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3 - Metabolic Rate (2) - Coggle Diagram
3 - Metabolic Rate (2)
Circulatory Systems in Vertebrates
All vertebrates have
closed circulatory systems
where the
blood
is c
ontained in a continuous circuit of blood vessels
and is
kept moving by a heart
Systems are either single or double as reference to how many times blood is pumped through the heart.
Oxygen Delivery
High metabolic rates require efficient delivery of oxygen to cells.
Single circulatory system
The circulatory system of a
fish
is described as
single
because
blood passes through the 2-chambered heart
only
once
for each circuit of the body
In the
fish the blood flows to the gills
at
high pressure
but is
delivered
to the
capillaries
at
low pressure
.
It is a
relatively primitive
and
inefficient
method.
The
gradient of oxygenated to deoxygenated
blood helps
limit mixing
; however, mixing of blood still occurs
Incomplete double circulatory system
Reptiles and amphibians
circulatory systems are described as
incomplete
This is because there is
only one ventricle
and s
ome mixing of oxygenated blood
from the
lungs
and
deoxygenated blood
from the
body
occurs.
Amphibian Circulatory System
In
amphibians
the mixing is not a major problem as the blood returning from the body has been partially oxygenated through its moist skin
Complete circulatory systems
They are complete because the heart has 2 ventricles completely separated by a septum
Complete
Double
circulatory system
The most efficient and most advanced circulatory system
Enables endothermic vertebrates
to deliver lots of
oxygenated blood to the respiring tissues
and to
pick up the heat released
by these tissues and
circulate it.
Birds and mammals have complete circulatory systems.
