Transcript Slide 1

Chapter 23
Circulation
PowerPoint Lectures for
Campbell Biology: Concepts & Connections, Seventh Edition
Reece, Taylor, Simon, and Dickey
© 2012 Pearson Education, Inc.
Lecture by Edward J. Zalisko
Introduction
 In many animals, the pull of gravity influences the
flow of blood through the body.
 To regulate the pressure of blood in the head, the
circulatory system of a giraffe uses
– special valves,
– saclike sinuses, and
– other mechanisms.
 In humans, special one-way valves in veins prevent
blood from flowing back down the legs.
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Figure 23.0_1
Chapter 23: Big Ideas
Circulatory
Systems
The Human Cardiovascular
System and Heart
Structure and Function
of Blood Vessels
Structure and Function
of Blood
Figure 23.0_2
CIRCULATORY
SYSTEMS
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23.1 Circulatory systems facilitate exchange with
all body tissues
 All cells must
– receive nutrients,
– exchange gases, and
– remove wastes.
 Diffusion alone is inadequate for large and complex
bodies.
 In most animals, circulatory systems facilitate
these exchanges.
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23.1 Circulatory systems facilitate exchange with
all body tissues
 An internal transport system assists diffusion by
moving materials between
– surfaces of the body and
– internal tissues.
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23.1 Circulatory systems facilitate exchange with
all body tissues
 A gastrovascular cavity in cnidarians and flatworms
– promotes digestion and
– distributes substances.
 Most animals use a true circulatory system that
consists of a
– circulatory fluid (blood),
– muscular pump (heart), and
– set of tubes (blood vessels) to carry the fluid.
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23.1 Circulatory systems facilitate exchange with
all body tissues
 Open circulatory systems are found in arthropods
and many molluscs and consist of
– a heart,
– open-ended vessels, and
– blood that directly bathes the cells and functions as the
interstitial fluid.
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Figure 23.1A
Pores
Tubular
heart
23.1 Circulatory systems facilitate exchange with
all body tissues
 Closed circulatory systems are found in
vertebrates, earthworms, squids, and octopuses and
consist of
– a heart and
– vessels that confine blood, keeping it distinct from
interstitial fluid.
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23.1 Circulatory systems facilitate exchange with
all body tissues
 The vertebrate circulatory system is often called a
cardiovascular system, including three types of
vessels.
1. Arteries carry blood away from the heart.
2. Veins return blood to the heart.
3. Capillaries convey blood between arteries and veins.
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23.1 Circulatory systems facilitate exchange with
all body tissues
 The cardiovascular system of a fish includes a heart
with two main chambers:
1. The atrium receives blood from veins.
2. The ventricle pumps blood to gills via large arteries.
These large arteries branch into
– arterioles that give rise to
– capillaries, the smallest blood vessels, which branch into
networks called capillary beds.
– Capillaries converge into venules, which in turn converge into
larger veins.
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Figure 23.1B
Capillary
beds
Artery
(O2-rich blood)
Arteriole
Venule
Vein
Gill
capillaries
Atrium
Artery
(O2-poor blood)
Ventricle
Heart
23.2 EVOLUTION CONNECTION: Vertebrate
cardiovascular systems reflect evolution
 A two-chambered heart
– is characteristic of fish and
– pumps blood in a single circulation in which blood
moves
– from gill capillaries,
– to systemic capillaries, and
– back to the heart.
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Figure 23.2A
Gill
capillaries
Heart:
Ventricle
Atrium
Body
capillaries
23.2 EVOLUTION CONNECTION: Vertebrate
cardiovascular systems reflect evolution
 Land vertebrates have a double circulation
consisting of a separate
– pulmonary circuit and
– systemic circuit.
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23.2 EVOLUTION CONNECTION: Vertebrate
cardiovascular systems reflect evolution
 Three-chambered hearts
– are found in amphibians, turtles, snakes, and lizards and
– consist of
– two atria and
– one undivided ventricle.
– This arrangement generally separates oxygen-poor and
oxygen-rich blood.
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Figure 23.2B
Lung and
skin capillaries
Pulmocutaneous
circuit
Atrium
Atrium
Ventricle
Left
Right
Systemic
circuit
Systemic
capillaries
23.2 EVOLUTION CONNECTION: Vertebrate
cardiovascular systems reflect evolution
 Four-chambered hearts
– are found in crocodilians, birds, and mammals and
– consist of
– two atria and
– two ventricles.
– These two circuits do not mix
– oxygen-rich and
– oxygen-poor blood.
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Figure 23.2C
Lung
capillaries
Pulmonary
circuit
Atrium
Atrium
Ventricle
Ventricle
Right
Left
Systemic
circuit
Systemic
capillaries
THE HUMAN
CARDIOVASCULAR
SYSTEM AND HEART
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23.3 The human cardiovascular system illustrates
the double circulation of mammals
 Blood flow through the double circulatory system of
humans
– drains from the superior vena cava (from the head and
arms) or inferior vena cava (from the lower trunk and
legs) into the right atrium,
– moves out to the lungs via the pulmonary artery,
– returns to the left atrium through the pulmonary vein,
and
– leaves the heart through the aorta.
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Animation: Path of Blood Flow in Mammals
Right click on animation / Click play
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Figure 23.3A
8
Capillaries of
head, chest and
arms
Superior
vena cava
Pulmonary artery
Pulmonary artery
Aorta
9
Capillaries of
right lung
2
7
Capillaries
of left lung
2
3
3
5
4
10
4
Pulmonary vein
6
1
Right atrium
9
Pulmonary vein
Left atrium
Left ventricle
Right ventricle
Aorta
Inferior vena cava
8
Capillaries of
abdominal region
and legs
Figure 23.3B
To lung
To lung
Left atrium
Right atrium
From lung
From lung
Semilunar
valve
Semilunar
valve
Atrioventricular
(AV) valve
Atrioventricular
(AV) valve
Right
ventricle
Left
ventricle
23.4 The heart contracts and relaxes rhythmically
 The repeated contraction and relaxation of pumping
blood is called the cardiac cycle. The cycle consists
of two main phases.
1. During diastole, blood flows
– from veins
– into heart chambers.
2. During systole, blood flows
– from atria
– into ventricles.
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Figure 23.4_s1
Diastole
1 The heart
is relaxed.
The semilunar
valves are
closed.
0.4 sec
The AV
valves are
open.
Figure 23.4_s2
Systole
Diastole
1 The heart
is relaxed.
The semilunar
valves are
closed.
2 The atria
contract.
0.1 sec
0.4 sec
The AV
valves are
open.
Figure 23.4_s3
Systole
Diastole
1 The heart
is relaxed.
The semilunar
valves are
closed.
2 The atria
contract.
0.1 sec
3 The ventricles
contract.
0.4 sec
0.3 sec
The AV
valves are
open.
The
semilunar
valves are
open.
The AV valves
are closed.
23.4 The heart contracts and relaxes rhythmically
 Cardiac output is the amount of blood pumped per
minute from the ventricles.
 Heart rate is the number of heart beats per minute.
 Heart valves prevent the backflow of blood.
 A heart murmur
– is a defect in one or more heart valves that
– permits a backflow of blood and
– reduces the cardiac output.
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23.5 The SA node sets the tempo of the heartbeat
 The SA (sinoatrial) node
– generates electrical signals in atria and
– sets the rate of heart contractions.
 The AV (atrioventricular) node
– relays these signals to the ventricles and
– causes ventricular contraction.
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Figure 23.5A
1 Signals from the
SA node spread
through the atria.
SA node
(pacemaker)
2 Signals are
delayed at the
AV node.
AV node
3 Specialized muscle
4 Signals spread
fibers pass signals
to the heart apex.
throughout the
ventricles.
Specialized
muscle fibers
Right
atrium
Apex
ECG
Figure 23.5A_1
1
Signals from the
SA node spread
through the atria.
SA node
(pacemaker)
Right
atrium
ECG
2
Signals are
delayed at the
AV node.
AV node
Figure 23.5A_2
3
Specialized muscle
fibers pass signals
to the heart apex.
4
Signals spread
throughout the
ventricles.
Specialized
muscle fibers
Apex
23.5 The SA node sets the tempo of the heartbeat
 An electrocardiogram (ECG) records electrical
changes in the heart.
 Heart rates normally adjust to body needs.
 Abnormal rhythms may occur in a heart attack.
 Automatic external defibrillators (AEDs)
– shock the heart,
– reset the SA node, and
– save thousands of lives.
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Figure 23.5B
Wire
leading
to SA node
Artificial
pacemaker
Heart
23.6 CONNECTION: What is a heart attack?
 A heart attack
– is damage or death of cardiac muscle and
– usually results from a blocked coronary artery.
 Cardiovascular diseases are disorders of the heart
and blood vessels. These include
1. a stroke, death of brain tissue from blocked or ruptured
arteries in the head, and
2. atherosclerosis, in which fatty deposits in the walls of
arteries narrow the blood vessels and restrict blood flow.
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Figure 23.6A
Superior
vena cava
Pulmonary
artery
Right coronary
artery
Aorta
Left coronary
artery
Blockage
Dead muscle
tissue
Figure 23.6B
Connective
tissue
Smooth
muscle
Epithelium
Plaque
Figure 23.6B_1
Connective
tissue
Smooth
muscle
Epithelium
Figure 23.6B_2
Plaque
STRUCTURE AND FUNCTION
OF BLOOD VESSELS
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23.7 The structure of blood vessels fits their
functions
 Capillaries
– have thin walls consisting of a single layer of epithelial
cells,
– are narrow, about as wide as one red blood cell, and
– increase surface area for gas and fluid exchange with the
interstitial fluid.
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Figure 23.7A
Capillary
Red blood
cell
Figure 23.7B
Capillary
Interstitial
fluid
Tissue
cell
Diffusion of
molecules
23.7 The structure of blood vessels fits their
functions
 Arteries and veins
– are lined by a single layer of epithelial cells and
– have elastic fibers in an outer connective tissue layer that
allows these vessels to recoil after stretching.
– Arteries contain a thick layer of smooth muscle in their
walls that can constrict and reduce blood flow.
– Veins have one-way valves that restrict backward flow of
blood.
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Figure 23.7C
Epithelium
Basal lamina
Capillary
Epithelium
Epithelium
Smooth
muscle
Connective
tissue
Artery
Arteriole
Valve
Smooth
muscle
Connective
tissue
Venule
Vein
23.8 Blood pressure and velocity reflect the
structure and arrangement of blood vessels
 Blood pressure
– is the force blood exerts on vessel walls,
– depends on cardiac output and resistance of vessels to
expansion, and
– decreases as blood moves away from the heart.
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Pressure
(mm Hg)
Figure 23.8A
120
100
80
60
40
20
0
Systolic
pressure
Diastolic
pressure
Venae cavae
Veins
Venules
Capillaries
Arterioles
Arteries
50
40
30
20
10
0
Aorta
Velocity
(cm/sec)
Relative sizes and
numbers
of blood
vessels
23.8 Blood pressure and velocity reflect the
structure and arrangement of blood vessels
 Blood pressure is
– highest in arteries and
– lowest in veins.
 Blood pressure is measured as
– systolic pressure—caused by ventricular contraction, and
– diastolic pressure—low pressure between contractions.
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23.8 Blood pressure and velocity reflect the
structure and arrangement of blood vessels
 How does blood travel against gravity, up legs?
– Veins are squeezed by pressure from muscle
contractions between
– two muscles or
– muscles and bone or skin.
– One-way valves limit blood flow to one direction, toward
the heart.
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Figure 23.8B
Direction of
blood flow
in vein
Valve
(open)
Contracting
skeletal
muscle
Valve
(closed)
23.9 CONNECTION: Measuring blood pressure
can reveal cardiovascular problems
 A typical blood pressure for a healthy young adult
is about 120/70.
 Blood pressure is commonly measured using a
sphygmomanometer.
 Hypertension is a serious cardiovascular problem
in which blood pressure is persistent at or above
– 140 systolic and/or
– 90 diastolic.
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Figure 23.9_s1
Typical blood
pressure:
120 systolic
70 diastolic
Pressure
in the cuff
above 120
Rubber cuff
inflated
with air
Artery
1
120
Artery
closed
2
Figure 23.9_s2
Typical blood
pressure:
120 systolic
70 diastolic
Rubber cuff
inflated
with air
Artery
1
Pressure
in the cuff
above 120
Pressure
in the cuff
at 120
120
120
Sounds
audible
in the
stethoscope
Artery
closed
2
3
Figure 23.9_s3
Typical blood
pressure:
120 systolic
70 diastolic
Rubber cuff
inflated
with air
Artery
1
Pressure
in the cuff
above 120
Pressure
in the cuff
at 120
120
120
Pressure
in the cuff
at 70
70
Sounds
audible
in the
stethoscope
Artery
closed
2
3
Sounds
stop
4
23.9 CONNECTION: Measuring blood pressure
can reveal cardiovascular problems
 Hypertension causes
– the heart to work harder, weakening the heart over time,
– increased plaque formation from tiny ruptures, and
– increased risk of blood clot formation.
 Hypertension can contribute to
– heart attacks,
– strokes, and/or
– kidney failure.
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23.10 Smooth muscle controls the distribution of
blood
 Blood flow through capillaries is restricted by
precapillary sphincters.
 By opening and closing these precapillary
sphincters, blood flow to particular regions can be
increased or decreased.
 Only about 5–10% of capillaries are open at one
time.
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Figure 23.10
Precapillary
sphincters
Arteriole
1
Thoroughfare
channel
Capillaries
Venule
Sphincters are relaxed.
Thoroughfare
channel
Venule
Arteriole
2 Sphincters are contracted.
23.11 Capillaries allow the transfer of substances
through their walls
 Capillaries have very thin walls.
 Substances leave blood and enter interstitial fluid by
– diffusion and
– pressure-driven flow through clefts between epithelial
cells.
 Blood pressure forces fluid out of capillaries at the
arterial end.
 Osmotic pressure draws in fluid at the venous end.
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Figure 23.11A
Interstitial fluid
Capillary wall
Capillary lumen
Nucleus of
epithelial cell
Clefts between
the cells
Muscle cell
Figure 23.11A_1
Interstitial fluid
Capillary wall
Capillary lumen
Nucleus of
epithelial cell
Clefts between
the cells
Muscle cell
Figure 23.11B
Tissue cells
Blood
pressure
Arterial
end
Interstitial
fluid
Osmotic
pressure
Venous
end
Net fluid movement
out of the capillary
Fluid enters a lymph vessel
STRUCTURE
AND FUNCTION
OF BLOOD
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23.12 Blood consists of red and white blood cells
suspended in plasma
 Blood consists of several types of cells suspended in
a liquid called plasma, which
– is about 90% water and
– contains many different substances.
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Figure 23.12_1
Plasma (55%)
Constituent
Major functions
Water
Solvent for
carrying other
substances
Ions (blood electrolytes)
Osmotic balance,
pH buffering, and
maintaining ion
concentration of
interstitial fluid
Sodium
Potassium
Calcium
Magnesium
Chloride
Bicarbonate
Plasma proteins
Osmotic balance
and pH buffering
Fibrinogen
Clotting
Immunoglobulins
(antibodies)
Defense
Substances transported by blood
Nutrients (e.g., glucose, fatty acids, vitamins)
Waste products of metabolism
Respiratory gases (O2 and CO2)
Hormones
23.12 Blood consists of red and white blood cells
suspended in plasma
 Two classes of cells are suspended in blood plasma.
1. Red blood cells or erythrocytes transport O2 bound to
hemoglobin.
2. White blood cells, or leukocytes,
– function inside and outside the circulatory system and
– fight infections and cancer.
– Monocytes and neutrophils are white blood cells called
phagocytes, which engulf and digest bacteria and
debris from our own dead cells.
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Figure 23.12_2
Cellular elements (45%)
Cell type
Number
per L (mm3) of blood)
Red blood cells
(erythrocytes)
White blood cells
(leukocytes)
Basophils
Functions
5–6 million
Transport of
O2 and
some CO2
5,000–10,000
Defense
and immunity
Lymphocytes
Eosinophils
Monocytes
Neutrophils
Platelets
250,000–
400,000
Blood clotting
Figure 23.12
Plasma (55%)
Constituent
Major functions
Water
Solvent for
carrying other
substances
Ions (blood electrolytes)
Sodium
Potassium
Calcium
Magnesium
Chloride
Bicarbonate
Plasma proteins
Osmotic balance,
pH buffering, and
maintaining ion
concentration of
interstitial fluid
Cellular elements (45%)
Cell type
Centrifuged
blood
sample
Red blood cells
(erythrocytes)
White blood cells
(leukocytes)
Osmotic balance
and pH buffering
Fibrinogen
Clotting
Immunoglobulins
(antibodies)
Defense
Substances transported by blood
Nutrients (e.g., glucose, fatty acids, vitamins)
Waste products of metabolism
Respiratory gases (O2 and CO2)
Hormones
Number
per L (mm3) of blood)
Functions
5–6 million
Transport of
O2 and
some CO2
5,000–10,000
Defense
and immunity
Lymphocytes
Basophils
Eosinophils
Monocytes
Neutrophils
Platelets
250,000–
400,000
Blood clotting
23.13 CONNECTION: Too few or too many red
blood cells can be unhealthy
 Anemia can be caused by low amounts of
– hemoglobin or
– red blood cells.
– Anemia causes fatigue due to lack of oxygen in tissues.
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23.13 CONNECTION: Too few or too many red
blood cells can be unhealthy
 The hormone erythropoietin (EPO) regulates red
blood cell production.
 Some athletes artificially increase red blood cell
production by
– training at high altitudes,
– injecting erythropoietin, and
– withdrawing, storing, and then reinjecting their blood cells
just before a competition.
– Abuse of these methods can lead to clotting, stroke, heart
failure, or even death.
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Figure 23.13
23.14 Blood clots plug leaks when blood vessels
are injured
 When a blood vessel is damaged
– platelets rapidly adhere to the exposed connective tissue
and
– a cluster of sticky platelets forms a plug.
– Clotting factors released from platelets and in the plasma
help trigger the conversion of the plasma protein
fibrinogen to fibrin, a threadlike protein that helps form a
clot that plugs the leak.
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Figure 23.14A_s1
1 Platelets adhere.
Epithelium
Connective
tissue
Platelet
Figure 23.14A_s2
1 Platelets adhere.
2 A platelet plug
forms.
Epithelium
Connective
tissue
Platelet
Platelet
plug
Figure 23.14A_s3
1 Platelets adhere.
2 A platelet plug
forms.
3 A fibrin clot
forms.
Epithelium
Connective
tissue
Platelet
Platelet
plug
Fibrin clot
23.14 Blood clots plug leaks when blood vessels
are injured
 Within an hour after a fibrin clot forms, the platelets
contract, pulling the torn edges closer together.
 Chemicals released by platelets also stimulate cell
division in smooth muscle and connective tissue,
initiating the healing process.
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Figure 23.14B
23.15 CONNECTION: Stem cells offer a potential
cure for blood cell diseases
 Multipotent stem cells
– are unspecialized and
– replace themselves throughout the life of an organism.
 Multipotent stem cells can differentiate into two main
types of stem cells.
1. Lymphoid stem cells can in turn produce two types of
lymphocytes, which function in the immune system.
2. Myeloid stem cells can differentiate into
– erythrocytes,
– other white blood cells, and
– platelets.
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Figure 23.15
Multipotent
stem cells
(in bone marrow)
Lymphoid
stem cells
Myeloid
stem cells
Erythrocytes
Platelets
Lymphocytes
Monocytes
Basophils
Eosinophils
Neutrophils
23.15 CONNECTION: Stem cells offer a potential
cure for blood cell diseases
 Leukemia
– is cancer of white blood cells,
– results in extra leukocytes that do not function
properly, and
– is usually fatal unless treated.
 Leukemia may be treated by
– radiation,
– chemotherapy, or
– the replacement of cancerous bone marrow with
healthy bone marrow.
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You should now be able to
1. Describe the general functions of a circulatory
system.
2. Compare the structures and functions of
gastrovascular cavities, open circulatory systems,
and closed circulatory systems.
3. Compare the cardiovascular systems of a fish, an
amphibian, a reptile, a bird, and a mammal.
4. Describe the pathway of blood through the
mammalian cardiovascular system.
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You should now be able to
5. Distinguish between diastole and systole.
6. Explain how heartbeats are controlled.
7. Define a heart attack and cardiovascular disease.
8. Relate the structure of blood vessels to their
function.
9. Explain how and why blood pressure changes as
blood moves away from the heart.
10. Explain how blood is moved back to the heart.
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You should now be able to
11. Explain how blood pressure is measured. Give
examples of normal and high blood pressure
readings.
12. Explain how blood flow through capillaries is
regulated.
13. Explain how the structure of a capillary relates to
its functions.
14. Describe the components of blood and their
functions.
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You should now be able to
15. Describe the structure, function, and production of
red blood cells.
16. Describe the process of blood clotting.
17. Define leukemia and describe the most common
forms of treatment.
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Figure 23.UN01
Capillary
Epithelium
Basal
lamina
Valve
Smooth
muscle
Connective
tissue
Artery
Vein
Figure 23.UN02
p.
a.
b.
o.
c.
n.
d.
m.
e.
l.
f.
k.
g.
j.
h.
i.
Figure 23.UN03
a.
b.