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Removing Int racellular Waste. Kidney Structure & Function. Glucose. H 2 O. Na + Cl -. Amino acids. H 2 O. H 2 O. Na + Cl -. H 2 O. Mg ++ Ca ++. H 2 O. H 2 O. Collecting duct. Loop of Henle. aa. O 2. CH. CHO. CO 2. aa. NH 3. CHO. O 2. CH. O 2. aa. CO 2. CO 2. - PowerPoint PPT Presentation
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AP Biology
Kidney Structure& Function
Collecting ductLoop of Henle
Aminoacids
Glucose
H2O
H2O
H2O
H2O
H2O
H2O
Na+ Cl-
Mg++ Ca++Na+ Cl-
Removing IntracellularWaste
AP Biology
intracellular waste
Animal systems evolved to support multicellular life
O2
CHO
CHO
aa
aaCH
CO2
NH3aa
O2
CH
O2
aa
CO2CO2
CO2
CO2
CO2
CO2 CO2
CO2
CO2
CO2
NH3
NH3 NH3
NH3
NH3
NH3
NH3NH3
O2
aa
CH
aa
CHO
O2
Diffusion too slow!
single cell
but whatif the
cells areclustered?
for nutrients in & waste out
extracellular waste
AP Biology
Overcoming limitations of diffusion Evolution of exchange systems for
distributing nutrients circulatory system
removing wastes excretory system
systems to support multicellular organisms aa
CO2CO2
CO2
CO2
CO2
CO2 CO2
CO2
CO2
CO2
NH3
NH3 NH3
NH3
NH3
NH3
NH3NH3
O2
aa
CH
aa
CHO
O2
AP Biology
Osmoregulation
Why do all land animals have to conserve water? always lose water (breathing & waste) may lose life while searching for water
Water balance vs. Habitat freshwater
hypotonic to body fluids water flow into cells & salt loss
saltwater hypertonic to body fluids water loss from cells
land dry environment need to conserve water may also need to conserve salt
hypotonic
hypertonic
AP Biology
Intracellular Waste What waste products
are made inside of cells? what do we digest our food into…
carbohydrates = CHO lipids = CHO proteins = CHON nucleic acids = CHOPN
CO2 + H2ONH2
=ammonia
CO2 + H2O CO2 + H2O
CO2 + H2O + N CO2 + H2O + P + N
|
| ||H
HN C–OH
O
R
H–C–
Animalspoison themselves
from the insideby digesting
proteins!
lots!verylittle
cellular digestion…cellular waste
AP Biology
Nitrogenous waste disposal Ammonia (NH3)
very toxic very soluble
easily crosses membranes must dilute it & get rid of it… fast!
How you get rid of nitrogenous wastes depends on who you are (evolutionary relationship) where you live (habitat)
aquatic terrestrial terrestrial egg layer
AP Biology
Nitrogen waste Aquatic organisms
can afford to lose water ammonia
most toxic Terrestrial
need to conserve water
urea less toxic
Terrestrial egglayers
need to conserve water need to protect
embryo in egg uric acid
least toxic
AP Biology
Freshwater animals Hypotonic environment
water diffuses into cells Manage water & waste together
remove surplus water & waste use surplus water to dilute ammonia & excrete it also diffuse ammonia continuously through gills
overcome loss of salts reabsorb in kidneys or active transport across gills
AP Biology
Land animals Nitrogen waste disposal on land
need to conserve water must process ammonia so less toxic
urea = larger molecule = less soluble = less toxic 2NH2 + CO2 = urea produced in liver
kidney filter solutes out of blood reabsorb H2O (+ any useful solutes) excrete waste
urine = urea, salts, excess sugar & H2O urine is very concentrated concentrated NH3 would be too toxic
OC
HNH
HNH
Ureacosts energyto synthesize,
but it’s worth it!
mammals
AP Biology
Egg-laying land animals
itty bittyliving space!
Nitrogen waste disposal in egg no place to get rid of waste in egg need even less soluble molecule
uric acid = BIGGER = less soluble = less toxic birds, reptiles, insects
AP Biology
N
N N
N
O
HO
O
H
HH
Uric acid And that folks,is why most
male birds don’t have a penis! Polymerized urea
large molecule precipitates out of solution
doesn’t harm embryo in eggwhite dust in egg
adults still excrete N waste as white pasteno liquid wasteuric acid = white bird “poop”!
AP Biology
Mammalian System Filter solutes out of blood &
reabsorb H2O + desirable solutes Key functions
filtration fluids (water & solutes) filtered out
of blood reabsorption
selectively reabsorb (diffusion) needed water + solutes back to blood
secretion pump out any other unwanted
solutes to urine excretion
expel concentrated urine (N waste + solutes + toxins) from body
blood filtrate
concentratedurine
AP Biology
Mammalian Kidney
kidney
bladder
ureter
urethra
renal vein& artery
nephron
microvilli onepithelial
cells
adrenal glandinferior
vena cavaaorta
AP Biology
Nephron Functional units of kidney
1 million nephrons per kidney
Function filter out urea & other
solutes (salt, sugar…) blood plasma filtered
into nephron high pressure flow
selective reabsorption ofvaluable solutes & H2O back into bloodstream greater flexibility & control “counter current
exchange system”
whyselective reabsorption
& not selectivefiltration?
AP Biology
Mammalian kidney
Proximaltubule
Distal tubule
Glomerulus
Collecting ductLoop of Henle
Aminoacids
Glucose
H2O
H2O
H2O
H2O
H2O
H2O
Na+ Cl-
Mg++ Ca++
Interaction of circulatory & excretory systems
Circulatory system glomerulus =
ball of capillaries Excretory system
nephron Bowman’s capsule loop of Henle
proximal tubule descending limb ascending limb distal tubule
collecting duct
How candifferent sectionsallow the diffusion
of different molecules?
Bowman’s capsule
Na+ Cl-
AP Biology
Nephron: Filtration At glomerulus
filtered out of blood H2O glucose salts / ions (Na+ / Cl–) urea
not filtered out cells proteins
high blood pressure in kidneys force to push (filter) H2O & solutes out of blood vesselBIG problems when you start out with high blood pressure in systemhypertension = kidney damage
H2O&
solutes
cells &large
molecules
AP Biology
Nephron: Re-absorption Proximal tubule
reabsorbed back into blood NaCl
active transport of Na+
Cl– follows by diffusion
H2O glucose HCO3
-
bicarbonate buffer for
blood pH
AP Biology
Nephron: Re-absorptionstructure fits
function! Loop of Henle descending limb reabsorbed
H2O structure
many aquaporins in cell membranes
high permeability to H2O
no Na+ or Cl– channels impermeable
to salt
AP Biology
Nephron: Re-absorptionstructure fits
function! Loop of Henle ascending limb reabsorbed
Na+ & Cl–
structure many Na+ / Cl– channels
in cell membranes high permeability
to Na+ & Cl–
no aquaporins impermeable to H2O
AP Biology
Nephron: Re-absorption Distal tubule
reabsorbed salts H2O bicarbonate
HCO3-
regulate blood pH
AP Biology
Nephron: Reabsorption & Excretion Collecting duct
reabsorbed H2O = through
aquaporins excretion
concentrated urine
to bladder impermeable
lining = no channels in cell membranes
AP Biology
Osmotic control in nephron How is all this re-absorption achieved?
tight osmotic control to reduce the energy cost of excretion
use diffusion instead of active transportwherever possible
the value of acounter current exchange system
AP Biology
Summary Not filtered out of blood
cells u proteins remain in blood (too big)
Reabsorbed back to blood: active transport Na+ u amino acidsu glucose
Reabsorbed back to blood: diffusion H2O u Cl–
Excreted out of body urea excess H2O u excess solutes (glucose,
salts) toxins, drugs, “unknowns”
whyselective reabsorption
& not selectivefiltration?
AP Biology
Any Questions?