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Water and WasteWater and Waste
Animal Survival Animal Survival
Pages 130 – 137 Pages 130 – 137
TorranceTorrance
Water BalanceWater Balance We We gain watergain water from from
foodfood, , drinkdrink and and chemical reactionschemical reactions
We We lose waterlose water from from sweatingsweating, , breathingbreathing, , passing passing urineurine and and passing passing faecesfaeces..
Water gainWater gain must must equalequal water losswater loss
See fig 14.6 p131See fig 14.6 p131
Kidney Structure and FunctionKidney Structure and Function Our two kidneys are Our two kidneys are
attached to our blood attached to our blood supply by the supply by the renal arteryrenal artery and and renal veinrenal vein..
The The renal arteryrenal artery carries carries “dirty” blood “dirty” blood toto the the kidneyskidneys
The The renal veinrenal vein carries carries “clean” blood “clean” blood awayaway from from the the kidneyskidneys
A A ureterureter carries carries urineurine from the from the kidneyskidneys to the to the bladderbladder
The kidneysThe kidneys The The kidneyskidneys are the are the main organsmain organs for for
regulatingregulating the the water contentwater content in a in a mammalmammal The kidneys work by The kidneys work by filtration of bloodfiltration of blood and and
re absorptionre absorption of of useful materialsuseful materials such as such as glucoseglucose
UreaUrea is a is a wastewaste product product removedremoved in the in the urineurine
CREDITCREDIT UreaUrea is formed in the is formed in the liverliver from the from the
breakdown of surplus amino acidsbreakdown of surplus amino acids.. It It passespasses into the into the bloodblood and is carried round and is carried round
the body until it reaches the the body until it reaches the kidneyskidneys where it where it is is removedremoved
Urinary System DiagramUrinary System Diagram
11
22
33
44
55
66
Renal artery – transports blood to the kidney
Kidney – filters blood
Renal vein – transports blood from the kidney
Urethra – transports urine to outside of body
Ureter – transports urine to bladder
Bladder – stores urine
The Structure of a Kidney The Structure of a Kidney CREDITCREDIT
• Each kidney is made up of tiny filtration units called nephrons
•A nephron is made up of a Bowman`s capsule, a glomerulus and a tubule.
•Two main processes occur here :
• Filtration and Reabsorption
Nephron Diagram Nephron Diagram CREDITCREDIT
11
22
33
44
Glomerulus - filters blood
Bowman’s Capsule – collects filtrate
Blood capillaries – reabsorbs useful substances
Collecting duct – collects urine
Nephron function Nephron function CREDITCREDIT
StructureStructure FunctionFunction DecriptionDecription
GlomerulusGlomerulus
Bowman`s Bowman`s capsulecapsule
Blood capillariesBlood capillaries
Collecting ductCollecting duct
Filtration of blood
Proteins and cells stay in blood. Water, glucose and urea forced out
Collects glomerular filtrate
Contains water, glucose and urea
Useful materials (water and glucose) leave tubule and enter blood
Carries urine to the ureter
Urine contains water and urea only
Reabsorb and transport useful materials
Water BalanceWater Balance The kidneys The kidneys controlcontrol the the
water balancewater balance of the body of the body in a in a mammalmammal
70% of the body is water70% of the body is water
We produce We produce differentdifferent volumesvolumes of urine to of urine to regulate our water needs.regulate our water needs.
The kidneys are controlled The kidneys are controlled by a hormone called by a hormone called ADHADH (anti diuretic hormone)(anti diuretic hormone)
ADH is released by the ADH is released by the pituitary glandpituitary gland in the in the brainbrain . .
Pituitary and ADHPituitary and ADH
How How ADHADH regulates the kidneys regulates the kidneys CREDITCREDIT
ADHADH is produced by the pituitary gland is produced by the pituitary gland in the brainin the brain
If the If the waterwater content of our blood is content of our blood is too hightoo high - - Less ADHLess ADH is produced and is produced and the kidneys make the kidneys make lotslots of of watery watery urineurine..
If the If the waterwater content of the blood is content of the blood is too lowtoo low we produce we produce more ADHmore ADH and and the kidneys make the kidneys make small volumessmall volumes of of concentratedconcentrated urine urine
See p132 fig 14.7 for detailsSee p132 fig 14.7 for details
Role of ADH Role of ADH CREDIT CREDIT
3
1
2
4
5
6
sweating
High ADH
Small volume of
Concentrated urine
High water in blood
little water reabsorbed
low water back into blood
1
2
3
6
5
4
Low water in blood
Lot of water reabsorbed
Lot of water back into blood
Drinking lots of water
Low ADH
Large volume of dilute urine
•Too much water drunk
• High water level in blood
•Pituitary releases less ADH
•Kidney reabsorbs less water
•High volume of dilute urine produced
ADHADH and and too muchtoo much water water CREDITCREDIT
1
2
3
ADHADH and and too littletoo little water water CREDITCREDIT
Too little water drunk
Low water level in blood
Pituitary releases more ADH
Kidney reabsorbs more water
Low volume of concentrated urine
2
4
3
1
Kidney failure treatmentsKidney failure treatments Since the kidney is responsible for the Since the kidney is responsible for the removalremoval of of
wasteswastes from the blood, any from the blood, any damagedamage, either from , either from accidentsaccidents or or diseasedisease, can lead to a , can lead to a build up of build up of poisonous wastespoisonous wastes in the body. in the body.
Kidney MachineKidney Machine Kidney Kidney transplanttransplant
BenefitsBenefits
LimitationsLimitations
Purifies the blood
No rejection
Can live a more normal life if it is successful
Expensive
dialysis takes 12 hours twice a week
Rejection of kidney
Anti rejection drugs reduce bodies ability to fight disease
Kidney DIALYSISKidney DIALYSIS
Involves being Involves being connected to connected to a machinea machine for for long periods long periods of timeof time