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Maxilliped
An appendage (or outgrowth) is an external body part or natural prolongation that protrudes from an organism's body such as an arm or a leg. Protrusions from single-celled bacteria and archaea are known as cell-surface appendages or surface appendages. In many kinds of eukaryotic cells, the protrusions are known as membrane protrusions or cell appendages (examples include microvilli and cilia). Types in animals In arthropods, an appendage refers to any of the homologous body parts that may extend from a body segment, including antennae, mouthparts (including mandibles, maxillae and maxillipeds), gills, locomotor legs ( pereiopods for walking, and pleopods for swimming), sexual organs (gonopods), and parts of the tail (uropods). Typically, each body segment carries one pair of appendages. An appendage which is modified to assist in feeding is known as a maxilliped or gnathopod. In annelids lateral protrusions from the body are called parapodia. In echinoderms an app ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod Mouthparts
The mouthparts of arthropods have evolved into a number of forms, each adapted to a different style or mode of feeding. Most mouthparts represent modified, paired appendages, which in ancestral forms would have appeared more like legs than mouthparts. In general, arthropods have mouthparts for cutting, chewing, piercing, sucking, shredding, siphoning, and filtering. This article outlines the basic elements of four arthropod groups: insects, myriapods, crustaceans and chelicerates. Insects are used as the model, with the novel mouthparts of the other groups introduced in turn. Insects are not, however, the ancestral form of the other arthropods discussed here. Insects Insect mouthparts exhibit a range of forms. The earliest insects had chewing mouthparts. Specialisation includes mouthparts modified for siphoning, piercing, sucking and sponging. These modifications have evolved a number of times. For example, mosquitoes and aphids both pierce and suck; however, female ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleopod
The anatomy of a decapod consists of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (abdomen). Each segment – often called a somite – may possess one pair of appendages, although in various groups these may be reduced or missing. Cephalothorax Head # antennules # antennae # mandibles # first maxillae # second maxillae The head also bears the (usually stalked) compound eyes. The distal portion of a mandible or maxilla which has a sensory function is known as a palp. Thorax / pereon #first maxillipeds #second maxillipeds #third maxillipeds #first pereiopods #second pereiopods #third pereiopods #fourth pereiopods #fifth pereiopods Maxillipeds are appendages modified to function as mouthparts. Particularly in the less advanced decapods, these can be very similar to the pereiopods. Pereiopods are primarily walking legs and are also used for gathering food. They are also the ten legs from which decapods take their name. Those pereiopods which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Procerus Middle Leg
The procerus muscle (or pyramidalis nasi) is a small pyramidal muscle in the glabella. It is involved in facial expressions such as frowning and those associated with attentional control, and it indirectly helps shield the eyes from bright light. Because it contributes to wrinkle formation on the nasal bridge, it is often targeted in non-surgical facial rejuvenation treatments, such as botulinum toxin injections. ''Procerus'' is Latin, meaning tall or extended. Structure The procerus muscle arises by tendinous fibers from the fascia covering the lower part of the nasal bone and upper part of the lateral nasal cartilage. It is inserted into the skin over the lower part of the forehead between the two eyebrows on either side of the midline, its fibers merging with those of the frontalis muscle. Nerve supply The procerus muscle is supplied by the temporal branch of the facial nerve (VII). It may also be supplied by other branches of the facial nerve, which can be varied, in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod Leg
The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip (anatomy), hip, : ''coxae''), ''trochanter'', ''femur'' (: ''femora''), ''tibia'' (: ''tibiae''), ''tarsus'' (: ''tarsi''), ''ischium'' (: ''ischia''), ''metatarsus'', ''carpus'', ''dactylus'' (meaning finger), ''patella'' (: ''patellae''). Homology (biology), Homologies of leg segments between groups are difficult to prove and are the source of much argument. Some authors posit up to eleven segments per leg for the most recent common ancestor of Neontology, extant arthropods but modern arthropods have eight or fewer. It has been argued that the ancestral leg need not have been so complex, and that other events, such as successive loss of function of a Homeobox, ''Hox''-gene, could result in Parallel evolution, parallel gains of leg segments ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pedicellaria
A pedicellaria (: pedicellariae) is a small wrench- or claw-shaped appendage with movable jaws, called valves, commonly found on echinoderms (phylum Echinodermata), particularly in sea stars (class Asteroidea) and sea urchins (class Echinoidea). Each pedicellaria is an effector organ with its own set of muscles, neuropils, and sensory receptors and is therefore capable of reflex responses to the environment. Pedicellariae are poorly understood but in some taxa, they are thought to keep the body surface clear of algae, encrusting organisms, and other debris in conjunction with the ciliated epidermis present in all echinoderms. These structures are derived from the mesodermal skeleton. In sea stars Types There are two major types of pedicellaria in sea stars: straight and crossed. Straight pedicellaria are typically larger and located on the body surface, whereas crossed pedicellaria are smaller and found more commonly on stalks, raised above the body surface or in clum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echinoderm
An echinoderm () is any animal of the phylum Echinodermata (), which includes starfish, brittle stars, sea urchins, sand dollars and sea cucumbers, as well as the sessile sea lilies or "stone lilies". While bilaterally symmetrical as larvae, as adults echinoderms are recognisable by their usually five-pointed radial symmetry (pentamerous symmetry), and are found on the sea bed at every ocean depth from the intertidal zone to the abyssal zone. The phylum contains about 7,600 living species, making it the second-largest group of deuterostomes after the chordates, as well as the largest marine-only phylum. The first definitive echinoderms appeared near the start of the Cambrian. Echinoderms are important both ecologically and geologically. Ecologically, there are few other groupings so abundant in the deep sea, as well as shallower oceans. Most echinoderms are able to reproduce asexually and regenerate tissue, organs and limbs; in some cases, they can undergo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parapodia
In invertebrates, the term parapodium ( Gr. ''para'', beyond or beside + ''podia'', feet; : parapodia) refers to lateral outgrowths or protrusions from the body. Parapodia are predominantly found in annelids, where they are paired, unjointed lateral outgrowths that bear the chaetae. In several groups of sea snails and sea slugs, 'parapodium' refers to lateral fleshy protrusions. __TOC__ Annelid parapodia Most species of polychaete annelids have paired, fleshy parapodia which are segmentally arranged along the body axis. Parapodia vary greatly in size and form, reflecting a variety of functions, such as, anchorage, protection and locomotion. General description Parapodia in polychaetes can be uniramous (consisting of one lobe or ramus) but are usually biramous (two lobes or rami). In the latter case, the dorsal lobes are called notopodia and the ventral lobes neuropodia. Both neuropodia and notopodia may possess a bundle of chaetae (neurochaetae and notochaetae respectively ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annelid
The annelids (), also known as the segmented worms, are animals that comprise the phylum Annelida (; ). The phylum contains over 22,000 extant species, including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecologies – some in marine environments as distinct as tidal zones and hydrothermal vents, others in fresh water, and yet others in moist terrestrial environments. The annelids are bilaterally symmetrical, triploblastic, coelomate, invertebrate organisms. They also have parapodia for locomotion. Most textbooks still use the traditional division into polychaetes (almost all marine), oligochaetes (which include earthworms) and leech-like species. Cladistic research since 1997 has radically changed this scheme, viewing leeches as a sub-group of oligochaetes and oligochaetes as a sub-group of polychaetes. In addition, the Pogonophora, Echiura and Sipuncula, previously regarded as separate phyla, are now regarded as sub-grou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maxilliped
An appendage (or outgrowth) is an external body part or natural prolongation that protrudes from an organism's body such as an arm or a leg. Protrusions from single-celled bacteria and archaea are known as cell-surface appendages or surface appendages. In many kinds of eukaryotic cells, the protrusions are known as membrane protrusions or cell appendages (examples include microvilli and cilia). Types in animals In arthropods, an appendage refers to any of the homologous body parts that may extend from a body segment, including antennae, mouthparts (including mandibles, maxillae and maxillipeds), gills, locomotor legs ( pereiopods for walking, and pleopods for swimming), sexual organs (gonopods), and parts of the tail (uropods). Typically, each body segment carries one pair of appendages. An appendage which is modified to assist in feeding is known as a maxilliped or gnathopod. In annelids lateral protrusions from the body are called parapodia. In echinoderms an app ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uropod
Uropods are posterior appendages found on a wide variety of crustaceans. They typically have functions in locomotion. Definition Uropods are often defined as the appendages of the last body segment of a crustacean. An alternative definition suggested by Frederick R. Schram restricts the term to those structures arising from the segment before the anal segment (the segment which carries the anus). Under this latter definition, the appendages of the anal segment are caudal ramus, caudal rami, which are analogy (biology), analogous to uropods. Form Uropods are typically biramous – comprising an endopod and an exopod. The exopod is typically the larger, and may be divided in two by a transverse suture known as the diaeresis. The uropods may work in concert with the telson to form a "tail fan". References {{Reflist, 32em Crustacean anatomy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tail
The tail is the elongated section at the rear end of a bilaterian animal's body; in general, the term refers to a distinct, flexible appendage extending backwards from the midline of the torso. In vertebrate animals that evolution, evolved to lose their tails (e.g. frogs and hominid primates), the coccyx is the homologous vestigial of the tail. While tails are primarily considered a feature of vertebrates, some invertebrates such as scorpions and springtails, as well as snails and slugs, have tail-like appendages that are also referred to as tails. Tail-shaped objects are sometimes referred to as "caudate" (e.g. lobes of liver#Caudate lobe, caudate lobe, caudate nucleus), and the body part associated with or proximal to the tail are given the adjective "caudal (anatomical term), caudal" (which is considered a more precise anatomical terminology). Function Animal tails are used in a variety of ways. They provide a source of thrust for aquatic locomotion for fish, cetaceans and cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
