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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.
The adductor muscles have been cut, the valves are gaping. The internal anatomy is visible, including the paired siphons to the right A siphon is an anatomical structure which is part of the body of aquatic molluscs in three classes : Gastropoda , Bivalvia and Cephalopoda (members of these classes include saltwater and freshwater snails , clams ...
The common octopus (Octopus vulgaris) is a mollusk belonging to the class Cephalopoda. Octopus vulgaris is one of the most studied of all octopus species, and also one of the most intelligent. It ranges from the eastern Atlantic, extends from the Mediterranean Sea and the southern coast of England , to the southern coast of South Africa.
A Galapagos shark hooked by a fishing boat. Pain negatively affects the health and welfare of animals. [1] " Pain" is defined by the International Association for the Study of Pain as "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage."
Autoreceptors may be located in any part of the cell membrane: in the dendrites, the cell body, the axon, or the axon terminals. [1] Canonically, a presynaptic neuron releases a neurotransmitter across a synaptic cleft to be detected by the receptors on a postsynaptic neuron. Autoreceptors on the presynaptic neuron will also detect this ...