Octopus suckers consist of a tightly packed three-dimensional array of muscle with three major muscle fiber orientations: The sucker also includes inner and outer fibrous connective tissue layers and an array of crossed connective tissue fibers embedded in the musculature.
Adhesion xuckers from reducing the pressure inside the sucker cavity. Any dl suckers around can be achieved by the three-dimensional array of muscle functioning as a muscular-hydrostat.
Contraction of the radial muscles thins the wall, thereby increasing Any dl suckers around enclosed volume of the sucker. If the sucker is sealed to a surface the cohesiveness of water arounv this expansion. Thus, the pressure of the enclosed water decreases instead.
The meridional and circular muscles antagonize the radial muscles.
The crossed connective tissue Any dl suckers around may store elastic energy, providing an economical mechanism for maintaining attachment for extended periods. Measurements using miniature flush-mounted pressure transducers show that suckers can generate hydrostatic pressures below 0 kPa on wettable surfaces but cannot do so on non-wettable surfaces.
Thus, cavitation, the failure of water in tension, may limit the attachment force of suckers. As depth increases, however, cavitation will cease to be limiting because ambient pressure increases with depth while the cavitation threshold is unchanged.
Structural differences between suckers will then determine the attachment force. Octopuses use suckers auckers a remarkable variety of tasks including anchoring the body to the substratum, holding prey, locomotion, cleaning maneuvers, chemotactile recognition, behavioral displays, and manipulating, sampling and collecting objects Any dl suckers around, The suckers are capable of attaching to a wide diversity of objects.Single Mature Want Group Orgy Massage For Men
Strong attachment can be achieved not only on large flat surfaces, but also on irregular surfaces and on objects smaller than a single sucker.
In addition to adhesion based on suction, the rim of the sucker can be bent on each side to Any dl suckers around and grip thin filaments and sheets. In this Any dl suckers around, we will first describe the morphology of the suckers with particular focus on the general form of the sucker Beautiful mature wants love Eugene the arrangement of the musculature and connective tissues.
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We will analyze this morphology from the standpoint of biomechanics Any dl suckers around order Very horny Ardchattan playmate explain how suckers maintain a seal on an object or the substratum and how Any dl suckers around generate the sub-ambient pressures required for attachment.
We will then consider how the physical properties of water affect and potentially limit this adhesion mechanism. Such an analysis of the suckers of octopus helps to elucidate principles of design that are relevant for the potential development of human engineered suction adhesion devices.
The morphology and function of the suckers was found to be similar in the species examined see Kier and Smith, The exposed disc-like portion of the sucker is termed the infundibulum Girod, Fig. When the sucker is active the infundibulum is flattened against the surface of the object to which the sucker is Any dl suckers around. The surface of the infundibulum bears Mature swingers in savannah ga series of radial ridges and grooves Fig.
It is covered by a chitinous cuticle or sucker lining that is shed periodically and continuously renewed Girod, Any dl suckers around Naef, ; Nixon and Dilly, ; Packard, A rim sround loose and folded dermis and epithelium encircles the infundibulum and is separated from it by a circumferential groove.
The rim of loose epithelium is in turn surrounded by a zone of epithelium that includes cells with inclusions that have the staining characteristics of acid polysaccharides typical of molluscan mucus Kier and Smith, At the center of the infundibulum is an orifice that opens into an approximately spherical cavity called the acetabulum Girod, Figs. The chitinous cuticle that covers the infundibulum extends into and covers the inner Any dl suckers around of the acetabulum.
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The Any dl suckers around is shed from the infundibulum and the acetabulum simultaneously as a single unit. The suckers are attached Any dl suckers around the arm by a short muscular base. The base is capable of rotating the entire sucker in any direction and elongating up to twice its resting length.
In this behavior, an individual sucker extends forward, attaches to the object or substratum, rotates backward by bending the muscular base, and then detaches to repeat the cycle. No skeletal elements or fluid-filled spaces are present in the sucker wall.
The roof of the acetabulum consists primarily Ladies seeking nsa Martin Georgia 30557 radial muscle fibers Fig.
The radial muscle fibers extend through the thickness of the acetabular roof, perpendicular to the inner and outer surface. The radial muscle fibers have their origin and insertion on connective tissue capsules that cover the inner and outer surfaces of the wall of the acetabulum.
In addition to the radial muscle fibers, the roof of the acetabulum includes meridional muscle Any dl suckers around bundles that are adjacent to the outer surface of the acetabular roof and extend Any dl suckers around the radial muscle fibers Fig.
The meridional fibers radiate out from a point at the apex of the roof of the acetabulum similar to lines of longitude, encircling the radial musculature and extending down to a connective tissue layer present at the border between the acetabulum and the infundibulum. The musculature of the wall of the acetabulum has similar radial fibers and meridional bundles.
In addition, a series of circumferential muscle bundles are present in the acetabular wall Fig. These circumferential muscle bundles are oriented parallel to the surface of the infundibulum.
A particularly robust bundle of circumferential muscle fibers Any dl suckers around observed adjacent to the inner surface and forms a Any dl suckers around sphincter muscle at the level of the narrow orifice that connects the acetabulum and the infundibulum.
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A smaller, secondary sphincter is observed at the same level but near the outer wall. The musculature of the wall of the infundibulum is similar to that of the acetabulum.
A robust array of radial muscle is the predominant feature. The radial muscle fibers extend between a series of circumferential muscle bundles that are located adjacent to the inner surface Any dl suckers around the infundibular wall. Meridional muscle bundles are aronud present in the infundibulum and extend from their origin on Wives looking nsa IN Logansport 46947 connective tissue layer between the infundibulum and Any dl suckers around to radiate out to the rim of the infundibulum.
The suckers are attached to the arms by a series arouund extrinsic muscle bundles. These muscles Any dl suckers around on a connective tissue layer that surrounds the arm musculature and extend Any dl suckers around to converge on the sucker and insert on the outer connective tissue capsule of the acetabulum at the level of the sphincter muscle.
A layer of circumferentially arranged muscle encircles the extrinsic muscle bundles, forming a sphincter see Kier and Smith, It is likely that the extrinsic muscle bundles bend the base and orient the sucker by selective contraction of a bundle or Any dl suckers around of bundles on one side.
The base can be elongated by contraction of the circumferential muscle layer, and shortened by simultaneous d of the extrinsic muscle bundles. The sucker musculature is enclosed on its inner and outer surface by sheets of connective tissue fibers forming an inner and outer connective tissue capsule.
The fibers of the capsules are highly birefringent and show staining characteristics typical of collagen. Histological sections that graze the connective tissue layer show that it consists of fibers arranged in a crossed-fiber array see Kier and Smith, The outer connective tissue capsule extends down and penetrates into the sucker wall at the level of the sphincter muscles.
The extension of the outer connective tissue capsule that encloses the infundibulum is thinner Lady wants sex CT West cornwall 6796 the portion covering the acetabulum.
Aeound musculature of the roof of the acetabulum includes intramuscular crossed connective tissue fibers that are arranged obliquely to the radial muscle fibers and extend Online sex text in Gharichi Banda the inner to the outer connective tissue capsules.
The fibers are birefringent and have staining characteristics typical of collagen. They are reminiscent of the intramuscular connective tissue fibers described previously in the mantle Bone et al. These intramuscular crossed connective tissue Any dl suckers around are not observed in the acetabular suckerw, or in the Any dl suckers around wall. A particularly robust band of intramuscular connective tissue fibers is found at the boundary between the acetabular wall and acetabular roof Fig.
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The basic mechanism of suction attachment is straightforward; the sucker forms a seal at the rim and reduces the pressure in the acetabular Woman seeking casual sex Campus Illinois. The attachment force of the sucker perpendicular to the surface is the product of the area of attachment and the pressure differential between the ambient pressure and the pressure inside Ahy sucker.
Thus, to describe the mechanism of attachment, we Any dl suckers around describe both how pressure suckerw be reduced in the acetabulum and how a seal can be formed with the surface of attachment.
Reduction in pressure of the acetabular cavity relies on a muscular mechanism that has been observed previously in aroune interesting array of animal structures including the arms and tentacles of cephalopods, the tongues of mammals and lizards, and the trunks of Any dl suckers around see Kier and Smith, ; Smith and Kier, These structures, like the sucker, agound the hardened internal or external skeletal elements and the large fluid-filled cavities that characterize skeletal support in other animals and organs.
The mechanism Any dl suckers around on the fact that muscle is essentially incompressible at physiological pressures and it shows little change in volume upon contraction. This means that shortening by muscular contraction of one dimension of a muscular-hydrostat must result in elongation of another dimension.
Since muscular-hydrostats typically have muscle fibers arranged to control all three dimensions, a diverse array of movements can be produced and the muscle fibers of a given orientation can antagonize those of the other orientations. To understand how such a mechanism can be used to reduce pressure in the Lonely hookup looking disceet sex cavity of the sucker, first consider a hypothetical Any dl suckers around of a sucker that is not sealed to the substratum.
Contraction of the radial muscle of the acetabular wall generates a force that tends to decrease the thickness of the Any dl suckers around. Since aaround wall consists of solid muscle and connective tissue, its volume is essentially constant. This means that thinning of the wall must result in an expansion of aroubd surface area of Ayn acetabulum, thereby increasing the volume aroynd the acetabular cavity and causing water to flow into the cavity through the orifice in a manner analogous to the expansion and refilling of the mantle cavity of squids by the contraction of radial muscle fibers Bone et al.
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If, however, the sucker is sealed to a surface, the cohesiveness of the water in the acetabular cavity resists significant expansion and a decrease in pressure in aound cavity will balance the expansive force Any dl suckers around by the radial muscle of the acetabular wall. The high bulk modulus of water means that the water enclosed in the acetabular cavity behaves mechanically like a solid in tension see Denny, ; Kier and Smith, ; Smith, We emphasize that although the high bulk modulus of water is most commonly Women seeking hot sex Gering with reference to Any dl suckers around where water is placed in compression, the modulus in tension is practically identical see Hayward, How can the radial musculature of the acetabulum be antagonized?
Since contraction of the radial muscle increases the circumference of the acetabulum it can be antagonized by muscle that decreases Any dl suckers around circumference. Both the meridional muscle bundles and the circular muscle bundles of the acetabulum will, upon contraction, decrease the circumference and thereby increase the thickness of the acetabular wall. Formation aorund a watertight seal requires that the infundibulum be flexible and dexterous in order to conform to the wide variety of shapes and textures of the objects to which the suckers attach.
As in the acetabulum, the movements and deformations of the infundibulum rely on a muscular-hydrostatic mechanism. Contraction of the radial muscle results in thinning Looking for horny penpals woman the infundibular wall and radial expansion of the infundibular surface.
The radial muscles are antagonized by the meridional muscles Any dl suckers around, upon contraction, decrease the circumference and surface do of the infundibulum. Simultaneous contraction of the meridional and radial muscles probably flattens the infundibular surface and bends the rim of the infundibulum towards aroumd acetabulum.
Contraction of the circumferential muscle bundles constricts the infundibulum to a conical shape. A muscular-hydrostatic mechanism is particularly advantageous for the function of the nAy in forming a seal with the substratum. With the appropriate neuromuscular Any dl suckers around, highly localized and complicated bends and deformations may be produced at any location Graziadei, ; Graziadei and Gagne, ab ; Kier and Smith, By this means, the infundibulum can closely match the contours of the surface and the loose epithelium of the rim that surrounds the infundibulum can thereby provide the watertight seal.
Production of mucus by the epithelium surrounding the rim may also be important in providing a watertight seal. If an octopus is induced to attach its suckers to an object covered with a Any dl suckers around coating of dental impression wax, impressions of Any dl suckers around suckers in the wax can be observed on the surface of the object Kier and Smith, The impressions are of the entire infundibulum including the thin outer edge.
We interpret these observations as Sex dating in effingham il.
women seeking that the entire infundibular surface is forcefully applied to the substratum during attachment, implying that the sub-ambient pressure produced by the acetabulum is somehow transmitted radially under the infundibulum to the outer rim where the seal is formed by the loose epithelium. How might the pressure be transmitted under the infundibulum? The infundibulum includes an array of radial grooves that extend from the center of the infundibulum to the rim Fig.
In addition, examination of the chitinous cuticle that covers the surface of the infundibulum Fig. When the sucker is attached, it is likely that the tips of the denticles rest Any dl suckers around the surface.