Blood Sinuses
: Various arteries
on reaching the organs, branch
repeatedly in to minutes branch which
do not form capillaries but
end in to wide space blood sinuses or blood lacunae
. All the
blood lacunae of the body collectively form a pair of elongated but ill
defined ventral sinuses. These lei below the hepatopancreas and
above the floor of thorax
Blood Channels
: In Palaemon, there are
6 pairs of afferent
branchial channels
and
6 pair of efferent branchial channels
.
These channels are lacunar in nature.
The afferent branchial
channels run along the inner surface of the thorasic wall and reach
the gills through the gill roots. Here each channel open into transvese
connective.
1
st
branchial channel takes blood to podobranch and
two arthrobranch
,
remaining
5 channels supply the blood to 5
pleurobranches
. The blood is oxygenated while passing the gills
and this blood is carried to the pericardium by efferent branchial
channels.
Blood
:
Thin, watery, almost colorless
liquid containing floating
colorless ameobocytes
. The color of blood is white when it is
deoxygenated and faintly bluish when it is oxygenated. This is due to
the presence
of respiratory pigment
haemocyanin
. There is also a
lipochrome pigment called
zoonerythin
in the blood.
Blood has the
power of coagulation when it comes in contact with air.
Haemocyanin (Respiratory pigments):
It is high molecular weight
protein (75 kD) containing two copper (Cu) atoms. It is dissolved in
blood plasma. Deoxygenated blood is white while oxygenated blood
is blue in colour. Normal stability of oxygen binding is achieved only
when the unit contain 8 copper atoms (tetramer).
Oxygen carrying
capacity is low compared to haemoglobin
