T22 Excretion wrksht.ppt · Topic 22: Excretory System Urogenital integration How does the excretory system develop? How has the excretory system evolved? What is the gross anatomy
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1/10/2013
1
Topic 22: Excretory System
� Urogenital integration
� How does the excretory system develop?
� How has the excretory system evolved?
� What is the gross anatomy of the kidney?
� What are the functional units of the kidney
and how do they work?
� What are the possible excretory products?
� Who excretes what?
Urogenital Integration
� Urogential structures
� ______________
� ______________
� Functions differ
� Some structures shared
� ____________
� ____________
� ____________
� Common developmental origin
� What does the excretory system do?
© infovisual.info
How does the excretory
system develop?
Liem et al. Fig. 20- ; Wolpert 1998
Intermediate
Mesoderm
_________
_________
__________
__________
___________
Nephron/
Renal Tubule
Drains kidney
or testis
Segmentation Evagination
How does the excretory system develop?
� Nephrotomes form along much of length of body
� Archinephric ductruns along anteroposterior axis
� Anteroposterior formation:
� _________________
� _________________
� _________________
Liem et al. Fig. 20-1
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Mammalian Kidney
Development
1. _______________
� Develops from nephric ridge
� Anterior & not functional
� Drained by archinephric duct
2. _______________
� Middle part of nephric ridge
� Functional in embryo
� Drained by archinephric duct
3. _______________
� Posterior end of nephric ridge
� Functional in adult
� Drained by ureter
� Archinephric duct
� Drains testes in males
� Degenerates in femalesLiem et al. Fig. 20-6
1
2
3
Excretory Ducts
� Ureter
� Always drains __________
� Ureteric bud � evagination
of archinephric duct
� Opening becomes independent from archinephric duct
� Homologous to _________ ____________________ in anamniotes (shark)
Liem et al. Fig. 20-7
How has the kidney evolved?
Liem et al. Fig. 20-5
� _______________
� Hypothetical ancestral condition
� Segmental
� Entire nephric ridge
� Drained by archinephric duct
� ___________________
� Hagfishes
� Anterior tip not functional
� Segmental
� Drained by archinephric duct
Liem et al. Fig. 20-5
� _______________________
� Fishes & Amphibians
� Posterior end of nephric ridge
� Multiplication of renal tubules � no longer segmental
� Drained by accessory urinary duct in males
� ______________________
� Amniotes
� Degeneration of all but posterior end of nephric ridge
� Drained by ureter
� What happens to archinephric duct in amniotes?
How has the kidney
evolved?
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Human Excretory Gross Anatomy
� Superior to inferior position
� Dorsal body wall & __________________
� Kidney
� Ureter
� Ventral body wall
� ___________________
� Through body wall
� Urethra
© spanglerscience.com
What is the gross
anatomy of the kidney?
� What kind of kidney do each of these animals have?
� Shape is variable within types of kidney
� Always retroperitoneal
� Always paired
© infovisuals.info; web-books.com; grassfedtraditions.com; pc.maricopa.edu
Human
Cow Frog
Shark
What are the functional units of the kidneys?
� ______________
� Tubular
� Recieves filtrate from blood
� Concentrates urine
� Proximal to distal
� _______________
� Proximal convoluted tubule
� _______________
� Distal convoluted tubule
� _______________
© bisbio.in
Human Kidney Gross Anatomy
� ________________� Superficial
� Bowman’s capsules
� Proximal convoluted tubules
� Distal convoluted tubules
� Renal ___________� Deep
� Loops of Henle
� Collecting ducts
� Renal ___________� Receives urine from
collecting ducts
� Drains into ureter
Liem et al. Fig. 20-13
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A Detailed Look at the Nephron
� _________________
� Glomerulus
� Bowman’s capsule
� Filtration of blood plasma
� Nitrogenous waste
� Ions & Water
� Blood flow
� Renal artery
� Afferent arteriole
� Glomerulus
� Efferent arteriole
� Vasa recta (resorption)
� Renal vein
© D Proffitt 1994; Benjamin Cummings 2001
Nephron
Function
Liem et al. Fig. 20-14
Blood Flow
Diffusion
Active
Transport
NH4+
K+
H+
Na+
Cl-
Glucose
Amino A
Na+
Cl-
HCO3-
Ca+
PO2-
NA+
1. Filtrate with all small water-soluble molecules
2. Resorption of useful ions & molecules
3. Water diffusion out along loop of Henle
� Due to salt gradient
� Established in ascending loop
� Water carried away via vasa recta �countercurrent
4. Adjustment of ions
5. Further concentration
1
5
4
3
2
Salt Gradient
What are the possible excretory products?
What animals would you expect to excrete each type of waste?
Liem et al. Fig. 20-9
Waste Structure
Solubility in Water Toxicity
Water Usage
Ammonia NH4
+
Urea CO(NH2)2
ModeratelyHigh
Low Medium
Uric Acid C5H4N4O3
Myxiniformes
Petromyzontif.
Testudines
Lissamphibia
Dipnoi
Actinistia
Actinopterygii
Chondrichthyes
Aves
Crocodylia
Lepidosauria
Mammalia
Who Excretes W
hat?
Liem et al. Fig. 3-1,
Table 20-2
Kidney Type
Environ-ment
1o
Waste2o
Waste
Primitive Opistho~
Marine
(M)Ammonia
(A)Urea
(U)
Advanced Opistho~
(AO)M
AOFresh Water
(FW)
AO M
AO FW
AO FW
AOTerrestrial
(T)
Meta~ T
Meta T
Meta T
Meta T
Meta T
Larva
Adult
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Excretion in Fishes
Liem et al. Fig. 20-11
� Excretory structures
� Gills
� Kidneys
� Excretion depends on medium
� Fresh water is hypoosmotic relative to fish blood
� Sea water is hyperosmotic
� Where does water tend to move if a fish is in fresh water?
� Salt water?
� Why?
Excretion in Fishes
Liem et al. Fig. 20-11; usace.army.mil; costaricafishing.info
� ___________________
� Does not drink (some with food)
� Lots of dilute urine with ammonia
� Lots of water & ammonialost at gills
� Active uptake of salts at gills
� ___________________
� Drink lots of water
� Comes with lots of salt
� Less dilute urine with ammonia
� Lots of water & ammonialost at gills
� Salts actively excreted at gills
Excretion in Fishes
Liem et al. Fig. 20-11; costaricafishing.info; derm.qld.gov.au
� _________________
� Adapted to excrete urea
� Do not drink (some water & salt with food)
� Lots of dilute urine with urea
� Salt enters at gills
� _______________________
� Sea water is hypoosmotic, so diffuses in
� Need to pass a lot of urine
� What else would rush in?
� Digitiform gland
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