Download Animal Anatomy and Physiology- Excretory System

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Excretion
AP Biology
Ms. Day
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Waste disposal
 What
Animals
can’t store
extra
proteins
waste products?
 what do we breakdown?
 carbohydrates = CHO  CO2 + H2O (in CR)
 lipids = CHO  CO2 + H2O (in CR)
 proteins = CHON  CO2 + H2O + N
 nucleic acids = CHOPN  CO2 + H2O + P + N

relatively small amount in cell
=can store
NH2 + H+=
2005-2006
ammonia
H| OH
||
H
N–C– C–OH
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H
R
CO2 + H2O
+ Types of Nitrogenous Wastes
 Nitrogenous
wastes = wastes that contain nitrogen
 Toxic by-products of metabolism
 Result from breakdown of proteins & nucleic
acids
3 Types of wastes
 Ammonia (NH3) Excreting it directly is very
efficient  no energy expended
 Very
toxic!!!
 Ex: Marine fish
 Urea
and Uric Acid
 Requires energy to convert NH4 to these forms
 Less toxic (uric acid is more toxic than urea b/c
not soluble in water)
 Ex: Mammals (urea) and Birds (uric acid)
produced in liver
VERY TOXIC; very
soluble in H2O
LESS TOXIC;
soluble in H2O
NOT TOXIC; Form ppt 
NOT soluble in H20
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Mammalian Kidneys
 Bean
shaped
organs
 Fist

sized
Filters water and
solutes such as
toxins (except
proteins…TOO
BIG) from blood
 Make urine
 Helps
maintain
salt/H2O balance
+Mammalian
Kidney
 Two
regions
 Renal cortex – outer
 Renal medulla – inner
 Both
regions have nephrons
 Nephron
 the
functional unit of the kidney
 Single long tube
 Has ball of capillaries called glomerulus
 Cup shaped structure at beginning of
tubule called “Bowman’s capsule”
 Surrounds the glomerulus like a funnel
Nephron Structure
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Human Excretory System
 Unfiltered
blood enters the
kidney by the renal artery
 Filtered
blood leaves by the
renal vein
 Urine
exits the kidney through a
tube called the ureter
 Ureters
drain into the urinary
bladder
 Urine
exits the bladder through
the urethra
 Think
“a” for away
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The kidneys, ureters,
bladder, and urethra make up
the urinary tract.
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Excretory System in
Kidney
Built
on a complex network of tubules
(TUBES!!!)
Provides a large surface area for the
exchange of water and solutes
Including nitrogenous bases (ex:
urea)
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4 Main
Steps in
Excretory
System
2
3
4
4 Main Processes of
Excretory Systems
1. Filtration
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Blood
goes through filter made of
selectively permeable membranes
Keeps proteins and other large molecules
Blood pressure in renal artery forces
water/small solutes into kidney
Salts, Sugars, Amino acids, Nitrogenous
wastes
• This makes a liquid called the
FILTRATE
+2. Reabsorption
 Active
transport used
 Water and valuable solutes (ex: Ca+2) are
moved from filtrate back to blood
 Required because filtration is not
Occurs in
tubes and
extremely selective
capillaries
3. Secretion
 Solutes
are removed from animal’s body
and added to the filtrate
 Excess salts & toxins (like urea, drugs)
 Urine is drained into the renal pelvis
4. Excretion
 the
filtrate (urine) leaves the system
1
2
3
4
2
1= filtrate collected here
2= Reabsorption into blood occurs
transport)
(osmosis /active
3= secretion occurs in filtrate
4= urine is collected and dumped into renal pelvis 
URINE
FORMED!!
Animation #4
http://classic.hippocampus.org/course_locator?course=AP%20Biology%20II&lesson=49&topic=1&width=600&height=350&topicTitle=Osm
oregulation%20and%20Excretion%3A%20Overview&skinPath=http://www.hippocampus.org/hippocampus.skins/default
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Not
Summary
filtered out (remain in blood)
Blood cells and proteins
Reabsorbed: active transport
Na+, Cl-, Ca+2 (at times), glucose and
amino acids
Reabsorbed: diffusion
Na+ and ClReabsorbed: osmosis
H2O
Excreted
Urea, H2O, any excess solutes,
toxins/drugs
Maintaining
Water
Balance
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Monitor
blood osmolarity
amount of dissolved material in blood
Acts on
collecting
duct!!
2005-2006
ADH
= anti-diuretic hormone
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Any
Questions??
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
http://wps.aw.com/bc_martini_eap_4/40/10469/2680237.cw/content/inde
x.html

http://www.hippocampus.org/hippocampus.php/course_locator.php?cou
rse=AP Biology
II&lesson=49&topic=5&width=600&height=350&topicTitle=Osmoregulatio
n%20and%20Excretion%3A%20Summary&skinPath=http://www.hippoca
mpus.org/hippocampus.skins/default

http://www.dnatube.com/video/2754/Nephron-Function

http://www.dnatube.com/video/8472/The-Nephron-Functional-Unit-ofKidney

http://www.dnatube.com/video/8599/Kidney-and-Nephron