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Chordotonal Organ
Chordotonal organs are stretch receptor organs found only in insects and crustaceans. They are located at most joints and are made up of clusters of scolopidia that either directly or indirectly connect two joints and sense their movements relative to one another. They can have both extero- and proprioceptive functions, for example sensing auditory stimuli or leg movement. The word was coined by Vitus Graber in 1882, though he interpreted them as being stretched between two points like a string, sensing vibrations through resonance. Structure Chordotonal organs can be composed of a single scolopidium with only a single sensory, bipolar neuron (such as the tympanal ear of a notodontid moth), or up to several thousand scolopidia, each equipped with up to four sensory neurons (as in the mosquito Johnston's organ). The bipolar sensory neurons each have an apical dendritic structure with a cilium densely packed with microtubules and surrounded by two specialized cells, the sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stretch Receptor
Stretch receptors are mechanoreceptors responsive to distention of various organs and muscles, and are neurologically linked to the Medulla oblongata, medulla in the brain stem via Afferent nerve fiber, afferent nerve fibers. Examples include stretch receptors in the arm and leg muscles and tendons, in the heart, in the colon wall, and in the lungs. Stretch receptors are also found around the carotid artery, where they monitor blood pressure and stimulate the release of antidiuretic hormone (vasopressin, ADH) from the posterior pituitary gland. Types include: * Golgi organ * Muscle spindle, sensory receptors within the belly of a muscle, which primarily detect changes in the length of this muscle * Pulmonary stretch receptors, mechanoreceptors found in the lungs * Chordotonal organ, in insects See also * Stretch sensor References {{biology-stub Sensory receptors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscle Spindle
Muscle spindles are stretch receptors within the body of a skeletal muscle that primarily detect changes in the length of the muscle. They convey length information to the central nervous system via afferent nerve fibers. This information can be processed by the brain as proprioception. The responses of muscle spindles to changes in length also play an important role in regulating the contraction of muscles, for example, by activating motor neurons via the stretch reflex to resist muscle stretch. The muscle spindle has both sensory and motor components. * Sensory information conveyed by primary type Ia sensory fibers which spiral around muscle fibres within the spindle, and secondary type II sensory fibers * Activation of muscle fibres within the spindle by up to a dozen gamma motor neurons and to a lesser extent by one or two beta motor neurons Structure Muscle spindles are found within the belly of a skeletal muscle. Muscle spindles are fusiform (spindle-shaped), and the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod Anatomy
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chitin, often mineralised with calcium carbonate. The arthropod body plan consists of segments, each with a pair of appendages. Arthropods are bilaterally symmetrical and their body possesses an external skeleton. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. Some species have wings. They are an extremely diverse group, with up to 10 million species. The haemocoel, an arthropod's internal cavity, through which its haemolymph – analogue of blood – circulates, accommodates its interior organs; it has an open circulatory system. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. Their nervous system is "ladder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxford University Press
Oxford University Press (OUP) is the university press of the University of Oxford. It is the largest university press in the world, and its printing history dates back to the 1480s. Having been officially granted the legal right to print books by decree in 1586, it is the second oldest university press after Cambridge University Press. It is a department of the University of Oxford and is governed by a group of 15 academics known as the Delegates of the Press, who are appointed by the vice-chancellor of the University of Oxford. The Delegates of the Press are led by the Secretary to the Delegates, who serves as OUP's chief executive and as its major representative on other university bodies. Oxford University Press has had a similar governance structure since the 17th century. The press is located on Walton Street, Oxford, opposite Somerville College, in the inner suburb of Jericho. For the last 500 years, OUP has primarily focused on the publication of pedagogical texts an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subgenual Organ
The subgenual organ is an organ in insects that is involved in the perception of sound. The name (Latin ''sub: "''below" and ''genus: "''knee") refers to the location of the organ just below the knee in the tibia of all legs in most insects. The function of the organ is performed by aggregations of scolopidia, the unit mechanoreceptor in invertebrates. The organ is thought to be an evolutionary artifact of ancestral insects who used their legs to detect vibrations in the underlying substrate. The anatomy and innervation of the organ is highly variable between species. However, the organ may be sensitive enough to detect less than 1 nm of displacement in the ground, and sometimes airborne sound waves. The sensitivity of the organ varies from species to species; in Orthoptera, Hymenoptera and Lepidoptera, sensitivity is on the order of one (or greater) kilohertz, while in Hemiptera sensitivity reaches only a few hundred hertz. Characteristics within orders * Lepidopte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crista Acustica
Crista acustica (also Siebold's organ, or crista acoustica) is a part of the hearing organ (tibial organ) in some insects (e.g. grasshoppers, crickets, katydids). It is a collection of sensory cells that form a crest (hence the name) on top of the hollow tube (the foreleg trachea) behind the hearing membrane (tympanum) on the legs of the insect. The crista acustica is a transition from the intermedia organ (from the midline to the periphery), together which compose the tibial hearing organ (as opposed to the tympanal hearing organ). The crista acustica is one of three fiddle-string-like organs or chordotonal organ in insects: the others are the intermediate organ and the supratympanal organ/subgenual organ. These chordotonal organs are actually collections of sensory cells sensitive to vibration (these cells are called scolopidia cells). Their cells are attached to the tube in the legs of the insects (the trachea, "''trah-key-ah''"). So when the tube vibrates, the ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halteres
''Halteres'' (; singular ''halter'' or ''haltere'') (from grc, ἁλτῆρες, weights held in the hands to give an impetus in leaping) are a pair of small club-shaped organs on the body of two orders of flying insects that provide information about body rotations during flight. Insects of the large order Diptera (flies) have halteres which evolved from a pair of ancestral hindwings, while males of the much smaller order Strepsiptera (stylops)Merriam-Webster: stylops broadly: an insect of the order Strepsiptera/ref> have halteres which evolved from a pair of ancestral forewings. Halteres oscillate rapidly along with the wings and operate like vibrating structure gyroscopes: any rotation of the plane of oscillation causes a force on the vibrating halteres by the Coriolis effect. The insect detects this force with sensory organs called campaniform sensilla and chordotonal organs located at the base of the halteres and uses this information to interpret and correct its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dipterans
Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced mechanosensory organs known as halteres, which act as high-speed sensors of rotational movement and allow dipterans to perform advanced aerobatics. Diptera is a large order containing an estimated 1,000,000 species including horse-flies, crane flies, hoverflies and others, although only about 125,000 species have been described. Flies have a mobile head, with a pair of large compound eyes, and mouthparts designed for piercing and sucking (mosquitoes, black flies and robber flies), or for lapping and sucking in the other groups. Their wing arrangement gives them great maneuverability in flight, and claws and pads on their feet enable them to cling to smooth surfaces. Flies undergo complete metamorphosis; the eggs are often laid on the la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beetle
Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 described species, is the largest of all orders, constituting almost 40% of described insects and 25% of all known animal life-forms; new species are discovered frequently, with estimates suggesting that there are between 0.9 and 2.1 million total species. Found in almost every habitat except the sea and the polar regions, they interact with their ecosystems in several ways: beetles often feed on plants and fungi, break down animal and plant debris, and eat other invertebrates. Some species are serious agricultural pests, such as the Colorado potato beetle, while others such as Coccinellidae (ladybirds or ladybugs) eat aphids, scale insects, thrips, and other plant-sucking insects that damage crops. Beetles typically have a particularly hard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subgenual Organ
The subgenual organ is an organ in insects that is involved in the perception of sound. The name (Latin ''sub: "''below" and ''genus: "''knee") refers to the location of the organ just below the knee in the tibia of all legs in most insects. The function of the organ is performed by aggregations of scolopidia, the unit mechanoreceptor in invertebrates. The organ is thought to be an evolutionary artifact of ancestral insects who used their legs to detect vibrations in the underlying substrate. The anatomy and innervation of the organ is highly variable between species. However, the organ may be sensitive enough to detect less than 1 nm of displacement in the ground, and sometimes airborne sound waves. The sensitivity of the organ varies from species to species; in Orthoptera, Hymenoptera and Lepidoptera, sensitivity is on the order of one (or greater) kilohertz, while in Hemiptera sensitivity reaches only a few hundred hertz. Characteristics within orders * Lepidopte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hymenoptera
Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are parasitic. Females typically have a special ovipositor for inserting eggs into hosts or places that are otherwise inaccessible. This ovipositor is often modified into a stinger. The young develop through holometabolism (complete metamorphosis)—that is, they have a wormlike larval stage and an inactive pupal stage before they mature. Etymology The name Hymenoptera refers to the wings of the insects, but the original derivation is ambiguous. All references agree that the derivation involves the Ancient Greek πτερόν (''pteron'') for wing. The Ancient Greek ὑμήν (''hymen'') for membrane provides a plausible etymology for the term because species in this order have membranous wings. However, a key characteristic of this order is that the hindwings are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Dimorphism
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most animals and some plants. Differences may include secondary sex characteristics, size, weight, colour, markings, or behavioural or cognitive traits. These differences may be subtle or exaggerated and may be subjected to sexual selection and natural selection. The opposite of dimorphism is ''monomorphism'', which is when both biological sexes are phenotypically indistinguishable from each other. Overview Ornamentation and coloration Common and easily identified types of dimorphism consist of ornamentation and coloration, though not always apparent. A difference in coloration of sexes within a given species is called sexual dichromatism, which is commonly seen in many species of birds and reptiles. Sexual selection leads to the exaggerated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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