Search results
Results From The WOW.Com Content Network
The main olfactory sense is derived from the more ancient neural system, broadly present across insects and mammals. [23] This system is specialized to detect volatile, airborne molecules. The accessory olfactory system is the more recently evolved structure, first appearing in the common ancestor of modern amniotes and amphibians.
The olfactory receptor proteins are members of a large family of G-protein-coupled receptors (GPCR) arising from single coding-exon genes. Olfactory receptors share a 7-transmembrane domain structure with many neurotransmitters and hormone receptors and are responsible for the recognition and G protein-mediated transduction of odorant signals. [5]
For example, OR1A1 in the first isoform of subfamily A of olfactory receptor family 1. Members belonging to the same subfamily of olfactory receptors (>60% sequence identity) are likely to recognize structurally similar odorant molecules. [34] Two major classes of olfactory receptors have been identified in humans: [35]
Inside of these olfactory organs there are neurons called olfactory receptor neurons which, as the name implies, house receptors for scent molecules in their cell membranes. The majority of olfactory receptor neurons typically reside in the antenna. These neurons can be very abundant, for example Drosophila flies have 2,600 olfactory sensory ...
The olfactory system, is the sensory system used for the sense of smell (olfaction). Olfaction is one of the special senses directly associated with specific organs. Most mammals and reptiles have a main olfactory system and an accessory olfactory system.
The surface of the cilia is covered with olfactory receptors, a type of G protein-coupled receptor. Each olfactory receptor cell expresses only one type of olfactory receptor (OR), but many separate olfactory receptor cells express ORs which bind the same set of odors. The axons of olfactory receptor cells which express the same OR converge to ...
The olfactory nerve zone is composed of preterminals and terminals of the olfactory nerve and is where the olfactory receptor cells make synapses on their targets. [2] The non-olfactory nerve zone is composed of the dendritic processes of intrinsic neurons and is where dendrodendritic interactions between intrinsic neurons occur.
The other small carnivoran families Nandiniidae, Prionodontidae, Viverridae, Herpestidae, Eupleridae, Mephitidae and Mustelidae have through convergent evolution maintained the small, ancestral appearance of the miacoids, though there is some variation seen such as the robust and stout physicality of badgers and the wolverine (Gulo gulo).