Secretory system

In the process of evolution is differentiated special v. s. in the lowest worms (flat, gastrotricha, kinorinkhi, Rotifer, skrebni, nemertiny), and also in priapulid and some the annelid and in the larvas of polys-hair and mollusks secretory organs - protonefridii - the system of the small tubes, which are opened outside by times, and inside blindly concluding with the special hollow cells, in which are located the beams of the long fixed cilia, which continuously accomplish the oscillating motions ("blinking flame") (Fig. 1, 2). In annulated worms the blind ends of the proto-nephridial channels conclude with the groups of the bottle-shaped cells (solenotsitov), in the draft of which it is located through one braid (Fig. 3). In the majority of annulated worms v. s. - metanefridii, i.e. the metameric located paired tubular ectodermal organs, which are opened into the coelomic bags by ciliary funnel, and outside - now and then on the surface track, segment. If into the composition of such organs of isolation enter mesodermal elements, then they speak about nefromiksii. It will isolate, the organs, which are developed from the mesoderm, Vol. n. of tselomodukty - available in the mollusks: funnel is opened into the pericardial cavity (remainder of tseloma), external opening - into the mantle cavity. In crustaceans it will isolate, organs - coiled tubes, which are begun by blind "coelomic" sack and which are opened outside in antenna mounting or maksill (hence title. "antennal" and "maxillary" glands) (Fig. 4). Are similar it will isolate, the organs in the Xiphosura ("koksal'nye glands"), which are opened in the base of the 5th pair of feet. Opening it will outside isolate, the organs, through which the readily soluble products of exchange are derived, they are typical for the aqueous invertebrates.
 

Fig. 1. Secretory system of plathelminth Allocreadium isoporum: 1 - secretory opening; 2 - bladder; 3 - right main channel of secretory system; 4 - end starlike cells with the blinking flame; 5 - oral sucker; 6 - abdominal sucker.
 

Fig. 2. Ardent cell of the ciliated worm: 1 - nucleus; 2 - blinking braid.
 
 

Fig. 3. Blind end of protonefridiya of annulated worm with sitting on it solenotsitami: 1 - solenotsity; 2 - secretory tube of protongfridiya; 3 - nucleus; 4 - braid of solenotsita.
 

Fig. 4. Antennal gland of river cancer (in the straightened form): 1 - coelomic sack; 2 - "green channel"; 3 - intermediate channel; 4 - "white channel"; 5 - bladder; 6 - excretory duct; 7 - external opening of gland.

The inhabiting on dry land, which requires the savings of the expenditure of moisture, produces a change in the nature of catabolites - readily soluble ammonia and urea are substituted those low-solubility by guanine (in arachnids) or by urinary acid (in myriapods and insects). It will isolate, organs of the type of tselomoduktov from the ground-based invertebrates have only hygrophilous forms - onikhofory and some arachnids (for example, senokostsy). It is characteristic passage it will isolate for the ground-based arthropods, functions to the walls of bowels (they become sometimes only it will isolate, by organ, for example, in lozhnoskorpionov) or are more frequent to the Malpighian vessels to the long blind outgrowths of bowels on the boundary of average and rear gut, which are formed as the outgrowths of average (arachnids) or rear (insects, myriapod) gut (Fig. 5). Physiolog. advantage of Malpighian vessels (with the inhabiting under the conditions of the scarcity of moisture) in the fact that through them the easily falling out into the sediment products of exchange (urinary acid and other.) they are derived with the urinary liquid not outside, but into the rear gut, where the suction of water occurs; the dehydrated excreta together with the neperevarennymi remainders of food are derived through the anal opening outside how is achieved the retention of water into tele- animal.

Unique type of isolation - deposit of transferred into the insoluble form catabolites (urinary acid and other.) in the special cells -"pochkakh of accumulation" in nematode, in the khloragogennykh cells in rain worms, in the interstitial tissue in spiders, in the fatty tele- in insects and myriapods, in the hepatic outgrowths in woodlice, etc., which is also connected with the savings of the consumption of water with the excretion. Are similar to these it will isolate, by organs and ekskretofory - cells, which accumulate excreta and ejecting them, for example, into the opening of bowels (in lozhnoskorpionov, in eight-ray corals, etc.).

The second passage of ground-based invertebrates to the life in the water, for example, the larvas of insects, led to the return of excreta to the characteristic for aqueous animals type (osn catabolite - ammonia) and to the growth of osmoregular function will isolate, the organs (they are Malpighian vessels and bowels).

Among chord in obolochnikov and ascidia as the organs of isolation serve the sacks of the accumulation (in some obolochnikov it will isolate, elements they are not discovered). Lantsetnika in the branchiate region has by ok. 100 pairs Vol. n. of nefromiksiyev, which by one opening are opened into the near-branchiate cavity, and with several other openings (by densely seated solenotsitami) are connected with the cavity of body. In vertebrates as the organs of isolation serve typical tselomodukty, whose the accumulations form kidneys. From the kidneys will move away the ureters, which fall directly into the cesspool or into the bladder, which is opened by outside urethra. In an evolutionary number of vertebrates, as with the individual development of the highest vertebrates, is observed the sequential replacement of three types of kidneys. First appear front, or head, kidneys, NAZ also by predpochkami (see Pronefros). Further are developed primary, average, or tulovishchnye, the kidneys of vol'fovy of the body (see mid-kidney). By the latter appear second, rear, or pelvic, the kidneys (see Metanefros). Tselomodukty of predpochki and primary kidney, usually on the pair to the segment, appear from Vol. n. of nefrotoma (Fig. 6). The part of nefrotoma, which is opened into the second cavity of body, forms the blinking funnel (nefrostom). Against nefrostomov of predpochki in the cavity of body usually is developed ball of blood vessels general for all funnels; through it are filtered from the blood the liquid products of the isolations (aqueous solutions of salts), which enter funnels. Predpochka, which has segmental structure and which is pulled along the length body, remains in the continuation of entire life from the cyclostomata only in bdellostomy. In lampreys the remainders of pronefrosa, which form the front division of kidney, are opened into the pericardial cavity. In other vertebral pronefros it serves only as larual organ. It is especially well developed in the larvas of the majority of fishes and amphibious. In all fishes and amphibious in the adult state function primary kidneys. Their ducts are developed in the embryo to being similarly the ducts of predpocki, characterized by only the fact that they are opened into the finished pronefricheskiy duct, which is obtained from this time title of pervichnopochechnogo channel (Fig. 7 and 8). In elasmobranchii fishes this channel is split from front end to two ducts: Wolfs the channel, which serves as the ureter of primary kidney, and Muellers channel, which enters in the connection with the remainders of pronefrosa and fulfilling in females the function of oviduct. In amphibious Wolfs's males the channel is located in connection with the sexual gland and fulfills simultaneously the functions also of ureter, and the spermiduct. The presence of Malpighian corpuscles is characteristic for the primary kidney. In Amniote second kidney substitutes the functioning in the embryonic period primary kidney, which in adult females generally degenerates, while in males bears the function of the semyaprovodyashchego apparatus and NAZ by the appendage of testis, or by epididymis. Embryonic second kidney is formed from the special ureter, which grows from the rear end of vol'fova of channel (Fig. 9). This ureter has at the end several of final branchings off, into which fall the nephritic ducts, which appear from the nephrogenous tissue. The convoluted tubules of second kidney have funnels and begin never shityu boumenovoy capsule. In mammals and man the capsule follow the proximal convoluted tubules, further the straight descending and ascending ducts, which form Vol. n. loop Genle, and finally distal convoluted tubules and then connecting tubes, which fall into the excretory duct. The extended part of the ureter, from where will move away its final branchings off into the kidney, obtains title of renal pelvis. Three types of kidneys are connect together with known passages. Thus, even in predpochke can be section the balls, characteristic of primary kidney. In the latter the funnels fairly often disappear, and it becomes very similar on the structure to the second kidney.
 

Fig. 5. Organs of the isolation of the black cockroach: 1 - are Malpighian vessels; 2 and 3 - divisions of front gut; 4 - average gut; 5 - blind appendages of average gut; 6 and 7 - divisions of rear gut.
 

Fig. 6. Development of predpochki in vertebrates (A also B - two sequential stages): 1 - somite; 2 - predpochechnyy duct and duct; 3 - lateral plate; 4 - second cavity of body; the 5- neck of somite (or nefrotom); 6 - funnel.
 

Fig. 7. Stereogram of the head and developing primary kidneys in the vertebrates: 1 - aorta; 2 - second cavity of body; 3 - ball; 4 - mesentery; 5 - pronefricheskaya small tube; 6 - pronefricheskiy duct; 7 - cavity of nefrotoma (8); 9 - funnel; 10 - mezonefricheskaya small tube; 11 - chord; 12 - peritoneum; 13 - myotome; 14 - spinal cord.
 
 

Fig. 8. Stereogram of the formed primary kidneys in the vertebrates: 1 - aorta; 2 - second cavity of body; 3 - sexual roller; 4 - ball; 5 - mesentery; 6 - is Malpighian corpuscle; 7 - mezonefricheskaya small tube; 8 - myotome; 9 - funnel; 10 - chord; 11 - peritoneum; 12 - Wolfs duct; 13 - spinal cord.
 
 

Fig. 9. Schematic of the development of urino-genital system in the highest ground-based vertebrates (A - initial stage; B - urino-genital apparatus of female; C - the urino-genital apparatus of male): 1 - predpochka (pronefros); 2 - primary kidney (mid-kidney); 3 - second kidney (metanefros); 4 - gonad; 5 - ovary; 6 - testis; 7 - bladder; 8 - Wolfs channel; 9 Muellers channel; 10 - rectum; 11 - ureter; 12 - urethra; 13 - womb; 14 - appendage of ovary (remainder of primary kidney); 15 - appendage of testis (modified primary kidney).

The theory of the change of nephritic ducts is the most probable theory, which explains the sequential replacement of kidneys. The supporters of this theory consider that in the ancestors of vertebrates was the long kidney, built according to the type of pronefrosa. In their fish-descriptive descendants on the spinal side of the ducts of predpochki developed more advanced type ducts - ducts of the primary kidney, which extruded predpochechnye ducts for the elongation of entire body, with exception of its front end. In Amniote the ducts of the second kidney, which were being developed in the rear division of primary kidney, gradually extruded the latter. Cm. Isolation, respiration are organs, the skin.

Lit.: X about l about d k o in s to and and N. A., the textbook of zoology and comparative anatomy, 3 publ., SPB, 1914; Mashkovtsev A. A., the morphological and phylogenetic ratio of mid-kidney to pronefrosu, "tr. of the laboratory of the evolutionary morphology AN sssr", 1934, Vol. 2, in. 1; Management on zoology, edited by L.A. Of zenkevicha, Vol. 1, M. - l., 1937; Dogel' v. A., the comparative anatomy of invertebrates, h. 1, l., 1938; Kravchinskiy b. d., the physiology of kidneys. [ l. ], 1949; Koshtoyants X s., the bases of comparative physiology, 2 publ., Vol. 1, of M. - l., of 1951; Beklemiwev v. n., the bases of the comparative anatomy of invertebrates, 3 publ., Vol. 1 - 2, M., 1964; Course of zoology, edited by B. S. Matveyev, 7 publ., Vol. 1 - 2. M., 1966. M. S. gilyarov, A. n. druzhinin.