ap biology 2008-2009 excretory system kidneys and the urinary system, lungs, skin, & liver...
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AP Biology 2008-2009
Excretory SystemKidneys and the Urinary
System, Lungs, Skin, & Liver
(removing metabolic waste)
Regents Biology
Unicellular Multicellular
• All cells in direct contact with environment• All cells can easily get
nutrients in & waste out by diffusion
• Internal cells not in direct contact with environment• Internal cells can’t get
nutrients in & waste out• Need organ systems
Warm, diluteocean waters
Warm, diluteocean waters
Unicellular Multicellular
Limits cell size - Must stay small
Regents Biology
What liquid waste do we make?
Digesting protein makes poison nitrogen waste = ammonia = poison
H
CO2 + H2O
NH2 = ammonia
H
HN C—OH
|| O
H|
—C—| AMINO ACIDs and
Nitrogen Bases
Regents Biology
The kind of waste you make depends on where you live Freshwater
Ammonia Diffuse and dilute
quickly Land
Urea Humans
Egg layer/Insects uric acid Solid – crystals LEAST toxic
Nitrogen waste
Regents Biology
Human Excretory System Mammals have a pair of bean-shaped
kidneys supplied with blood by a renal artery
and a renal vein
Organ system
Organ
Tissue
Nephron
Regents Biology
Bladder
Regents Biology
Nephron = functional unit of kidney Not filtered out
cells and proteins (too big) Filtered out
“Bad” stuff Urea (from liver) Salts H2O toxins from food
“Good” stuff simple sugars, aa
“Good” stuff reabsorbed; “Bad” stuff makes urine
to
bladder
Regents Biology
Nephron Structure – functional unit
Renal
Renal
FILTRATIONRemoves “good” and
“bad” stuffNO Cells leave the
blood vessels
REABSORPTIONReabsorb “good”
stuff” (ss, aa, some salt and some water
to maintain water balance)
Capillaries – wrapped around loop to
increase surface area
Ball of capillariesBowman’s capsule
Regents Biology
Also• Skin – removes salt, water, and urea
• called sweat• Lungs – remove CO2 and water• Liver – PRODUCES UREA
Diseases/Disorders – failure to maintain homeostasis
• Kidney Disease – failure of kidneys to filter toxins from blood; treatment =dialysis or transplant
• Nephritis – inflammation of kidneys• Kidney stone – calcium deposit that blocks ureter • Gout – build up of uric acid in joints