noun
definition
A pipe, tube or canal which carries gas or liquid from one place to another.
example
heating and air-conditioning ducts
definition
An enclosure or channel for electrical cable runs.
definition
Guidance; direction.
verb
definition
To channel something through a duct (or series of ducts).
Examples of ducts in a Sentence
We can hardly any longer hesitate to recognize in this vast building, with its winding corridors and subterranean ducts, the Labyrinth of later tradition; and as a matter of fact a maze pattern recalling the conventional representation of the Labyrinth in Greek art actually formed the decoration of one of the corridors of the palace.
In these and other Chaetopods the coelom is also put into indirect relations with the outside world by the nephridia and by the gonad ducts.
To this pericardial coelom is frequently added a gonocoel enclosing the gonads and the funnels of their ducts.
In Lumbricus the connexion is a little closer; the funnel of the nephridium, in the segments in which the funnels of the gonad ducts are to be developed, persists and is continuous with the gonad duct funnels on their first appearance.
To this category will belong the oviducts in Teleostean fishes and probably the gonad ducts in several groups of invertebrates.
Nephridia sometimes of the type of those of the Oligochaeta; in other cases short, wide tubes with a large funnel serving also entirely or in part as gonad ducts.
It is possible that we have here gonad ducts distinct from nephridia which at the time of sexual maturity do open on to the exterior.
It seems that the posterior nephridia are mainly gonad ducts, and the gonads are developed in close association with the funnels.
It is noteworthy that in this family only among the Polychaeta, the nephridia are not restricted to a single pair in each segment; so that the older view that the gonad ducts are metamorphosed nephridia is not at variance with the anatomical facts which have been just stated.
The genital ducts are limited to one segment (the 8th in Capitella capitata), and there are genital setae on this and the next FIG.
Special gonad ducts always present.
Male ducts often open on to exterior through a terminal chamber which is variously specialized, and sometimes with a penis.
A complex network, however, does occur in Lybiodrilus and certain other Eudrilidae, where the paired nephridia possess ducts leading to the exterior which ramify and anastomose on the thickness of the body wall.
The Oligochaeta contrast with the Polychaeta in the general presence of outgrowths of the septa in the genital segments, which are either close to, or actually involve, the gonads, and into which may also open the funnels of the gonad ducts.
These cavities communicate with the exterior through the gonad ducts, which have nothing to do with them, but whose coelomic funnels are taken up by them in the course of their growth.
The gonad ducts are male and female, and open opposite to or, rarely, alongside of the gonads, whose products they convey to the exterior.
While the oviducts always open directly on to the exterior, it is the rule for the sperm ducts to open on to the exterior near to or through certain terminal chambers, which have been variously termed atrium and prostate, or spermiducal gland.
There are a clitellum and sperm ducts which though like nephridia have a larger funnel and a less complexly wound duct.
Spermatheca rarely with diverticula; sperm ducts as a rule occupying two segments only, usually opening by means of an atrium.
Sperm ducts and atria as in Limicolae; egg sacs large; body wall thick; vascular system and nephridia as in Terricolae.
Sperm ducts traverse several segments on their way to exterior.
The intervening segments contain the genitalia, which are on the Oligochaeta plan in that the gonads are independent of their ducts and that there are special spermathecae, one pair.
The male ducts are either one pair or two pairs, which open by a common and complicated efferent terminal apparatus furnished with a protrusible penis.
The gonads and their ducts in the Hirudinea invariably form a closed system of cavities entirely shut off from the coelom in which they lie.
The efferent ducts are ciliated, and there is a patch of cilia at the point where they communicate with the cavity of each testis.
It is therefore a haemocoel, the coelom of the developed insect being represented only by the cavities of the genital glands and their ducts.
So the Dermaptera, which retain distinct maxillulae and have no ectodermal genital ducts, have either specialized or aborted wings and a large number of Malpighian tubes.
To it belong (a) superficial grooves or deeper slits situated on the integument near the tip of the head, (b) nerve lobes in immediate connexion with the nervous tissue of the brain, and (c) ciliated ducts penetrating into the latter and communicating with the former.
There is no communication between the nephridia on one side and the other, but in Eupolia there are ducts opening into the alimentary canal as well as to the exterior, a condition of things which recalls what obtains in certain Oligochaetes.
Kaiser has described as kidneys two organs something like minute shrubs situated dorsally to the generative ducts into which they open.
Both male and female gonads consist of more or less lobulated hollow sacs connected with the epidermis by short ducts.
When they are arranged in uniserial or biserial rows the genital ducts open into or near the branchial grooves in the region of the pharynx and in a corresponding position in the post-branchial region.
The latter enlarges into a spherical stomach into which open the broad ducts of the so-called liver.
They are lined by cells charged with a yellow or brown pigment, and besides their excretory functions they act as ducts through which the reproductive cells leave the body.
The first pair of foliaceous appendages in each animal is the genital operculum; beneath it are found the openings of the genital ducts.
The genital ducts of Arthropoda are, like the green glands, shell glands and coxal glands, to be regarded as coelomoducts (gonocoels).
The only point in which the gut of Limulus resembles that of Scorpio rather than that of any of the Crustacea, is in possessing more than a single pair of ducts or lateral outgrowths connected with ramified gastric glands or gastric caeca.
Both male and female gonoducts open through acornmon atrium to the exterior by tkis pore, but in three bisexual genera the male and female ducts are developed in separate individuals (Bilharzia, Didymozoon, Koellikeria).
The former consist of one pair or more of vesicular testes communicating by fine ducts with a vesicula seminalis.
The female organs consist of distinct ovaries and yolk-glands, the ducts of which uniti.
Coincidently, to allow of fertilization and the escape of excess of yolk, and of spermatozoa, other accessory ducts open at this point.
The excretory system is highly developed; the larger collecting ducts are elaborately looped and open posteriorly by a single terminal aperture.
It has been shown that this parasite feeds upon the blood, not the bile of its host, though it occurs mainly in the bile ducts.
Reproductive organs with ducts leading to the vestibule.
Francis died on the 31st of March 1547, of a disease of the urinary ducts according to some accounts, of syphilis according to others.
The mouth, situated at the opposite end and armed with a pair of stylets, leads into an oesophagus, into which the ducts of a pair of so-called salivary glands open.
This fissure represents the hilum of the liver, and contains the right and left hepatic ducts and the right and left branches of the hepatic artery and portal vein, together with nerves and lymphatics, the whole being enclosed in some condensed subperitoneal tissue known as Glisson's capsule.
The right and left hepatic ducts, while still in the transverse fissure, unite into a single duct which joins the cystic duct from the gall bladder at an acute angle.
The same description applies to the reptiles, but a curious net work of cystic ducts is found in snakes and to a less extent in crocodiles.
A pair of genital apertures, connected by genital ducts with the paired gonads, are found right and left near the nephridial pores, except in a few cases where the genital duct joins that of the renal organ (Spondylus).