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A frog's ear drum works in very much the same way as does a human eardrum. It is a membrane that is stretched across a ring of cartilage like a snare drum that vibrates. Crossing the middle ear chamber there is an ossicle called the columella that is connected to the tympanum, and another ossicle, the operculum, that connects this to the oval ...
Surface rendering of the head of the frog Atelopus franciscus, with ear parts highlighted. Frogs can hear both in the air and below water. They do not have external ears; the eardrums (tympanic membranes) are directly exposed or may be covered by a layer of skin and are visible as a circular area just behind the eye. The size and distance apart ...
The human brain contains 86 billion neurons, with 16 billion neurons in the cerebral cortex. [ 2 ] [ 1 ] Neuron counts constitute an important source of insight on the topic of neuroscience and intelligence : the question of how the evolution of a set of components and parameters (~10 11 neurons, ~10 14 synapses) of a complex system leads to ...
The blood in the deep part of the brain drains, through a venous plexus into the cavernous sinus at the front, and the superior and inferior petrosal sinuses at the sides, and the inferior sagittal sinus at the back. [61] Blood drains from the outer brain into the large superior sagittal sinus, which rests in the midline on top of the brain.
The Acoela are basal bilaterians, part of the Xenacoelomorpha. They are small and simple animals with flat bodies. They have slightly more nerve cells at the head end than elsewhere, not forming a distinct and compact brain. This represents an early stage in cephalization. [8]
A true endoskeleton is derived from mesodermal tissue. In three phyla of animals, Chordata, Echinodermata and Porifera (), endoskeletons of various complexity are found.An endoskeleton may function purely for structural support (as in the case of Porifera), but often also serves as an attachment site for muscles and a mechanism for transmitting muscular forces as in chordates and echinoderms ...
In reptiles, the columella function to transduce sound through the middle ear as part of the auditory pathway. The columella is relatively straight and moves in a piston-like motion in response to vibration. [3] Due to the rigid bony structure, the columella primarily responds to low-frequency vibrations transmitted through the ground. [2]
The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals.It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for special senses such as vision, hearing and olfaction.