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Frogs have a highly developed nervous system that consists of a brain, spinal cord and nerves. Many parts of frog brains correspond with those of humans. It consists of two olfactory lobes, two cerebral hemispheres, a pineal body, two optic lobes, a cerebellum and a medulla oblongata.
Notochord is positioned just ventral to the neural tube and dorsal to the gut, flanked by myotome. (D) Notochord homolog in annelid. Cross-section showing the position of the proposed axochord to the ventral mesentery, blood vessel, and nerve chord. Axochord is found to be dorsal to the nerve chord and ventral to gut of the animal.
Not all animals have neurons; Trichoplax and sponges lack nerve cells altogether. Neurons may be packed to form structures such as the brain of vertebrates or the neural ganglions of insects. The number of neurons and their relative abundance in different parts of the brain is a determinant of neural function and, consequently, of behavior.
Adult frogs do not have tails and caecilians have only very short ones. [68] Didactic model of an amphibian heart. Salamanders use their tails in defence and some are prepared to jettison them to save their lives in a process known as autotomy. Certain species in the Plethodontidae have a weak zone at the base of the tail and use this strategy ...
Dissection of a frog. Pain is an aversive sensation and feeling associated with actual, or potential, tissue damage. [1] It is widely accepted by a broad spectrum of scientists and philosophers that non-human animals can perceive pain, including pain in amphibians.
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord.The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all parts of the bodies of bilaterally symmetric and triploblastic animals—that is, all multicellular animals except sponges and diploblasts.
The arachnoid mater covering the brain is referred to as the arachnoidea encephali, and the portion covering the spinal cord as the arachnoidea spinalis. The arachnoid and pia mater are sometimes considered as a single structure, the leptomeninx, or the plural version, leptomeninges ( lepto , from the Greek root meaning "thin" or "slender").
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. [45] [46]