Transport in Animals
• Gastrovascular cavities
– flatworms and cnidarians
• Nutrients and gases can move by processes
such as diffusion and active transport.
Figure 42.1 Internal transport in the cnidarian Aurelia
Earthworm
Closed Circulation
Water
Water
Water
Water Water
MouthWater
Incurrent
pore
Sponge Hydra Nematode
Gastrovas-
cular cavity
Gastrovas-
cular cavity
Gastrovascular cavity
Osculum
(excurrent
opening)
a.
b. c.
No Circulatory System
Grasshopper
Open Circulation
Anus
Hemolymph
Heart Heart
Lateral
hearts
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Open Circulatory systems
• Insects, other arthropods and most mollusks
• No distinction between blood and the
interstitial fluid
Open Circulatory systems
• Hemolymph
– name of general body fluid
– directly bathes the internal organs
• System of sinuses
• Heart and body movements cause
circulation
Open Circulatory systems
• Slower circulation
• sluggish animals BUT...
– Insects are very active
Figure 42.2 Open and closed circulatory systems
Closed Circulatory Systems
– Earthworms, squids, octopuses, and vertebrates
• Blood is confined to vessels and is distinct
from interstitial fluid
• Consists of the heart, blood vessels and
blood
Blood
• Plasma – about 55% of blood volume
– 90% water
– inorganic salts (electrolytes), metabolites
(vitamins, aa, glucose), wastes & hormones
– proteins
• osmotic balance, viscosity
• buffers, transport lipids, antibodies, clotting factors
(fibrinogen)
Plasma
(92% water, 55%
of whole blood)
Formed
elements
Platelets and
leukocytes (<1%)
Red blood cells
(erythrocytes)
(45% of whole
blood)
Other solutes (1.5%)
Electrolytes
Nutrients
Gases
Regulatory
substances
Waste products
Water (91.5%)
Plasma proteins (7%)
Albumin (54%)
Globulins (38%)
Fibrinogen (7%)
All others (1%)
Blood Plasma Red Blood Cells
PlasmaRed blood
cells
White blood cells
Platelets
Platelets
4 million–6 million/
mm3 blood
Neutrophils Eosinophils
Basophils LymphocytesMonocytes
3–8%
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
0.5–1% 20–25%
60–70% 2–4%
150,000–300,000
mm3 blood
Figure 42.14x Blood smear
Blood
Cellular Elements:
• Red Blood Cells (Erythrocytes)
– Most numerous (5-6 million in one cubic ml)
– Transport oxygen & carbon dioxide
Blood
Cellular Elements:
• White Blood Cells (Leukocytes)
– Function in body’s defense
– A cubic ml of blood has about 5,000 – 10,000
– in interstitial fluid or in the lymphatic system –
where your body fights pathogens
4. Threads of
fibrin trap
erythrocytes
and form
a clot.
1. Vessel is
damaged,
exposing
surrounding
tissue to blood.
5. Once tissue
damage
is healed,
the clot is
dissolved.
3. Cascade of
enzymatic
reactions is
triggered by
platelets,
plasma factors,
and damaged
tissue.
2. Platelets
adhere and
become
sticky, forming
a plug.
Prothrombin
Thrombin
Thrombin
Fibrinogen
Fibrin
Cellular Elements:
Platelets are cell fragments that pinch off from
larger cells in the bone marrow
-Function in the formation of blood clots
Blood
Figure 42.16x Blood clot
Heart
• one atrium or two atria
• one or two ventricles
Heart
• one atrium or two atria
– chambers that receive blood returning to the
heart
• one or two ventricles
– chambers that pump blood out of the heart.
Blood vessels
• Arteries
– branch into arterioles
• Capillaries
• Veins
– venules merge into veins
Blood vessels
• Arteries
– branch into arterioles
– carry blood away from heart
• Capillaries
– materials are exchanged
• Veins
– venules merge into veins
– carry blood back toward heart
Blood Vessel Structure
• Walls of arteries or veins have three layers:
– epithelium
– smooth muscle with elastic fibers
– connective tissue
– Arteries have thicker walls than veins
• Capillaries only have the inner epithelium
layer
Capillary Exchange
• Law of Continuity
– blood flows slowly in capillaries because larger
total cross-section
– allows materials to be exchanged
Figure 42.10 The interrelationship of blood flow velocity, cross-sectional area of
blood vessels, and blood pressure
Capillary Exchange
• About 85% of the fluid that exits capillaries
re-enters at the venule end.
Return of Blood to Heart
• Pressure too low in veins
• contraction of skeletal muscles move blood
• one-way valves in veins prevent backflow
Variation in Vertebrate
Circulation
FISH
• Two chambered heart and a single circuit of
blood flow
Systemic
capillaries
Respiratory
capillaries
Gills
Sinus
venosus VentricleConus
arteriosus
Atrium
Body
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Vertebrate Circulatory Systems
Variation in Vertebrate
Circulation
AMPHIBIAN
• Three chambered heart (two atria and one
ventricle) and double circulation (two
circuits of flow)
Lungs
Body
Pulmonary
capillaries
Systemic
capillaries
Ventricle
Conus
arteriosus
Right atrium Pulmonary vein
Pulmocutaneous
artery
Posterior vena cava
Truncus arteriosus
AortaCarotid artery
Systemic artery
Left atrium
Sinus venosus
Ventricle
Conus
arteriosus
Right atrium
Left atrium
a. b.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Amphibian Circulation
Variation in Vertebrate
Circulation
AMPHIBIAN
• Pulmonary circuit
– blood is pumped to the lungs, where it is
oxygenated and carried back to the left atrium
• Systemic circuit
– blood is pumped to the rest of the body, where
it gives up oxygen and is carried back to the
right atrium
Variation in Vertebrate
Circulation
AMPHIBIAN
• Double circulation assures a vigorous flow
of blood to the vital organs
• single ventricle --some mixing of oxygen-
rich and oxygen-poor blood.
Variation in Vertebrate
Circulation
MAMMALS & BIRDS
• Have a four chambered heart and double
circulation
• The left side of the heart handles oxygen-
rich blood and the right side handles only
oxygen-poor blood.
Head
Body
Lungs
Systemic
capillaries
Pulmonary artery
Pulmonary
semilunar valve
Inferior
vena cava
Superior
vena cava
Aorta
Tricuspid
valve
Right ventricle
Left
ventricle
Right atrium
Pulmonary
veinsLeft atrium
Bicuspid
mitral
valve
Systemic
capillaries
Pulmonary
artery
Superior
vena cava
Inferior
vena cava
Artery
Pulmonary
vein
Aorta
Respiratory
capillaries
a. b.
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Mammalian or Bird Heart
• Valves prevent backflow of blood when the
ventricles contract
– Between each ventricle and atrium is an
atrioventricular (AV) valve
• tricuspid and bicuspid (mitral)
– At the exits of the heart are the semilunar
valves
Head
Body
Lungs
Systemic
capillaries
Pulmonary artery
Pulmonary
semilunar valve
Inferior
vena cava
Superior
vena cava
Aorta
Tricuspid
valve
Right ventricle
Left
ventricle
Right atrium
Pulmonary
veinsLeft atrium
Bicuspid
mitral
valve
Systemic
capillaries
Pulmonary
artery
Superior
vena cava
Inferior
vena cava
Artery
Pulmonary
vein
Aorta
Respiratory
capillaries
a. b.
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
QS
Milliv
olt
s
Seconds
R
P wave
1 sec
+1
-1
0
1. The impulse begins at the SA node and travels to theAV node.
2. The impulse is delayed at the AV node. Itthen travels to the AV bundle.
SA node(pacemaker)
AV node
AV bundle
Left and rightbundle branches
Left and rightbundle branches
Purkinje fibers
Purkinje fibers
Left atriumRight atrium
Purkinje fibers
Interventri-cular septum
AV bundle
Interventricularseptum
AV
AV bundle
Internodalpathway
3. From the AV bundle, the impulse travels down the interventricular septum.
4. The impulse spreads to branches from the interven-tricular septum.
5. Finally reaching the Purkinje fibers,the impulse is distributed throughoutthe ventricles.
T waveThe control of heart rhythm
Cardiac Cycle
• a complete sequence of the heart
contracting to pump blood, relaxing to fill
with blood.
• total length is about 0.8 s
– The contraction phase is called systole
– The relaxation phase is called diastole
Figure 42.6 The cardiac cycle
Cuff
Blood pressure
gauge
Stethoscope
0
50
150100
200
250
1. Cuff pressure: 150 mm Hg
No sound:
Artery closed
2. Cuff pressure: 120 mm Hg
Pulse sound:
Systolic pressure
3. Cuff pressure: 75 mm Hg
Sound stops:
Diastolic pressure
0
50
150100
200
250 050
150100
200
250
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