Comparative Circulatory
System
The function of animal circulatory systems is mainly…
AND…
Two Different Circulatory Systems
• Open Circulatory
• Closed Circulatory
System
System
• Blood (hemolymph) is
• Blood is contained
pumped into open body
within blood vessels:
cavity (hemocoel).
– Arteries move blood
away from the heart.
• Blood reenters heart
– Veins move blood toward
through openings (ostia).
the heart.
• Does not require much
• Energetically costly to
energy to operate, but
operate, but allows
can’t sustain high levels
higher levels of activity.
of activity.
Invertebrate Circulatory Systems
Most Invertebrates have an open circulatory system.
Fish Circulation
Heart pumps blood to the
gills to be re-oxygenated
(gill circulation) after which
blood flows to rest of body
and back to the heart in
one circuit.
• A fish heart
has two
chambers,
one atrium
and one
ventricle.
• “Single-loop
circulation”
results in
lower blood
pressure in
the body
capillaries
Amphibian and Reptile Circulation
• Amphibian and Reptilian
heart is a “Double-loop
circulatory system.”
• Advent of lungs resulted in
two circulations:
– Pulmonary circulation (Lungs)
– Systematic circulation (Rest of body)
• Maintains blood pressure
in body capillaries
• Oxygen rich and oxygen
deficient blood mix in the
ventricle.
Mammalian and Bird Circulation
• Mammals, birds, and crocodiles
have four- chambered heart.
– right and left atria
– right and left ventricles
• The right and left ventricles are
separated by a muscular wall called
the septum
• This prevents oxygen rich and
oxygen deficient blood from mixing
• Made up of two pumping
systems/circuits.
– Pulmonary circulation
– Systemic circulation
Comparison of Vertebrate
Hearts
• Functions:
– Transports
gases,
nutrients,
hormones, and
waste
– Regulate body
temperature
– Fight infection
• Major Organs:
– Heart
– Blood vessels
Circulation through body
– Heart pumps blood
• Pulmonary circulation
(heart to lungs to heart)
• Systemic Circulation (heart
to body to heart)
Circulation through heart
•
•
•
•
•
•
•
•
•
•
Vena Cava
Right atria
Right ventricle
Pulmonary artery
Lungs
Pulmonary vein
Left atria
Left ventricle
Aorta
Body
Unoxygenated
blood enters the
atrium on the right
side of the heart.
Unoxygenated
blood comes in
from the top of the
body through the
superior vena
cava.
Unoxygenated
blood comes in
from the lower
body though the
inferior vena cava.
While the
unoxygenated
blood is in the
right atrium,
the tricuspid
valve is closed
to keep the
blood from
flowing down
to the
ventricle.
The
atrium
contracts
and the
tricuspid
valve
opens,
forcing
the blood
down into
the
ventricle.
The tricuspid
valve closes
again so that
blood cannot
move back up
into the atrium.
The ventricle
contracts.
This forces
the
unoxygenated
blood through
the
pulmonary
valve and into
the
pulmonary
arteries.
The right pulmonary
artery takes the
unoxygenated blood
to the right lung.
The left pulmonary
artery takes the
unoxygenated blood
to the left lung.
THE PULMONARY
ARTERIES ARE
THE ONLY
ARTERIES THAT
CARRY
UNOXYGENEATED
BLOOD.
Oxygenated
blood from the
lungs enters the
heart through
the left atrium.
The mitral valve
is closed to keep
the blood from
going into the
ventricle.
Oxygenated blood
from the right lung
returns to the heart
through the right
pulmonary vein.
Oxygenated blood
from the left lung
returns to the heart
through the left
pulmonary vein.
THE PULMONARY
VEINS ARE THE
ONLY VEINS THAT
CARRY
OXYGENATED
BLOOD.
The left atrium
contracts.
This forces
the
oxygenated
blood through
the mitral
valve into the
left ventricle.
The mitral
valve closes
again. This
keeps the
oxygenated
blood from
moving back
up into the
atrium.
Oxygenated
blood is forced
into the aorta
to be carried
to the rest of
the body.
Blood Vessels
• Tissues
– connective
– smooth
muscle
– endothelium
(type of
epithelial
tissue)
• Arteries
• Veins
• Capillaries
Blood
• Connective tissue
• Fluid structure
(can flow to all parts of
the body)
• Blood Cells
– Red blood cells
• lack nuclei
• transport oxygen
– White blood cells
• contain nuclei
• fight infection
– Platelets
• plasma proteins and
cell fragments
responsible for
clotting
• Blood Plasma
– 90% water
– 10 %
•
•
•
•
•
dissolved gases
salts
nutrients
enzymes
waste
• plasma proteins
– transport fatty acids,
hormones, vitamins
– fight infections
– involved in blood
clotting