The Ultrastructure of Articular Cartilage in the Prenatal Domestic Cat

Abstract

Horky D.: The Ultrastructure of Articular Cartilage in the Prenatal Domestic Cat. Acta vet. Brno, 62,1993: 115-120.The articular cartilage of 11 foetuses of the domestic cat, both males and females, was studied at 30, 40 and 48 days after fertilization. The tissue samples were collected from the femoral heads and processed by standard methods for observation by light and transmission electron microscopy.In the period studied, the cartilage surface was covered with the chondrosynovial membrane. Bundles of aperiodic filaments were seen under as well as on the cartilage surface, being a part of the membrane structure. Collagen fibrils, found in low numbers, were running in various directions in the ground amorphous substance.Chondrocytes in the surface layer were situated in two parallel rows. They had oval or spindle-like shapes, contained large nuclei and few organelles in the cytoplasm. Glycogen and lipid droplets occurred rarely. Occasional chondrocytes with atypical cilia were seen in the surface and deep layers. Of interest was a finding of erythrocytes in the intercellular matrix of the deep layer. Ultrastructure, articular cartilage, domestic cat, prenatal developmentThe SUbmicroscopic structure of adult articular cartilage has been know since 1959 (Zelander) and light and electron microscopic studies have provided a great deal of detailed information in various mammalian species, such as rabbit (Davies et a

Periods and Stages of the Prenatal Development of the Domestic Cat

“…21). Literature descriptions include: 98 mm hair, pigmentation and claws distinct (Evans and Sack, 1973), 70–120 mm lanugo (Sainmont, 1906), 103 mm (Windle and Griffin, 1931), 108–125 mm (Schnorr, 1989), corpus callosum is elongated and the sulcus coronalis, suprasylvius lateralis, sylvii, cruciatus, splenialis are formed (Martin, 1894a, b, 1895), first neurotransmitters in the brain (Chun and Shatz, 1989), in the retina all layers are formed (Ramoa et al, 1988), and start differentiation (Rapaport and Stone, 1983), the gland of the third eyelid starts its development, also the tarsal glands, first signs of iris muscles, the irido‐corneal region is fully developed, blood vessels at the cornea‐scleral junction are well outlined (Bernis and Wyman, 1980), first astrocyts in the optical nerve (Ling and Stone, 1988), vestibular nerve in the promyelin stage (Romand et al, 1976; Berthold et al, 1983), stage of terminal sacs of the lung (Glöckel, 1984), gustatory glands (Tichy, 1993), the prenatal differentiation of the salivary glands starts (Knospe and Böhme, 1995), first glandular branches in the stomach, the penis is differentiated, but the corpus cavernosum is still weaker as the corpus spongiosum, the prepuce is still connected (Martin, 1890c), 11.5–14.5 cm, 49–55 days, ossification of the humerus epiphyses, os pubis, os tarsi tibiale, os tarsi fibulare and toes (Schaeffer, 1932), articular cartilage becomes smooth (Horky, 1993, 1994), muscle blastemes with distinct fibres (Hoh and Hughes, 1989), lanugo, 90–120 mm, hair, wrinkles and pigment pattern of the skin is distinct (Günther, 1994), first sebaceous glands in the mentum (Backmund, 1904), proliferation of the labial gland (Künzel and Knospe, 1986), primary branches of the mammary gland, hairs free, first sebaceous glands (Gisler, 1922; Turner and DeMoss, 1934), with 90 mm conus formation and with 115–125 mm cavitation of the anal sac, first follicles and glands in the skin (Schwarz, 1987; Schwarz, 1987), 116 mm, division of stratum corneum unguis into two layers and completion of stratum tectorium, paries unguis is formed, capillaries have penetrated into sulcus matricis (Kato, 1977).…”