Excretory System
What does drinking water do to your urine?
makes it clear and yellow
What does ECF stand for?
extracellular fluid
Excretion
final filtrate leaves as urine
How does it get rid of nitrogenous waste?
gets rid of amine group
Urea
less toxic, water- soluble, used by placental animals, more E (2 amine groups)- O = C -NH2 - NH2
Functions of the excretory systom
1. controls volume of blood (ECF) 2. filters blood and makes urine 3. controls water and salt balance of blood 4. controls composition of blood (ECF) 5. gets rid of nitrogenous waste
Types of nitrogenous waste
AKA PEE
What is found in the glomerulus?
Blood
What are the 4 structures in the excretory system?
Kidney, Ureters, Bladder, Urethra
Amonia
NH3- very toxic, requires lots of H2O to dilute, used by fish that lay eggs without shells, less E
What is the functional unit of the kidney?
Nephron
Nitrogenous waste comes from the digestion of what 2 macromolecules?
Proteins and nucleic acids
What adjective that means related to the kidney?
Renal
Explain how this salt gradient is produced:
The salt gradient is produced by the ascending limb of the loop of Henle - salt is first passively transported out of the filtrate and then actively pumped out.
What is the purpose of the salt gradient in the kidney?
The salt gradient maximizes osmosis so water can be reabsorbed
What is a diuretic?
a chemical that decreases water reabsorption and therefore increases the amount of water in the urine
Who has osmoconformas?
all marine inverts.. sharks!
How goes through osmoregulation?
all terrestrial animals, all fresh water animals, all marine animals
Do secreted substances move from filtrate to blood or from blood to filtrate?
blood to filtrate
Filtrate flow
bowman's capsule-proximal convoluted tubular- descending limb LOH- ascending limb LOH- distal convoluted tubular- collection ducts
How does the kidney control the volume of the blood?
controls how much water is reabsorbed versus lost in urine
Osmoregulation
controls salt/water balance internally despite external conditions (homeostasis)
What is the difference in permeability between the descending and ascending limbs of the loops of Henle?
descending is permeable to water but not to salt, ascending is permeable to salt but not to water
What is the difference in the blood in the afferent/ efferent arteriole?
efferent would have less water and fewer solutes than afferent since they were filtered out into the Bowman's capsule
Countercurrent exchange
maximize diffusion (CCE)
How does the countercurrent exchange work in the kidney?
maximizes osmosis in Loop of Henle by presenting an increasingly hypertonic environment
IS filtration nonspecific or specific?
nonspecific- only size
Uric Acid
not toxic, not very soluble, used by insects and birds (eggs have shells), more E!!
Descending Limb
pemeable to H20 (impermeable to salts)
Substances reabsorbed from the nephron are reabsorbed into what blood vessel?
peritubular capillaries
Ascending limb
permeable to salt, impermeable to H20, maintain saltiness (active/ passive transport)
Which does the filtrate flow through first, proximal or distal?
proximal
Blood Flood
renal artery- afferent arteriole- glomerulus (cap bed)- efferent arteriole- peritubular capillaries- renal vein- heart
Osmoconformas
same salt/water balance as enviroment
Filtration
small molecules are pushed through (by BP) out of the glomerulus and into the Bowman's capsule (nonspecific) glomerulus-- bowman's capsule
Reabsorbtion
take beneficial (glucose) molecules and move them through (passive and active transport) from filtrate back to blood (peritubular capillaries) SPECIFIC (proximal tubular---- collecting duct)-- peritubular capillaries
Secretion
take harmful/ waste molecules out of blood and move to filtrate (urea) SPECIFIC, (peritubular cap to proximal tubulars ----- collecting duct)
What is the difference (other than size) between the thin and thick segments of the ascending Limb of the Loop of henle?
thin - passive transport of NaCl, thick - active transport of NaCl
