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Transport Systems
Transport Systems
• What type of organisms have
transport systems?
• Why do organisms need a
transport system?
Insects
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Insects don't have veins or arteries,
They do have circulatory systems.
An open circulatory system.
Insect blood (hemolymph), flows freely
through the body cavity and makes direct
contact with organs and tissues.
• A single blood vessel runs along the dorsal
side of the insect, from the head to the
abdomen.
• In the abdomen, the vessel divides into
chambers and functions as the insect heart
• Perforations in the heart wall (ostia) allow
hemolymph to enter the chambers from the
body cavity.
• Muscle contractions push the hemolymph
from one chamber to the next, moving it
forward toward the thorax and head.
• Insect blood is only about 10% hemocytes
(blood cells); most of the hemolymph is
watery plasma.
• The insect circulation system does not carry
oxygen, so the blood does not contain red
blood cells as ours does.
• Hemolymph is usually green or yellow in
colour.
Closed circulatory Systems
• Closed circulatory systems are more efficient
than open ones
• Closed system consists of arteries, veins, and
capillaries.
• Capillaries surround the organs, making sure
that all cells have an equal opportunity for
nourishment and removal of their waste
products
Earthworms
• One of the simplest types of closed circulatory
systems is found in annelids such as the
earthworm.
• Earthworms have two main blood vessels -- a
dorsal and a ventral vessel -- which carry
blood towards the head or the tail,
respectively.
• Blood is moved along the dorsal vessel by
waves of contraction in the wall of the vessel.
• In the anterior region of the worm, there are
five pairs of vessels, which we loosely term
"hearts," that connect the dorsal and the
ventral vessels.
• These connecting vessels function as
rudimentary hearts and force the blood into
the ventral vessel.
• Since the outer covering (the epidermis) of
the earthworm is so thin moist, there is ample
opportunity for exchange of gases, making this
relatively inefficient system possible
Earthworm Quiz
• Have a go at this quiz!