as molecules that trigger the immune response:

– )n antigen is a molecule that tigges the immune esponse

– /oe specifically, antigens cause the fomations of anti"odies%

– )ntigen )53"ody-*85eating su"stance

– 3t may "e pat of a pathogen o e!en a to&ic molecule – .G. – he glyco-potein spi4es on the suface of the influen.a !ius act as

antigens, tiggeing the immune esponse% he !enom of poisonous sna4es also

contains antigens%

• !xplain why organ transplants trigger an immune response:

– )ll an indi!idual’s cells ae ecognised "y the immune system as "elonging to the

"ody – the "ody ecognises it as ‘self’

– )ny othe su"stances ae ecognised as ‘non-self’ – foeign% – ) tansplanted ogan contains su"stances which the immune system ecognises as

"eing foeign% hese su"stance acts as )53*85S%

– his stimulates the "ody to ma4e anti"odies and othe su"stances which attac4

and can possi"ly destoy the ogan





• 'dentify defence adaptations, including:

♦ 'nflammation response:

♦ %hagocytosis:

♦ 9ymph system:

♦ "ell death to seal off pathogen:

– S8C75$ ;358 7@ $8@85C8

– his second line of the immune system is also non-specific +li4e the fist line of

defence% 3t is pesent fom "ith%

– his means that it will ecognise any antigen and ma4e no distinction "etweenthem% he immune esponse will "e the same egadless of the natue of the

antigen%

– 0nflammation es"onse:

<hen "ody tissue is damaged, whethe physically, o "y mico"es, the

inflammation esponse "egins

3t is chaacteised "y F symptoms – pain, edness, heat and swelling

he in#ued cells elease chemo4ines which stimulate basophils and mast cells

to elease the chemicals H3S)/358 and :7S7*;)5$35%

hese two chemicals cause the "lood !essels aound the aea to dilate and

incease thei pemea"ility

3t has = stages(

>% Blood !essels aound the damaged aea !ilate and incease thei

pemea"ility +due to histamine and postaglandin – this inceases "lood

flow to the aea%

2% he inceased "lood flow "ings heat and fl'i!s, which ma4e the

en!ionment inhospita"le to the mico"es% )lso, the inceased "lood flow

"ings H)*7C8S – these cells engulf foeign "odies%

=% issues "egin to epai afte the theat is emo!ed% 5ew tissue is ceated,

with the s4in epaiing fist, to pe!ent moe infectious agents enteing%





he = "eneficial functions of inflammation ae(

3t destoys the cause of infection and emo!es it fom the "ody

3t limits the cause of infection to a small aea

:eplaces o epais tissue damaged "y infection

– %hagocytosis:

hagocytosis is the engulfing and destuction of foeign "odies "y phagocytes

hagocytes ae white "lood cells +leucocytes that can engulf foeign "odies –

thee ae two 4inds( /)C:7H)*8S and 58U:7H3;S

hagocytes can change shape and suound the foeign "odies% )fte it is

engulfed, the foeign "ody is destoyed "y com"ining it with en.ymes%

– 5ym"h System:

he lymphatic system is a system of !essels that "egins nea the capillaies,

un paallel to the !eins and e!entually empty into the !eins "efoe they each

the heat%

he lymph !essels contain a fluid called ;/H, which is "lood without ed

"lood cells, platelets and lage plasma poteins

he !essels collect into lymph nodes – these nodes ae stoage stuctues fo

lymphocytes and macophages%

he lymph system contains ogans which ae !ey impotant in the immune

system, such as the "one maow +whee white "lood cells ae fomed, and

whee B cells matue and the thymus gland +whee cells matue%

– ell Death to Seal )ff %athogen:

<hen the "ody is una"le to neutalise an antigen, it seals off the pathogens in

a cyst o within a goup of cells

hese cells die so the pathogen can no longe su!i!e

his cluste of cells, also called a ganuloma, is made of a coe of dead tissue,

suounded "y layes of macophages, then lymphocytes, then fi"o"lasts,

which poduce a tough oute wall%

hese stuctues ae poduced in diseases such as tu"eculosis and leposy

– $nti&Micro-ial %roteins J8&taK(





358@8:75S ae a goup of poteins poduced "y cells in!aded "y !iuses

hey cause suounding cells to fom thei own anti-!ial chemicals,

pe!enting the spead of the !ius J)cts 75; on !iusesK%

he C7/;8/85 SS8/ is a goup of 21 poteins that act in a

‘cascade’ of eactions to destoy pathogens%

his means that the fist potein causes the poduction of the second, and the

second the thid, and so on%

he final potein em"eds itself in the pathogen’s cell wall +o mem"ane

causing it to die "y lysis +cell-"usting%

• 4how how a named disease results from an imbalance of microflora in

humans:

– /icofloa ae mico-oganisms that li!e on o in the "ody, and usually do not

cause disease%

– hey ae often pat of the fist line of defence – the hamless "acteia that secete

acids to destoy pathogens ae an e&ample%

– an!i!iasis, o ‘thush’, is a disease caused "y an im"alance in the num"es of

the fungus, ‘Candida al"icans’%

– he disease can happen in the mouth, the espiatoy tact, the gastointestinal

tact, and the female epoducti!e tact%

– he fungus is usually 4ept in chec4 fom competition fom othe mico"es such as

"acteia li!ing in the same aea

– he ta4ing of cetain medications, such as wide-spectum anti"iotics +which can

4ill "eneficial "acteia , o contacepti!e pills, can upset the "alance of

micofloa in the "ody, which can esult in a incease in the num"es of the

Candida fungus, leading to thush%





8. Mac2arlane B'rnet;s or3 in the mi!!le of the tentieth cent'ry

contri-'te! to a -etter 'n!erstan!ing of the imm'ne res"onse an! the

effecti*eness of imm'nisation "rograms:

• 'dentify the components of the immune response:

♦ +ntibodies:

♦ "ells:

♦ * "ells:

– H3:$ ;358 7@ $8@85C8

– his is ac;uired immunity o specific immunity +‘he specific immune esponse’

– his immunity is 57 pesent at "ith – it is gained though e&posue to infection – he specific immune esponse acts only against s"ecific mico"es o su"stances

– hat is, it only acts against cetain antigens

– 3t has a /8/7:( this means that the cells can ecognise antigens fom pe!ious

infections, and so can act faste and moe efficiently in the second e&posue%

– )nti"odies(

)e poduced "y the "ody in esponse to the pesence of specific antigens

hey ae made "y ;)S/) B-C8;;S

hey ae made of poteins called 3//U57*;7BU;35 in a shape%

)nti"odies ciculate in "lood +in the plasma and com"ine with antigens to

destoy them%

)ll anti"odies ha!e 2 M"inding sitesN – these "ind to the antigens%

)nti"odies inacti!ateOdestoy antigens in F ways(

5eutalisation( hey can stic4 to the "inding sites of !iuses, o disa"le

"acteial to&ins "y coating them% hese ae then engulfed "y phagocytes%

)gglutination( )nti"odies ‘clump’ togethe solid antigens such as "acteia,

com"ining many "acteia into a solid mass% his mass is then engulfed%

ecipitation( Solu"le antigens ae stuc4 togethe "y multiple anti"odies,

and ae pecipitated out of the solute +plasma% hagocytosis follow%





Complement )cti!ation( he anti"odies can stic4 to the sufaces of

"acteial cells, acting as tags fo destuction "y complement poteins%

– B-Cells(

)e a type of ;/H7C8%

;ymphocytes ae white-"lood cells that act only against specific antigens

B-Cells ae lymphocytes that matued in the "one maow

B-Cell Bone maow

hese cells contol the specific immune esponse only in the B;77$

hus, B-Cells gi!e h'moral +"lood o anti-o!y&me!iate! immunity

B-Cells usually ae found inacti!ated in the "lood and lymph, "ut ae acti!ated

"y the pesence of antigens

hee is only 758 B-Cell fo 758 antigen%

7nce this 758 B-Cell is acti!ated, it clones itself, and then diffeentiates into(

%lasma B&ells( hese cells ceate the anti"odies% )fte the infection is

gone, these cells e!entually die off%

Memory B-ells( hese cells ae fomed in small num"es in the oiginal

infection, "ut do not die off% hey stay "ehind to ecognise the antigen if it

appeas again, hence ha!ing ‘memoy’% B-Cells wo4 mainly in the "lood and intestitial fluids%

– -Cells(

)e also lymphocytes +he and B-Cells ae the only lymphocytes

-Cells ae lymphocytes that matue in the thymus gland

T-Cell Thymus gland

hese cells contol the specific immune esponse in infected C8;;S

hus, -Cells po!ide cell&me!iate! immunity%

)fte the -Cells ae acti!ated "y antigens, they diffeentiate into F types,

which ae e&plained in moe detail lateP

Hel"er T&ells( hese cells ae fo acti!ating cytoto&ic +4ille -Cells

and the B-Cells Jhis will "e e&plained latePK





ytoto<ic 6iller T-ells( hese cells attach to infected cells and

poduce chemicals which destoy to pathogens

Memory T-ells( :emain in the "ody and gi!e long tem immunity%

S'""ressor T-ells( hey suppess the num"es of B and -cells%

• Describe and explain the immune response in the human body in terms of:

♦ 'nteraction between and * lymphocytes:

♦ *he mechanisms which allow interaction between and *

lymphocytes:

♦ *he range of * lymphocyte types and the difference in their

roles: – 3nteactions Between B and -Cells(

@istly, the antigen ta!els in the "lood until it is engulfed "y a macro"hage

he macophage then "ecomes an antigen&"resenting cell & it displays the

antigen it has engulfed on its suface%

he macophage then ‘alets’ the immune system to the pesence of lage

num"es of antigens in the "ody "y presenting the antigen to a Hel"er T&ell%

he Helpe -Cells then poduce the chemical 358:;8UE35, which

stimulates and B-Cells to diffeentiate into thei diffeent types

578( he B and -Cells can "e acti!ated eithe "y Helpe -Cells, li4e

a"o!e, o acti!ated directly "y antigens% Both pocesses ha!e the same esult(

he -Cells ae also acti!ated "y infected cells displaying the antigens

he B-Cells ae also acti!ated "y free antigens in the "lood%

he -Cells diffeentiate into iller 6cytoto<ic T&ells, Memory T&ells and

S'""ressor T&ells%

he B-Cells diffeentiate into %lasma B&ells and Memory B&ells

he lasma B-Cells then destoy the antigen "y seceting anti"odies, and the

Cytoto&ic -Cells also destoy the antigen in ways desci"ed lateP

– he /echanisms of 3nteaction(

lonal Selection:





his is the wo4 of /ac@alane Bunett

Befoe an antigen entes the "ody, thee ae aleady many types of

lymphocytes in the "ody

he enty of an antigen causes the selection of only 758 of the types of

lymphocyte – the one that has the "inding site which matches the antigen

his esults in this lymphocyte cloning itself into lage num"es of this

same lymphocyte, so it poduces the anti"ody that matches the antigen

his selection means that all the lymphocytes that ae poduced in the

esponse +all the and B Cells ae all specific 75; to that antigen

his means that, fo e&ample, the Cytoto&ic -Cells fo influen.a "acteia

cannot 4ill the pneumonia "acteia /acophages engulf and 4ill all foeign cells – lymphocytes only act

against the antigens that they specifically match%

yto3ines an! 0nterle'3ins(

Cyto4ines ae a goup of S3*5);;35* C7/7U5$S made of poteins

o polysacchaides that ae used fo communication "etween cells

hey coodinate the functions of cells so that they can act togethe as a

whole, such as in the immune esponse

3nteleu4ins ae a type of cyto4ine that ae seceted "y Helpe -Cells and

the macophages

<hen these cells secete inteleu4ins, they ae signalling, o stimulating,

the othe cells to diffeentiate, in esponse to an antigen – such as a B-Cell

changing into a lasma B-Cell

his is the main mechanism that is used fo intecellula inteaction

– ypes of -Cells(

Hel"er T&ells( hese cells stimulate the B-Cells and -Cells to diffeentiate

into thei diffeent foms% hey ecei!e the antigen fom macophages and

only stimulate the B and -Cells with the same antigen-"inding sites%





ytoto<ic T&ells( ) type of lymphocyte whose main function is to ecognise

and 4ill "ody cells that ae infected "y pathogens% hey only wo4 against

infected cells, not diectly against pathogens% How they wo4(

hey ae poduced in esponse to Helpe -Cells, o fee antigens

3nfected "ody cells display the antigen of the pathogen within them using

MH 0 ma4es on thei suface% hese /HC 3 molecules hold the antigen

and pesent it to the Cytoto&ic -Cells%

he Cytoto&ic -Cell has eceptos which then "ind to the antigen

3t then eleases a chemical called 8:@7:35 – this pefoates o ma4es

holes in the cell mem"ane of the infected cell%

he "ody cell lyses – wate apidly entes "y osmosis and it "usts

he infected "ody cell is 4illed, togethe with the mico"e inside it%

Memory T&ells( hese cells ae poduced duing the time of infection, li4e

all the othe lymphocytes, "ut they emain domant and su!i!e fo many

yeas afte the antigen is gone% hei function is to ecognise the antigen

apidly if it eappeas in a second e&posue and to po!ide a 'uic4 and

enhanced esponse – this is why in a second e&posue, the symptoms

disappea much faste, o aen’t e&peienced at all%

S'""ressor T-ells( hese ae poduced only fo a shot while% hese cells

secete chemicals to suppess the actions of B and -Cells afte the immune

esponse has ended%

• Outline the way in which vaccinations prevent infection:

– Aaccination +o immunisation is the pocess of ma4ing people esistant to

infection caused "y a pathogen

– 3t in!ol!es gi!ing people an in#ection o oal dose of a !accine

– Aaccines can "e(

;i!e !iuses

Eilled o wea4ened pathogens

)ttenuated +hamless stains of a pathogen

3nacti!ated to&ins





)nti"odies fom "lood of la"oatoy animals

– hese !accines ae in#ected into the "ody with the intention of po!iding

immunity to the disease without gi!ing the symptoms

– Aaccines can gi!e eithe )C3A8 o )SS3A8 immunity( $cti*e 0mm'nity: his is gained though in#ecting the antigen of the

pathogen in the !accine% his stimulates the whole immune esponse,

including anti"odies and and B /emoy Cells that ae specific to that

antigen, without the symptoms of the infection% he poduction of memoy

cells has 2 implications(

3f the pathogen does ente the !accinated indi!idual, the memoy cells

initiates a 'uic4 immune esponse, so the indi!idual does not e&peience

an ‘infection’%

3t po!ides long-tem potection, as memoy cells last a long time%

8%*% /easles !accine

%assi*e 0mm'nity( his in!ol!es the in#ection of anti"odies staight into the

indi!idual, in esponse to infection "y a pathogen% he anti"odies come fom

othe oganisms(

3t "y-passes the whole immune esponse – immediate potection

*i!es potection fom diseases the "ody has ne!e "een infected "y

5o memoy cells poduced% his means potection is only shot-tem

3t may "ing the is4 of a eaction against foeign "lood poteins

8%*% etanus seum

• Outline the reasons for the suppression of the immune response in organ

transplant patients:

– ) tansplanted ogan is ecognised as foeign tissue "y the immune system – SU:8SS375 of the immune system is needed to pe!ent the "ody fom

re=ecting the ogan

– <ithout suppession, the immune system would ceate anti"odies and cytoto&ic -

Cells to ty and destoy the ogan%





– he chances of e#ection is educed "y matching the tansplant ogan tissue with

the tissue of the patient, and "y po!iding immunosuppession dugs%

– he dange of this theapy is the ina"ility of the patient to fight off any infections,

since the immune system is suppessed% he "enefits of immunosuppession hasto "e "alanced against the change of life theatening infection%

• !valuate the effectiveness of vaccination programs in preventing the spread

and occurrence of once common diseases, including smallpox, diphtheria

and polio:

– S/);;7Q(

a'se an! Sym"toms:

Caused "y the smallpo& !ius

3t entes though the thoat and lungs, then undegoes a >2-day incu"ation

Symptoms of the disease includes o"!ious !esicles on the s4in, headaches,

"ac4aches and fe!e

History:

@ist appeaed in )sia o )fica aound >1111 BC

Spead aound the wold "y e&ploes, tades and cusades

:esponsi"le fo > in >1 of all deaths in 8uope in the >? th Centuy

:eached )ustalia in >I?, with ealy 8uopean settles, and had a

de!astating effect on )"oiginal communities

>accination %rograms:

8dwad 9enne pefomed the fist smallpo& !accination "y inoculating

people with cowpo&

he !accine was used "y the <H7 on a glo"al scale in >?6I

he <H7 outinely immunised people with the !accine, po!ided

supplementay !accinations and caefully supe!ised aeas with the

potential fo infections

3n >?1, the <H7 announced the wold fee of smallpo&

*al'ation of ffecti*eness(





Since the !accination pogams esulted in the complete eadication of the

disease fom the planet, it can "e said that the pogams wee e&temely

effecti!e%

– $3HH8:3)( a'ses an! Sym"toms:

3t is a "acteial infection that is spead though the ai into espiatoy

sufaces, o "y close physical contact

3t gi!es thoat infections, which esults in "eathing difficulties and death

History:

>11 yeas ago, 1L of all those infected with diphtheia would die

;age epidemics occued in 8uope afte <<33

hee ha!e "een ecent out"ea4s in )lgeia and China


3n >?2=, a !accine was eleased

3n >?IF the <H7 "egan to e&pand its immunisation pogam glo"ally

3n >??1, the woldwide immunity ate was 1L

*al'ation of ffecti*eness:

he !accination pogam educed the spead of the disease fom cyclic

academics to occasional "ea4outs of low density

8!en though the ate of immunity is high, the disease is still pesent in

de!eloping counties and has not yet "een eadicated

– 7;37(

a'ses an! Sym"toms:

olio is the attac4 "y polio !iuses on the moto neuones of the spinal

chod and the "ain Symptoms include high fe!e, "ac4 pains, muscle spasms and paalysis

History:

$isease e&isted in )ncient 8gypt and 4illed hundeds and thousands of

people in the >?th Centuy





he ate of polio "egan to fall in the 21th Centuy


he !accination was fist intoduced in >?

3n the >?61’s an oal fom of the !accine was intoduced and the polio

disease was "ought unde contol

3n >? the <H7 "egan an immunisation campaign

he num"e of cases dopped "y 1L in >??1

*al'ation of ffecti*eness:

$espite widespead success in polio contol, thee ae still small "ea4outs

in aound I1 counties%

olio infection ates ha!e "een successfully contolled R educed "y 1L





. "i!emiological st'!ies in*ol*e the collection an! caref'l statistical

analysis of large @'antities of !ata. S'ch st'!ies assist the ca'sal

i!entification of non&infectio's !iseases:

• 'dentify and describe the main features of epidemiology using lung cancer

as an example:

– "i!emiology is the study of the factos that influence the incidence, disti"ution,

and contol of diseases within a population

– @eatues of an epidemiological study that help po!e the cause of disease(

hough analysis of statistics, it must demonstate a significant lin4 "etween

the cause and the disease

hee has to "e a chonological ode of e!ents that is, the cause must come

"efoe the disease

he study must "e done on a lage ange of su"#ects, in tems of age, se&, ace,

occupation, socioeconomic status, and geogaphical position

he esults should pesist o!e time

he cause-and-effect elationship should "e independent of othe factos

he geate the e&posue to the cause, the geate the incidence should "e of

specific disease

he study should "e epeata"le "y othe in!estigatos at different time, and

diffeent places using different methods8

– hee ae thee types of epidemiological studies(

$escipti!e( hese studies in!estigate(

he fe'uency of the disease

he pat of the population affected – e%g% age, gende, occupation, etc

he location and time peiod of those affected

)nalytical( hese focus on finding a ca'se an! effect elationship in the

occuence of the disease(

hese studies loo4 at factos that peceded the epidemics

hey loo4 at control groups – simila indi!iduals without the disease





hey e&amine factos that affect the is4 of contacting the disease

8&peimental( hese ae used to test the effecti!eness of a paticula

teatment, such as clinical tials of a new dug%

– he epidemiological studies concening lung cance ae a good e&ample – the

studies ange o!e many decades, stating fom the >?1s, when le!els of lung

cance fist "egan to "ecome noticea"le%

– he people su!eyed in the studies came fom a wide ange of ages, fom <<3

!eteans who had stated smo4ing "ecause they wee gi!en fee cigaettes to the

wa!e of women who had "egun to ta4e up smo4ing in the >?I1s%

– he studies ha!e shown that thee is a stong coelation "etween smo4ing and

lung cance%

• 'dentify causes of noninfectious disease using an example from each of the

following categories:

♦ 'nherited diseases

♦ <utritional diseases

♦ !nvironmental diseases

– 5on-infectious diseases ae not caused "y pathogens

– hey ae not tansmitted fom one oganism to anothe

– 0nherite! Diseases:

hese diseases ae caused "y gene and chomosome a"nomalities

hey ae tansmitted "y epoduction

hey can "e mino disodes, such as myopia o seious such as haemophilia

8%*% $own Syndome is an inheited disease that is caused "y the inheitance

of once e&ta chomosome +tisomy 2>% eople with $own syndome ha!e a

chaacteistic appeaance and may ha!e a shotened life span% /othes who

ha!e childen late in life ae moe pone to poduce $own syndome childen%

– #'tritional Diseases:

hese ae caused "y incoect o insufficient diets

3t can "e o!e-eating +o"esity o unde-nouishment +anoe&ia





8%*% Scu!y – his disease is caused "y the lac4 of !itamin C in the diet% 3t

causes swelling of "ody pats and teeth stat to fall out%

– n*ironmental Disease:

/any factos in the en!ionment can cause disease

hey include adiation, hea!y metals, pollution, etc

8%*% )sthma – this disease is whee the muscles in the aiways contact and

can cause se!ee "eathing difficulties% Causes include pollution, pollen, dust

stoms, humidity, and many othe en!ionmental factos%

• 'dentify the cause and effect relationship of smoking and lung cancer:

– ) case study( ;U5* C)5C8:(

Definition( Uncontolled gowth of tumous in the lungs

a'ses( hee is a o"!ious lin4 "etween smo4ing and lung cance% o"acco

smo4e contains many cacinogens such as "en.ene%

ffect( )s the tumou gows, the ai sacs in the lungs ae destoyed and

"eathing "ecomes difficult% he lungs collapse and a"scess and the patient

may "egin coughing up "lood% he cance can metastasise +spead to othe

!ital ogans and cause death%

Statistical 0nformation( /ass poduction of cigaettes "egan in >1 – fee cigaettes wee gi!en

to <<3 soldies

3n the >?=1s thee was a sudden lung cance epidemic

he fist epidemiological studies which showed a elationship "etween

smo4ing and lung cance wee in the >?1s, "ut they did not ha!e

conclusi!e esults – they #ust showed a educed li!e e&pectancy

3n >?6F the Sugeon’s *eneal )d!isoy Committee concluded that

cigaette smo4ing was a cause of lung cance%

3n the >?I1s, as the num"es of female smo4es "egan to incease, lung

cance "ecame the num"e one cause of cance death%

Studies ha!e shown a coelation "etween the num"e of cigaettes

smo4ed each day and the is4 of contacting lung cance at an ealie stage





)lso, a gadual decease in the num"es of people smo4ing in the past 21

yeas has "een mioed "y a decease in suffees of lung cance

• +nalyse and present information about the occurrence, symptoms, cause,

treatment=management if a named noninfectious disease:

– Disease: $own syndome

– a'se: isomy - it is a genetic disease that is caused "y the pesence of an e&ta

chomosome in the 2>st position%

– Sym"toms: ;owe than a!eage mental a"ility, almond shaped eyes, shote

lim"s, speech impaiment, enlaged tongue and a high is4 of heat failue

– )cc'rrence: )ppo&imately > pe I== li!e "iths

– TreatmentAManagement: Childen with $own syndome will need special cae in many aeas of life,

including eating, washing and geneal hygiene

he educed mental capacity, a symptom of the disease, may "e a limiting

facto on the de!elopment on the indi!idual in espect to social de!elopment,

schooling and the wo4foce

)n impotant issue is the physical health of the patient with the disode(

hysiotheapy may "e needed, as childen "on with $own syndome ha!e

wea4ened muscles, and shote ams and legs

he inceased is4 of se!eal diseases, most nota"ly cadio!ascula failue,

is an impotant issue that must "e managed with $own syndome patients%





. 0ncrease! 'n!erstan!ing has lea! to a i!e range of strategies to

"re*ent an! control !isease:

• Discuss the role of ;uarantine in preventing the spread of disease and

plants and animals into +ustralia or across regions of +ustralia:

– C'arantine is the contolling of the impot o e&pot of animals, plants, and othe

poducts fo the pupose of contolling the spead of disease

– he :ole of Tuaantine(

otects the health of the human, animal and plant populations of )ustalia

e!ents the enty of foreign "ests and contagio's !iseases into )ustalia

Tuaantine laws pe!ent the enty of items consideed a is4

3mpotant animals face a time in isolation to ensue no disease is pesent%

;i!ing plants ae also 'uaantined to ma4e sue they ae not caying pests o

suffeing fom any infectious disease

lant seeds ae e&amined to chec4 that no weed seeds ae pesent

Used !ehicles and agicultual machiney ae inspected and cleaned to ensue

no soilOplant matte entes the county

• !valuate the effectiveness of ;uarantine in preventing the spread of plant

and animal diseases into +ustralia or across regions of +ustralia:

– Because of )ustalia’s stict 'uaantine laws, )ustalian plants and animals !o not

ha*e some of the seious disease found in othe counties, such as foot and mouth

disease, mad cow disease and a"ies

– 8%*% )nimal disease that has not enteed )ustalia – 2oot an! mo'th !isease(

) highly contagious muscle-wasting disease of clo!en-hoofed animals such as

cows, sheep and goat

Symptoms include fe!e, di""ling, lethagy and "listes on mouth, tongue,

lips, hoo!es and feet

3t is caused "y an ai"one !ius – it is spead not only "y li!e animals "ut also

"y the cacass, and also in soil and e'uipment%





Tuaantine egulations has pe!ented the enty of this disease – if an out"ea4

did occu, it would cost "illions of dollas in loss%

– 8%*% lant disease that has not enteed )ustalia – Sorgh'm !ony mil!e(

his disease has "een pe!ented fom enteing into )ustalia

Caused "y a fungus if it was eleased into )ustalia, it would de!astate wheat

and othe cops gown hee

he fungus inhi"its the plants a"ility to ma4e chloophyll, which esults in the

death of the plant

Tuaantine measues include the "anning of enty of any li!e plant mateial,

and the stict e&amination of any seeds "eing "ought in%

– 8%*% e!enting spead of disease acoss egions of )ustalia – 2r'it flies

Tuaantine measues ha!e "een implemented that fo"id the mo!ement of

fuit acoss state "odes

hese measues ae in place to contol the spead of fuit flies, which cause

se!ee damage to fuit cops such as "ananas

hee is the /editeanean fuit fly in <esten )ustalia, and the Tueensland

fuit fly, in easten )ustalia

he 5othen eitoy, South )ustalia and asmania do not ha!e these pests,

"ecause of 'uaantine measues

– 7!eall, 'uaantine pactices ha!e "een geatly effecti!e%

– $ue to the igoous implementation of 'uaantine pactices, most diseases and

pests ha!e not "een "ought to )ustalia%

• !xplain how one of the following strategies has controlled and=or prevented

disease Jesticides chosenK(

– esticides ae used usually to 4ill the !ectos that cay the disease

– )n e&ample is using pesticides to contol the malaia disease

– $$ +dichloo-diphenyl-tichlooethane is the pesticide that was used to 4ill

populations of the )nopheles mos'uito, the !ecto of malaia

– 3t was !ey effecti!e in the "eginning, and num"es of malaia suffees went

down, "ut then pesticide-esistance educed its efficacy





– $$ was also used to 4ill lice on the "odies of soldies duing <<33

– he lice caied diseases such as typhus fe!e

– he pesticide pe!ented thousands of deaths

• Discuss the changing methods of dealing with plant and animal diseases,

including the shift in emphasis from treatment and control to management

or prevention of disease:

– he incidence of disease has moe commonly "een met with an emphasis on

teatment and contol

– /oe ecently howe!e the emphasis has shifted to the impotance and

effecti!eness of pe!enting and managing diseases instead

– hese e&amples illustate this( Smallpo&( ) widespead disease that 4illed many in the >th Centuy%

eatments wee a!aila"le, "ut wee ineffecti!e – many died% e!ention came

in the fom of !accinations, and this has contolled the disease fa moe

successfully than any teatments

Cances( hee ae cuent teatments, such as chemotheapy, adiotheapy,

and sugical emo!als% hey ae 'uite successful, especially if detected ealy%

Howe!e, they ae not >11L successful and can cause physical tauma to the

"ody +scas% e!ention campaigns +pu"lic health campaigns such as gi!ing

people ad!ice on pope s4in cae +s4in cance and 'uit-lines fo smo4ing

ha!e educed the num"es of cances%

lant $iseases( hese include disease such as fungal oot infections, pests

such as aphids and disease causing oganisms% he usual teatment is spaying

with pesticides% Howe!e this has had a detimental effect on the en!ionment%

e!entati!e measues ae used, especially 'uaantine measues, "iological

contol +intoducing species to contol pests and genetic engineeing

• !vidence of pathogens and insect pests on plant leaves and shoots:

%athogens 0nsect %ests





- Bacteia cause spots on the suface of the

lea!es +‘ust’ on the Ban4sia lea!es

- @ungal infections ae shown "y da4

gowths on the stems +‘"lac4 stem ot’

o on the undesides of lea!es%

- 3nsects +‘a.alea lace-"ugs’ feed on the

plant itself, ceating holes and damage%

- 7the insects, such as psyllids, epoduce

on the plants, and lea!e "ehind egg shells

and holes%

9.4 - the search for better health

Documents