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'''Fundamental'Biology'
'''''''''''''''BI'1101''''
''''''''an'interdisciplinary'approach'to'introductory'biology'
Anggraini'Barlian,'
Iriawa-'
Tjandra'Anggraeni'
SITH4ITB'
1
Five'Levels'of'Organiza-on'
Molecular'
Cellular'
Organismal'
Popula-on'
Ecological'System'
2
Learning outcomes
After this lecture, you should be able to:
1. Describe four ways that heat is gained or lost by an animal.
2. Describe five categories of adaptations that help animals
thermoregulate.
3. Compare the osmoregulatory problems of freshwater fish,
saltwater fish, and terrestrial animals.
4. Compare the three ways that animals eliminate nitrogenous
wastes.
5. Describe the structure and functions of the human kidney.
6. Explain how the kidney promotes homeostasis.
7. Describe four major processes that produce urine and the key
events in the conversion of filtrate into urine.
8. Explain why a dialysis machine is necessary and how it
works.
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CONTROL OF BODY TEMPERATURE
AND WATER BALANCE
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Introduction
•  During cold winters, bears are often
dormant.
•  Physiological processes aid homeostasis,
keeping the body temperature about 5ºC
below normal.
–  Body fat and dense fur provide insulation.
–  Blood flow to extremities is reduced.
–  Nitrogen-containing wastes are metabolized
differently.
© 2012 Pearson Education, Inc.
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•  Animals live nearly everywhere on Earth ! The extremely dry, frigid
Arctic habitat or perpetual humidity of a tropical rain forest.
•  These habitats select for very different ways of regulating body
temperature, conserving water, and disposing of wastes.
•  In hot, dry areas, an animal must conserve enough water for cells
to function and, produce enough sweat to tolerate the heat.
•  At another extreme, frigid water surrounds an animal living in an
Arctic freshwater lake. An animal in this habitat must continually
pump excess water out of its body and conserve salts, all while
surviving the cold.
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Introduction
•  Homeostasis is the maintenance of steady
internal conditions despite fluctuations in the
external environment.
•  Examples of homeostasis include
–  thermoregulation—the maintenance of internal
temperature within narrow limits,
–  osmoregulation—the control of the gain and
loss of water and solutes, and
–  excretion—the disposal of nitrogen-containing
wastes.
© 2012 Pearson Education, Inc.
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Big Ideas
Thermoregulation
Osmoregulation and
Excretion
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THERMOREGULATION
© 2012 Pearson Education, Inc.
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An animal s regulation of body temperature
helps maintain homeostasis
Thermoregulation is
–  the process by which animals maintain an
internal temperature within a tolerable range !
requires the ability to balance heat gained from
and lost to the environment
–  a form of homeostasis.
"  An animal maintain homeostasis by controlling how much heat
it produces. When cells generate ATP in aerobic respiration
they also produce metabolic heat. The more active the animal,
the higher its metabolic rate and the more heat it produces.
© 2012 Pearson Education, Inc.
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An animal s regulation of body temperature
helps maintain homeostasis
•  Ectothermic animals
–  gain most of their heat from external sources and
–  include many fish, most amphibians, lizards, and most
invertebrates.
•  Endothermic animals
–  derive body heat mainly from their metabolism and
–  include birds, mammals, a few reptiles and fish, and many insects.
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Heat is gained or lost in four ways
•  Heat exchange with the environment may
occur by
–  conduction—the transfer of heat by direct
contact,
–  convection—the transfer of heat by movement
of air or liquid past a surface,
–  radiation—the emission of electromagnetic
waves, or
–  evaporation—the loss of heat from the surface
of a liquid that is losing some of its molecules
as a gas.
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Figure 25.2
Evaporation
Radiation
Convection
Conduction
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Thermoregulation involves adaptations that
balance heat gain and loss
Five general categories of adaptations help
animals thermoregulate.
•  Increased metabolic heat production occurs
when
–  hormonal changes boost the metabolic rate in
birds and mammals,
–  birds and mammals shiver,
–  organisms increase their physical activity, and
–  honeybees cluster and shiver.
© 2012 Pearson Education, Inc.
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Figure 25.3_UN01
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Thermoregulation involves adaptations that
balance heat gain and loss
•  Insulation is provided by
–  hair,
–  feathers, and
–  fat layers.
•  Circulatory adaptations include
–  increased or decreased blood flow to skin and
–  countercurrent heat exchange, with warm and
cold blood flowing in opposite directions.
© 2012 Pearson Education, Inc.
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Figure 25.3_2
Blood from
body core
in artery
Blood
returning to
body core
in vein
35°
33°C
30°
27°
20°
18°
10°
9°
Blood from
body core
in artery
Blood
returning
to body
core in vein
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Thermoregulation involves adaptations that
balance heat gain and loss
•  Evaporative cooling may involve
–  sweating,
–  panting, or
–  spreading saliva on body surfaces.
•  Behavioral responses
–  are used by endotherms and ectotherms and
–  include
•  moving to the sun or shade,
•  migrating, and
•  Bathing.
© 2012 Pearson Education, Inc.
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OSMOREGULATION
AND EXCRETION
© 2012 Pearson Education, Inc.
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Animals balance the level of water and solutes
through osmoregulation
#  Osmoregulation is the homeostatic control of the
uptake and loss of water and solutes such as salt
and other ions.
#  Osmosis is one process whereby animals regulate
their uptake and loss of fluids.
© 2012 Pearson Education, Inc.
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Animals balance the level of water and
solutes through osmoregulation
•  Osmoconformers
–  have body fluids with a solute concentration
equal to that of seawater,
–  face no substantial challenges in water balance,
and
–  include many marine invertebrates.
© 2012 Pearson Education, Inc.
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Animals balance the level of water and
solutes through osmoregulation
#  Osmoregulators
•  have body fluids whose solute concentrations differ from
that of their environment,
•  must actively regulate water movement, and
•  include
–  many land animals,
–  freshwater animals such as trout, and
–  marine vertebrates such as sharks.
© 2012 Pearson Education, Inc.
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Animals balance the level of water and solutes
through osmoregulation
#  Freshwater fish
• 
• 
• 
• 
gain water by osmosis (mainly through gills),
lose salt by diffusion to the more dilute environment,
take in salt through their gills and in food, and
excrete excess water in dilute urine.
Uptake of
some ions
in food
Osmotic water gain through gills
and other parts of body surface
Uptake
of salt ions
by gills
Fresh water
Excretion of large
amounts of water
in dilute urine
from kidneys
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25.4 Animals balance the level of water and
solutes through osmoregulation
•  Saltwater fish
–  lose water by osmosis from the gills and body surface,
–  drink seawater, and
–  use their gills and kidneys to excrete excess salt.
Gain of water and
salt ions from food
and by intake of
seawater
Osmotic water loss through gills
and other parts of body surface
Excretion of
salt from gills
Salt water
Excretion of excess ions
and small amounts of
water in concentrated
urine from kidneys
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Animals balance the level of water and
solutes through osmoregulation
•  Land animals
– 
– 
– 
– 
face the risk of dehydration,
lose water by evaporation and waste disposal,
gain water by drinking and eating, and
conserve water by
• 
• 
• 
• 
reproductive adaptations,
behavior adaptations,
waterproof skin, and
efficient kidneys.
© 2012 Pearson Education, Inc.
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EVOLUTION CONNECTION: A variety of ways
to dispose of nitrogenous wastes has evolved in
animals
•  Metabolism produces toxic by-products.
•  Nitrogenous wastes are toxic breakdown
products of proteins and nucleic acids.
•  Animals dispose of nitrogenous wastes in
different ways.
© 2012 Pearson Education, Inc.
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EVOLUTION CONNECTION: A variety of ways
to dispose of nitrogenous wastes has evolved in
animals
•  Ammonia (NH3) is
– 
– 
– 
– 
poisonous,
too toxic to be stored in the body,
soluble in water, and
easily disposed of by aquatic animals.
© 2012 Pearson Education, Inc.
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EVOLUTION CONNECTION: A variety of ways
to dispose of nitrogenous wastes has evolved
in animals
•  Urea is
–  produced in the vertebrate liver by combining
ammonia and carbon dioxide,
–  less toxic,
–  easier to store, and
–  highly soluble in water.
© 2012 Pearson Education, Inc.
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EVOLUTION CONNECTION: A variety of ways
to dispose of nitrogenous wastes has evolved in
animals
•  Uric acid is
–  excreted by some land animals (insects, land
snails, and many reptiles),
–  relatively nontoxic,
–  largely insoluble in water,
–  excreted as a semisolid paste, conserving
water, but
–  more energy expensive to produce.
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© 2012 Pearson Education, Inc.
Proteins
Amino acids
Nitrogenous bases
Nucleic acids
NH2
(amino groups)
Most aquatic animals,
including most bony
fishes
Mammals, most
amphibians, sharks,
some bony fishes
Birds and many other
reptiles, insects, land
snails
Uric acid
Ammonia
Urea
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The urinary system plays several major roles
in homeostasis
•  The urinary system
–  forms and excretes urine and
–  regulates water and solutes in body fluids.
•  In humans, the kidneys are the main
processing centers of the urinary system.
© 2012 Pearson Education, Inc.
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The urinary system plays several major roles
in homeostasis
•  Nephrons
–  are the functional units of the kidneys,
–  extract a fluid filtrate from the blood, and
–  refine the filtrate to produce urine.
•  Urine is
–  drained from the kidneys by ureters,
–  stored in the urinary bladder, and
–  expelled through the urethra.
© 2012 Pearson Education, Inc.
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Figure 25.6
Renal cortex
Renal medulla
Aorta
Inferior
vena cava
Renal artery (red)
and vein (blue)
Ureter
Kidney
Renal pelvis
Urinary bladder
Urethra
The urinary system
Bowman s
capsule
Glomerulus
Arteriole
from renal
artery
1
Ureter
Proximal tubule
Capillaries
3
Arteriole
from
glomerulus
From
another
nephron
Branch of
renal vein
2
Distal
tubule
Collecting
duct
Loop of Henle
with capillary
network
Detailed structure of a nephron
The kidney
Bowman s
capsule
Tubule
Renal cortex
Branch of
renal artery
Branch of
renal vein
Collecting
duct
Renal medulla
To
renal
pelvis
Orientation of a nephron within the kidney
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Overview: The key processes of the urinary system
are filtration, reabsorption, secretion, and excretion
•  Filtration
–  Blood pressure forces water and many small
molecules through a capillary wall into the start
of the kidney tubule.
•  Reabsorption
–  refines the filtrate,
–  reclaims valuable solutes (such as glucose,
salt, and amino acids) from the filtrate, and
–  returns these to the blood.
© 2012 Pearson Education, Inc.
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Figure 25.7
Bowman s
From
capsule
renal
artery
Filtration
Reabsorption
Secretion
Excretion
Nephron tubule
H2O, other small molecules
Urine
Interstitial fluid
To renal vein
Capillary
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Figure 25.7_1
From Bowman s
Filtration
renal capsule
artery
Nephron tubule
H2O, other small molecules
Interstitial fluid
Capillary
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Figure 25.7_2
Reabsorption
Secretion
Excretion
Nephron tubule
Urine
Capillary
To renal vein
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25.7 Overview: The key processes of the urinary
system are filtration, reabsorption, secretion,
and excretion
•  Substances in the blood are transported into
the filtrate by the process of secretion.
•  By excretion the final product, urine, is
excreted via the ureters, urinary bladder,
and urethra.
© 2012 Pearson Education, Inc.
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Blood filtrate is refined to urine through
reabsorption and secretion
•  Reabsorption in the proximal and distal tubules
removes
–  nutrients,
–  salt, and
–  water.
•  pH is regulated by
–  reabsorption of HCO3– and
–  secretion of H+.
•  High NaCl concentration in the medulla promotes
reabsorption of water.
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© 2012 Pearson Education, Inc.
Figure 25.8_1
Bowman s
capsule
Proximal tubule
Nutrients H2O
NaCl HCO3
Blood
Cortex
Filtrate composition
H 2O
Salts (NaCl
and others)
HCO3H+
Urea
Glucose
Amino acids
Some drugs
Some H+
drugs
and poisons
Medulla
Reabsorption
Secretion
Filtrate movement
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Figure 25.8_2
Proximal tubule
Nutrients H2O
NaCl HCO3
Cortex
1
Distal tubule
H 2O
NaCl HCO3K+ H+
Some H+
drugs
and poisons
3
Collecting
duct
Medulla
Interstitial
Loop of
fluid
Henle
2
NaCl
NaCl
H 2O
NaCl
Urea
H 2O
Reabsorption
Secretion
Filtrate
movement
Urine (to
renal pelvis)
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Hormones regulate the urinary system
•  Antidiuretic hormone (ADH) regulates the
amount of water excreted by the kidneys by
–  signaling nephrons to reabsorb water from the
filtrate, returning it to the blood, and
–  decreasing the amount of water excreted.
•  Diuretics
–  inhibit the release of ADH and
–  include alcohol and caffeine.
© 2012 Pearson Education, Inc.
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CONNECTION: Kidney dialysis can be lifesaving
•  Kidney failure can result from
–  hypertension,
–  diabetes, and
–  prolonged use of common drugs, including
alcohol.
•  A dialysis machine
–  removes wastes from the blood and
–  maintains its solute concentration.
© 2012 Pearson Education, Inc.
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Figure 25.9_1
Line from artery to apparatus
Pump
Line from
apparatus
to vein
Tubing made of a
selectively permeable
membrane
Dialyzing
solution
Fresh dialyzing
solution
Used dialyzing solution
(with urea and excess ions)
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Figure 25.9_2
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