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The octopus central brain contains 40 to 45 million cells. The brain-to-body mass ratio of the octopus is the highest of all the invertebrates and larger than that of most fish and reptiles (i.e. vertebrates). However, scientists have noted that brain size is not necessarily related to the complexity of its function.
The octopus Amphioctopus marginatus. Two groups of invertebrates have notably complex brains: arthropods (insects, crustaceans, arachnids, and others) and modern cephalopods (octopuses, squid, cuttlefish) and other molluscs. [14] The brains of arthropods and cephalopods arise from twin parallel nerve cords that extend through the body of the ...
' pain receptor ') is a sensory neuron that responds to damaging or potentially damaging stimuli by sending "possible threat" signals [1] [2] [3] to the spinal cord and the brain. The brain creates the sensation of pain to direct attention to the body part, so the threat can be mitigated; this process is called nociception.
An octopus (pl.: octopuses or octopodes [a]) is a soft-bodied, eight-limbed mollusc of the order Octopoda (/ ɒ k ˈ t ɒ p ə d ə /, ok-TOP-ə-də [3]).The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids.
Bone pain belongs to the class of deep somatic pain, often experienced as a dull pain that cannot be localized accurately by the patient. This is in contrast with the pain which is mediated by superficial receptors in, e.g., the skin. Bone pain can have several possible causes ranging from extensive physical stress to serious diseases such as ...
Squids do not have the longitudinal muscles that octopus do. Instead, they have a tunic. [81] This tunic is made of layers of collagen and it surrounds the top and the bottom of the mantle. Because they are made of collagen and not muscle, the tunics are rigid bodies that are much stronger than the muscle counterparts.
Researchers have identified an extinct vampire squid-like creature that is the first of its kind with 10 functional arms. The earliest known relative of octopuses and vampire squid has been named ...
Receptors are located throughout the body including the skin, epithelia, internal organs, skeletal muscles, bones, and joints. The cutaneous receptors of the skin project in an orderly fashion to the spinal cord , and from there, via different afferent pathways ( dorsal column-medial lemniscus tract and spinothalamic tract ), to the ventral ...