Scanning electron microscopic study of different hair types in various breeds of rabbits

The microarchitecture of the cover hairs, wool hairs and tactile (sinus) hairs of feral, New Zealand White and Angora rabbits was studied by means of scanning electron microscopy. The morphology and variability of the cuticular scale patterns, hair cortex, medullary arrangement and profile of the hairs are described, illustrated and compared with findings resulting from conventional light microscopy, cuticular casting and medullary impregnation. All parameters examined in cover hairs presented a considerable variation along the length of the hair shaft. In wool hairs, in contrast, only the cuticular scale pattern was subject to manifest segmental variation, whereas the shaft diameter, cortical profile and medullar composition changed little over the entire length of the hair. The tactile hairs of the head were characterised by a round profile of the hair shaft, a cylindrical central medullar canal, and a thick cortex covered by cuticular scales that were arranged in a waved pattern and oriented transversally in relation to the longitudinal axis of the hair. It was concluded that the scanning electron microscopic observation of hair samples is a fast and valuable method for identifying hair types with useful applications in different disciplines such as mammalian biology, the textile industry and forensic medicine

Scanning electron microscopic study of the posterior ciliary veins in domestic ungulates

Vascular corrosion casts of 12 equine, 15 bovine and 50 porcine eyes were studied scanning electron microscopically for the presence of posterior ciliary veins. These veins drain a postequatorial segment of the choroid and emerge near the posterior bulbar pole. They complement the four vorticose veins that emerge near or at the equatorial zone of the eyeball and the slender choroidoretinal veins that drain the peridiscal area of the choroid. Posterior ciliary veins were observed in all equine and bovine eyes examined. In these species they presented a large variation in size, number and position. In contrast, posterior ciliary veins were only present in two porcine eyes where they were represented by one and two vessels, respectively. The morphology and variability of these vessels is illustrated and their nomenclature and functional significance are discussed

Geluidsproducrie bij vogels

The syrinx plays an important role in the sound production of birds. Its most important structures are the labia and the lateral tympaniform membranes that produce sound by vibrating during expiration. Since the left and right sides of the syrinx are innervated independently from each other, two sound sources are present which can act either simultaneously or separately with one side acting as sound source and the other side as air inlet. The bird's song is generated in specific neural brain centres via a seamless synchronization of the respiration and the muscles of the upper respiratory tract, the trachea and the syrinx. Hormones also play a role by influencing the volume of the brain centres in relation to the season. The acquisition of the bird's song starts with a sensory phase in which the juvenile bird learns the species specific song, and is followed by a sensorimotor phase during which the young bird fine-tunes its song via auditory feedback

Respiratie bij vogels: een functioneel-anatomische benadering

The mechanism of avian respiration is still controversial. It is fundamentally different from respiration in mammals. Although during in-and expiration a continuous caudocranial airflow is present within the tertiary bronchi and the air capillaries of the avian lung, the air flow within the entire respiratory system is still equivocal. Several patterns explaining the air flow during in-and expiration have been proposed during the past century. Moreover, various anatomical structures and aerodynamic mechanisms have recently been described in an attempt to explain the proposed mechanisms of respiration. This manuscript gives an overview of the anatomy of the avian respiratory system and the hypotheses concerning the physiology of avian respiration

Acute instability of the nuchal ligament following cervical neuromuscular dysfunction in a dressage horse

A ten-year-old Warmblood dressage gelding was presented with acute instability of the nuchal ligament after paddock turnout. Based on the clinical signs, orthopedic and neurologic examination, diagnostic imaging and electromyography, cervical neuromuscular dysfunction of the M. obliquus capitis caudalis on the right side of the neck was diagnosed. Conservative treat-ment including steroidal anti-inflammatory medication in combination with oral supplementation with vitamin B1 and box rest resulted in complete recovery of the horse within six months

The Tonsils Revisited: Review of the Anatomical Localization and Histological Characteristics of the Tonsils of Domestic and Laboratory Animals

This paper gives an overview of the anatomical localization and histological characteristics of the tonsils that are present in ten conventional domestic animal species, including the sheep, goat, ox, pig, horse, dog, cat, rabbit, rat, and pigeon. Anatomical macrographs and histological images of the tonsils are shown. Six tonsils can be present in domestic animals, that is, the lingual, palatine, paraepiglottic, pharyngeal, and tubal tonsils and the tonsil of the soft palate. Only in the sheep and goat, all six tonsils are present. Proper tonsils are absent in the rat, and pigeon. In the rabbit, only the palatine tonsils can be noticed, whereas the pig does not present palatine tonsils. The paraepiglottic tonsils lack in the ox, horse, and dog. In addition, the dog and cat are devoid of the tubal tonsil and the tonsil of the soft palate