 |
|
|
|
more info
this link is for researching information about the giant squid, especially info about the body parts
The pattern in which squid move, pumping water through its mantle, is also how squid breathe.
Most sea animals have visible gills, but squids do not possess gills like most fish do, instead they obtain oxygen through
a pair of long ‘gills’ covered in leaflets called lamellae. When fresh water is pumped in, the squid’s gills
are also refilled with oxygen.
-----------------------------------------------------------------------------------------------
|
|
|
Squid have three hearts. Two branchials hearts, feeding the gills, each surrounding the
larger systemic heart that pumps blood around the body. The hearts have a faint greenish appearance and are surrounded by
the renal sacs - the main excretory system of the squid. The kidneys are faint and difficult to identify and stretch
from the hearts (located at the posterior side of the ink sac) to the liver. The systemic heart is made of three chambers,
a lower ventricle and two upper auricles.
-----------------------------------------------------------------------------------------------
Giant Squids have a very well-developed circulatory system. It is considered closed
because blood is confined in vessels and hearts, so it does not flow freely around the bodily tissues. The blood is blue when
oxygenated because the respiratory pigment (hemocyanin) contains copper. (Human blood is red because our respiratory pigment,
hemoglobin, contains iron that becomes red when oxygenated.) Two branchial hearts (one per gill) pump blood into the gills
where water restores it with oxygen. The blood then goes to the systemic heart (between the gills) which pumps it throughout
the rest of the body. Squids need this third heart to work against the hydrostatic skeleton. Muscles squeeze other bodily
liquids and provide strength and shape to the body. [Hydrostatic skeleton note: hydro (water) static (movement) skeleton (support).
Remember, if you squeeze water into a tube, it gives support and shape to that tube.] Each blood vessel has its own nerves
and can contract independently, making some injuries less dangerous. If an arm is bitten off by predator, the blood supply
to that arm is shut off quickly and the squid or octopus does not bleed to death. Imagine the effects on humans with such
an ability!
-----------------------------------------------------------------------------------------------
|
|
|
|
|
|
|
|
|
The main body mass of the squid is enclosed in the mantle, which has two swimming fins along each side. It
should be noted that these fins, unlike in other marine organisms, are not the main source of ambulation. The skin of
the squid is covered in chromatophores, which enable the squid to change color to suit its surroundings. The underside of
the squid is also found to be lighter than the topside, in order to provide camouflage from both prey and predator.Under
the body are openings to the mantle cavity, which contains the gills (ctenidia) and openings to the excretory and reproductive
system. At the front of the mantle cavity lies the siphon, which the squid uses for locomotion via precise jetpropulsion.
This is done by sucking water into the mantle cavity and quickly expelling it out of the siphon in a fast, strong jet. The
direction of the siphon can be changed in order to suit the direction of travel.Inside the mantle cavity, beyond the siphon,
lies the visceral mass of the squid, which is covered in a thin, membranous epidermis. Under this are all the major internal
organs of the squid.
-----------------------------------------------------------------------------------------------------------------------
The main part of the body is the mantle. Squids have no external shell so this soft, dotted
and colored tube encloses the main part of the body. All the small dots the students see are pigment cells called chromatophores.
Muscles controlled by the nervous system surround each chromatophores. The chromatophore muscles expand or contract
to reveal the colors of the pigments within. When the muscles tighten the squid will darken in color, when they relax the
squid becomes a lighter color.
-----------------------------------------------------------------------------------------------
A Giant Squid has many responses to stimuli,
but the escape response is the one that most giant squids use the most. In this case, it's really called the giant
squid axon. Escape reflex is a kind of escape response, that is a type of response to stimuli. In easier terms, it's
a simple reflectory reaction. It's also an indicator of danger, that initiates an escape motion of an animal. In higher
animals examples of escape reflex include the withdrawal reflex, which is when the Sensory receptors in the body
send signals to other body parts. The squid giant axon is very large and it controls part of the squid's water jet propulsion
system. Squid use this system primarily for making brief but very fast movements through the water usually when escaping predators.
Between the tentacles of a squid is a siphon through which water can be rapidly expelled by the fast contractions of the body
wall muscles of the animal. This giant axon is used to improve the speed of their escape response. This has obvious adaptive
advantage when escaping from predators.
-----------------------------------------------------------------------------------------------------------------------
|
|
