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2008-2009 AP Biology
Regulating the InternalEnvironment
AP Biology
Conformers vs. Regulators Two evolutionary paths for organisms
______________________________________ maintain relatively constant internal conditions
______________________________________ allow internal conditions to fluctuate along with external changes
conformer
thermoregulation
regulator
conformer
osmoregulation
regulator
AP Biology
Homeostasis Keeping the balance
animal body needs to coordinate many systems all at once temperature blood sugar levels energy production water balance & intracellular waste disposal nutrients ion balance cell growth
maintaining a “steady state” condition
2008-2009 AP Biology
Regulating the InternalEnvironment
Water Balance & Nitrogenous Waste
Removal
AP Biology
intracellular waste
extracellular 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!
AP Biology
Overcoming limitations of diffusion Evolution of exchange systems for
distributing nutrients _________________
removing wastes _________________
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?
Water balance freshwater
_________________ water flow into cells & salt loss
saltwater _________________ 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?
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)
______________________ carcinogenic
______________________ 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 ____________________
can afford to lose water _________________
most toxic ____________________
need to conserve water
_________________ less toxic
________________ ________________
need to conserve water need to protect
embryo in egg _________________
least toxic
AP Biology
Freshwater animals Water removal & nitrogen waste disposal
remove surplus water use surplus water to dilute ammonia & excrete it
need to excrete a lot of water so dilute ammonia & excrete it as very dilute urine
also diffuse ammonia continuously through gills or through any moist membrane
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
_____ = larger molecule = less soluble = less toxic 2NH2 + CO2 = urea produced in liver
_______________ filter solutes out of blood reabsorb H2O (+ any useful solutes) excrete waste
_____ = urea, salts, excess sugar & H2O urine is very concentrated concentrated NH3 would be too toxic
OC
HNH
HNH
Ureacosts energy
to synthesize,but it’s worth it!
mammals
AP Biology
Egg-laying land animals
itty bittyliving space!
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Nitrogen waste disposal in egg no place to get rid of waste in egg need even less soluble molecule
_________ = 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 a male bird
doesn’t have a penis! Polymerized urea
large molecule __________________________
doesn’t harm embryo in eggwhite dust in egg
adults excrete N waste as white pasteno liquid wasteurea = white bird “poop”!
AP Biology
Mammalian System Filter solutes out of blood &
reabsorb H2O + desirable solutes Key functions
____________________ fluids (water & solutes) filtered out
of blood ____________________
selectively reabsorb (diffusion) needed water + solutes back to blood
____________________ pump out any other unwanted
solutes to urine ____________________
expel concentrated urine (N waste + solutes + toxins) from body
blood filtrate
concentratedurine
AP Biology
Mammalian Kidney
kidney
bladder
ureter
urethra
renal vein& artery
nephron
epithelialcells
adrenal glandinferior
vena cavaaorta
AP Biology
Nephron Functional units of kidney
1 million nephrons per kidney
Function filter out urea & other
solutes (salt, sugar…) ________________________
into nephron high pressure flow
________________________ of valuable 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 _______________ =
ball of capillaries Excretory system
__________________ __________________ __________________
proximal tubule descending limb ascending limb distal tubule
__________________
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 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
AP Biology
Nephron: Re-absorption
Descendinglimb
Ascendinglimb
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
Descendinglimb
Ascendinglimb
Nephron: Re-absorption Loop of Henle
________________ _________________
_________________ __________________
__________________ low permeability to
salt few Na+ or Cl–
channels reabsorbed
H2O
structure fitsfunction!
AP Biology
Nephron: Re-absorption
Descendinglimb
Ascendinglimb
Loop of Henle ________________
low permeability to H2O
_________________ _________________
_________________ different membrane
proteins reabsorbed
salts maintains osmotic
gradient
structure fitsfunction!
AP Biology
Nephron: Re-absorption Distal tubule
reabsorbed salts H2O HCO3
-
bicarbonate
AP Biology
Nephron: Reabsorption & Excretion Collecting duct
reabsorbed H2O
excretion concentrated
urine passed to bladder impermeable
lining
Descendinglimb
Ascendinglimb
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 _____________________
cells proteins remain in blood (too big)
Reabsorbed: __________________ Na+ amino acids Cl– glucose
Reabsorbed: __________________ Na+ Cl–
H2O Excreted
urea excess H2O excess solutes (glucose, salts) toxins, drugs, “unknowns”
whyselective reabsorption
& not selectivefiltration?
2008-2009 AP Biology
Any Questions?
2008-2009 AP Biology
Regulating the InternalEnvironment
Maintaining Homeostasis
AP Biology
sensor
Negative Feedback Loop
high
low
hormone or nerve signal
lowersbody condition(return to set point)
hormone or nerve signal
gland or nervous system
raisesbody condition (return to set point)
gland or nervous system
sensorspecific body condition
AP Biology
Controlling Body Temperature
high
low
nerve signals
sweat
nerve signals
body temperature
shiver brain
dilates surfaceblood vessels
constricts surfaceblood vessels
Nervous System Control
brain
AP Biology
nephron
low
Blood Osmolarity
blood osmolarityblood pressure
ADH
increasedwater
reabsorption
increasethirst
high
Endocrine System Control
pituitary
ADH = AntiDiuretic Hormone
AP Biology
H2O
H2O
H2O
Maintaining Water BalanceGet morewater intoblood fast
Alcohol suppresses ADH…
makes youurinate a lot!
High blood osmolarity level too many solutes in blood
dehydration, high salt diet stimulates thirst = drink more release ADH from pituitary gland
antidiuretic hormone increases permeability of collecting duct
& reabsorption of water in kidneys increase water absorption back into blood decrease urination
AP Biology
low
Blood Osmolarity
blood osmolarityblood pressure
increasedwater & saltreabsorption
in kidney
high
Endocrine System Control
angiotensigenangiotensin
nephronadrenalgland
aldosterone
JGA
JGA = JuxtaGlomerular Apparatus
Oooooh,zymogen!
renin
AP Biology
Maintaining Water Balance Low blood osmolarity level
or low blood pressure JGA releases renin in kidney renin converts angiotensinogen to angiotensin angiotensin causes arterioles to constrict
increase blood pressure angiotensin triggers release of aldosterone from
adrenal gland increases reabsorption of NaCl & H2O in kidneys
puts more water & salts back in blood
Get morewater & salt into
blood fast!
adrenalglandWhy such a
rapid responsesystem?
Spring a leak?
AP Biology
nephron
low
Blood Osmolarity
blood osmolarityblood pressure
ADH
increasedwater
reabsorption
increasethirst
renin
increasedwater & saltreabsorption
high
Endocrine System Control
pituitary
angiotensinogenangiotensin
nephronadrenalgland
aldosterone
JuxtaGlomerularApparatus
2008-2009 AP Biology
Don’t get batty…Ask Questions!!