| 单词 | notochord |
| 例句 | Immediately beneath the nerve cord is a notochord that also runs the length of the organism. Fundamentals of Biology 2015-01-01T00:00:00Z In some chordates, the notochord acts as the primary axial support of the body throughout the animal’s lifetime. Concepts of Biology 2013-04-25T00:00:00Z The mesoderm also forms a structure called the notochord, which is rod-shaped and forms the central axis of the animal body. Biology for AP Courses 2022-06-09T00:00:00Z Formation of the axial skeleton begins during early embryonic development with the appearance of the rod-like notochord along the dorsal length of the early embryo. Anatomy and Physiology 2013-06-19T00:00:00Z Cao and colleagues’ study provides at least two insights into the evolution of vertebrates from this common ancestor: one concerning the notochord, and the other concerning the CNS, which becomes especially complex in vertebrates. A deep dive into the development of sea squirts 2019-07-09T04:00:00Z It then attaches via the head to the surface and undergoes metamorphosis into the adult form, at which point the notochord, nerve cord, and tail disappear. Fundamentals of Biology 2015-01-01T00:00:00Z Vertebrates do not have a notochord at any point in their development; instead, they have a vertebral column. Concepts of Biology 2013-04-25T00:00:00Z They found that the transplanted embryo now had two notochords: one at the dorsal site from the original cells and another at the transplanted site. Biology for AP Courses 2022-06-09T00:00:00Z However, small areas of notochord tissue persist between the adjacent vertebrae and this contributes to the formation of each intervertebral disc. Anatomy and Physiology 2013-06-19T00:00:00Z The narrow white line stretching across the center of the image is the notochord, or an early backbone. Watch This Blob of Cells Become an Embryo in High-Resolution 2018-10-12T04:00:00Z Lampreys possess a notochord as adults; however, this notochord is surrounded by a cartilaginous structure called an arcualia, which may resemble an evolutionarily early form of the vertebral column. Fundamentals of Biology 2015-01-01T00:00:00Z It then attaches by the head to the substrate and undergoes metamorphosis into the adult form, at which point the notochord, nerve cord, and tail disappear. Concepts of Biology 2013-04-25T00:00:00Z This suggested that the dorsal cells were genetically programmed to form the notochord and define the axis. Biology for AP Courses 2022-06-09T00:00:00Z The tissue overlying the notochord enlarges and forms the neural tube, which will give rise to the brain and spinal cord. Anatomy and Physiology 2013-06-19T00:00:00Z Others resulted from the absence of a spine, filled in instead with an elongated notochord, a flexible rod made up of something similar to cartilage. Open Wide: Deep-Sea Fishes That Are Built to Eat Big 2017-02-01T05:00:00Z In adult vertebrates, the vertebral column replaces the notochord, which is only seen in the embryonic stage. Fundamentals of Biology 2015-01-01T00:00:00Z This notochord provides support to the fish’s body. Concepts of Biology 2013-04-25T00:00:00Z The mesoderm gives rise to somites and the notochord. Biology for AP Courses 2022-06-09T00:00:00Z By the fourth week, mesoderm tissue located on either side of the notochord thickens and separates into a repeating series of block-like tissue structures, each of which is called a somite. Anatomy and Physiology 2013-06-19T00:00:00Z “We discovered that this feature was the notochord, the primitive backbone,” said Dr. McCoy. Solving the Tully Monster’s Cold Case 2016-03-16T04:00:00Z A dorsal hollow nerve cord run along the upper back, and a notochord runs beneath the nerve cord. Fundamentals of Biology 2015-01-01T00:00:00Z The chordates are named for the notochord, which is a flexible, rod-shaped structure that is found in the embryonic stage of all chordates and in the adult stage of some chordate species. Concepts of Biology 2013-04-25T00:00:00Z The notochord cells of the mesoderm signal the ectodermal cells to form epidermal cells as well as the neural plate. Biology for AP Courses 2022-06-09T00:00:00Z As the developing vertebrae grow, the notochord largely disappears. Anatomy and Physiology 2013-06-19T00:00:00Z But several fossils revealed that the band bore the hallmark traits of a notochord, the rubbery tube surrounding some primitive vertebrates’ spinal cords. Scientists Finally Know What Kind of Monster a Tully Monster Was 2016-03-16T04:00:00Z The notochord extends into the head, which gives the subphylum its name. Fundamentals of Biology 2015-01-01T00:00:00Z In vertebrates, the notochord is present during embryonic development, at which time it induces the development of the neural tube and serves as a support for the developing embryonic body. Concepts of Biology 2013-04-25T00:00:00Z The animal will possess two notochords and may not have a dorsal-ventral or anterior- posterior side. Biology for AP Courses 2022-06-09T00:00:00Z Repeating, paired blocks of tissue called somites then appear along either side of notochord. Anatomy and Physiology 2013-06-19T00:00:00Z Human embryos develop a notochord, too, but it later turns into the disks of cartilage between the vertebrae in our spine. A Long-Ago Ancestor: A Little Fish, With Incipient Jaws 2014-06-11T04:00:00Z The skeleton of a hagfish is composed of cartilage, which includes a cartilaginous notochord that runs the length of the body. Fundamentals of Biology 2015-01-01T00:00:00Z Sessile adult tunicates lose the notochord; what does this suggest about one function of this structure? Concepts of Biology 2013-04-25T00:00:00Z It is reorganized into groups of cells called somites, which develop into ribs, lungs, segmental muscle, and the notochord. Biology for AP Courses 2022-06-09T00:00:00Z Mesenchyme accumulates around the notochord and produces hyaline cartilage models of the vertebrae. Anatomy and Physiology 2013-06-19T00:00:00Z Skeleton.—The vertebral column of the lamprey is represented by a persistent notochord surrounded by a thick sheath, which shows no signs of invasion by cartilage cells or of segmentation. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 8 "Cube" to "Daguerre, Louis" 2012-01-31T03:00:17.257Z This notochord provides support to the hagfish’s body. Fundamentals of Biology 2015-01-01T00:00:00Z The skeleton of a hagfish is composed of cartilage, which includes a cartilaginous notochord, which runs the length of the body, and a skull. Concepts of Biology 2013-04-25T00:00:00Z Later on these surrounding portions become cartilage, and, still later, bone; the notochord meanwhile gradually disappearing where the bony spinal column appears. Embryology The Beginnings of Life 2011-09-12T02:00:28.483Z The notochord largely disappears, but remnants of the notochord contribute to formation of the intervertebral discs. Anatomy and Physiology 2013-06-19T00:00:00Z It has no arch elements on its notochord. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 8 "Cube" to "Daguerre, Louis" 2012-01-31T03:00:17.257Z He reared gastrulæ and older embryos with notochord and nerve-tube, which were perfect and normal, except in size. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z When the medullary tube of the notochord enlarges to form the brain the end of the head bends over to make room for that enlargement. Degeneracy Its Causes, Signs and Results 2011-05-02T02:00:17.657Z The heart, proboscis gland and notochord are located in the posterior part of the proboscis. Journal of Entomology and Zoology Volume Eleven, Number Two, June 1919 A useful introduction to the study of the vertebrate brain is that of the Amphioxus, one of the lowest of the Chordata or animals having a notochord. Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 4 "Bradford, William" to "Brequigny, Louis" The hoops of each side are connected together dorsally by a pair of longitudinal bars, lying ventral to the notochord, and ventrally by a similar pair of rods which are fused in the middle line. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 8 "Cube" to "Daguerre, Louis" 2012-01-31T03:00:17.257Z The protruding cells, which normally would have developed into notochord and nerve plate, grew into a simple fold of the external skin. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z The spinal cord is at first essentially a notochord as in the lowest types of vertebrates. Degeneracy Its Causes, Signs and Results 2011-05-02T02:00:17.657Z The collar contains the central nervous system, part of the notochord, the dorsal blood vessel, ventral and dorsal mesenteries, mouth opening and anterior part of the alimentary canal. Journal of Entomology and Zoology Volume Eleven, Number Two, June 1919 The two pleurocentra of each vertebra are separate ventrally as well as dorsally, but form thin, broad plates of about the same height as the notochord. A New Order of Fishlike Amphibia From the Pennsylvanian of Kansas It presents, however, a rudimentary backbone, in the form of what is called a notochord. Darwin, and After Darwin (Vol. 1 and 3, of 3) An Exposition of the Darwinian Theory and a Discussion of Post-Darwinian Questions The notochord arises from a set of cells which are in close relation with the fused tips of the blastopore. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z The investing mass of the head and of the notochord is the skeleton of the occipital bone. Degeneracy Its Causes, Signs and Results 2011-05-02T02:00:17.657Z Because this diverticulum has the vacuolated appearance of the notochordal tissue of higher animals, it has been regarded as a notochord. Journal of Entomology and Zoology Volume Eleven, Number Two, June 1919 The notochord seems to have been slightly constricted by the intercentra, but not interrupted. A New Order of Fishlike Amphibia From the Pennsylvanian of Kansas The medullary folds and notochord are evident at this stage, but no mesoblastic somites are to be seen. Development of the Digestive Canal of the American Alligator Hence the notochord has a beaded form within this, at first, continuous cartilaginous sheath. Text Book of Biology, Part 1: Vertebrata Around the notochord is later formed a species of membrane which protects it, called the perichord. Degeneracy Its Causes, Signs and Results 2011-05-02T02:00:17.657Z The microscope shows that these animals have notochords, nervous systems, and ganglia, or brains. The Dawn of Reason or, Mental Traits in the Lower Animals Now the brain capsule, like the sheath of the spinal cord, is a development from the outer sheath of the notochord. Form and Function A Contribution to the History of Animal Morphology The entoderm, which has the appearance of being thickened because of the fact that the notochord has not yet completely separated from it, is continuous, through the blastopore, with the ectoderm. Development of the Digestive Canal of the American Alligator Before throwing tail and hinder part of body away, note the myotomes of body wall, the notochord and vertebral body, neural canal, and, in the tail, the haemal canal. Text Book of Biology, Part 1: Vertebrata But to return to the developing human embryo, there is formed from and above the embryonic food-canal a skeletal rod, which is called the notochord. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told The axial skeleton consists, in the lowest fish, of the notochord, a cylindrical unsegmented rod of cartilage running nearly the length of the body. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 The next bone, however, the basisphenoid, develops in front of the notochord, and shows very little analogy with a vertebral body. Form and Function A Contribution to the History of Animal Morphology The foregut is here more inclosed, and the notochord, nt, having separated from the entoderm, en, is seen as a distinct layer of cells extending from the foregut to the blastopore. Development of the Digestive Canal of the American Alligator The cartilage is hard and semi-transparent, the notochord jelly-like, least at the centres of the centra, and at a maximum intervertebrally.- Text Book of Biology, Part 1: Vertebrata They have no backbone in the strict sense, but they have this notochord. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told The nerve-centres are therefore here all dorsal, and the notochord or skeleton lies between these and the digestive or alimentary canal. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 The vertebral column develops as a segmented structure round the notochord; the skull develops first as an unsegmented plate extending far beyond the notochord. Form and Function A Contribution to the History of Animal Morphology The two cavities project towards each other in the middle line, and are almost in contact with the notochord, in the region figured, but they do not fuse at any point. Development of the Digestive Canal of the American Alligator What is the notochord, and how is it developed in the frog? Describe the early stages in the development of the egg of the fowl as far as the closure of the neural groove. Text Book of Biology, Part 1: Vertebrata The interesting point is that although the notochord is only a vestige in the adults of these types, it is never absent from the embryo. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told These unite with the masses of cartilage surrounding the notochord to form cartilaginous vertebræ, which may be stiffened by an infiltration of carbonate of lime. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 Now of these bones, the basioccipital is in every way equivalent to a vertebral centrum, for it develops in the basilar plate round the notochord. Form and Function A Contribution to the History of Animal Morphology It possesses in its larval stage a notochord, the delicate structure which precedes the formation of a backbone, extending along the upper part of the body below the spinal cord. Composition-Rhetoric This becomes truly cartilaginous, and at regular intervals is alternately thicker and thinner, compressing the notochord at the thicker parts. Text Book of Biology, Part 1: Vertebrata The Vertebrata always have a dorsal, or neural, cavity above the notochord or backbone, and a ventral, or visceral, cavity below it. The Gutenberg Webster's Unabridged Dictionary Section T, U, V, and W The primitive skeleton was the notochord, still appearing in the embryos of all vertebrates and persisting throughout life in fish. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 The substance of the notochord consisted of polyhedral cells having attached to their wall an oval disc similar in all respects to the nucleus of the plant-cell, and like it containing one or more nucleoli. Form and Function A Contribution to the History of Animal Morphology The blood is colorless; the brain, renal organs, and limbs are wanting, and the backbone is represented only by a simple, unsegmented notochord. The Gutenberg Webster's Unabridged Dictionary Section I, J, K, and L Having the notochord reaching in front of the brain. Text Book of Biology, Part 1: Vertebrata As I understand it, he actually anticipated in his pamphlet Saint Hilaire's theory of the universal type, and supported the hypothesis by describing the notochord of the amphioxus as a cartilaginous vertebral column. Crucial Instances The vertebræ with few exceptions are hollow in front and behind, biconcave; and between each two vertebræ there is a large cavity still occupied by the notochord. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 Müller himself had not only recognised the cellular nature of the notochord, but had observed the cells of the vitreous humour, fat cells and pigment cells, and even the nuclei of cartilage cells. Form and Function A Contribution to the History of Animal Morphology The scope and activity of the notochord in some of the invertebrates present phenomena far more wonderful per capita than many a brain produces. The Minds and Manners of Wild Animals A Book of Personal Observations The hypoblast is the lining of the intestine and of the glands which open into it; and the material of the notochord is also regarded, as hypoblast. Text Book of Biology, Part 1: Vertebrata The skeleton is completely ossified and the notochord removed. The Elements of Geology Around this primitive notochord was a layer of connectile tissue which later gave rise to the vertebræ forming our backbone. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 The capsule for the ear-labyrinth develops quite independently of the cranial basis and the notochord. Form and Function A Contribution to the History of Animal Morphology Thus the notochord is the necessary forerunner of the vertebral column, cartilage the precursor of bone. Form and Function A Contribution to the History of Animal Morphology The notochord persists between the centra in the dog-fish and rabbit, within the centra in frog. Text Book of Biology, Part 1: Vertebrata These, the highest vertebrates of the time, had not yet advanced beyond the embryonic stage of the more or less cartilaginous skeleton and the persistent notochord. The Elements of Geology Now this is a very peculiar origin for cartilage, and the notochord is a very strange cartilage even if we have not made a mistake in calling it cartilage at all. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 In Ammocoetes, as Johannes Müller had shown, the foundation of the skull is formed by two long cartilaginous bars, between the hinder portions of which the notochord ends. Form and Function A Contribution to the History of Animal Morphology This point of view is strengthened by the fact that in Molgula, studied by Lacaze-Duthiers, the embryo is practically stationary, and forms no notochord, nor ever develops sense-organs in the cerebral vesicle. Form and Function A Contribution to the History of Animal Morphology This sheath is soon cut into a series of vertebral bodies by jointings appearing through the points where the cartilage is thickest and the notochord most constricted. Text Book of Biology, Part 1: Vertebrata The notochord is a continuous rod of cartilage, or gristle, which in the embryological growth of vertebrate animals supports the spinal nerve cord before the formation of the vertebrae. The Elements of Geology Only gradually is the notochord crowded out so that the vertebræ join by their whole adjacent surfaces. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 With the notochord he homologised the supporting rod in the proboscis of Balanoglossus, which like the notochord arises from the dorsal wall of the archenteron, and has a vacuolated structure. Form and Function A Contribution to the History of Animal Morphology He pointed out also that the "notochord" was confined to the tail of the ascidian larva. Form and Function A Contribution to the History of Animal Morphology Having the notochord reaching anteriorly to the mid-brain, a brain of three primary vesicles and a skull. Text Book of Biology, Part 1: Vertebrata This strand of cells, he concludes, must clearly be the notochord, and the type of development is obviously the double-symmetrical met with in Vertebrates. Form and Function A Contribution to the History of Animal Morphology Furthermore, a cartilaginous rod, like the notochord, even fully developed, hardly enabled the animal to fight directly with the mail-clad crab. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 He admits that there exists a real homology between, for instance, the notochord of Vertebrates and that of Ascidians. Form and Function A Contribution to the History of Animal Morphology That a notochord should develop out of the archenteric wall because a supporting axis would be beneficial to the animal may be a teleological assumption, but it is at the same time an evolutional heresy. Form and Function A Contribution to the History of Animal Morphology Dohrn assumed also that the primitive Annelid ancestor must have possessed a notochord to give support in swimming. Form and Function A Contribution to the History of Animal Morphology He found a strong positive argument for his theory that Vertebrates are descended from unsegmented forms in the fact that the notochord arises as an unsegmented structure. Form and Function A Contribution to the History of Animal Morphology The skull of the Amphioxus presents a modification of that plan which is exhibited by the frog's skull when its walls are still membranous and the notochord is not yet embedded in cartilage. Form and Function A Contribution to the History of Animal Morphology |
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