FEEDiNG/DiGESTiON--
Octopuses could be said to have an external digestion. They bite open a
crab's armour and afterwards spill digestion liquid over it's internal organs. The liquid contains a nerve poison that paralyses
the prey and proteases, enzymes, that digest its organs, so the crab's interior can be sucked by the octopus.
RESPiRATiON--
Cephalopods breath by gills, Like other molluscs cephalopods have got a
radula or rasp tongue to rasp their food to pieces. In addition to that they also have a beak made out of horn, like that
of a parrot, with which the prey is cut to pieces before being swallowed. The beak can also serve to crack open the prey's
armour, as many cephalopods' favourite food are crustaceans.
iNTERNAL TRANSPORT--
A new internal perfusion method has been developed which
allows control of the internal solute composition in squid axons. The superiority of this technique compared to the old perfusion
methods is shown by the experiments performed which have reproduced, both qualitatively and quantitatively, the Na+ and Ca2+
fluxes observed in intact and dialyzed axons. Compared with the internal dialysis, the perfusion method has the advantage
that the permeability barrier give by the porous capillary has been eliminated. This allows the introduction into the axon
of solutes with very high molecular weight, at the same time that a fast and reliable internal control can be achieved.
EXCRETiON--
Excretory functions are carried out by a pair of nephridia, tubular structures that collect fluids from
the coelom and exchange salts and other substances with body tissues as the fluid passes along the tubules for excretion.
The nephridia empty into the mantle cavity.
RESPONSE TO STiMULi--
The mechano-electrical transduction in the squid axon was studied. A certain
volume of solution was intracellularly injected, subsequently redrawn, by a microsyringe, and the
resultant expansion and shrinkage of the cell was employed as the mechanical stimulus. Upon stimulation, two types of responses
appeared: a depolarizing response and a hyperpolarizing response.
MOVEMENT--
Squid's rear body is shaped like a
torpedo. At it's tail end there are two larger or smaller fins serving for locomotion and changing it's direction.Mainly
squid's locomotion, however, is by another method. Squid are the fighter jets among the cephalopods. Driven by the cephalopods'
well known propulsion by pressing water from their pallial cavity, squid move backwards through the water like a rocket. Squid
almost exclusively move that way. The jet's direction (and thus the direction of the movement) can be changed by altering
the sipho's angle.
REPRODUCTiON--
Little is known regarding the reproductive cycle of the
squid, but what
has been learned is that the male of the species has a prehensile spermatophore-depositing tube, or penis, of over 3 ft (90
cm) in length, which extends from inside the animal's mantle and apparently is used to inject sperm-containing packets into
the female squid's arms — the means by which the sperm is transferred to the egg mass is a matter of much debate.
