IB Biology Unit 5b: Osmoregulation and Kidneys (HL Only)
Annotate/draw a diagram of the nephron with specific structures.
*Hints*
Draw a diagram of the human kidney, and label the parts.
*Hints*: Renal artery, renal vein, cortex, medulla, renal pelvis, and ureter.
Define osmoregulator and osmoconformers
*Osmoregulators* keeps the organism's body osmolarity constant, regardless of environmental conditions. *Osmoconformers* maintains internal conditions that are equal to the osmolarity of their environments.
State the nitrogenous waste products released by: aqutic organisms, terrestrial organisms, marine mammals, amphibians, birds and insects
-Aquatic (most bony fishes) releases NH3 (ammonia) -Mammals, terrestrials, aphibians, sharks and some bony fishes releases urea. -Many reptiles, birds and insect releases uric-acid.
What happens in reabsorption?
-At the convoluted tubules, salt, glucose, amino acids and water is reabsorbed. -Salts are ACTIVELY reabsorbed back and water follows by osmosis. -Proximal Convoluted tubule has many mitochondria for energy and microvilli for extra SA. -1 cell thick so it's easy to transport. *LOOP OF HENLE* -Where osmoregulation takes place -Descending (water) and ascending (salt) -Makes the medulla salty (concentration gradient). -Counter-current and the vasa recta is going the opposite direction, picking up water molecules. - Medulla salty = water from collecting duct reabsorbs. -ADH
Outline the production and effect of ammonia in animals.
-By osmoconformation/osmoregulation. -Ammonia is a type of nitrogenous (toxic) waste, therefore it is required to leave the body. -Formed by the breaking down of nitrogen-containing molecules such as amino acids or nucleotides. -Ammonia is highly toxic but is soluble with water so aquatic animals can easily wash it out.
What is the benefit of having a 1 layer of cell.
-Easier to transport molecules, efficient absorption and secretion.
Outline the role of fenestration, the basement membrane and podocyte in ultrafiltration.
-Fenestration are *small gaps* that allows the exchange between blood vessles and tissues (pores in Bowman's capsule). -Basement membrane provides support to tissue and modulate cellular function. Separates blood from capillaries from filtrated waste in Bowman's capsule. -Podocyts wrap around capillaries of glomerulus and sit between them to allow fenestration (water, flucose, aminos acids, salt and urea) Regulates and modulates filtration rate.
What happens in ultrafiltration?
-Glomerulus filtrates: water, salt, amino acids, glucose and urea from the blood. -Fenestration are gaps which only allows small molecules such as those to pass. -Pressure from the wider entrance to narrow exit. -The basement membrane filters out what can pass. -Travels to the proximal convoluted tubule.
Outline the cause and effect of high blood pressure in the kidneys.
-High blood pressure pushes the molecules through the capillary walls. Past the basement membrane and to Bowmans capsule. -From the afferent (short and wide) to the efferent (narrow) arterioles. 1) Blood isn't far from the heart (enters kidneys from the aorta). 2) The arterioles leaving the capsule is narrower than the entering.
Explain why plasma proteins and blood cells are not part of the glomerular filtrate?
-Plasma proteins are too large -Blood cells would also be too large to pass through the Bowman's capsule.
Outline the use of a urine test strip in detection of diabetes, kidney damage and drug use.
-Presence of glucose can indicate diabetes -Presence of proteins can indicate hormonal conditions -Drugs/toxins passing through the body can be detected (enhanced drugs)
Compare urea and uric acid.
-Urea is less toxic than ammonia, and uric acid is not toxic. *Urea* is less toxic and can be stored at a higher concentration and flushed in urine. *Uric acid* is non-toxic and requires less water to flush. Eliminates semi-solid waste, though requires more energy to make.
List solutes found in glomerular filtrate.
-Water, glucose, amino acids, sodium chloride, urea (Proteins, blood cells and platelets are too big to pass through the Bowman's capsule).
Outline the structure and fuction of the Mapighian tubule system
1) Salts, water and uric acid are filtered from the hemolymph to the malpighian tubules. -Tubule then would be hypertonic to hemolymph. Water moves into tubule through osmosis. 2) In the hindgut, some salts are actively reabsorbed back into the hemolymph. Water flows OUT. -Wastes are released out by anus.
Outline the process of hemodialysis
1) there are tubes connecting the patient's artery and vein to the machine. 2) Arterial blood from patient enters the dialyzer. 3) Dialyzer would remove the waste from the blood via filtration (with constant new dialysis fluid being replaced) 4) Purified blood is returned to a vein.
Distinguish between the Afferent and Efferent arterioles.
Afferent brings blood INTO the glomerulus whereas Efferent takes blood out of the glumerulus.
Define osmoregulation.
Blood is filtered and urine is formed, takes place in the kidneys. -> The control of water balance of the blood, tissue or cytoplasm.
Describe why the loop of Henle is countercurrent multiplier system?
Countercurrent: cross over of some property. -Ascending tube is permeable to NaCl (active), making the surrounding (medulla) *hypertonic* (salty). -Descending limb is permeable to only water, since Ascending limb made the surrounding (medulla) salty, water leaves descending tube via *osmosis* and descending tube is *hypertonic* -Vasa recta around the loop of Henle also takes up bits of water, so it makes the medulla salty as well.
List 2 common cause of kidney failure
Diabetes and high blood pressure.
Outline the relationship between habitat and relative medullary thickness
Dry habitat animals has a higher salt gradient, and reabsorbs more water, to accomodate that, the meddula has to become thicker as well.
Outline the causes and consequences of over-hydration.
Excessive intake of water than results too much water than sodium. Consequences: often the brain can adapt to only mild symptoms — confusion, siezures, and coma might develop.
What happens in excretion?
Excreted: urea, toxins/drugs and excess water. Keeps: water, glucose, amino acids, salt and proteins.
Outline the process of a kidney transplant
Fact: A person only need 1 kidney to live and function like normal. 1) Donor from an alive person or deceased. 2) Old kidney from patient is replaced with the healthy kidneys. 3) RISK OF REJECTION THOUGH!
Define nephron.
Functional unit of the kidenys. -Tube with a wall consisting of one layer of cells. -Consists of smaller different parts which has different functions.
Outline the effect of high blood solute concentration on the volume of urine produced, solute concentration in urine, permeability of the distal convoluted tubule and collecting duct to water and volume of water absorbed.
Higher blood concentration = dehydration. More ADH is produced thus more aquaporins. -In a high blood solute concentration, the individual would urinate less and it's less diluted because ADH is allowing more reabsorption of water.
List the substances in the glomerular filtrate that are reabsorbed in the proximal *CONVOLUTE* tubule.
Ions such as: salts, glucose, and amino acids. (With the salt pumping back, water would also follow by osmosis)
Define urinalysis
It is a type of test which uses your urine to detect things like infections, kidney disease and diabetes.
Outline the process of treatment of kidney stones by ultrasound
Kidney stones can result from chronic dehydration. -Ultrasonic waves from outside the body targets the stones. -Shatters the stone to smaller fragments and the patient can pee it out.
Outline the effect of low blood solute concentration on the volume of urine produced, solute concentration in urine, permeability of the distal convoluted tubule and collecting duct to water and volume of water absorbed.
Medulla is *hypertonic* by ascending side. The amount released by collecting duct is controlled by the anti diuretic hormone (produced in the pituitary gland in response of dehydration). -In low blood solute concentration, the individual would urinate more and it's much more dilute (b/c less ADH is produced).
List 4 substances that are found in higher concentrations in the renal artery than the renal vein.
More water, oxygen, glucose and urea-toxins, amino acids
State the function of the kidneys.
OSMOREGULATION. -Active regulation of osmolarity of blood to maintain homeostasis. -Keeps the amount of solutes and water in the blood balanced. BLOOD FILTRATION/EXCRETION. -Removal of metabolic waste (UREA — NH3 is toxic) from the body.
Describe the structure of the descending limp of the loop of Henle
On the PCT's side, permeable to water but not salts, thus creates a high concentration of solute in the loop of Henle.
Describe the structure and function of the ascending limb of the loop of Henle.
Only salts are permeable in the ascending side, thus creating a high solute (NaCl) concentration in the (salty) medulla (hypertonic). -Due to that, there's a concentration gradient, thus water would be going out from the collecting duct to keep blood osmolarity at a homeostasis stage.
Distinguish between osmoregulation and excretion.
Osmoregulation: regulation of osmolarity of blood to maintain homeostasis. Excretion: removal of metabolic waste from the body.
List three examples osmoregulatory animals and three examples of osmoconformer animals.
Osmoregulatory: humans, birds, reptiles (most animals) Osmoconformer: Starfish, lobster, jellyfish (most marine)
Outline the mechanism of reabsorption of sodium ion, glucose and water.
Proximal convoluted tubule has many mitochondria and microvilli. -Some substances in the filtrated fluid entering the PCT would be absorbed by the microvilli with all the channels and pumps and is returned to blood by cells. (Small molecules like water, salts, amino acids and glucose, which was filtrated by the glomerulus.)
Compare relative glucose, oxygen and carbon dioxide concentrations between the renal artery and renal vein.
Renal artery has a higher concentration of glucose and oxygen than the renal vein. However, it has a lower carbon dioxide concentration.
Outline the source and function of the ADH in osmoregulation.
The anti-diuretic hormone is produced in the hypothalamus in response to dehydration. -ADH triggers thirst and controls the water reabsorption during osmoregulation in the kidneys (CONTROLS THE WATER PERMEABILITY OF THE COLLECTION DUCT) -More ADH = more aquaporins in the collecting duct for water reabsorption.
Describe the relationship between the glomerulus and Bowman's capsule.
The glomerulus filtrates the blood and metabolic waste and it would go through to the Bowman's capsule and gets carried through the tubules and to anus.
Outline the relationship between habitat and length of loop of henle
The length of the loop is postively correlated with the need for water. Animals adapted to *dry habitats* has a longer loop of Henle (increases salt gradient in the medulla, more water in reabsorbed), and thicker medulla. Animals adapted to *moist habitats* has a shorter loop of Henle to decrease the salt gradient and less water is reabsorbed.
State the overall function of the loop of Henle
The loop of Henle is to carry out osmoregulation.
Outline the causes and consequences of dehydration
The loss of body fluids, mostly water, exceeds the amount that is intake. Causes: fevers, heat exposure, too much excercise, vomiting, diarrhea and extreme burns. Consequences: increase in thirst, dry mouth, weakness, dizzy, decrease of urine, confusion and inability to sweat.
State that the plasma proteins are not filtered by the kidneys so should be present in the same concentration in the renal artery.
The plasma proteins are found in both renal and vein artery. -During ultrafiltration, only small molecules can pass, so no blood proteins.
Where is the vasa recta?
The veins/capillaries around the loop of Henle.
Explain why cells lining in the lumen of the proximal convoluted tubule have many mitochondria and microvillis.
To transport/reabsorbe the ions, it would require a lot of energy, therefore the presence of the mitochondria is to produce enough sufficient energy for the reabsorption to happen. The prescense of microvillis allow a larger surface area, thus more absorption can happen
