Zur pränatalen Entwicklung der Glandula mandibularis und Glandula parotis der Katze

Abstract

The prenatal development of the cat's mandibular and parotid gland was examined by means of serial section of 36 cat embryos at 14-62 days of development. Both glands were excised from the epithelium of the primitive oral cavity and branched up to day 36 of the branching phase into a specific connective tissue. This tissue contained besides fine collagenous fibres, a high amount of proteoglycans. In the subsequent separation phase, ducts and acini differentiated themselves in primitive lobules which were separated by connective tissue. In the prenatal differentiation phase, from about day 50 up to birth, intercalated ducts and striated ducts were formed. In the acini, mucous and serous cells contained different amounts of complex carbohydrates. This secretory component changed shortly before birth.

Periods and Stages of the Prenatal Development of the Domestic Cat

“…14). Literature descriptions inlcude: 10 mm, primordium of mammary gland, external ear, pigmented optic cup, physiological hernia of the midgut, interdigital furrows (Windle and Griffin, 1931; Evans and Sack, 1973), 10 mm, 21 days, the operculum covers the third branchial arch, differentiation of the pharyngeal pouches and cranial nerves takes place (Halley, 1955), genital ridge elongated and first genital cords are visible (Sainmont, 1906), yolk sac placenta fades till day 24 (Rüsse and Sinowatz, 1991), eye lid, cornea, pigment in the retina and vitreal body develop (Bernis and Wyman, 1980), 9 mm (Noden and DeLahunta, 1985), digital plate of the hindlimb is distinct, inside tongue formation, gonads, cortex suprarenalis, metanephros and cartilage in the scapula and humerus are developing (Davies, 1973; Günther, 1994), beginning of the branching phase of salivary glands (Knospe and Böhme, 1995), with 13.5 mm the apical epidermal ridge (AER) is visible (Kato, 1977).…”

“…Organum vomeronasale is in differentiation, the hypophysis is lobed, thymus is separated into neck and thoracic parts, parathyroids are shifted near the thyroid gland, the first two neck joints are distinct, the neural arch of lumbal vertebrae are closed, in the liver haematopoiesis is occurring, the intestinal lumen is nearly obstructed by the growing villi, first goblet cells, differentiation of the plica urogenitalis, kidney with medulla and cortex and differentiating tubuli. Literature descriptions iclude: 45–70 mm (Schnorr, 1989 ), 70 mm and 14.0 g (Tiedemann and Ooyen, 1978), internodal swellings of the uterus are less prominent (Rüsse and Sinowatz, 1991), type II vestibular cells are innervated (Favre and Sans, 1979), 39 days, 49–73 (61) mm, vomeronasal organ in differentiation (Wöhrmann‐Repenning, 1989b), ciliary processes can be identified, the choriocapillaris, large choriodal vessel and vessels in the iris and corneo‐scleral junction develop, first bundles of orbicularis oculi muscle in the lids and the cartilage of the third eyelid are identified, formation of retinal layers (Büssow, 1974; Bernis and Wyman, 1980), separation phase of the salivary glands (Knospe and Böhme, 1995), development of the vallate papillae (Tichy, 1993), 50–80 mm, the thymus is filled with medium‐sized and small lymphocytes (Huntingdon and McClure, 1910, 1920; Windle and Griffin, 1931; Ackermann, 1967), number and size of intrafollicular lumina increase in the thyroid (Velicky and Titlbach, 1986), the lumen of the spinal cord is reduced to the final central canal (Böhme, 1988), first myelinization of the nerves (Chun and Shatz, 1989), canalicular stage of the lung (Glöckel, 1984), first glands and glandular pits in the stomach (Knospe, 1996), formation of the colon transversum (Krüger, 1929), haematopoiesis in the spleen (Ooyen, 1977; Canfield and Johnson, 1984), 50–65 mm, ovarian differentiation (Sainmont, 1906), 50–90 mm, ovary with cords and oogonia, mesonephros reduced (Tiedemann, 1976b), Nuda vibrissa, eyelids closed, claws in differentiation, breakthrough of the vibrissae, physiological hernia of the midgut reduced, canalicular lung, genitals differentiated (Günther, 1994), hair development is well established, epidermis with five layers, hair follicles and sebaceous gland buds in the upper third (Baker, 1974), 55 mm and 4.8 g, first visible vibrissae in the head region (Evans and Sack, 1973), mammary glands with nipples in the bulbous stage, hair follicles in bulbous‐peg stage (Gisler, 1922), hair germs in the dorsal skin, circumoral sweat gland germs (Backmund, 1904), 65–75 mm, differentiation of the paranal sinus, first hairs in the skin (Schwarz et al, 1983, 1984; Schwarz, 1987), dimorphism of the external genitals (Künzel, 1976), 7.1 cm, 35 days, ossification of the distal phalanges of the hindlimb and with 8.4–8.7 cm, 38–43 days, ossification of McI, Ph I of the forelimb and the body o...…”

Development of the Glandular Epithelium of the Bovine Parotid Gland during Ontogenesis

“…In comparison with other mammalian species, the anlage of the bovine parotid gland appears rather early in gestation (40–45 days), in the cat, the primordium of the gland is seen during the second trimester of gestation (Knospe and Böhme, 1995), in the rat even within the third trimester (Redman and Sreebny, 1970a), while there is no information available on the first budding in man.…”

“…Luminization of the primary cords takes place during the second foetal month in the bovine. Luminized ducts were found in 12 week old human foetuses (Donath et al, 1978), in the rat at the 17th day (Redman and Sreebny, 1970a) and in the cat at the 29th day of gestation (Knospe and Böhme, 1995).…”

“…In contrast very little information restricted to light microscopical results (Asari et al, 1994; Miura et al, 1996) is available on the parotid gland ontogenesis of the big group of ruminants especially cattle. In other mammalian species the ontogenesis of the parotid gland has been extensively examined on the light and electron microscopical level including man (Hammar, 1901; Yaku, 1983; Donath et al, 1978; Lee et al, 1990; Guizetti and Radlanski, 1996), cat (Knospe and Böhme, 1995), rat (Redman and Sreebny, 1970a,b, 1971; Redman et al, 1980), mouse (Moral, 1919) and rabbit (Leeson and Forman, 1981). Most of these authors stated the slow development of the parotid gland compared with the other salivary glands.…”