11.3 The Kidney & Osmoregulation
Essential Idea: All animals excrete nitrogenous waste products and some animals also balance water and solute concentrations.
Nature of Science: Curiosity about particular phenomena—investigations were carried out to determine how desert animals prevent water loss in their wastes.
http://www.bio.miami.edu/tom/courses/protected/ECK/CH14/figure-14-17.jpg
By Darren Aherne
11.3 The Kidney & Osmoregulation Essential Idea: All animals excrete nitrogenous waste products and some animals also balance water and solute concentrations.
Assessment Statement Guidance
11.3 U1 Animals are either osmoregulators or osmoconformers.
11.3 U2 The Malpighian tubule system in insects and the kidney carry out osmoregulation and removal of nitrogenous wastes.
11.3 U3 The composition of blood in the renal artery is different from that in the renal vein.
11.3 U4 The ultrastructure of the glomerulus and Bowman’s capsule facilitate ultrafiltration.
11.3 U5 The proximal convoluted tubule selectively reabsorbs useful substances by active transport.
11.3 U6 The loop of Henle maintains hypertonic conditions in the medulla.
11.3 U7 ADH controls reabsorption of water in the collecting duct.
ADH will be used in preference to vasopressin.
11.3 U8 The length of the loop of Henle is positively correlated with the need for water conservation in animals.
11.3 The Kidney & Osmoregulation Essential Idea: All animals excrete nitrogenous waste products and some animals also balance water and solute concentrations.
Assessment Statement Guidance
11.3 U9 The type of nitrogenous waste in animals is correlated with evolutionary history and habitat.
11.3 A1 Application: Consequences of dehydration and overhydration.
11.3 A2 Application: Treatment of kidney failure by hemodialysis or kidney transplant.
11.3 A3 Application: Blood cells, glucose, proteins and drugs are detected in urinary tests.
11.3 S1 Skill: Drawing and labelling a diagram of the human kidney.
11.3 S 2 Skill: Annotation of diagrams of the nephron.
The diagram of the nephron should include glomerulus, Bowman’s capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule; the relationship between the nephron and the collecting duct should be included.
11.3 U1 Animals are either osmoregulators or osmoconformers.
Jellyfish are osmoconformers; the solute concentration of their cells is the same as the ocean.
http://fc06.deviantart.net/fs71/f/2012/135/d/6/jellyfish_1_by_archangelical_stock-d4zy2bj.jpg
Ligers are osmoregulators. They maintain homeostasis for solutes in their blood. http://thingd-media-ec5.thefancy.com/default/289660058877299361_0a3754098a27.jpg
Osmolarity means how much solutes are dissolved in a solution. Osmoregulators: maintain homeostasis for osmolarity- they keep their internal solute concentrations within a narrow range. Examples: terrestrial animals, freshwater fish, bony marine fish, marine mammals Osmoconformers: Let their osmolarity match that of the environment. Examples: jellyfish, sea stars
11.U9 The type of nitrogenous waste in animals is correlated with evolutionary history and habitat.
Where does nitrogenous waste come from? • Breakdown of proteins (amino acids) • Breakdown of nucleic acids
Forms ammonia (NH4) Ammonia is toxic & must be excreted
Animal lives in terrestrial environment (needs to conserve water)
Animal lives in water environment (no need to conserve water)
Excrete NH4 directly Convert NH4 to urea (mammals) - costs energy
Convert NH4 to uric acid (birds) - costs even more energy
Nitrogenous wastes are poisonous to animals. They must be excreted!
11.3 U2 The Malpighian tubule system in insects and the kidney carry out osmoregulation and removal of nitrogenous wastes.
Animals need to maintain homeostasis. -Homeostasis for osmolarity & the removal of nitrogenous wastes is maintained by the Malpigian tubule system in arthropods (insects). 1. Nitrogenous wastes in insects
is uric acid. 2. Uric acid & ions are moved
into Malpighian tubules by active transport.
3. Water follows by osmosis. 4. Moves to gut- water & ions
are reabsorbed. 5. Uric acid is excreted with
feces.
Homeostasis: maintaining a constant internal conditions within a narrow range, despite fluctuations in the external environment.
From Biology Course Companion, Allott & Mindorf,, Oxford University Press, 2014, p. 487
11.3 U3 The composition of blood in the renal artery is different from that in the renal vein.
Main idea: Structure is related to function
Kidneys function to remove wastes and in osmoregulation (the amount of water in the blood). • Blood enters the kidney through
the renal artery • Unneeded substances are
removed: • Excretory products:
Toxins & products of metabolism, urea and other nitrogenous wastes
• Non-excretory products: excess water, excess salt
• Blood exits the kidney through the renal vein
http://www.chemistry.wustl.edu/~edudev/LabTutorials/Dialysis/images/KidneyFlow.jpg
http://www.slideshare.net/gurustip/the-kidney?ref=http://i-biology.net/ahl/11-human-physiology-ahl/the-kidney/
11.3 S1 Skill: Annotation of diagrams of the nephron.
The diagram of the nephron should include: • Glomerulus • Bowman’s capsule • Proximal
convoluted tubule • Loop of Henle • Distal convoluted
tubule
From I-Biology.net
View this animation about kidney function:
http://www.biologymad.com/resources/kidney.swf View this video by Craig Savage: Introduction to the Kidney
https://www.youtube.com/watch?v=Z6L8TZaou6k
11.U4 The ultrastructure of the glomerulus and Bowman’s capsule facilitate ultrafiltration.
From I-Biology.net
Ultrafiltration: Nearly all substances are filtered out of the blood except proteins & blood cells
11.U4 The ultrastructure of the glomerulus and Bowman’s capsule facilitate ultrafiltration.
From Biology Course Companion, Allott & Mindorf,, Oxford University Press, 2014, p. 488
From Biology Course Companion, Allott & Mindorf,, Oxford University Press, 2014, p. 490
Podocytes: irregularly shaped cells in glomerulus that wrap around capilaries Basement membrane: Filter-allows only water and small molecules through. Fenestrations: tiny pores (holes)
Small molecules are filtered out of the blood due to high pressure and the structure of glomerulus & Bowman’s capsule
Large molecules stay in the blood
(Structure)
Topic 1.4: Membrane Transport Review: Compare & Contrast active transport, cotransport, and osmosis.
Characteristic: Active Transport Cotransport Osmosis
Uses ATP
Direction
Substances
Membrane protein needed
Compare: Give an account of the similarities between two (or more) items or situations, referring to both (all) of them throughout. Compare & Contrast: Give an account of similarities and differences between two (or more) items or situations, referring to both (all) of them throughout.
Tip: When asked to compare or compare & contrast, make a table
Topic 1.4: Membrane Transport Review: Compare & Contrast active transport, cotransport, and osmosis.
Characteristic: Active Transport Cotransport Osmosis
Uses ATP Yes No No
Direction From areas of low concentration to high concentration
From areas of high concentration to low concentration
From Areas of low solute concentration to areas of low solute concentration
Substance • Ions/small molecules Ions/small molecules Water
Membrane protein needed
Yes Yes No
Tip: When asked to compare or compare & contrast, make a table
Compare: Give an account of the similarities between two (or more) items or situations, referring to both (all) of them throughout. Compare & Contrast: Give an account of similarities and differences between two (or more) items or situations, referring to both (all) of them throughout.
11.U5 The proximal convoluted tubule selectively reabsorbs useful substances by active transport.
• In ultrafiltration, small molecules are filtered out of the blood. • Substances that are useful are later reabsorbed in the
proximal convoluted tubule. • Active transport moves substances against concentration
gradients and requires ATP.
Structure follows function: Function: absorption Structure: high surface area
Substance How it’s reabsorbed
Sodium (Na+) Active transport from filtrate to space outside of tubule
Chloride (Cl-) Follow Na+ ions due to charge attraction
Glucose & amino acids
Cotransport – when Na+ ions move back down concentration gradient through special cotransport proteins , glucose & amino acids are moved out of filtrate
Water Outside of tubule is hypertonic, so water moves by osmosis.
11.U7 ADH controls reabsorption of water in the collecting duct.
ADH is AntiDiuretic Hormone • A diuretic is something that increases urine production (more water in urine). • So increase in ADH means smaller volume of concentrated urine is produced.
https://bluelotusfertility.files.wordpress.com/2012/01/adam_hypothalamus_pituitary_17135.jpg
Hypothalmus- senses solute concentration of the blood, & sends signal to pituitary to release more/less ADH
Pituitary gland- secretes ADH into the blood stream, which takes it to the cells in the kidney
http://highered.mheducation.com/sites/0072495855/student_view0/chapter20/animation__hormonal_communication.html From I-Biology.net
Osmoregulation uses negative feedback to keep the solute concentration of blood at the right level.
http://diabetesdietssolution.com/tag/dihybrid-cross-college-of-the-siskiyous-home
11.U8 The length of the loop of Henle is positively correlated with the need for water conservation in animals.
The function of the loop of Henle is the recovery of water and salts from the urine. • The longer the loop of Henle is, the more water and salt
it is able to recover. • Loop of Henle uses countercurrent exchange.
http://www.colorado.edu/intphys/Class/IPHY3430-200/countercurrent_ct.swf
11.A1 Application: Consequences of dehydration and overhydration.
Consequences of Dehydration Consequences of Overhydration
Dark, concentrated urine Headache
Tiredness & lethargy due to muscles working inefficiently
Disruption of nerve function- neurons need sodium, potassium, & calcium ions to work properly (Na+ K+ Ca+)
Falling blood pressure as blood volume decreases
Increased heart rate as heart works to pump thick, viscous blood through body
No sweating leads to difficulty controlling body temperature
• Dehydration occurs when too much water is lost from the body from exercise or diarrhea, or from insufficient drinking
• Overhydration occurs when large amounts of water are consumed without electrolytes (salts) after heavy exercise.
11.A2 Application: Treatment of kidney failure by hemodialysis or kidney transplant.
• Kidneys can fail, usually as a result of diabetes or chronic high blood pressure. • A doner kidney may be transplanted into the patient, but there are risks of an immune
response & rejection of the new organ (see topic 6.3 & 11.1).
When the cells of a donated organ are recognized as non-self, Lymphocytes (white blood cells) destroy them as part of an immune response.
Image from Biology Course Companion, Allott & Mindorf,, Oxford University Press, 2014, p. 497
http://www.gujaratkidneyfoundation.com/images/dialysis.jpg
Dialysis works in the place of a non-functioning kidney • Blood from a vein is pumped through semipermeable membrane that allows small
waste molecules to pass through but not larger molecules like proteins & cells • The tube passes through dialysis fluid which creates a concentration gradient • Filtered blood is returned to the body through a vein.
How does this use countercurrent exchange?
11.A3 Application: Blood cells, glucose, proteins and drugs are detected in urinary tests.
http://www.albertaventure.com/wp-content/uploads/2008/06/peecup.jpg
Urine be used to check a number of potential health issues.
Blood Cells
White blood cells urinary tract infection Red blood cells kidney stones
Glucose Glucose is normally reabsorbed in the P.C.T. Presence of glucose Diabetes
Proteins Proteins are not taken out of the blood in ultrafiltration Presence of proteins Diabetes / kidney damage
Drugs Drugs or their metabolites can be tested for in urine.
http://www.bodywellgroup.co.uk/assets/Uploads/Urinalysis3.png