Fuente: Jones y Mackean

1. EXCRETION AND THE KIDNEYS

2. EXCRETION Theremovalfromorganisms of: - toxicmaterials, - thewasteproducts of metabolism (chemical reactions in cellsincludingrespiration) and - substancesin excess of requirements.

3. ExcretionEgestion EGESTION: Isthepassing out of food that has not been digested, as faeces, through the anus.

4. Excretoryorgans Lungs Kidneys Liver Skin

5. LUNGS: carbondioxideand watervapour (incidental)

6. KIDNEYS: urea, water, salts, toxins, hormones, drugs.

7. LIVER:bilepigments.

8. SKIN: water, salts, urea (incidental losses)

9. EXCRETORY PRODUCTS AND INCIDENTAL LOSSES

10. LIVERFunctions Regulation of bloodsugars. Production of bile. Deamination Storage of iron. Manufacture of plasma proteins. Detoxication: breakingdown of alcohol, drugs Breakingdown of hormones. Storage of vitamins

11. Alcohol and theliver Theliverreceivesalltheuseful and harmfulmoleculesthatthegutabsorbsfromfood. Drugsorpoison are harmfulmolecules. Alcoholis a drug. Itaffectsthe normal working of thebody. Itis absorbed fromthestomach and liver. Thecell of theliverconvert alcohol in anothersubstancewhichdoesnotpassthroughtherest of thebody´scirculation.

12. Alcohol In workingtoprotectothertissuestheliverislikelytoharmitself. Thesubstanceproducedfrom alcohol can bedangeroustothelivercells in highconcentration. It can cause a seriousdiseasecalledcirrhosis. Iftheliverisdamagedbyexcessive alcohol consumption, thentheholebodyisaffected. E.g: Bloodglucoseconcentrationcannotbecontrolledefficiently.

14. Renal artery: ?

15. Renal veins: ?

16. Longitudinal section: 3 mainparts: - cortex, medullaand pelvis. - Leadingfromthe pelvis is a tube, calledureter, whichcarriesurinethatthekidney has madetothebladder.

19. NEPHRON Is a single glomerulus(tangle of bloodcapillaries), withitsrenal capsule, renal tubeand bloodcapillaries. Kidneys are made of thousands of nephrons. Eachnephronbegins in thecortex, loopsdown in themedulla, back intothecortex, and thengoesdownagainthroughthemedullatothe pelvis. In the pelvis thenephronsjoin up withtheureter.

20. Kidneys and nephron

21. KIDNEY: FUNCTION 1) FILTRATION: - Bloodisbroughttothe renal capsule in a branch of the renal artery. - Onlysmallmolecules can gothrough. They are squeezedout of thebloodintothe renal capsule. - Water, salt, glucose and urea. - Mostproteins are toobig, so theystay in thebloodalongwithbloodcells.

22. KIDNEY:FUNCTION 2) REABSORPTION: - Some of thesubstances in the fluid in the renal capsule are neededbythebody. - All of theglucose, some of thewater and some of thesaltsneedtobekept in theblood. - Usefulesubstances in thekidneytubuleare reabsorbed and pass back intotheblood in thebloodcapillarieswrappedaroundeachkidneytubule. - Theremaining fluid continuesonitswayalongthetubule - In thecollectingductitismostlywater, with urea and saltsdissolved in it. ItiscalledURINE.

24. THE BLADDER STORES URINE Theurinefromallthenephronsflowsintotheureterswhichtakeittothebladder. Thebladderstoresurine. Whenitisfulled, thesphinctermuscle opens and theurineflowsalongtheurethra and out of thebody.

26. DIALYSIS Maintenance of glucose and protein concentration in blood and diffusion of urea from blood to dialysis fluid, which has water, glucose, salts that should be present in the blood. Inside the machine the blood is separated from the dialysis fluid by a partially permeable membrane. Dialysisdoesthework of damagedkidneys. Patientsneedtobetreatedtwoorthree times a week and thetreatmentlastsforseveralhours (disadvantage Application of dialysis in kidneymachines:

29. Thebesttreatmentis a KIDNEYTRANSPLANTbut: THE IMMUNE SYSTEM CAN REJECT TRANSPLANTS: Thepersonreceivingthetransplantistherecipient. Thepersonfromwhoseorganthebodywastakenisthedonor. Therecipient´simmunesystemrecognisesthedonororgan as being “foreign”, and attaksit. ThisiscalledREJECTION. Therecipientisgivendrugscalledimmunosuppresants. Thetroubleisthatthey stop theimmunesystemfromdoingits normal job, so thepersonis more likelytosufferfromallsorts of infectiousdiseases. The chances of rejection are reducedifthedonoris a closerelative of therecipient, becausethey are more likelytohaveantigensontheircellswhich are simmilartoeachother, so therecipient´simmunesystemislesslikelytoreacttothedonatedorgan as itwere ¨foreign¨.

30. Successfulkidneytransplantshaveadvantagesoverdyalisistreatment In thelongterm, a transplantismuchcheaper. Thepatient´slifeislessdisrupted once theyhaverecoveredfromtheoperation.