1. Test info
Average: 15 out of 30
Range: 3 – 24
Correction due: Friday
Lab notebooks: Monday
Add data to table coming around
Data up on website later today
6th Period
Pass out tests & scantrons
record # correct at top of test
record correct answers on test
Richard, collect scantrons
I will return at 1:40 – I’m touring the Leadership WS group
Thank you!

2. Chapter 44: Osmoregulation and Excretion
What is osmoregulation?
How animals regulate solute concentrations &
balance the gain & loss of water
What is excretion?
How animals get rid of nitrogenous waste of metabolism
What is the difference between an osmoregulator & an osmoconformer?
Osmoconformer – does not actively adjust its internal osmolarity
Isoosmotic to environment
Marine animals
Osmoregulator – actively controls osmolarity
NOT isoosmotic with environment

3. Figure 44.3 Osmoregulation in marine and freshwater bony fishes
Gain of water and
salt ions from food
and by drinking
seawater
Osmotic water loss
through gills and other parts
of body surface
Excretion of
salt ions
from gills
Excretion of salt ions
and small amounts
of water in scanty
urine from kidneys
Uptake of
water and some
ions in food
Osmotic water gain
by gills
large amounts of
water in dilute
(a) Osmoregulation in a saltwater fish
(b) Osmoregulation in a freshwater fish
Hypoosmotic to ocean
loses LOTS of water at gills
“Drinks like a fish”
excretes salt & little urine
Hyperosmotic to lake
gain LOTS of water at gills
LOTS of dilute urine

4. Chapter 44: Osmoregulation and Excretion
What is osmoregulation?
What is excretion?
What is the difference between an osmoregulator & an osmoconformer?
What is the biggest issue for land animals?
Dehydration
Many adaptations to prevent this
What are the different nitrogenous waste products that animals excrete?
Ammonia
Urea
Uric acid

5. Figure 44.8 Nitrogenous wastes
Proteins
Nucleic acids
Amino acids
Nitrogenous bases
–NH2
Amino groups
Most aquatic
animals, including
most bony fishes
Mammals, most
amphibians, sharks,
some bony fishes
Many reptiles
(including
birds), insects,
land snails
Ammonia
Urea
Uric acid
NH3
NH2 O C N H HN
Ammonia – very soluble in water
- VERY toxic
- easily passes through membranes
- 1 N at a time
Urea ,000X less toxic than –NH3
- -NH3 + CO2 in liver
- helps conserve water
- 2 N at a time
Uric acid- not very soluble in water
- excreted in paste-like form
- little water loss
- stored in amniotic egg
- 4 N at a time

6. Chapter 44: Osmoregulation and Excretion
What is osmoregulation?
What is excretion?
What is the difference between an osmoregulator & an osmoconformer?
What is the biggest issue for land animals?
What are the different nitrogenous waste products that animals excrete?
What are the 4 main functions of excretory systems?
Filtration
Reabsorption
Secretion
Excretion

7. Figure 44.9 Key functions of excretory systems: an overview
Filtration. The excretory tubule collects a filtrate from the blood.
Water and solutes are forced by blood pressure across the
selectively permeable membranes of a cluster of capillaries and
into the excretory tubule.
Reabsorption. The transport epithelium reclaims valuable substances
from the filtrate and returns them to the body fluids.
Secretion. Other substances, such as toxins and excess ions, are
extracted from body fluids and added to the contents of the excretory
tubule.
Excretion. The filtrate leaves the system and the body.
Capillary
Excretory
tubule
Filtrate
Urine 1 2 3 4

8. Chapter 44: Osmoregulation and Excretion
What is osmoregulation?
What is excretion?
What is the difference between an osmoregulator & an osmoconformer?
What is the biggest issue for land animals?
What are the different nitrogenous waste products that animals excrete?
What are the 4 main functions of excretory systems?
How have excretory systems evolved?
Protonephridia – Planaria
Metanephridia – Earthworm
Malpighian tubules – insects
Kidney - us

9. Figure 44.10 Protonephridia: the flame-bulb system of a planarian
Nucleus
of cap cell
Cilia
Interstitial fluid
filters through
membrane where
cap cell and tubule
cell interdigitate
(interlock)
Tubule cell
Flame
bulb
Nephridiopore
in body wall
Tubule
Protonephridia
(tubules)

10. Figure 44.11 Metanephridia of an earthworm
Nephrostome
Metanephridia
Nephridio-
pore
Collecting
tubule
Bladder
Capillary
network
Coelom

11. Figure 44.12 Malpighian tubules of insects
Digestive tract
Midgut
(stomach)
Malpighian
tubules
Rectum
Intestine
Hindgut
Salt, water, and
nitrogenous
wastes
Feces and urine
Anus
tubule
Reabsorption of H2O,
ions, and valuable
organic molecules
HEMOLYMPH

12. Chapter 44: Osmoregulation and Excretion
What is osmoregulation?
What is excretion?
What is the difference between an osmoregulator & an osmoconformer?
What is the biggest issue for land animals?
What are the different nitrogenous waste products that animals excrete?
What are the 4 main functions of excretory systems?
How have excretory systems evolved?
What is the structure and function of the kidney?

13. My tolerance for cell phones is GONE!!!
The letter of the law will be followed!!

14. Figure 44.13 The mammalian excretory system
Posterior vena cava
Renal artery and vein
Aorta
Ureter
Urinary bladder
Urethra
(a) Excretory organs and major
associated blood vessels
Juxta-
medullary
nephron
Cortical
Collecting
duct To
renal
pelvis
Renal
cortex
medulla
20 µm
(b) Kidney structure
Kidney
Section of kidney from a rat
Afferent
arteriole
from renal
artery
Glomerulus
Bowman’s capsule
Proximal tubule
Peritubular capillaries
SEM
Efferent
arteriole from
glomerulus
Branch of
renal vein
Descending
limb
Ascending
Loop of
Henle
Vasa
recta
Distal
tubule
(d) Filtrate and
blood flow
(c) Nephron

15. Chapter 44: Osmoregulation and Excretion
What is osmoregulation?
What is excretion?
What is the difference between an osmoregulator & an osmoconformer?
What is the biggest issue for land animals?
What are the different nitrogenous waste products that animals excrete?
What are the 4 main functions of excretory systems?
How have excretory systems evolved?
What is the structure and function of the kidney?
What is the structure & function of the nephron?

16. Chapter 44: Osmoregulation and Excretion
What is osmoregulation?
What is excretion?
What is the difference between an osmoregulator & an osmoconformer?
What is the biggest issue for land animals?
What are the different nitrogenous waste products that animals excrete?
What are the 4 main functions of excretory systems?
How have excretory systems evolved?
What is the structure and function of the kidney?
What is the structure & function of the nephron?
Glomerulus – filtration due to BP
Proximal tubule – secretion & reabsorption
Loop of Henle
Descending – reabsorption
Ascending – reabsorption
Distal tubule – secretion & reabsorption
Collecting duct - reabsorption

17. Figure 44.14 The nephron and collecting duct: regional functions of the transport epithelium
Proximal tubule
Filtrate
H2O
Salts (NaCl and others)
HCO3– H+
Urea
Glucose; amino acids
Some drugs
Key
Active transport
Passive transport
CORTEX
OUTER
MEDULLA
INNER
Descending limb
of loop of
Henle
Thick segment
of ascending
limb
Thin segment
limbs
Collecting
duct
NaCl
Distal tubule
Nutrients
HCO3 K+
NH3 1 4 3 2 5

18. Chapter 44: Osmoregulation and Excretion
What is osmoregulation?
What is excretion?
What is the difference between an osmoregulator & an osmoconformer?
What is the biggest issue for land animals?
What are the different nitrogenous waste products that animals excrete?
What are the 4 main functions of excretory systems?
How have excretory systems evolved?
What is the structure and function of the kidney?
What is the structure & function of the nephron?
What causes the movement of water out of the filtrate?
- Increasing salt concentration within the kidney

19. Figure 44.15 How the human kidney concentrates urine
300
100
400
600
900
1200
700
200
Active transport
Passive transport
OUTER MEDULLA
INNER MEDULLA
CORTEX
Osmolarity of interstitial fluid (mosm/L)

20. Figure 44.15 How the human kidney concentrates urine
Nacl
300
100
400
600
900
1200
700
200
Active transport
Passive transport
OUTER MEDULLA
INNER MEDULLA
CORTEX
Osmolarity of interstitial fluid (mosm/L)

21. Figure 44.15 How the human kidney concentrates urine
Nacl
300
100
400
600
900
1200
700
200
Active transport
Passive transport
OUTER MEDULLA
INNER MEDULLA
CORTEX
Urea
Osmolarity of interstitial fluid (mosm/L)

22. Chapter 44: Osmoregulation and Excretion
What is osmoregulation?
What is excretion?
What is the difference between an osmoregulator & an osmoconformer?
What is the biggest issue for land animals?
What are the different nitrogenous waste products that animals excrete?
What are the 4 main functions of excretory systems?
How have excretory systems evolved?
What is the structure and function of the kidney?
What is the structure & function of the nephron?
What causes the movement of water out of the filtrate?
How is blood osmolarity regulation?
- ADH
- RAAS

23. Figure 44.16 Hormonal control of the kidney by negative feedback circuits
Osmoreceptors
in hypothalamus
Drinking reduces
blood osmolarity
to set point
Increased Na+
and H2O reab-
sorption in
distal tubules
Homeostasis:
Blood pressure,
volume
STIMULUS:
The juxtaglomerular
apparatus (JGA) responds
to low blood volume or
blood pressure (such as due
to dehydration or loss of
blood)
H2O reab-
sorption helps
prevent further
osmolarity
increase
The release of ADH is
triggered when osmo-
receptor cells in the
hypothalamus detect an
increase in the osmolarity
of the blood
Blood osmolarity
Hypothalamus
ADH
Pituitary
gland
Increased
permeability
Thirst
Aldosterone
Adrenal gland
Angiotensin II
Angiotensinogen
Renin
production
Collecting duct
Distal
tubule
Arteriole
constriction
JGA
Antidiuretic hormone (ADH) enhances fluid retention by making
the kidneys reclaim more water.
The renin-angiotensin-aldosterone system (RAAS) leads to an increase
in blood volume and pressure.
(a)
(b)