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 S1 Skill: Drawing and labelling a diagram of the human kidney.

From I-Biology.net

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

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)

From I-Biology.net

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.

From I-Biology.net

From I-Biology.net

From I-Biology.net

From I-Biology.net

From I-Biology.net

From I-Biology.net

11.U6 The loop of Henle maintains hypertonic conditions in the medulla.

From I-Biology.net

From I-Biology.net

From I-Biology.net

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

From I-Biology.net

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

Thanks to these fine folks, and any others that I may have forgotten!