Download AP Biology Chapter 42 Circulation Guided Notes

LECTURE PRESENTATIONS
For CAMPBELL BIOLOGY, NINTH EDITION
Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson
Chapter 42
Circulation and Gas Exchange
Lectures by
Erin Barley
Kathleen Fitzpatrick
© 2011 Pearson Education, Inc.
Overview: Trading Places
• Every organism must _________________with its
environment
• Exchanges ultimately occur at the _____________
by crossing the _____________________
• In unicellular organisms, these exchanges occur
_______________ with the environment
© 2011 Pearson Education, Inc.
• For most cells making up multicellular organisms,
direct exchange with the environment is not
possible
• __________are an example of a specialized
exchange system in animals
– ___ diffuses from the water into blood vessels
– ___ diffuses from blood into the water
• Internal transport and gas exchange are
functionally related in most animals
© 2011 Pearson Education, Inc.
Concept 42.1: Circulatory systems link
exchange surfaces with cells throughout
the body
• __________________is proportional to the square
of the distance
• Diffusion is only efficient over ________distances
• In _______________animals, cells can exchange
materials directly with the surrounding medium
• In most animals, cells exchange materials with the
environment via a _________________________
© 2011 Pearson Education, Inc.
Gastrovascular Cavities
• Some animals ________ a circulatory system
• Some cnidarians, such as jellies, have elaborate
___________________________________
• A ________________________functions in both
digestion and distribution of substances
throughout the body
• The body wall that encloses the gastrovascular
cavity is only ________ cells thick
• ________________ have a gastrovascular cavity
and a large surface area to volume ratio
© 2011 Pearson Education, Inc.
Figure 42.2
Circular
canal
Mouth
Gastrovascular
cavity
Mouth
Pharynx
Radial canals
5 cm
(a) The moon jelly Aurelia, a cnidarian
2 mm
(b) The planarian Dugesia, a flatworm
Evolutionary Variation in Circulatory
Systems
• A ____________________ minimizes the diffusion
distance in animals with many cell layers
© 2011 Pearson Education, Inc.
General Properties of Circulatory Systems
• A circulatory system has
– A circulatory __________
– A set of interconnecting _________
– A muscular pump, the ___________
• The circulatory system connects the
______________________with the
_______________ gases, ________ nutrients,
and __________________of wastes
• Circulatory systems can be _____ or _______ and
vary in the number of circuits in the body
© 2011 Pearson Education, Inc.
Open and Closed Circulatory Systems
• In insects, other arthropods, and most molluscs,
blood bathes the organs directly in an __________
______________________
• In an open circulatory system, there is no
distinction between blood and interstitial fluid, and
this general body fluid is called _______________
© 2011 Pearson Education, Inc.
Figure 42.3a
(a) An open circulatory system
Heart
Hemolymph in sinuses
surrounding organs
Pores
Tubular heart
• In a ____________________ is confined to
vessels and is distinct from the interstitial fluid
• Closed systems are more ________________ at
transporting circulatory fluids to tissues and cells
• Annelids, cephalopods, and vertebrates have
closed circulatory systems
© 2011 Pearson Education, Inc.
Figure 42.3b
(b) A closed circulatory system
Heart
Interstitial fluid
Blood
Small branch
vessels in
each organ
Dorsal
Auxiliary
vessel
hearts
(main heart)
Ventral vessels
Organization of Vertebrate Circulatory
Systems
• Humans and other vertebrates have a closed
circulatory system called the _________________
_________________
• The three main types of blood vessels are ______
___________________
• Blood flow is _____________ in these vessels
© 2011 Pearson Education, Inc.
• ___________ branch into ____________ and
carry blood away from the heart to ____________
• Networks of capillaries called ______________
are the sites of chemical exchange between the
blood and interstitial fluid
• _____________ converge into _________ and
return blood from capillaries to the heart
© 2011 Pearson Education, Inc.
• Arteries and veins are distinguished by the
___________________, not by O2 content
• Vertebrate hearts contain two or more _________
• Blood enters through an ______________ and is
pumped out through a ____________________
© 2011 Pearson Education, Inc.
Single Circulation
• Bony fishes, rays, and sharks have single
circulation with a ___________________heart
• In __________________, blood leaving the heart
passes through two capillary beds before returning
© 2011 Pearson Education, Inc.
Figure 42.4a
(a) Single circulation
Gill
capillaries
Artery
Heart:
Atrium (A)
Ventricle (V)
Vein
Body
capillaries
Key
Oxygen-rich blood
Oxygen-poor blood
Double Circulation
• Amphibian, reptiles, and mammals have
__________________________
• Oxygen-poor and oxygen-rich blood are pumped
____________ from the _________ and ______
sides of the heart
© 2011 Pearson Education, Inc.
Figure 42.4b
(b) Double circulation
Pulmonary circuit
Lung
capillaries
A
V
Right
A
V
Left
Systemic
capillaries
Key
Systemic circuit
Oxygen-rich blood
Oxygen-poor blood
• In reptiles and mammals, oxygen-poor blood flows
through the _________________to pick up
oxygen through the lungs
• In amphibians, oxygen-poor blood flows through a
_____________________ to pick up oxygen
through the lungs and skin
• Oxygen-rich blood delivers oxygen through the
___________________
• Double circulation maintains ______________
_______________ in the organs than does single
circulation
© 2011 Pearson Education, Inc.
Adaptations of Double Circulatory Systems
• Hearts vary in different vertebrate groups
© 2011 Pearson Education, Inc.
Amphibians
• Frogs and other amphibians have a __________
_______________: two atria and one ventricle
• The ventricle pumps blood into a forked artery that
splits the ventricle’s output into the
_______________circuit and the ________circuit
• When underwater, blood flow to the lungs is nearly
________________
© 2011 Pearson Education, Inc.
Figure 42.5a
Amphibians
Pulmocutaneous circuit
Lung
and skin
capillaries
Atrium
(A)
Atrium
(A)
Right
Left
Ventricle (V)
Systemic
capillaries
Systemic circuit
Key
Oxygen-rich blood
Oxygen-poor blood
Reptiles (Except Birds)
• Turtles, snakes, and lizards have a __________
________________: two atria and one ventricle
• In alligators, caimans, and other crocodilians a
________________ divides the ventricle
• Reptiles have _____________________, with a
pulmonary circuit (lungs) and a systemic circuit
© 2011 Pearson Education, Inc.
Figure 42.5b
Reptiles (Except Birds)
Pulmonary circuit
Lung
capillaries
Right
systemic
aorta
Atrium
(A)
Ventricle
(V)
A
Right
V
Left
Left
systemic
aorta
Incomplete
septum
Systemic
capillaries
Systemic circuit
Key
Oxygen-rich blood
Oxygen-poor blood
Mammals and Birds
• Mammals and birds have a ______________ with
two atria and two ventricles
• The ___________of the heart pumps and receives
only oxygen-rich blood, while the ____________
receives and pumps only oxygen-poor blood
• Mammals and birds are endotherms and require
more _______ than ectotherms
© 2011 Pearson Education, Inc.
Figure 42.5c
Mammals and Birds
Pulmonary circuit
Lung
capillaries
A
Atrium
(A)
Ventricle
(V)
Right
V
Left
Systemic
capillaries
Systemic circuit
Key
Oxygen-rich blood
Oxygen-poor blood
Figure 42.5
Amphibians
Pulmocutaneous circuit
Pulmonary circuit
Lung
and skin
capillaries
Atrium
(A)
Atrium
(A)
Right
Pulmonary circuit
Lung
capillaries
Lung
capillaries
Right
systemic
aorta
A
V
Right
Left
Mammals and Birds
Reptiles (Except Birds)
A
V
Left
Left
systemic
aorta
Incomplete
septum
A
V
Right
A
V
Left
Ventricle (V)
Systemic circuit
Key
Oxygen-rich blood
Oxygen-poor blood
Systemic
capillaries
Systemic
capillaries
Systemic
capillaries
Systemic circuit
Systemic circuit
Concept 42.2: Coordinated cycles of heart
contraction drive double circulation in
mammals
• The mammalian cardiovascular system meets the
body’s continuous demand for _______
© 2011 Pearson Education, Inc.
Mammalian Circulation
• Blood begins its flow with the ________ ventricle
pumping blood to the __________
• In the lungs, the blood loads ___ and unloads ___
• Oxygen-rich blood from the lungs enters the heart
at the ____________and is pumped through the
_________ to the body tissues by the __________
• The aorta provides blood to the heart through the
_____________________
© 2011 Pearson Education, Inc.
• Blood returns to the heart through the ________
________________(blood from head, neck, and
forelimbs) and ___________________ (blood
from trunk and hind limbs)
• The superior vena cava and inferior vena cava
flow into the _________________
Animation: Path of Blood Flow in Mammals
© 2011 Pearson Education, Inc.
Figure 42.6
Capillaries of
head and forelimbs
Superior vena cava
Pulmonary
artery
Capillaries
of right lung
Pulmonary
vein
Right atrium
Right ventricle
Pulmonary
artery
Aorta
Capillaries
of left lung
Pulmonary vein
Left atrium
Left ventricle
Aorta
Inferior
vena cava
Capillaries of
abdominal organs
and hind limbs
The Mammalian Heart: A Closer Look
• A closer look at the mammalian heart provides a
better understanding of double circulation
© 2011 Pearson Education, Inc.
Figure 42.7
Aorta
Pulmonary artery
Pulmonary
artery
Right
atrium
Left
atrium
Semilunar
valve
Semilunar
valve
Atrioventricular
valve
Atrioventricular
valve
Right
ventricle
Left
ventricle
• The heart contracts and relaxes in a rhythmic
cycle called the _________________
• The contraction, or pumping, phase is called
_______________
• The relaxation, or filling, phase is called ________
© 2011 Pearson Education, Inc.
Figure 42.8-3
2 Atrial systole and ventricular
diastole
1 Atrial and
ventricular diastole
0.1
sec
0.4
sec
0.3 sec
3 Ventricular systole and atrial
diastole
• The______________, also called the pulse, is the
number of beats per minute
• The _________________is the amount of blood
pumped in a single contraction
• The ___________________ is the volume of
blood pumped into the systemic circulation per
minute and depends on both the heart rate and
stroke volume
© 2011 Pearson Education, Inc.
• Four __________ prevent backflow of blood in the
heart
• The _____________________ separate each
atrium and ventricle
• The ____________________ control blood flow to
the aorta and the pulmonary artery
© 2011 Pearson Education, Inc.
• The “lub-dup” sound of a heart beat is caused by
the ____________ against the AV valves (lub)
then against the semilunar (dup) valves
• Backflow of blood through a defective valve
causes a ____________________
© 2011 Pearson Education, Inc.
Maintaining the Heart’s Rhythmic Beat
• Some cardiac muscle cells are _______________,
meaning they contract without any signal from the
nervous system
• The __________________, or pacemaker, sets
the rate and timing at which cardiac muscle cells
contract
• Impulses that travel during the cardiac cycle can
be recorded as an ________________________
__________________
© 2011 Pearson Education, Inc.
Figure 42.9-4
1
SA node
(pacemaker)
ECG
2
AV
node
3
Bundle
branches
4
Heart
apex
Purkinje
fibers
• Impulses from the SA node travel to the
_______________________________
• At the AV node, the impulses are delayed and
then travel to the __________________that make
the ventricles contract
© 2011 Pearson Education, Inc.
• The pacemaker is regulated by two portions of the
nervous system: the __________________ and
__________________ divisions
• The _________division speeds up the pacemaker
• The _________________division slows down the
pacemaker
• The pacemaker is also regulated by __________
and ___________________
© 2011 Pearson Education, Inc.
Concept 42.3: Patterns of blood pressure and
flow reflect the structure and arrangement
of blood vessels
• The _______________________ that govern
movement of water in plumbing systems also
influence the functioning of animal circulatory
systems
© 2011 Pearson Education, Inc.
Blood Vessel Structure and Function
• A vessel’s cavity is called the _______________
• The epithelial layer that lines blood vessels is
called the ____________________
• The endothelium is __________________and
minimizes resistance
© 2011 Pearson Education, Inc.
Figure 42.10a
Valve
Basal lamina
Endothelium
Smooth
muscle
Connective
tissue
Endothelium
Capillary
Smooth
muscle
Connective
tissue
Artery
Vein
Arteriole
Venule
• __________have thin walls, the endothelium plus
its basal lamina, to facilitate the exchange of
materials
• __________and __________have an
endothelium, smooth muscle, and connective
tissue
• ______________ have thicker walls than veins to
accommodate the high pressure of blood pumped
from the heart
• In the thinner-walled _______, blood flows back to
the heart mainly as a result of __________ action
© 2011 Pearson Education, Inc.
Blood Flow Velocity
• Physical laws governing movement of fluids
through pipes affect blood ________ and blood
_________________
• Velocity of blood flow is slowest in the ________
beds, as a result of the high _____________ and
large total __________________________
• Blood flow in capillaries is necessarily slow for
__________________ of materials
© 2011 Pearson Education, Inc.
Velocity
(cm/sec)
5,000
4,000
3,000
2,000
1,000
0
50
40
30
20
10
0
Pressure
(mm Hg)
Area (cm2)
Figure 42.11
120
100
80
60
40
20
0
Systolic
pressure
Diastolic
pressure
Blood Pressure
• Blood flows from areas of __________ pressure to
areas of ________________ pressure
• _________________ is the pressure that blood
exerts against the wall of a vessel
• In rigid vessels blood pressure is _____________;
less rigid vessels ______________ and blood
pressure is lost
© 2011 Pearson Education, Inc.
Changes in Blood Pressure During the
Cardiac Cycle
• ________________ is the pressure in the arteries
during ventricular systole; it is the highest pressure
in the arteries
• ________________is the pressure in the arteries
during diastole; it is lower than systolic pressure
• A __________ is the rhythmic bulging of artery
walls with each heartbeat
© 2011 Pearson Education, Inc.
Regulation of Blood Pressure
• Blood pressure is determined by ____________
and ___________________ due to constriction of
arterioles
• __________________is the contraction of smooth
muscle in arteriole walls; it increases blood
pressure
• ___________________is the relaxation of smooth
muscles in the arterioles; it causes blood pressure
to fall
© 2011 Pearson Education, Inc.
• Vasoconstriction and vasodilation help maintain
adequate blood flow as the body’s demands
change
• ____________ is a major inducer of vasodilation
• The peptide ________________ is an important
inducer of vasoconstriction
© 2011 Pearson Education, Inc.
Blood Pressure and Gravity
• Blood pressure is generally measured for an
____________ in the arm at the same height as
the heart
• Blood pressure for a healthy 20-year-old at rest is
_______ mm Hg at systole and ______ mm Hg at
diastole
© 2011 Pearson Education, Inc.
Figure 42.12
Blood pressure reading: 120/70
1
3
2
120
120
70
Artery
closed
Sounds
audible in
stethoscope
Sounds
stop
• _____________ is caused by inadequate blood
flow to the head
• Animals with longer necks require a higher
___________ pressure to pump blood a greater
distance against gravity
• Blood is moved through _________ by smooth
muscle contraction, skeletal muscle
contraction, and expansion of the vena cava
with inhalation
• _____________ in veins prevent backflow of
blood
© 2011 Pearson Education, Inc.
Figure 42.13
Direction of blood flow
in vein (toward heart)
Valve (open)
Skeletal muscle
Valve (closed)
Capillary Function
• Blood flows through only ______% of the body’s
capillaries at a time
• Capillaries in _______________ are usually filled
to capacity
• Blood supply ____________ in many other sites
© 2011 Pearson Education, Inc.
• Two mechanisms regulate distribution of blood in
capillary beds
– ___________________________ layer in the wall
of an arteriole constricts the vessel
– ______________________control flow of blood
between arterioles and venules
• Blood flow is regulated by __________impulses,
____________, and other__________________
© 2011 Pearson Education, Inc.
Figure 42.14
Precapillary
sphincters
Thoroughfare
channel
Arteriole
(a) Sphincters relaxed
Arteriole
(b) Sphincters contracted
Capillaries
Venule
Venule
• The exchange of substances between the blood
and interstitial fluid takes place across the thin
endothelial walls of the _____________
• The difference between _________________ and
_______________________ drives fluids out of
capillaries at the arteriole end and into capillaries
at the venule end
• Most blood __________and all blood _________
are too large to pass through the endothelium
© 2011 Pearson Education, Inc.
Figure 42.15
INTERSTITIAL
FLUID
Net fluid movement out
Body cell
Blood
pressure
Osmotic
pressure
Arterial end
of capillary
Direction of blood flow
Venous end
of capillary
Fluid Return by the Lymphatic System
• The _________________ returns fluid that leaks
out from the capillary beds
• Fluid, called_____________, reenters the
circulation directly at the venous end of the
capillary bed and indirectly through the lymphatic
system
• The lymphatic system drains into _____________
________________________
• ________________ in lymph vessels prevent the
backflow of fluid
© 2011 Pearson Education, Inc.
• __________________ are organs that filter lymph
and play an important role in the body’s defense
• _______________ is swelling caused by
disruptions in the flow of lymph
© 2011 Pearson Education, Inc.
Concept 42.4: Blood components contribute
to exchange, transport, and defense
• With________________, the fluid that is pumped
comes into direct contact with all cells
• The _______________________of vertebrates
contain ________, a specialized connective tissue
© 2011 Pearson Education, Inc.
Blood Composition and Function
• Blood consists of several kinds of cells suspended
in a liquid matrix called ____________
• The cellular elements occupy about ___% of the
volume of blood
© 2011 Pearson Education, Inc.
Figure 42.17a
Plasma 55%
Constituent
Major functions
Water
Solvent for
carrying other
substances
Ions (blood
electrolytes)
Sodium
Potassium
Calcium
Magnesium
Chloride
Bicarbonate
Osmotic balance,
pH buffering,
and regulation
of membrane
permeablity
Plasma proteins
Albumin
Fibrinogen
Immunoglobulins (antibodies)
Osmotic balance, pH buffering
Clotting
Defense
Substances transported by blood
Nutrients
Waste products
Respiratory gases
Hormones
Separated
blood
elements
Figure 42.17b
Cellular elements 45%
Number per L
(mm3) of blood
Cell type
Leukocytes (white blood cells)
Separated
blood
elements
5,000–10,000
Functions
Defense and
immunity
Lymphocytes
Basophils
Eosinophils
Neutrophils
Monocytes
Platelets
Erythrocytes (red blood cells)
250,000–400,000
5–6 million
Blood
clotting
Transport
of O2 and
some CO2
Plasma
• Blood plasma is about 90% ____________
• Among its solutes are inorganic salts in the form of
dissolved ions, sometimes called______________
• Another important class of solutes is the ________
____________, which influence blood pH, osmotic
pressure, and viscosity
• Various plasma proteins function in __________
___________, __________, and _____________
© 2011 Pearson Education, Inc.
Cellular Elements
• Suspended in blood plasma are two types of cells
– ______________________________ transport
oxygen O2
– ______________________function in defense
• _______________, a third cellular element, are
fragments of cells that are involved in clotting
© 2011 Pearson Education, Inc.
Erythrocytes
• Red blood cells, or_______________, are by far
the most numerous blood cells
• They contain_________________, the ironcontaining protein that transports O2
• Each molecule of hemoglobin binds up to _______
molecules of O2
• In mammals, mature erythrocytes lack ________
_________________________
© 2011 Pearson Education, Inc.
• ___________________is caused by abnormal
hemoglobin proteins that form aggregates
• The aggregates can deform an erythrocyte into a
sickle shape
• Sickled cells can rupture or block blood vessels
© 2011 Pearson Education, Inc.
Leukocytes
• There are five major types of white blood cells, or
________________: monocytes, neutrophils,
basophils, eosinophils, and lymphocytes
• They function in defense by ______________
bacteria and debris or by producing
______________ They are found both in and
outside of the circulatory system
© 2011 Pearson Education, Inc.
Platelets
• ______________ are fragments of cells and
function in blood clotting
© 2011 Pearson Education, Inc.
Blood Clotting
• _________________ is the formation of a solid
clot from liquid blood
• A cascade of complex reactions converts
inactive fibrinogen to fibrin, forming a clot
• A blood clot formed within a blood vessel is called
a _______________ and can block blood flow
© 2011 Pearson Education, Inc.
Figure 42.18a
3
2
1
Collagen fibers
Platelet
plug
Platelet
Fibrin
clot
Clotting factors from:
Platelets
Damaged cells
Plasma (factors include calcium, vitamin K)
Enzymatic cascade
Prothrombin

Thrombin
Fibrinogen
Fibrin
Fibrin clot
formation
Stem Cells and the Replacement of Cellular
Elements
• The cellular elements of blood ____________ and
are being replaced constantly
• Erythrocytes, leukocytes, and platelets all develop
from a common source of ______________ in the
red marrow of bones, especially ribs, vertebrae,
sternum, and pelvis
• The hormone __________________ stimulates
erythrocyte production when O2 delivery is low
© 2011 Pearson Education, Inc.
Figure 42.19
Stem cells
(in bone marrow)
Myeloid
stem cells
Lymphoid
stem cells
B cells T cells
Erythrocytes
Neutrophils
Basophils
Lymphocytes
Monocytes
Platelets
Eosinophils
Cardiovascular Disease
• _______________________are disorders of the
heart and the blood vessels
• Cardiovascular diseases account for more than
____________________ in the United States
• ___________________ , a steroid, helps maintain
membrane fluidity
© 2011 Pearson Education, Inc.
• _________________________ delivers
cholesterol to cells for membrane production
• _________________________ scavenges
cholesterol for return to the liver
• Risk for heart disease increases with a ______
LDL to HDL ratio
• ____________________ is also a factor in
cardiovascular disease
© 2011 Pearson Education, Inc.
Atherosclerosis, Heart Attacks, and Stroke
• One type of cardiovascular disease
,____________ , is caused by the buildup of
plaque deposits within arteries
© 2011 Pearson Education, Inc.
Figure 42.20
Lumen of artery
Endothelium
Smooth
muscle
1
LDL
Foam cell
Macrophage
Plaque
2
Extracellular
matrix
Plaque rupture
4
3
Fibrous cap
Cholesterol
Smooth
muscle
cell
T lymphocyte
• A_________________, or myocardial infarction, is
the death of cardiac muscle tissue resulting from
blockage of one or more coronary arteries
• _______________ supply oxygen-rich blood to the
heart muscle
• A _____________ is the death of nervous tissue
in the brain, usually resulting from rupture or
blockage of arteries in the head
• ______________ is caused by partial blockage of
the coronary arteries and results in chest pains
© 2011 Pearson Education, Inc.
Risk Factors and Treatment of
Cardiovascular Disease
• A high _____ to ________ ratio increases the risk
of cardiovascular disease
• The proportion of LDL relative to HDL can be
decreased by _____________________________
____________________
• Drugs called ____________ reduce LDL levels
and risk of heart attacks
© 2011 Pearson Education, Inc.
• ________________ plays a role in atherosclerosis
and thrombus formation
• _____________ inhibits inflammation and reduces
the risk of heart attacks and stroke
• ________________, or high blood pressure,
promotes atherosclerosis and increases the risk of
heart attack and stroke
• Hypertension can be reduced by dietary
changes, exercise, and/or medication
© 2011 Pearson Education, Inc.
Concept 42.5: Gas exchange occurs across
specialized respiratory surfaces
• __________________ supplies O2 for cellular
respiration and disposes of CO2
© 2011 Pearson Education, Inc.
Partial Pressure Gradients in Gas Exchange
• A gas diffuses from a region of ______________
___________to a region __________________
______________
• _________________ is the pressure exerted by a
particular gas in a mixture of gases
• Gases diffuse _____________ pressure gradients
in the lungs and other organs as a result of
differences in partial pressure
© 2011 Pearson Education, Inc.
Respiratory Media
• Animals can use _____ or __________ as a
source of O2, or respiratory medium
• In a given volume, there is __________ available
in water than in air
• Obtaining O2 from water requires __________
__________________ than air breathing
© 2011 Pearson Education, Inc.
Respiratory Surfaces
• Animals require large, moist respiratory surfaces
for exchange of gases between their cells and the
respiratory medium, either air or water
• Gas exchange across respiratory surfaces takes
place by ______________
• Respiratory surfaces vary by animal and can
include the outer surface, ___________________
___________________________
© 2011 Pearson Education, Inc.
Gills in Aquatic Animals
• ___________ are outfoldings of the body that
create a large surface area for gas exchange
© 2011 Pearson Education, Inc.
Figure 42.22
Coelom
Gills
Parapodium
(functions as gill)
(a) Marine worm
Gills
Tube foot
(b) Crayfish
(c) Sea star
• _______________ moves the respiratory medium
over the respiratory surface
• Aquatic animals move through water or move
water over their gills for ventilation
• Fish gills use a _____________________ system,
where blood flows in the opposite direction to
water passing over the gills; blood is always less
saturated with O2 than the water it meets
© 2011 Pearson Education, Inc.
Figure 42.23
O2-poor blood
Gill
arch
O2-rich blood
Lamella
Blood
vessels
Gill arch
Water
flow
Operculum
Water flow
Blood flow
Countercurrent exchange
PO (mm Hg) in water
2
150 120 90 60 30
Gill filaments
Net diffusion of O2
140 110 80 50 20
PO (mm Hg)
2
in blood
Tracheal Systems in Insects
• The ______________ of insects consists of tiny
branching tubes that penetrate the body
• The tracheal tubes supply O2 ____________ to
body cells
• The respiratory and circulatory systems are
__________________
• Larger insects must ventilate their tracheal system
to meet O2 demands
© 2011 Pearson Education, Inc.
Tracheoles Mitochondria
Muscle fiber
2.5 m
Figure 42.24
Tracheae
Air sacs
Body
cell
Air
sac
Tracheole
Trachea
External opening
Air
Lungs
• _____________ are an infolding of the body
surface
• The _______________ system (open or closed)
transports gases between the lungs and the rest of
the body
• The size and complexity of lungs correlate with an
animal’s_______________________
© 2011 Pearson Education, Inc.
Mammalian Respiratory Systems: A Closer
Look
• A system of branching ducts conveys air to the
lungs
• Air inhaled through the ______________ is
warmed, humidified, and sampled for odors
• The _________________directs air to the lungs
and food to the stomach
• Swallowing tips the epiglottis over the glottis in the
pharynx to prevent food from entering the_______
© 2011 Pearson Education, Inc.
Figure 42.25a
Nasal
cavity
Pharynx
Left
lung
Larynx
(Esophagus)
Trachea
Right lung
Bronchus
Bronchiole
Diaphragm
(Heart)
Figure 42.25b
Branch of
pulmonary vein
(oxygen-rich
blood)
Terminal
bronchiole
Branch of
pulmonary artery
(oxygen-poor
blood)
Alveoli
Capillaries
• Air passes through the pharynx,___________,
trachea, ___________, and _______________ to
the alveoli, where gas exchange occurs
• Exhaled air passes over the vocal cords in the
larynx to create sounds
• ________ and _________ line the epithelium of
the air ducts and move particles up to the pharynx
• This “________________” cleans the respiratory
system and allows particles to be swallowed into
the esophagus
© 2011 Pearson Education, Inc.
• Gas exchange takes place in__________, air sacs
at the tips of bronchioles
• Oxygen diffuses through the moist film of the
epithelium and into ______________
• __________________ diffuses from the capillaries
across the epithelium and into the air space
© 2011 Pearson Education, Inc.
• Alveoli lack __________ and are susceptible to
contamination
• Secretions called _________________ coat the
surface of the alveoli
• Preterm babies lack surfactant and are vulnerable
to respiratory distress syndrome; treatment is
provided by artificial surfactants
© 2011 Pearson Education, Inc.
Concept 42.6: Breathing ventilates the lungs
• The process that ventilates the lungs is
__________ , the alternate inhalation and
exhalation of air
© 2011 Pearson Education, Inc.
How an Amphibian Breathes
• An amphibian such as a frog ventilates its lungs by
___________________, which forces air down the
trachea
© 2011 Pearson Education, Inc.
How a Bird Breathes
• Birds have eight or nine ____________ that
function as bellows that keep air flowing through
the lungs
• Air passes through the lungs in _______________
• Every exhalation _____________________ the air
in the lungs
© 2011 Pearson Education, Inc.
Figure 42.27
Anterior
air sacs
Posterior
air sacs
Lungs
Airflow
Air tubes
(parabronchi)
in lung
1 mm
Posterior
air sacs
Lungs
3
Anterior
air sacs
2
4
1
1 First inhalation
3 Second inhalation
2 First exhalation
4 Second exhalation
How a Mammal Breathes
• Mammals ventilate their lungs by______________
________________, which pulls air into the lungs
• Lung volume increases as the rib muscles and
___________________ contract
• The _________________ is the volume of air
inhaled with each breath
© 2011 Pearson Education, Inc.
Figure 42.28
1
Rib cage
expands.
2
Air
inhaled.
Lung
Diaphragm
Rib cage gets
smaller.
Air
exhaled.
• The maximum tidal volume is the _____________
• After exhalation, a __________________ of air
remains in the lungs
© 2011 Pearson Education, Inc.
Control of Breathing in Humans
• In humans, the main __________________ are in
two regions of the brain, the _________________
and the _________
• The medulla regulates the rate and depth of
breathing in response to ____ changes in the
_________________
• The medulla adjusts breathing rate and depth to
match ___________________ demands
• The pons regulates the ___________
© 2011 Pearson Education, Inc.
• Sensors in the aorta and carotid arteries monitor
____ and ____ concentrations in the blood
• These sensors exert ___________________ over
breathing
© 2011 Pearson Education, Inc.
Figure 42.29
Homeostasis:
Blood pH of about 7.4
CO2 level
decreases.
Response:
Rib muscles
and diaphragm
increase rate
and depth of
ventilation.
Stimulus:
Rising level of
CO2 in tissues
lowers blood pH.
Carotid
arteries
Sensor/control center:
Cerebrospinal fluid
Medulla
oblongata
Aorta
Concept 42.7: Adaptations for gas exchange
include pigments that bind and transport
gases
• The metabolic demands of many organisms
require that the blood transport large quantities of
O2 and CO2
© 2011 Pearson Education, Inc.
Coordination of Circulation and Gas
Exchange
• Blood arriving in the lungs has a low partial
pressure of __ and a high partial pressure of ____
relative to air in the alveoli
• In the__________, O2 diffuses into the blood and
CO2 diffuses into the air
• In tissue capillaries, partial pressure gradients
favor diffusion of O2 into the ________________
and CO2 into the _____________
© 2011 Pearson Education, Inc.
Figure 42.30a
1 Inhaled air
8 Exhaled air
Alveolar
epithelial
cells
2 Alveolar
spaces
CO2
O2
Alveolar
capillaries
7 Pulmonary
arteries
3 Pulmonary
veins
6 Systemic
veins
4 Systemic
arteries
Heart
CO2
O2
Systemic
capillaries
5 Body tissue
(a) The path of respiratory gases in the circulatory
system
Partial pressure (mm Hg)
Figure 42.30b
160
PO
2
PCO
Inhaled
air
2
Exhaled
air
120
80
40
0
1
2
3
4
5
6
7
8
(b) Partial pressure of O2 and CO2 at different points in the
circulatory system numbered in (a)
Respiratory Pigments
• _________________, proteins that transport
oxygen, greatly increase the amount of oxygen
that blood can carry
• Arthropods and many molluscs have
_________________with __________ as the
oxygen-binding component
• Most vertebrates and some invertebrates use
________________
• In vertebrates, hemoglobin is contained within
___________________
© 2011 Pearson Education, Inc.
Hemoglobin
• A single hemoglobin molecule can carry
__________ molecules of O2, one molecule for
each _______________________ group
• The hemoglobin dissociation curve shows that a
small change in the partial pressure of oxygen can
result in a large change in delivery of O2
• CO2 produced during cellular respiration lowers
blood pH and decreases the affinity of hemoglobin
for O2; this is called the___________________
© 2011 Pearson Education, Inc.
Figure 42.UN01
Iron
Heme
Hemoglobin
O2 saturation of hemoglobin (%)
Figure 42.31a
100
O2 unloaded
to tissues
at rest
80
O2 unloaded
to tissues
during exercise
60
40
20
0
0
20
40
60
Tissues during Tissues
at rest
exercise
PO2 (mm Hg)
80
100
Lungs
(a) PO2 and hemoglobin dissociation at pH 7.4
O2 saturation of hemoglobin (%)
Figure 42.31b
100
pH 7.4
80
pH 7.2
Hemoglobin
retains less
O2 at lower pH
(higher CO2
concentration)
60
40
20
0
0
20
40
60
80
PO2 (mm Hg)
(b) pH and hemoglobin dissociation
100
Carbon Dioxide Transport
• Hemoglobin also helps transport ________and
assists in buffering the blood
• CO2 from respiring cells diffuses into the blood
and is transported in blood plasma, bound to
hemoglobin, or as ________________________
Animation: O2 from Blood to Tissues
Animation: CO2 from Tissues to Blood
Animation: CO2 from Blood to Lungs
Animation: O2 from Lungs to Blood
© 2011 Pearson Education, Inc.
Figure 42.32a
Body tissue
CO2 produced
CO2 transport
from tissues
Interstitial
CO2
fluid
Plasma
CO2
within capillary
Capillary
wall
CO2
H2O
Red
blood
cell
H2CO3
Hb
Carbonic
acid
HCO3 
Bicarbonate
Hemoglobin (Hb)
picks up
CO2 and H+.
H+
HCO3
To lungs
Figure 42.32b
To lungs
CO2 transport
to lungs
HCO3
HCO3 
H2CO3
H+
Hb
Hemoglobin
releases
CO2 and H+.
H2O
CO2
CO2
CO2
CO2
Alveolar space in lung
Respiratory Adaptations of Diving Mammals
• _______________ have evolutionary adaptations
that allow them to perform extraordinary feats
– For example, Weddell seals in Antarctica can
remain underwater for ____minutes to an ____
– For example, elephant seals can dive to 1,500 m
and remain underwater for __ hours
• These animals have a high ________ to _______
__________ ratio
© 2011 Pearson Education, Inc.
• Deep-diving air breathers stockpile ____ and
deplete it slowly
• Diving mammals can store oxygen in their
_____________ in _____________ proteins
• Diving mammals also conserve oxygen by
– Changing their buoyancy to glide passively
– Decreasing blood supply to muscles
– Deriving ATP in muscles from fermentation once
oxygen is depleted
© 2011 Pearson Education, Inc.