an albatross can drink salt water – how can they do this without getting sick?!
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An albatross can drink salt water – how can they do this without getting sick?!. Thought Questions:. If you eat a lot of salt, what happens to your urine?. If you do not drink enough water, what happens to your urine?. If you drink excess water, what happens to your urine?. - PowerPoint PPT PresentationTRANSCRIPT
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An albatross can drink salt water – how can they do this without getting sick?!
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If you eat a lot of salt, what happens to your
urine?
Thought Questions:
If you do not drink enough water, what
happens to your urine?
If you drink excess water, what happens
to your urine?
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Lecture 12 Outline (Ch. 44)
I. Homeostasis
II. Water Balance
III. Animal Excretory Systems
IV. Human Urinary System
I. Bladder
II. Kidneys
V. Water Control
VI. Preparation for next lecture
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Maintains homeostasis of body fluids via water balance
aka ‘Excretory System’
Urinary System
Osmolarity, (solute concentration of solution), determines movement
of water across selectively permeable membranes
Hypoosmotic: lower solute conc, higher water
Hyperosmotic: higher solute conc, lower water
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Excretesalt ionsfrom gills
Gain water, salt ions from food
Osmotic waterloss from gills,body surface
Excrete salt ions &little water in scanty urine from kidneys
Gain water, salt ions fromseawater
(a) Osmoregulation in a saltwater fish
Uptake water, ions in food
Uptakesalt ionsby gills
Osmotic watergain from gills, body surface
Excretion of largeamounts of dilute urine
(b) Osmoregulation in a freshwater fish
Water BalanceOsmoconformer: isoosmotic with surrounding
Osmoregulator: control internal osmoslarity
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Watergain(mL)
Waterloss(mL)
Urine(0.45)
Urine(1,500)
Evaporation (1.46) Evaporation (900)
Feces (0.09) Feces (100)
Derived frommetabolism (1.8)
Derived frommetabolism (250)
Ingestedin food (750)
Ingestedin food (0.2)
Ingestedin liquid (1,500)
Waterbalance in akangaroo rat(2 mL/day)
Waterbalance ina human(2,500 mL/day)
Water Balance
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Flatworms use protonephridia
Animal Excretory Systems
Simplest system
Wastes stored in excretory pore, drawn out by waterenvironment
Tubule
Tubules ofprotonephridia
Cilia
Interstitialfluid flow
Opening inbody wall
Nucleusof cap cell
Flamebulb
Tubule cell
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Animal Excretory Systems
Remaining waste excreted
Capillarynetwork
Components ofa metanephridium:
External opening
Coelom
Collecting tubule
Internal opening
Bladder
Worms use metanephridia
Collect body waste
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Most urinary waste nitrogenous – from digesting protein
Vertebrate Urinary System
Blood filtered by kidneys
Fish excrete ammonia (toxic at high levels)
Land vertebrates convert to urea – add to urine
To reduce water-loss, desert animals (reptiles, snakes, birds) excrete uric acid (non-toxic, hydrophobic)
Desert kangaroo rat – excretes very concentrated urine
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urethra
left renalartery
left kidney
left renalvein
left ureter
urinarybladder
Human Urinary System1) Kidneys
• Blood w wastes brought by renal artery to kidney
• Filtered blood carried away by renal vein
2) Ureters• Transport urine away from kidney
3) Bladder• Stores urine
• Max capacity ~ 1 L
4) Urethra• Transport urine from bladder to outside body
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Bladder
Ureter
Urogenital diaphragm
Internal urethralsphincter (involuntary)
External urethralsphincter (voluntary)
Human Urinary System - Bladder
Micturition(urination)
Gotta pee?
Stretch stimulates contractions
Sphincters control release
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Human Urinary System - Bladder
Sensory Input(spinal cord)
(-)
Stretch(~200 ml)
(-)
Brain
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Urinary Disasters
Tycho Brahe: When you SHOULD go
The infamous candiru: When NOT TO go
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Human Urinary System - Kidneys
Urine forms in the nephron, ~1 million/kidney
Kidney Structure
Renalcortex
Renalmedulla
Renal artery
Renal vein
Ureter
Renal pelvis
nephron
Renalcortex
Renalmedulla
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Each nephron is a filter:
Glomerulus- network of capillaries
Bowman’s capsule- cup around glomerulus
Loop of Henle-Tubule network for adjusting water, salt, and waste levels
Collecting duct- carries fluid from nephron
Human Urinary System - KidneysAfferent arteriolefrom renal artery Glomerulus
Bowman’s capsule
Proximaltubule
Peritubularcapillaries
Distaltubule
Efferentarteriolefrom glomerulus
Collectingduct
Branch ofrenal vein
Descendinglimb
Ascendinglimb
Loopof
Henle
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Human Urinary System - Kidneys
FiltrationWater, nutrients, and wastes - filtered fromglomerulus into Bowman’s capsule
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Human Urinary System - Kidneys
Reabsorption
In proximal tubule, most water along with bicarbonate, K+, and NaCl are reabsorbed into blood.
Proximal tubule Distal tubule
Filtrate
CORTEX
Loop ofHenle
OUTERMEDULLA
INNERMEDULLA
Key
Active transportPassive transport
Collectingduct
NutrientsNaCl
NH3
HCO3 H2O K
H
NaClH2O
HCO3
K H
H2ONaCl
NaCl
NaCl H2O
Urea
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Human Urinary System - Kidneys
Proximal tubule Distal tubule
Filtrate
CORTEX
Loop ofHenle
OUTERMEDULLA
INNERMEDULLA
Key
Active transportPassive transport
Collectingduct
NutrientsNaCl
NH3
HCO3 H2O K
H
NaClH2O
HCO3
K H
H2ONaCl
NaCl
NaCl H2O
Urea
• Loop of Henle – increasing
osmolarity cortex to medulla
– active transport of Na+ & Cl– at ascending loop
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Human Urinary System - Kidneys
Secretion
In distal tubule, additional wastes (like H+ and K+) are actively secreted into the tubule from the blood
Proximal tubule Distal tubule
Filtrate
CORTEX
Loop ofHenle
OUTERMEDULLA
INNERMEDULLA
Key
Active transportPassive transport
Collectingduct
NutrientsNaCl
NH3
HCO3 H2O K
H
NaClH2O
HCO3
K H
H2ONaCl
NaCl
NaCl H2O
Urea
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Human Urinary System - Kidneys
Concentration
Proximal tubule Distal tubule
Filtrate
CORTEX
Loop ofHenle
OUTERMEDULLA
INNERMEDULLA
Key
Active transportPassive transport
Collectingduct
NutrientsNaCl
NH3
HCO3 H2O K
H
NaClH2O
HCO3
K H
H2ONaCl
NaCl
NaCl H2O
Urea
At collecting duct, additional water (and NaCl) leaves; urine more concentrated than blood.
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Human Urinary System - Kidneys
Two-solute model:
NaCl and Urea are moved into the kidney medulla
The filtrate in the nephron passes into this area three times
Osmolarityof interstitial
fluid(mOsm/L)
Key
ActivetransportPassivetransport
INNERMEDULLA
OUTERMEDULLA
CORTEX H2O
H2O
H2O
H2O
H2O
H2O
H2O
1,200
1,200
900
600
400
300
NaCl
NaCl
H2O
H2O
H2O
H2O
H2O
H2O
H2O
Urea
Urea
Urea1,200
300
400
600
100
NaCl
NaCl
NaCl
NaCl
NaCl
NaCl
NaCl
100
200
400
700900
600
400
300
300300
ThirstHypothalamus
ADHPituitarygland
Osmoreceptors inhypothalamus trigger
release of ADH.
STIMULUS:Increase in blood
osmolarity (forinstance, after
sweating profusely)
Homeostasis:Blood osmolarity
(300 mOsm/L)
Drinking reducesblood osmolarity
to set point.
H2O reab-sorption helpsprevent further
osmolarityincrease.
Increasedpermeability
Distaltubule
Collecting duct
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Body detects dehydration. Signal from hypothalamus to posterior pituitary.
Posterior pituitary releases ADH into the bloodstream.
ADH (antidiuretic hormone) allows more water reabsorbed into the blood.
Concentrated urine produced
Water Balance
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Water Balance
Urine: Waste and remaining water from nephron
• 95% water / 5% solutes (ions, urea)
Alcohol interferes with ADH
Production of dilute urine – Dehydration
HeadacheFatigueNausea
Things To Do After Lecture 12…Reading and Preparation:
1. Re-read today’s lecture, highlight all vocabulary you do not understand, and look up terms.
2. Ch. 44 Self-Quiz: #1, 3, 4, 6(correct answers in back of book)
3. Read chapter 44, focus on material covered in lecture (terms, concepts, and figures!)
4. Skim next lecture.
“HOMEWORK” (NOT COLLECTED – but things to think about for studying):
1. Compare and contrast the four different types of excretory systems.
2. Diagram the nephron, labeling regions and describing uptake/excretion at each region.
3. Explain the parts of the human urinary system.
4. Discuss the role of ADH – location of secretion and effect.