Internal Transport
Chapter 43
KEY CONCEPTS
•
A circulatory system typically consists of
blood, a heart, and a system of blood
vessels or spaces through which blood
circulates
Learning Objective 1
•
Compare and contrast internal transport in
animals with no circulatory system, those
with an open circulatory system, and those
with a closed circulatory system
Internal Transport
•
Diffusion
•
•
in small, simple invertebrates (sponges,
cnidarians, flatworms)
Specialized circulatory systems
•
•
in larger animals
blood, heart, blood vessels or spaces
No Circulatory System
Fig. 43-1a, p. 920
Gastrovascular
cavity
Pharynx
Mouth
(b)
Fig. 43-1b, p. 920
Interstitial Fluid
•
Tissue fluid between cells
•
•
in all animals
Brings oxygen, nutrients in contact with
cells
Open Circulatory System
•
Found in arthropods, most mollusks
•
Blood flows into a hemocoel
•
bathing tissues directly
Open
Circulatory
Systems
Stomach
Ventricle
Atrium
Gills
Fig. 43-2a, p. 921
Artery
Ostia
Tubular heart
Fig. 43-2b, p. 921
Closed Circulatory System
•
Found in all vertebrates
•
•
and some invertebrates
Blood flows through a continuous circuit of
blood vessels
Closed Circulatory System
Dorsal vessel
Ventral vessel
Contractile blood
vessels
Lateral vessels
Fig. 43-3, p. 921
KEY CONCEPTS
•
Arthropods and most mollusks have an
open circulatory system in which blood
bathes the tissues directly
•
Some invertebrates and all vertebrates
have a closed circulatory system in which
blood flows through a continuous circuit of
blood vessels
Vertebrate Circulatory System 1
•
Muscular heart
•
•
pumps blood into arteries, capillaries, veins
Transports
•
nutrients, oxygen, wastes, hormones
Vertebrate Circulatory System 2
•
Helps maintain
•
•
fluid balance, pH, body temperature
Defends body against disease
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closed circulatory systems by
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KEY CONCEPTS
•
The vertebrate circulatory system
transports nutrients, oxygen, wastes, and
hormones; helps maintain fluid balance,
appropriate pH, and body temperature;
and defends the body against disease
Learning Objective 2
•
Compare the structure and function of
plasma, red blood cells, white blood cells,
and platelets
Plasma
•
Water and salts
•
Substances in transport
•
Plasma proteins
•
•
•
albumins
globulins
fibrinogen
Red Blood Cells (Erythrocytes)
•
Transport oxygen and carbon dioxide
•
Produce hemoglobin
•
red pigment that binds with oxygen
White Blood Cells (Leukocytes)
•
Defend body against disease organisms
•
Lymphocytes and monocytes
•
•
agranular white blood cells
Neutrophils, eosinophils, basophils
•
granular white blood cells
Platelets
•
Patch damaged blood vessels
•
Release substances essential for blood
clotting
Vertebrate Blood
Whole
blood
Plasma
Cell
components
Plasma
proteins
Lipoproteins
Albumins
Globulins
White
blood cells
(leukocytes)
Fibrinogen
Clotting
proteins
Water
Salts
Dissolved
gases
Hormones
Glucose
Wastes
7 µm
Granular
leukocytes
Agranular
leukocytes
1 to 2 µm
Red blood cells Platelets
(erythrocytes)
Fig. 43-4a, p. 923
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Learning Objective 3
•
What is the sequence of events involved in
blood clotting?
Blood Clotting
•
Damaged cells and platelets
•
•
Prothrombin is converted to thrombin
•
•
release substances that activate clotting factors
converts fibrinogen to insoluble protein (fibrin)
Fibrin forms long threads
•
make up webbing of clot
Blood Clotting
1 Injury to blood
vessel
Blood flow
2 Wall of vessel
contracts
Blood flow
decreases
3 Platelets adhere
4 More permanent
to collagen fibers
clot forms
of damaged vessel
wall
Platelet
Blood flow plug
Blood flow
decreases
ceases
Fig. 43-5a, p. 924
1. Injury to blood
vessel
Blood flow
2. Wall of
vessel
contracts
Blood flow
decreases
3. Platelets adhere
to collagen fibers
of damaged vessel
wall
Blood flow
decreases
4. More permanent
clot forms
Blood flow
Platelet ceases
plug
Stepped Art
Fig. 43-5a, p. 924
Prothrombin
Damaged cells and
platelets release
substances that activate
clotting factors
Prothrombin
activator
Ca2+
Thrombin
Fibrinogen
Ca2+
Fibrin threads
(clot)
Fig. 43-5b, p. 924
Learning Objective 4
•
Compare the structure and function of
different types of blood vessels, including
arteries, arterioles, capillaries, and veins
Blood Vessels 1
•
Arteries
•
•
carry blood away from the heart
Veins
•
return blood to the heart
Blood Vessels 2
•
Arterioles
•
•
•
constrict (vasoconstriction)
dilate (vasodilation)
Arterioles regulate blood pressure and
distribution of blood to tissues
Blood Vessels 3
•
Capillaries
•
•
thin-walled exchange vessels
allow materials to transfer between blood and
tissues
Blood and
Lymphatic
Vessels
Vein
Lymphatic
Artery
Venule
Arteriole
Lymph
node
Capillary
bed
Capillaries
(a)
Movement of
interstitial fluid
Lymph
capillaries
Fig. 43-6a, p. 926
Outer coat
(connective tissue)
VEIN
Smooth
muscle
Endothelium
ARTERY
Outer coat
(connective tissue)
Endothelium
CAPILLARY
(b)
Fig. 43-6b, p. 926
Fig. 43-6c, p. 926
A Capillary Network
Precapillary
sphincter
Metarteriole
True
capillaries
Arteriole
(a) Sphincters closed
Venule
Fig. 43-7a, p. 927
Precapillary
sphincter
Metarteriole
True capillaries
Arteriole
(b) Sphincters open
Venule
Fig. 43-7b, p. 927
Learning Objective 5
•
Trace the evolution of the vertebrate
cardiovascular system from fish to
mammal
The Vertebrate Heart
•
One or two atria
•
•
receive blood
One or two ventricles
•
pump blood into arteries
The Vertebrate Heart
The Fish Heart
•
One atrium and ventricle
•
single circuit of blood flow
Atrium
Sinus venosus
Veins from the
body
Valve
Ventricle
Valve
Aorta
(a) Fishes
Fig. 43-8a, p. 928
Terrestrial Vertebrates
•
Circulatory systems separate oxygen-rich
from oxygen-poor blood
•
Allows higher metabolic rate
•
supports active terrestrial lifestyle
Amphibian Heart
•
Two atria and one ventricle
•
Blood flows through a double circuit
•
oxygen-rich blood partly separated from
oxygen-poor blood
Sinus venosus
Pulmonary vein
Veins from
the body
Pulmonary artery
Aorta
Partition separating
atria
Valves
Ventricle
Conus
Atria
(b) Amphibians
Fig. 43-8b, p. 928
Reptile Heart
•
Most have a wall that partly divides the
ventricles
•
minimizing mixing of oxygen-rich and oxygenpoor blood
Pulmonary vein
Aorta
Sinus venosus
Veins from the body
Pulmonary
artery
Right atrium
Ventricle
Left atrium
Semilunar valves
Conus
Incomplete partition
of the ventricle
(c) Reptiles
Fig. 43-8c, p. 928
Bird and Mammal Hearts
•
Four-chambered hearts
•
Separate oxygen-rich blood from oxygenpoor blood
Left atrium
AV valve
Veins from
the body
Pulmonary artery
Right atrium
Aorta
Ventricles
Semilunar valves
(d) Birds and mammals
Fig. 43-8d, p. 928
KEY CONCEPTS
•
During the evolution of terrestrial
vertebrates, adaptations in circulatory
system structures separated oxygen-rich
from oxygen-poor blood
•
The four-chambered hearts and double
circuits of endothermic birds and
mammals completely separate oxygenrich blood from oxygen-poor blood
Learning Objective 6
•
Describe the structure and function of the
human heart
•
Include the heart’s conduction system in
your answer
The Human Heart 1
•
Pericardium encloses heart
•
Valves prevent backflow of blood
•
•
•
right atrioventricular (AV) valve (tricuspid
valve) between right atrium and ventricle
mitral valve between left atrium and ventricle
semilunar valves guard exits from heart
The Human Heart 2
•
Intercalated discs
•
•
Sinoatrial (SA) node (pacemaker)
•
•
join cardiac muscle fibers
initiates each heartbeat
Specialized electrical conduction system
•
coordinates heartbeats
The Human Heart
Superior vena cava
Right pulmonary
arteries
Pulmonary valve
Right atrium
Pulmonary veins
Tricuspid valve
Aorta
Left pulmonary
arteries
Pulmonary artery
Pulmonary veins
Left atrium
Mitral valve
Aortic valve
Chordae tendineae
(“heartstrings”)
Papillary muscles
Right ventricle
Left ventricle
Inferior vena cava
Interventricular
septum
Aorta
Fig. 43-9, p. 929
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Heart Conduction
System
SA node or
pacemaker
Left atrium
Right atrium
AV node
Purkinje fibers
Right ventricle
AV bundle
Left ventricle
Right and left
branches
of AV bundle
Fig. 43-10a, p. 930
Nucleus
25 µm
Intercalated discs
Fig. 43-10b, p. 930
Intercalated discs
Z-line
Mitochondria
1 µm
Fig. 43-10c, p. 930
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conduction”
cardiac_conduction.dcr
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Learning Objective 7
•
Trace the events of the cardiac cycle
•
Relate normal heart sounds to these
events
Cardiac Cycle
•
One complete heartbeat
•
Contraction occurs during systole
•
Period of relaxation is diastole
Heart Sounds
•
Closing of AV valves
•
•
•
at beginning of ventricular systole
makes low-pitched “lub” sound
Closing of semilunar valves
•
•
at beginning of ventricular diastole
makes short, loud “dup” sound
Cardiac Cycle
Superior vena cava Aorta
Right atrium
Tricuspid valve
Inferior vena cava
Pulmonary artery
Semilunar valves
Pulmonary vein
Left atrium
Mitral valve
1 Atrial systole. Atria
5 Period of falling
pressure. Blood
flows from veins
into relaxed atria.
Right
Left
ventricle ventricle
contract, pushing blood
through open tricuspid
and mitral valves into
ventricles. Semilunar
valves are closed.
2 Beginning of
Heart
sounds
ventricular systole.
Ventricles contract;
pressure within
ventricles increases
and closes tricuspid
and mitral valves,
causing first heart
sound.
4 Beginning of
ventricular diastole.
Pressure in relaxing
ventricles drops
below that in arteries.
Semilunar valves
snap shut, causing
second heart sound.
3 Period of rising pressure.
Semilunar valves open
when pressure in ventricle
exceeds that in arteries.
Blood spurts into aorta and
pulmonary artery.
Fig. 43-11, p. 931
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Learning Objective 8
•
Define cardiac output
•
Describe how it is regulated
•
Identify factors that affect it
Cardiac Output (CO)
•
Equals stroke volume times heart rate
•
Stroke volume depends on
•
•
venous return
neural messages and hormones (especially
epinephrine and norepinephrine)
Starling’s Law of the Heart
•
The more blood delivered to the heart by
the veins, the more blood the heart pumps
Heart Rate
•
Regulated mainly by the nervous system
•
Influenced by hormones and body
temperature
Factors in
Cardiac
Output
Stressors and
other stimuli
Increases
Decreases
Hypothalamus
Cardiac centers in
the medulla
Brain
Increased
venous
return
Adrenal
Sympathetic Parasympathetic Increase
glands
nerves
nerves
in body
(accelerator nerves) (vagus)
temperature
Ephinephrine
Norepinephrine
and
Norepinephrine
Acetylcholine
X
STROKE
VOLUME
=
HEART
RATE
CARDIAC
OUTPUT
Fig. 43-12, p. 932
Learning Objective 9
•
What factors determine and regulate blood
pressure?
•
Compare blood pressure in different types
of blood vessels
Blood Pressure 1
•
The force blood exerts against inner walls
of the blood vessel
•
Is greatest in the arteries
•
Decreases as blood flows through the
capillaries
Blood Pressure 2
•
Depends on
•
•
•
•
cardiac output
blood volume
resistance to blood flow
Peripheral resistance to blood flow
•
caused by blood viscosity, friction between
blood and blood vessel wall
Blood Pressure
Blood pressure
Blood
volume
Blood
viscosity
Blood
flow
Peripheral
resistance
Cardiac
output
Vasoconstriction
Blood pressure depends on blood flow and resistance to that flow.
Fig. 43-14a, p. 936
Fig. 43-14b, p. 936
Area
Velocity
Blood pressure varies in different types
of blood vessels
Pulse pressure
Total cross-sectional area (cm2) of the
vascular bed
Vena
cavae
Diastolic
pressure
Veins
Venules
Capillaries
Arterioles
Arteries
Aorta
Blood pressure (mm Hg)
Systolic pressure
Fig. 43-14b, p. 936
Nervous Control 1
•
Baroreceptors
•
•
sense increase in blood pressure
send messages to cardiac and vasomotor
centers in medulla of brain
Nervous Control 2
•
Cardiac center
•
•
Vasomotor center
•
•
stimulates parasympathetic nerves that slow
heart rate
inhibits sympathetic nerves that constrict
blood vessels
Blood pressure is reduced
Sympathetic and
Parasympathetic
Actions
Parasympathetic
neuron
1
Acetylcholine
2
Acetylcholine
receptor
Plasma
membrane
5
K+
K + channel
G-protein
3
4
K+
Cardiac
muscle
Fig. 43-13a, p. 933
Sympathetic neuron
1
Norepinephrine
2 -adrenergic
receptor
6
G protein
Ca2+
Plasma
membrane
Adenylyl
cyclase
4
3
Ca2+
ATP
cAMP
Cardiac
muscle
Gate
open
5
Protein
Kinase
Fig. 43-13b, p. 933
Hormonal Control
•
Angiotensin II
•
•
raises blood pressure
Aldosterone
•
•
helps regulate salt excretion
affects blood volume and blood pressure
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pressure”
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Learning Objective 10
•
Trace a drop of blood through the
pulmonary and systemic circulations
•
Name in sequence each structure through
which it passes
Blood Circulation
•
Pulmonary circulation
•
•
connects heart and lungs
Systemic circulation
•
connects heart and tissues
Systemic and
Pulmonary
Circulation
Systemic circulation
Capillary network
Superior
vena
cava
Brain
Pulmonary
artery
Carotid artery
Pulmonary artery
Pulmonary
circulation
Left lung
Right lung
Aorta
LA
RA
RV
Pulmonary
vein
Inferior
vena cava
LV
Pulmonary vein
To lower parts of the
body
Capillary network
Fig. 43-16, p. 937
Pulmonary Circulation
•
From right ventricle to pulmonary arteries
to lungs
•
Through pulmonary capillaries in the lung
•
Return by pulmonary vein to left atrium
Systemic Circulation 1
•
Left ventricle to the aorta
•
Aorta branches into arteries
•
•
leading to body organs
Through capillary networks within organs
Systemic Circulation 2
•
From capillaries into veins
•
From veins to the superior vena cava or
inferior vena cava
•
Returns to right atrium
Principle Arteries and Veins
Carotid arteries
Jugular veins
Right subclavian
artery
Left subclavian vein
Aortic arch
Left pulmonary vein
Left pulmonary artery
Superior vena cava
Axillary artery
Left ventricle
Right ventricle
Right lung
Liver
Renal vein
Inferior vena cava
Common iliac vein
Femoral vein
Renal artery
Kidney
Abdominal aorta
Inferior mesenteric
artery
Common iliac artery
External iliac artery
Femoral artery
Fig. 43-17, p. 938
Venous Blood Flow
(a) Resting condition.
(b) Muscles contract.
(c) Muscles relax.
Fig. 43-15, p. 936
Special Circulations
•
Coronary arteries
•
•
supply heart muscle with blood
Hepatic portal system
•
circulates nutrient-rich blood through the liver
Cardiovascular Disease
500 µm
(a) Normal coronary artery.
500 µm
(b) This artery is almost completely
blocked with atherosclerotic plaque.
p. 934
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Learning Objective 11
•
Describe the structure and functions of the
lymphatic system
The Lymphatic System
•
Collects interstitial fluid, returns it to blood
•
important in homeostasis of fluids
•
Defends body against disease
•
Absorbs lipids from digestive tract
Lymphatic System Structures 1
•
Lymphatic vessels conduct lymph
•
Lymph
•
clear fluid formed from interstitial fluid
Lymphatic System Structures 2
•
Thoracic duct and right lymphatic duct
•
•
•
in shoulder region
return lymph to blood circulatory system
Lymph nodes
•
•
small masses of tissue
filter bacteria, harmful materials out of lymph
Lymphatic System
Right lymphatic duct
Right subclavian vein
Tonsil
Cervical lymph
nodes
Left subclavian vein
Thymus
Thoracic duct
Axillary lymph nodes
Spleen
Lymphatics of breasts
Superficial lymphatics
of upper limb
Superficial lymphatics
of lower limb
Fig. 43-18, p. 939
Lymph Capillaries
Arteriole
Venule
Red blood cells
Valve
Plasma
Connective tissue
fibers
Capillary bed
Lymph
Plasma
Fig. 43-19, p. 939
Blood and Interstitial Fluid
Arterial end
of capillary
Venous end
of capillary
Blood
pressure
(+40)
Osmotic
pressure
of plasma
(-28)
Osmotic
pressure
of interstitial
fluid (+3)
(40 + 3) - 28 = +15
Net filtration
Blood
pressure
(+15)
Osmotic
pressure
of plasma
(-28)
Osmotic
pressure
of interstitial
fluid
(+3)
(15 + 3) - 28 = -10
Net absorption
Fig. 43-20, p. 940
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KEY CONCEPTS
•
The lymphatic system helps maintain fluid
homeostasis by returning interstitial fluid to
the blood