The ductus ad narem, though wide in the skeleton, is of very limited dimensions in the living body, and is in consequence readily made impermeable to mucous fluid, by even slight thickening of its lining membrane.
This it accomplishes by the structures in the ductus cochlearis.
In the vestibule we find two sacs, the saccule next to and communicating with the ductus cochlearis, and the utricle communicating with the semicircular canals.
He observed, too, the canal which passes in the fœtus between the umbilical vein and vena cava, and which has since been known as the ductus venosus.
By stage O its anterior end has dilated into a distinct gall-bladder, whose duct receives in succession the hepatic ducts, and so forms the ductus choledochus.
The ductus choledochus opens on the ventral side of the intestine immediately in front of the commencement of the spiral valve.
The subintestinal vessel, absent or only represented by the caudal vein and in part by the ductus venosus in higher Vertebrates and adult Fish, forms the main and only posterior venous trunk of Amphioxus and the embryo Scyllium.
Mr. Dyce's ductus literarum) in the word to be substituted.
The left hepatic vein loses its direct connection with the sinus venosus, and now opens into the termination of the ductus venosus, into which the right hepatic vein also empties.
The same obtains in the case of the ductus venosus continued from the umbilical vein (umbilical fissure and fissure of ductus venosus of adult liver).
A) and along the fissure for the ductus venosus (Fig.
Beyond the ductus venosus on the other hand the proximal segment of the left umbilical vein diminishes in size, and loses its independent character by incorporation in the hepatic circulation.
This vessel grows very rapidly up to its connection with the ductus venosus and soon exceeds the right umbilical vein in size (Fig.
While at first the ductus venosus communicates throughout its entire length with the meshwork of the hepatic capillary system, a separation into two segments, i.
A portion of the dorsal liver surface lying just to the left of the vena cava, between it and the ductus venosus, remains invested by peritoneum which is reflected from the boundaries of this space to the diaphragm.
The left angle of the Spigelian lobe and the fissure for the ductus venosus appear to the left of the portal vein and hepatic artery.
After surrounding this vein it is continued into the left leaf of the same membrane, which in turn passes into the left layer of the portion attached along the fissure for the ductus venosus.
A posterior cavity becomes specialised as the ductus ejaculatorius, while the hindmost part of the thickening, which is at first double, afterwards by coalescence single, forms the penis (figs.
The ductus endolymphaticus (vide Rabbit) is indicated by a dotted line in our figure.
The ductus Botalli of the fifth arch (known in Man as the ductus arteriosus) of the side on which the pulmonary arteries are formed, may remain (e.
Ca) cardinal veins, joining on each side to form the short transverse ductus Cuvieri (DC), both of which unite with the sinus venosus close to the heart.
These veins, running along the anterior abdominal wall, are formed somewhat later than the vitelline vein, and fall into the twoductus Cuvieri.
The first branchial is mainly continued into the carotid and other cephalic branches, but a narrow remnant of the trunk, which originally connected it with the dorsal aorta, remains, forming what is known as a ductus Botalli.
The second and third branchial arches are continued as simple trunks into the dorsal aorta, and the blood from the fourth arch mainly passes to the lungs, but a narrow ductus Botalli still connects this arch with the dorsal aorta.
In the Rabbit a ductus choledochus is formed by a diverticulum from the intestine at the point of insertion of the two primitive lobes.
According to Rathke the original trunk connecting the allantoic vein directly with the heart through the liver is aborted, and the ductus venosus Arantii is a secondary connection established in the latter part of foetal life.
Figure A shews the separation of the body cavity from the pericardial cavity by a horizontal septum in which runs the ductus Cuvieri; on the left side is seen the narrow passage which remains connecting the two cavities.
The two venae cavae superiores are the original 'ductus Cuvieri,' they open into the sinus venosus.
The vena cava inferior joins the continuation of the ductusvenosus in front of the liver, and, as it becomes more important, it receives directly the hepatic veins which originally brought back blood into the ductus venosus.
It is this right ductus Cuvieri which forms the dorsal part of what is usually termed the sinus venosus.
It is interesting to note that in Polypterus, one of the Crossopterygian ganoids, there is a somewhat similar asymmetrical condition of inferior jugulars and ductus Cuvieri.
The two posterior cardinals--with their continuations forwards, the anterior cardinals--approach the median plane and undergo fusion in the region of their opening into the two ductus Cuvieri.
The left ductus Cuvieri then atrophies so that all the blood from the cardinals reaches the heart by way of the originally right ductus Cuvieri.
The Determination of Longitude by the Satellites, the Discovery of the Ductus Thoracicus, a more convenient, and more exact Level, are not Novelties so fit to make a noise as a pleasant Poem, or a handsome Piece of Oratory.
The round ligament and the remains of the ductusvenosus are hidden in the depths of their fissures.
To the left of this is the fissure for the ductus venosus, and to the left of this again, the left lobe, in which a broad shallow groove for the oesophagus may usually be seen.
The latter are stored in both ductus deferens and ductus epididymis.
As in the Amphibia the ductus endolymphaticus sometimes extends into the cranial cavity and on into other parts of the body.
SV), the middle and outer the scala media, ductus cochlearis or true membranous cochlea (fig.
Anteriorly the saccule communicates with the membranous cochlea or scala media by a short ductus reuniens (fig.
In the lower forms the ductus endolymphaticus retains its communication with the exterior on the dorsum of the head, and in some Elasmobranchs the opening is wide enough to allow the passage of particles of sand into the saccule.
The utricle, saccule, semicircular canals, ductus endolymphaticus and a short lagena are the only parts of the ear present in fish.
From the lower part of the saccule a small canal called the ductus endolymphaticus (fig.
The ductus endolymphaticus has lost its communication with the skin, but it is frequently prolonged into the skull and along the spinal canal, from which it protrudes, through the intervertebral foramina, bulging into the coelom.
In making these observations upon the formation of the ductus arteriosus, we must request our readers to consider this as still an unsettled question.
A similar process takes place in the auricles, the foramen ovale being apparently formed in the same manner as the ductus arteriosus; these changes commence in the human embryo about the fourth week, and are completed about the seventh.
Nothing like the 'ductus literarum,' or attraction of the eye to a neighbouring word, can be alleged here.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "ductus" in a variety of sentences. We hope that you will now be able to make sentences using this word.
