Chapter 36: pp. 665 - 678
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
10th Edition
Sylvia S. Mader
Body Fluid Regulation
& Excretory Systems
BIOLOGY
© Georgette Douwma/Photo Researchers, Inc.
PowerPoint® Lecture Slides are prepared by Dr. Isaac Barjis, Biology Instructor
Copyright © The McGraw Hill Companies Inc. Permission required for reproduction or display
1
Outline

Body Fluid Regulation


Aquatic Animals

Marine Bony Fish

Freshwater Bony Fish
Terrestrial Animals

Nitrogenous Waste Products

Organs of Excretion

Urinary System in Humans

Kidneys

Urine
2
Nitrogenous Waste Products

Catabolism of amino acids and nucleic acids
results in ammonia


High solubility permits it to be excreted directly by
many aquatic animals
Terrestrial animals must convert ammonia to urea or
uric acid

Urea causes loss of much water per unit of nitrogen



Mammals and amphibians
Must drink lots of water
Uric acid requires much less water per unit of nitrogen
excreted



Reptiles, birds, and arthropods
Require much less water than mammals and amphibians
Allows invasion of drier habitats far from standing water
3
Nitrogenous Wastes
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proteins
amino acids
NH2
most fishes and
other aquatic
animals
adult amphibians,
sharks, and
mammals
Insects, birds, and
reptiles
ammonia
urea
uric acid
O
H
N
O
H
H2N
C
HN
NH2
C
H
C N
C
O
C
H
O
C N
N
H
H
water needed to excrete
energy needed to produce
4
Organs of Excretion in Invertebrates

Most animals have tubular excretory organs


Regulate the water-salt balance of the body
Excrete metabolic wastes into the environment

Flame Cells in Planarians

Nephridia in Earthworms

Malpighian Tubules in Insects
5
Excretory Organs in Animals
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flame cell
excretory tubule
fluid filtering
into flame cell
flame cell
nucleus
cilia
excretory
pore
excretory
tubule
a.
Flame-cell excretory system in planarians
capillary network
tubule
bladder
septum
entrance of
nephridiostome
pore
b.
Earthworm nephridium
6
Body Fluid Regulation

An excretory system regulate body fluid
concentrations

Dependent upon concentration of mineral ions
such as sodium and potassium

Water can enter the body through:

Drink

Food

Metabolism
7
Body Fluid Regulation

Water tends to move into the region with the
lowest water concentration

A marine environment






High in dissolved salts
Tends to promote the osmotic loss of water, and
The gain of ions by drinking water
Marine invertebrates nearly isotonic to seawater
Blood of cartilaginous fishes contains enough urea to match
the tonicity of sea water
Fresh water environment


Tends to promote a gain of water by osmosis, and
A loss of ions as excess water is excreted
8
Aquatic Animals

Bony Fishes


Body fluids of bony fishes with only moderate amount
of salt
Marine bony fishes





Body fluids hypotonic to sea water
Passively lose water through gills
Must constantly drink seawater to compensate
Excess salt ions actively transported back into seawater
through the gills
Freshwater bony fishes have opposite problem



Body fluids hypertonic to fresh water
Passively gain water through gills
Eliminate excess water through copious hypotonic urine
9
Body Fluid Regulation in Bony Fishes
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
passive loss
of water
through
gills
drinks seawater
salts actively
excreted by gills
scanty amount
of isotonic
urine contains
some salts
a. Marine bony fish
passive gain of
water through gills
does not drink
salts actively
taken up by gills
b. Freshwater bony fish
large amounts of hypotonic
urine contain few salts
10
Osmoregulation in a Shark
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
© Digital Vision Ltd
11
Terrestrial Animals

Terrestrial animals lose water through
excretion and respiration

Must drink water to make up for loss

Some reduce excretory loss by excreting
nitrogen as relatively insoluble uric acid

Certain animals also have a highly convoluted
nasal passage with a mucous membrane
surface
12
Adaptations of a Kangaroo Rat
to a Dry Environment
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Exhaled air is
cooled and dried
in long convoluted
air passages.
Animal fur prevents
evaporative loss of
water at skin.
Urine is the
most hypertonic
known among
animals.
Fecal pellets
are dry.
Oxidation of
food results in
metabolic water.
© Bob Calhoun/Bruce Coleman, Inc.
13
Adaptations of Marine Birds to a
High Salt Environment
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salt solution
exits here
salt solution
runs down
beak here
© Eric Hosking/Photo Researchers, Inc.
14
Urinary System in Humans

Human kidneys

Located on either side of vertebral column, just
below the diaphragm
Each connected to a ureter
 Conducts urine from the kidney to the urinary
bladder


Urine voided through urethra

Tube between bladder and exit
15
The Human Urinary System
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
renal artery
1. Kidneys produce
urine.
renal vein
aorta
inferior vena cava
2. Ureters transport
urine.
3. Urinary bladder
stores urine.
4. Urethra passes
urine to outside.
a.
b.
© James Cavallini/Photo Researchers, Inc.
16
Kidneys


Renal cortex

Outer region

Granular appearance
Renal medulla


Cone-shaped renal pyramids
Renal pelvis

Hollow-chambered innermost part of the kidney
17
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Macroscopic & Microscopic
Anatomy of the Kidney
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nephrons
renal
pelvis
renal
cortex
renal
medulla
collecting
duct
ureter
renal artery
and vein
a. Gross anatomy
renal pyramid
in renal medulla
renal
pelvis
b. Two nephrons
19
Nephrons
Each kidney composed of many tubular
nephrons
 Each nephron composed of several parts

Glomerular capsule
 Glomerulus
 Proximal convoluted tubule
 Loop of the nephron
 Distal convoluted tube
 Collecting duct

20
Nephron Anatomy
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peritubular capillary
Renal Cortex
proximal
convoluted
tubule
glomerular capsule
(Bowman's capsule)
distal
convoluted
tubule
afferent arteriole
efferent arteriole
glomerulus
efferent
arteriole
glomerulus
b. Surface view of glomerulus and its blood supply
distal
convoluted tubule
afferent arteriole
microvilli
proximal
convoluted tubule
venule
c. Cross sections of proximal and distal convoluted
tubules
renal
artery
renal vein
peritubular
capillary
network
20 µm
ascending limb
descending limb
collecting duct
Loop of the nephron (loop of Henle)
descending limb
capillaries
ascending limb
collecting duct
Renal Medulla
a. Anephron and its blood supply
d. Cross sections of a loop of nephron limbs and
collecting duct. (The other cross sections are
those of capillaries.)
10 µm
b: © R.G. Kessel and R H. Kardon, Tissues and Organs: A Text-Atlas of Scanning Electron Microscopy. W. H. Freeman & Co., San Francisco 1979; c, d: Journal of Ultrastructure Research by Maunsbach, Arvid B. Copyright 1966 by Elsevier
Science & Technology Journals. Reproduced with permission of Elsevier Science & Technology Journals in the format Textbook via Copyright Clearance Center
21
Proximal Convoluted Tubule
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peritubular capillary
proximal convoluted
tubule cell
lumen
microvilli
mitochondrion
nucleus
a.
500×
b.
a: © Joseph F. Gennaro, Jr./Photo Researchers, Inc.
22
Urine Formation

Urine production requires three distinct
processes:

Glomerular filtration in glomerular capsule

Tubular reabsorption at the proximal
convoluted tubule

Tubular secretion at the distal convoluted
tubule
23
Processes in Urine Formation
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
glomerular capsule
H2O
Glomerular Filtration
Water, salts, nutrient molecules, and
waste molecules move from the
glomerulus to the inside of the glomerular
capsule. These small molecules are
called the glomerular filtrate.
urea
glucose
amino
acids
uric
acid
salts
proximal
convoluted
tubule
Tubular Reabsorption
Nutrient and salt molecules are actively
reabsorbed from the convoluted tubules
into the peritubular capillary network, and
water flows passively.
glomerulus
efferent
arteriole
Tubular Secretion
Certain molecules (e.g., H+ and
penicillin) are actively secreted from the
peritubular capillary network into the
convoluted tubules.
afferent
arteriole
distal
convoluted
tubule
renal
artery
renal
vein
venule
collecting
duct
peritubular
capillary
network
loop of the
nephron
H2O
urea
uric acid
salts
NH4+
creatinine
24
Animation
Please note that due to differing
operating systems, some animations
will not appear until the presentation is
viewed in Presentation Mode (Slide
Show view). You may see blank slides
in the “Normal” or “Slide Sorter” views.
All animations will appear after viewing
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animation. Most animations will require
the latest version of the Flash Player,
which is available at
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Reabsorption of Salt and Water
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
C1-
Na+
Increasing solute concentration in renal medulla
H2O
Renal
cortex
Outer
medulla
ascending
limb
Na+
H2O
H2O
C1-
descending
limb
Urea
H2O
H2O
Inner
medulla
loop of the
nephron
collecting
duct
26
Urine Formation and Homeostasis

Excretion of hypertonic urine


Dependent upon the reabsorption of water
Absorbed from




Loop of the nephron, and
The collecting duct
Osmotic gradient within the renal medulla causes
water to leave the descending limb along its entire
length
Antidiuretic hormone (ADH)


Plays a role in water reabsorption
Released by the posterior lobe of the pituitary
27
The Renin-Angiotensin-Aldosterone System
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
liver
kidneys
adrenal cortex
secrete
renin
blood vessel
stimulates
secretes
secretes
speeds
angiotensin I
angiotensin II
angiotensinogen
aldosterone
28
Maintenance of pH and Osmolality

More than 99% of sodium filtered at glomerulus is
returned to blood at the distal convoluted tubule

Reabsorption of sodium regulated by hormones


Aldosterone

Renin

Atrial Natriuretic Hormone (ANH)
pH adjusted by either

The reabsorption of the bicarbonate ions, or

The secretion of hydrogen ions
29
Review

Body Fluid Regulation


Aquatic Animals

Marine Bony Fish

Freshwater Bony Fish
Terrestrial Animals

Nitrogenous Waste Products

Organs of Excretion

Urinary System in Humans

Kidneys

Urine
30
Chapter 36: pp. 665 - 678
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
10th Edition
Sylvia S. Mader
Body Fluid Regulation
& Excretory Systems
BIOLOGY
© Georgette Douwma/Photo Researchers, Inc.
PowerPoint® Lecture Slides are prepared by Dr. Isaac Barjis, Biology Instructor
Copyright © The McGraw Hill Companies Inc. Permission required for reproduction or display
31