IQ1: How is an organism's internal environment maintained in response to a changing external environment?

1.1 construct and interpret negatie eedback loops that show homeostasis, including temperature and glucose

HOMEOSTASIS Homeostasis is the maintenance o a stable internal eniironment despite changes in

the external eniironment. Stmulus (change)n receptors (detect change and coniert into nerie impulse)n

control centre (brain/spinal cord)n messenger (communicates message rom CNS to effector)n effector (receiies message and causes response)n response (change in body)n.

Mal unctons in homeostatc mechanisms can lead to disease.o e.g. hyperglycaemia or hypoglycaemia diabeteso e.g. hypothermia or hyperthermia heat stroke, pneumonia, etc.

TEMPERATURE FEEDBACK LOOP

GLUCOSE FEEDBACK LOOP

1.2 iniestgate mechanisms used by organisms to maintain their internal eniironment, includingr − behavioural, structural and physiological adaptatons in endotherms that assist homeostasis ANIMAL ADAPTATIONS FOR HOMEOSTASIS

Heat is exchanged with the eniironment through conducton, coniecton, radiaton and eiaporatie cooling.

Endotherms produce their own body heat through metabolism e.g. mammals and birds Ectotherms use the external eniironment to obtain heat energy e.g. fsh, reptles,

iniertebrates Structural adaptatons relate to the size and shape o an organism and its body parts.

o e.g. kangaroos haie network o ieins under thin orelimb skino e.g. body proportons suited to climate

Physiological adaptatons relate to how an organism's body works.o e.g. temperature regulaton iasoconstricton, iasodilaton, sweatngo e.g. hormonal control o water leiels (seer kidneys)n

Behaiioural adaptatons relate to an organism's behaiiours.o e.g. snakes seeking sun or shadeo e.g. kangaroos licking orelimbs to promote eiaporatie coolingo e.g. penguins huddling or warmth

− mechanisms in plants that allow water balance to be maintained PLANT ADAPTATIONS FOR WATER BALANCE

Xerophytes are plants which are adapted to liie in dry conditons haie eatures that minimise water loss rom transpiraton.

Tough cutcles e.g. pig aceo Thick, waxy sur ace reduces transpiraton

Fine hairs e.g. paper fowero Create humid eniironment around stomata, reducing water loss

Water storage e.g. pig aceo Leaies and stems haie large iacuoles to store water

Extensiie root systems e.g. pig aceo Absorb and store large amounts o water rom the soil

Rolled-up leaies e.g. porcupine grasso Leaies curl up when too much water is lost, creatng a humid chamber or the

stomatao Stomata only on one side o the lea so none are exposed when curled

No leaies e.g. watleso Flatened stems (phyllodes)n instead o leaies allow photosynthesis to occur but lack

stomata, reducing transpiraton Angled branches and leaies e.g. mulga trees

o Angled down (not horizontal)n to direct any water to the roots and minimise amount o sun on leaies

Transparent leaies e.g. frewheel treeo Leaies do not absorb as much heat, slowing water loss

− internal coordinaton systems that allow homeostasis to be maintained, including hormones and neural pathways

ENDOCRINE SYSTEM Hormones are signalling molecules that regulate the actiity o specifc target cells,

interactng with specifc receptors.o Endocrine glands typically release hormones directly into circulatory system e.g.

pituitary gland NERVOUS SYSTEM

Three types o nerie cellsr sensory, inter and motor. o Sensory neurones receiie in ormaton and

send it to the CNS. o Motor neurones relay signals rom the CNS to

effector organs (muscles or glands)n.o Interneurons connect sensory neurones to

motor neurones within the CNS. Neurotransmiters e.g. noradrenaline are signalling

molecules released by nerie cells that communicateelectrical signals to chemical signals across a synapse. o Presynaptc knobs contain iesicles that

release neurotransmiters.o Impulses cannot traiel across synapses, so

neurotransmiters bind to receptors andstmulate dendrites to begin acton potental in the next neuron.

ACTION POTENTIALS (NERVE IMPULSES) Acton potental = change in polarity on the inside o the neurone compared to the outside

(when nerie is stmulated)no i.e. traieling electrical current caused by ions moiing through ioltage-gated

channels. Restng potental = charge difference between inside and outside o neurons

o Sodium ions sit outside, potassium ions sit inside. Stepsr

o The cell membrane o the neurone is stmulated. o The membrane becomes permeable to sodium

(Na+)n ions, and they enter.o I the threshold (-55) is reached, the membrane

becomes more positie on the inside than theoutside, creatng an acton potental.

o After hal a millisecond, the membrane is nolonger permeable to Na+ ions. Potassium (K+)n ionsmoie out, and the restng potental is restored.

o The resultng depolarisaton adjacent to the initalacton potental stmulates a new AP as Na+ ionsenter.

o The AP contnues to moie along the neurone in this manner.

TYPICAL CHANGES IN MEMBRANE POTENTIAL

Threshold = minimum intensity o a stmulus needed to initate a response.

o Intensity is recorded by the rate at which APs are generated stronger stmuli create more rapid fring and an increase in the number o cells that respond

o Speed and strength o APs are constant, it is the FREQUENCY that changes to cause different responses.

IQ2: Do non-infectoos diseases caose more deaths than infectoos diseases?

2.1 iniestgate the causes and effects o non-in ectous diseases in humans, including genetc diseases, diseases caused by eniironmental exposure, nutritonal diseases, and cancer

INTRO A disease is defned as any conditon that impairs the body's normal unctoning. Non-in ectous is NOT about contagion it is about whether or not they can be PASSED ON

GENERATIONALLY e.g. germline mutatons.o In ectous = caused by a pathogen.o Contagious = able to be spread rom person to person.o E.g. tetanus is in ectous (soil bacteria)n but NOT contagious.

GENETIC DISEASES Genetc diseases are caused by changes to the DNA sequence, e.g. by mutaton.

o e.g. haemophilia is a blood disorder caused by a mutaton in the blood clotng gene (recessiie sex-linked inheritance)n

Symptoms include requent/uncontrollable/unexplained bleeding, bruising etc.

Treatments include medicatons to aid blood clotng e.g. plasma or clot actors

ENVIRONMENTAL DISEASES

Eniironmental diseases are illnesses caused by actors in the eniironment e.g. exposure to UV radiaton, chemicals, or li estyle actors such as diet.o e.g. lead poisoning is caused by prolonged exposure to lead-contaminated sources,

which affects the brain and nerious system (as it is a toxic heaiy metal)n. Symptoms include deielopmental delays, abdominal pain, neurological

changes Treatments include medicaton to help remoie lead rom the body

May be minimised by limitng exposure to these actors and using protectie gear e.g. sunscreen.

NUTRITIONAL DISEASES

Nutritonal defciencies occur when there is insufcient intake o nutrients or the body does not absorb nutrients. o e.g. anaemia is caused by insufcient iron intake or inability o the body to absorb

enough iron - leads to iron defciency, and since iron is needed to orm red blood cells, the producton is slowed.

Symptoms include atgue, aintng, paleness, poor circulaton, etc. Treatments include iron supplementaton, changes in diet, or iron in usions.

CANCERS

Cancer iniolies a group o diseases (skin, breast, lung, etc)n in which abnormal cells multply and spread i.e. metastasize.

Cannot be neatly categorised as causes are broad and hard to narrow down.

o e.g. lung cancer can be caused by eniironmental exposure such as smoking, howeier it stll occurs in non-smokers.

o e.g. breast cancer has been linked to a genetc predispositon (BRCA1 and BRCA2)n, howeier it may stll occur without this.

SUMMARY

Category Caoses Examples Effects

Genetc Gene or chromosomal abnormalites caused by mutaton (e.g. by exposure to mutagens)n

May be inherited rom parents ora result o acquired changes to pre-existng genes

Huntngton's disease

Haemophilia

Huntngton's = degeneratie brain disorderrlose ability to walk, talk, think, etc.

Haemophilia = inability to clot blood

Eniironmental Exposure tomutagens e.g. lead

Li estyle actors e.g. poor diet, smoking

Some cancers e.g. skin, lung

Lead poisoning

Lung cancer = coughing up blood, collapsed lungs, difculty breathing

Lead poisoning = organ + brain damage

Nutritonal Insufcient nutrient intake e.g. poor diet

Inability to absorb nutrients e.g. H pylori and iron

Scuriy (Vitamin C)n

Anaemia (iron)n

Rickets (Vitamin D)n

Osteoporosis (calcium)n

Scuriy = wounds that do not heal, loose/lost teeth

Osteoporosis = britle bones prone to breakage

Cancer Genetcs e.g. amily history

Li estyle actors e.g. smoking

Eniironmental actors e.g. sun exposure

Lung cancer

Skin cancer

Breast cancer

All = pain, headaches, abnormal bleeding, tumours, etc.

2.2 iniestgate data to show the incidence, preialence and mortality rates o non-in ectous diseases, including nutritonal diseases and eniironmental diseases ENVIRONMENTAL DISEASE – MELANOMA

Featore Descripton of environmental disease

Name Melanoma (most lethal type o skin cancer)n

Cause Uncontrolled skin cell diiision due to changes in DNA that control cell diiision (e.g. in melanocytes which produce melanin)no Affected by exposure to UV radiaton e.g. sunlight, age, sunburnso Genetc component indiiiduals with air skin more prone

Symptoms Tumours/growths Changes in existng moles e.g. getng darker or larger Swollen lymph nodes Changes in skin pigmentaton

Host response

Primarily infammatory response/second line o de ense Cytotoxic T cells also moie to tumours to destroy them (cells send SOS

signals)n

Treatment Surgery (remoial o melanoma and surrounding cells)n Chemotherapy Radiotherapy

Incidence Approx. 35 per 100,000 in 2017 Most common cancer in young Australians Rates are remaining constant

Preialence Approx. 49 per 100,000 in 2016 Preialence is higher in males than emales Oierall VERY high in Aus due to outdoor li estyles and hole in ozone

(more UV)n

Mortality rate

Approx. 49 per 100,000 in 2016 Approx. 1900 deaths in 2018

NUTRITIONAL DISEASE – KWASHIORKOR

IQ3: Why are epidemiological stodies osed?

3.1 analyse paterns o non-in ectous diseases in populatons, including their incidence and preialence, such as diseases caused by eniironmental exposure

PATTERNS OF DISEASE Epidemiology is the study o the causes, effects and paterns o disease in populatons.

o Aids in the management, eialuaton and planning o seriices or preienton, control and treatment o diseases.

o Can be collected rom hospitals, insurance claims, GPs, health surieys, etc. Indicators include incidence, preialence, morbidity, mortality and li e expectancy.

o Incidence = number o NEW cases o a disease in a populatono Preialence = the PROPORTION o affected indiiiduals in a populaton (used to

measure morbidity)n.o Mortality = number o deaths rom the disease

EXAMPLEr 50-year study in the UK and US (beginning in the 1950s)n to determine the link between smoking and lung cancer results showed the test group had much higher incidence than the control group, confrming the link.

3.2 iniestgate the treatment, management, and possible uture directons or urther research o a named non-in ectous disease caused by eniironmental exposure

TREATMENT, MANAGEMENT AND FUTURE DIRECTIONS Treatment and cure o a disease will depend on the type o disease.

o e.g. treatment o scuriy iniolies adding appropriate amounts o Vitamin C to the diet.

o Other diseases, e.g. cancer, require more complex treatments. Screening, early diagnosis and management o symptoms is the best way to deal with

diseases that haie limited treatment optons.o e.g. CF currently has no success ul treatment management strategies concentrate

on reducing symptoms Research into many different types o diseases, how they mani est in the body, and the way

systems in the body work contribute to more success ul treatments. o e.g. research is currently being undertaken into the use o gene therapy to treat CF.

CASE STUDY: MELANOMA

Treatment Descripton

Surgery Iniolies remoiing the tumour and surrounding skin to ensure thatno cancerous cells are left behind.

Most common orm o treatment or early-stage melanoma.

Radiaton X-rays damage the DNA o cancer cells and kill them, whilst it allows normal cells to repair their DNA more easily.

Can be administered externally or by placing a radioactie source in the body near the cancer cells.

*Care must be taken in directng radiaton to specifc cells needing destructonn*

Chemotherapy Chemotherapy drugs slow the growth o cancer cells. Howeier, this has not been partcularly effectie in treatng

melanoma used more or other cancers.

Targeted therapy

Iniolies the use o drugs that affect molecules that control the growth o tumour cells, stopping it spreading.

Melanoma cells haie mutatons that cause uncontrolled cell diiision targeted therapy interrupts the pathways that cause this.

Immunotherapy Cause the body's own immune system to fght the melanoma can be done with checkpoint inhibitors or iaccinatons.

Checkpoint inhibitors = the use o drugs that cause the immune system to recognise and destroy melanoma cells (since cancer cells cause the immune system to ignore them)n.

Vaccinatons = an antgen is produced using the melanoma cells, and when used, it allows the immune system to more easily ident y + destroy the cancer.

Future research is required or melanoma, specifcally in the deielopment o targeted

therapies and immunotherapy treatments. Research or targeted therapiesr

Since this treatment is based on different mutatons that cause uncontrolled cell diiision, urther research is required to ident y all other mutatons and deielop more drugs.

Research or immunotherapyr Immunotherapy drugs are not success ul on all patents, so more research is

required to deielop a greater iariety or maximum beneft. Research will iniolie refning the process o iaccinatons to make them consistently

effectie, and iniestgatng the relatonship between melanoma and other cancers. 3.3 eialuate the method used in an epidemiological study

EPIDEMIOLOGY QUESTIONS Why conduct one?

o To discoier paterns that establish links between cause and effecto To deielop programs to preient and control disease.

What is looked at?o Who gets sick and why?o What is the most effectie treatment?

What is it used or?o To deielop programs e.g. iaccinaton programso To ident y people at risko To establish where money must be allocated

TYPES OF EPIDEMIOLOGICAL STUDIES

Descriptie studies proiide the who, what, where and when generate hypotheses about causes o disease.

Analytcal studies test hypotheses and proiide the why or how determine cause o disease.

Interienton studies are used to test the effectieness o a disease treatment or public health campaign.

STAGES OF COLLECTING DATA

Diagnostc phase confrms that disease is present Descriptie phase describes populaton at risk and distributon o disease Iniestgaton phase implementaton o feld studies Experimental phase experiments per ormed in controlled conditons to test hypotheses Analytcal phase results are analysed Decision making phase knowledge o epidemiology o disease is used to explore optons

aiailable or management TREATMENT VS. MANAGEMENT

Treatment = lessening symptoms/effects o diseaseo Can include cure e.g. antbiotcs or chest in ectono I incurable, helps control e.g. HIV and PrEP

Management = broader picture dealing with preienton, control and communicatono Can also oierlap with treatment, including managing indiiidual symptomso e.g. bowel cancer treatment iniolies surgery/chemotherapy, management

iniolies public educaton and bowel cancer test kits

HOW STUDIES ARE DONE

ERRORS IN EPIDEMIOLOGICAL STUDIES Random errors are unpredictable iariatons in data.

o Make the study less precise but do not shift the results in a partcular directon.o Can be corrected using statstcs.o Usually occur because o differences in subjects being studied ensuring

homogenous groups will reduce Res

Systematc errors (bias)n iniolie any process during a study that causes a consistent deiiatonin measurement rom what the true ialue should be.o Result in an incorrect estmate o the effect o exposure to a partcular actor and

the cause o a disease.o Selecton bias is bias in selectng subjects to include in the study must be

representatie o populaton

Sampling bias = the way subjects are chosen/where rom is not representatie o populaton

Volunteer bias = those who iolunteer already haie an interest in the conditon and may be at higher risk

Healthy worker bias = employed people are usually healthier than unemployed

Preialence/incidence bias = only current cases are included in the study.o In ormaton bias is errors in taking measurements or recording in ormaton

affects each study group differently Misclassifcaton bias = some subjects already suffer but are undiagnosed Recall bias = those affected by the conditon will haie greater recall than

those who are not Loss to ollow up bias = not all subjects are ollowed up to the same degree Interiiewer bias = questons indirectly lead study partcipants to the answer Measurement bias = measures are consistently inaccurate

o A con ounding actor is a type o systematc error that occurs when an unrecognised actor may be affectng the results o the study e.g. studying lung cancer in asbestos workers but ignoring cigarete use

Errors can be reduced byr

o Using statstcso Using multple obserierso Taking repeated measurementso Establishing standards/objectie defnitons be orehando Large sample sizeso Using controlso Long periods o study

3.4 eialuate, using examples, the benefts o engaging in an epidemiological study BENEFITS OF USING EPIDEMIOLOGY

Ident y causes o disease e.g. smoking and lung cancer Allows public health authorites to manage, eialuate and plan to control diseases

goiernments then allocate resources, deielop policies and health promoton strategies to improie health e.g. Natonal Tobacco Strategy

Ident y treatments and/or cures or diseases e.g. HIV and PrEP Predict possible uture outbreaks

IQ4: How can non-infectoos diseases be prevented?

4.1 eialuate the effectieness o current disease preienton methods and deielop strategies or the preienton o a non-in ectous disease, including educatonal programs, campaigns and genetc engineering

PREVENTION Preienton encompasses many actiitesr

o Reducing the likelihood that a disease or disorder will affect an indiiidualo Interruptng or slowing the progress o an already existng disordero Reducing disability.

e.g. mammograms do not preient breast cancer, BUT it is a preventatve acton because early detecton can stop/slow the disease.

e.g. wearing sunscreen does not preient melanoma, but reducing UV exposure reduces the likelihood that the disease will affect an indiiidual (1981 SlipSlop Slap campaign)n.

e.g. HIV and PrEP -> effectie in stopping symptoms, multplicaton o the iirus and transmission

e.g. Natonal Tobacco Strategy -> highly success ul EVALUATION OF ANTI-SMOKING CAMPAIGNS

GENETIC ENGINEERING

Genetc engineering is the deliberate modifcaton o an organism's DNA. o e.g. golden rice = highly effectie or Vitamin A defciencieso e.g. CRISPR Cas9 = gene editng technology or embryoso e.g. pre-implantaton screening (IVF)n = can preient offspring inheritng CFo e.g. GE insulin using recombinant DNA technology = highly effectie or diabetcs

EVALUATION OF GE INSULIN

Processr

o Human DNA is extracted rom pancreas cells, and the insulin-producing gene is isolated using specifc restricton enzymes.

o Plasmid DNA (iector)n is extracted rom a bacterium and cut with the same restricton enzyme.

o The human insulin-producing gene is inserted into the plasmid iector to orm recombinant DNA.

o The recombinant DNA plasmid is inserted into a bacterium cell to orm a recombinant/transgenic bacterium.

o The recombinant bacterium multplies in a ermentaton tank, producing insulin.o The insulin is extracted, purifed and botled or use.

Benefts o GE insulinro The insulin produced cannot trigger an immune response, because the hormone is

identcal to naturally-produced insulin in the bodyo Brings about a much more rapid response than cow insulin because o the exact ft

o insulin receptors in human liier cellso Reduces ethical issues e.g. objectons rom iegetarians

GENE THERAPY

Gene therapy is an experimental technique that manipulates genes in order to treat and preient disease at its source, i.e. at gene leiel.o Can be used to modi y genes or replace aulty genes with a healthy iersion.

Howeier it only targets body cells, not gametes so it is not passed onto offspring.

o Can help to treat incurable conditons e.g. genetc diseases like haemophilia and CF.o CF is caused by a aulty CFTR gene mutaton that causes a build-up o mucus in the

lungs (often lethal)n gene therapy aims to replace some o the aulty genes in the cells with healthy ones.

The missing genes are placed inside a modifed iirus that cannot reproduce. The iirus is inhaled by the patent to directly target/insert the gene into lung

cells (the iirus produces proteins that preient/control CF symptoms)n. The iirus is also encased in a at bubble, which stops the body's immune

response rom destroying the iirus. It is usually deliiered by a nebuliser.

IQ5: How can technologies be osed to help people who experience disorders?

5.1 explain a range o causes or disorders by iniestgatng the structures and unctons o releiant organs, thenr5.2 iniestgate technologies that are used to assist with the effects o these disorders

DISORDERS Disease and disorder are often used interchangeably, but they are DIFFERENT. Disease = a conditon in which the body's normal unctoning is impaired. Disorder = a disturbance that affects the mind or body.

o Due to intrinsic abnormalites (differences in an indiiidual's genome)n e.g. ADHDo Disorders can be caused by trauma, eniironmental actors, genetcs or naturally

through aging.

− hearing loss: hearing aids, bone conducton implants, cochlear implants

STRUCTURE OF EAR

FUNCTION OF EAR

PROCESS OF HEARING

Pinna unnels sound waies into the ear canal. Sound waies traiel down ear canal to eardrum and cause it to iibrate at the same

requency. The mechanical iibratons o the eardrum cause the ossicles to iibrate and ampli y the

sound. The iibratons are then trans erred to the fuids within the top canal o the cochlea. The iibratons passing through the top canal push the fuid in the middle canal (organ o

Cort)n. The hair cells (mechanoreceptors)n in the organ o Cort detect these iibratons, generatng

electrical nerie impulses.o High requencies are detected by cells nearest the oial window. o Low requencies are detected by cells urthest rom the oial window.

The impulses traiel iia the auditory nerie to the brain, where the sound is interpreted. TYPES OF HEARING LOSS

Conductie hearing loss = caused by blockage or damage in the outer and/or middle ear.o Leads to a loss o loudness causes includer

Blockages o the ear canal e.g. wax or oreign objects Per orated eardrum e.g. rom trauma (pencil)n Otosclerosis (bone grows around strrup bones)n

Sensorineural hearing loss = caused by damage/mal uncton o the cochlea or auditory nerieo Leads to a loss o loudness and/or lack o clarity causes includer

Ageing process Excessiie noise exposure Diseases e.g. rubella Congenital abnormalites

Mixed hearing loss = problems with both the conductie AND nerie pathway.

TECHNOLOGIES TO ASSIST HEARING LOSS

Hearing aids = electronic deiices that can ampli y sounds entering the external ear.o Can help with conductie or mild sensorineural hearing loss e.g. in the elderlyo Processr

Microphone detects sound and conierts it to electrical signal Amplifer magnifes/increases strength o sound Receiier conierts electrical signal back into sound Speaker transmits the sound into the ear

o Beneftsr Can be programmed to dull background noises, increasing quality o sound Do not require surgery Relatiely cheap

o Limitatonsr All parts o the ear must be unctoning (to an extent)n or it to work

Bone conducton implants = external processors that send sound as iibratons through bone

directly to the inner earo Can help with more seiere hearing loss, bypassing both the outer and middle earo Processr

Processor detects and amplifes soundwaies, then conierts them to iibratons

Implant transmits iibratons directly through bone to the cochleao Limitatonsr

Requires surgery

Cochlear implants = 'bionic ear' sends sound as electrical impulses directly to auditory nerieo Can help to treat seiere to pro oundly dea people with missing/damaged hair cellso Processr

Processor detects sound and conierts into digital code Implant conierts digital code into electrical impulses and transmits to

electrodes in the cochlea Electrodes stmulate auditory nerie, signals then recognised by the brain

o Beneftsr

Can acilitate hearing in pro oundly dea people, improiing QOLo Limitatonsr

Do not work i auditory nerie is damaged Very expensiie Requires surgery Patents with implants haie to be trained to interpret sound Do not ully reproduce normal sound (bad with tmbre and pitch)n

− visual disorders: spectacles, laser surgery

STRUCTURE OF EYE

FUNCTION OF EYE

PROCESS OF SIGHT I light is traielling rom a distant object, the light rays tend to be parallel.

o Less re racton needed = lens at rest + long ocal length. Light rays traielling rom a close source tend to diierge.

o More re racton needed = lens at maximum accommodaton + short ocal length. Accommodaton is the ocusing o objects at different distances, caused by changing the

coniexity o the lens.

EYE DISORDERS + TECHNOLOGIES

Myopia (short-sightedness)n = eye can ocus on near objects, but the ocal length when iiewing distant objects is too short o Causesr

Eyeball too elongated so image alls in ront o retna Lens cannot become thin enough to ocus distant objects Re ractie power o cornea is too great

o Technologies used to correctr Concaie lenses spread out light rays to increase ocal length Laser eye surgery changes curiature o cornea to decrease re ractie

power

Hyperopia (long-sightedness)n = eye can ocus on distant objects, but the ocal length when iiewing near objects is too longo Causesr

Eyeball is too short so image alls behind retna Lens cannot become round enough to ocus close objects Re ractie power o cornea is inadequate

o Technologies used to correctr Coniex lenses conierge light rays to shorten ocal length Laser eye surgery changes curiature o cornea to increase re ractie

power

Cataracts = any loss o transparency o the lens, causing blindness i untreatedo Causesr

Ageing process Congenital abnormalites Disease e.g. diabetes or glaucoma

o Technologies used to correctr Phacoemulsifcaton probe emits EM waies that break up the lens, debris

is remoied and new artfcial lens is inserted

− loss of kidney functon: dialysis, transplantaton

STRUCTURE OF KIDNEY

FUNCTION OF KIDNEYS The kidneys haie two unctonsr osmoregulaton + the remoial o nitrogenous wastes (urea)n.

o Wastes are conierted into ammonia in the liier, howeier this is toxic so it is conierted again into urea and excreted with water by the kidneys.

Kidneys (mostly adrenal glands)n hormonally control homeostasis byro Actiatng iitamin D to release renin raises blood pressureo Releasing erythropoietn increases producton o red blood cellso Releasing aldosterone increases reabsorpton o salts and thus water by osmosiso Releasing cortsol controls salt and water balance

FUNCTION OF NEPHRON

Stroctore Foncton

Nephron Functonal unit o the kidney regulates fuid compositon by fltraton, reabsorpton, secreton, and excreton.

Renal artery Blood iessel entering nephron containing urea, glucose, salts etc.

Glomerulus Network o capillaries where blood components are squeezed under high pressure into the nephron (fltrate)n.

Bowman's capsule Filters blood rom the capillaries based on SIZE only small partcles e.g. water and salts can enter the nephron.

Proximal tubule Use ul substances e.g. water, glucose, amino acids are reabsorbed into the blood by actie transport.

Bicarbonate ions reabsorbed to help regulate pH o surrounding blood.

Loop o Henle Water is absorbed in the descending loop and salts are reabsorbed in the ascending loop.

Distal tubule Selectie reabsorpton o ions and water occurs.

Renal iein Blood iessel leaiing nephron containing fltered blood.

Collectng duct Has selectiely permeable walls that allow or fnal reabsorpton o water.

Urea is concentrated and combined to orm urine.

PROCESS OF FILTRATION

Filtraton in the glomerulus allows urea, water, iitamins, minerals, amino acids, and hormones to enter the nephron.

The proximal tubule reabsorbs glucose, amino acids, bicarbonate ions and other nutrients. The descending part o the loop o Henle reabsorbs water. The ascending part o the loop o Henle reabsorbs salts. The distal tubule selectiely reabsorbs water and mineral ions to control blood fuid

concentratons. The collectng duct selectiely reabsorbs water.

o I blood water leiels are low, the walls become permeable and water moies out by osmosis.

Urine exits and traiels to the bladder iia the ureter to be excreted.

SUMMARY OF HORMONAL CONTROL

TECHNOLOGIES FOR KIDNEY FAILURE

Kidney transplant pre erred treatment but difcult to access.o Beneftsr

Prolongs li e Offers a more actie li e, as no dialysis is needed No restrictons on fuid or dietary intake

o Limitatonsr Wait lists are long, as a low number o kidneys are aiailable Transplant organs must be care ully matched to preient rejecton Patents with transplants must take immunosuppressants or the remainder

o their liies to aioid rejecton = more iulnerable to in ecton

Dialysis a li e-prolonging treatment (renalreplacement therapy)n.o Process o haemodialysisr

Patent's blood is pumpedthrough a dialyser

Blood passes through semi-permeable tubes surrounded bydialysate

Excess substances diffuse out o the blood, and fltered blood isreturned to the patent

o Beneftsr Does not cause pain Can increase li espan and

improie quality o li e Remoies wastes and regulates fuids

o Limitatonsr Many people stll die rom kidney ailure while on dialysis Very tme consuming Risk o in ecton at injecton site

5.3 eialuate the effectieness o a technology that is used to manage the effects o a disorder TECHNOLOGIES

Technologies may haie adierse effects or require regular costs and maintenance. Howeier, the side effects are outweighed by the benefts can allow people with disorders

to liie a more normal li e or prolong their li e.

COCHLEAR IMPLANTS

Beneftsro Allows dea people to hear iarious sounds e.g. cars or alarms or suriiialo Can help children assimilate into mainstream schools and eel more com ortableo Allow people to learn spoken language and communicate highly effectie or

children Limitatonsr

o Frequencies are limited because o the ew electrodes cannot ully restore hearing

o Require surgery, risking damage or post-operatie in ectons o Transitoning to sound is difcult less effectie or adults

LASER SURGERY Beneftsr

o Quick procedure and quick recoieryo Vision problems are fxed almost immediatelyo Usually no additonal correctie eyewear is needed (9/10)n

Limitatonsro Possibility o complicatons (1/10)n e.g. glare, dry eyeso People with strong lens prescriptons will not haie iision completely fxedo Expensiie and risk o damage/in ecton

HAEMODIALYSIS Beneftsr

o Can occur in hospital or in homeo Can be done during sleep

Limitatonsro Can take rom 3-10 hours and needs to be done 3x per weeko Requires external machineo Side effects include low blood pressure, iomitng, light-headedness, etc.

PERITONEAL DIALYSIS

Beneftsro Uninterrupted tme most patents able to contnue workingo Can be done during sleep

Limitatonsro Need to be able to set up and atach equipmento Risks include hernias, weight gain, in ecton at catheter site, weakening o

abdominal muscles, etc.