Burcu Onuk

The morphology of the pecten oculi in the common buzzard (Buteo buteo)

OBJECTIVE The pecten oculi are an intraocular, vascular, and pigmented structure peculiar to the avian eye. In this study, we investigated the pecten oculi of the common buzzard (Buteo buteo) using stereomicroscopy and light and scanning electron microscopy (SEM). PROCEDURES Twenty eyes from 10 adult buzzards were studied. Specimens from each buzzard were preserved in 10% buffered formalin and observed stereomicroscopically before being embedded in paraffin, sectioned, and stained with three stains: Mallorys triple staining technique as modified by Crossman, Hematoxylin-Eosin (HE), and Safranin O, and for examination by light microscopy. Specimens from two buzzards were also prepared for SEM. RESULTS Stereomicroscopy and SEM examination showed the pecten oculi in the common buzzard to be pleated-consisting of 17-18 100 μm thick folds. These folds are connected to one another by bands of connective tissue extending vertically between the plications. Blood vessels, approximately 30-40 μm in diameter, were seen on the surface of the each fold. These vessels arise from the base of pecten, becoming thinner toward the apical end of the structure. A network of capillary vessels at the base of the plicated structure resembles contour lines. At high amplification, melanin granule accumulations were observed around the vascular structures of the plica on SEM images. Light microscopy supported the SEM observations. CONCLUSIONS These findings reveal that the pecten oculi in the common buzzard are plicated and are remarkably similar to that of the other diurnal raptors.

Macroanatomic, Light and Scanning Electron Microscopic Studies of the Pecten Oculi in the Stork (Ciconia ciconia)

This study was undertaken to investigate the pecten oculi of stork by using macroscopic, light and electron microscopic techniques. A total of 20 eyes that were obtained from 10 storks were used. The eyes were cleaned and isolated by dissection. After various procedures, four of the pecten oculi were examined by light microscope while the other four with an electron microscope. The remaining 12 eyes were assigned for macroscopic investigation. Pecten oculi of the stork were determined as accordion‐like structures that originated from n. opticus, consisting of 15–17 plica and projecting up to 2/5 of the diameter of the bulbus oculi. Light microscopic examination revealed two types of blood vessels. Afferent–efferent vessels were larger in diamater (40–45 µm), fewer in numbers, and the capillary vessels were smaller in diamater (2–5 µm) and more in numbers. There were granules including amount of melanin pigment at the apical part of the pleats. These granules were fewer and scattered randomly on the basal part of the pleats. As a result, pecten oculi in the stork, which is a migrating bird, were determined to be similar to those of other diurnal birds. Microsc. Res. Tech. 76:963–967, 2013.

New method for estimating the volume and volume fractions of the nasal structures in the goose (Anser anser domesticus) using computed tomography images

1. The conchae within the nasal cavity of poultry are important for water and energy conservation, but have not been experimentally evaluated. The aim of the present study was to determine the accuracy of volume and volume fraction estimates of the conchae, nasal septum and nasal cavity. 2. The nasal cavities of 7 adult goose heads were scanned using computed tomography (CT), with images sampled randomly at a 1/5 sampling fraction. Physical sections were obtained from the same samples, using an electric saw that had an adjustable section range, and provided 14 to 15 sections with a thickness of 2.5 mm. The section surface areas of the nasal cavity, nasal septum and conchae were estimated using the Cavalieri principle. Results obtained using the CT and physical section images were compared. Volumes and volume fractions obtained from the physical sections were accepted as the gold standard and differences in the CT images were determined. 3. Multiplication of the data obtained on the CT images with the deviation percentage of the physical sections produced normalised values. No differences were observed between the gold standard data and the CT images. While it was possible to normalise the obtained data using the gold standard values, the raw data could also be used for comparative studies because the deviations from normal would be similar for all groups. 4. Our study showed that the nasal structures could be estimated in vivo using CT images.

Macroanatomic, light, and electron microscopic examination of pecten oculi in the seagull (Larus canus): INCE et al.

The present study was conducted to determine macroanatomic characteristic as well as light and electron microscopic examination (SEM) of pecten oculi and totally 20 bulbus oculi belonging to 10 seagulls (Larus canus) were used. Pecten oculi formations consisted of 18 to 21 pleats and their shape looked like a snail. Apical length of the pleats forming pecten oculi were averagely measured as 5.77 ± 0.56 mm, retina‐dependent base length was 9.01 ± 1.35 mm and height was measured as 6.4 ± 0.62 mm. In pecten oculi formations which extend up to 1/3 of the bulbus oculi, two different vascular formations were determined according to thickness of the vessel diameter. Among these, vessels with larger diameters which are less than the others in count were classified as afferent and efferent vessels, smaller vessels which are greater in size were classified as capillaries. Furthermore, the granules which were observed intensely in apical side of the pleats of pecten oculi were observed to distribute randomly along the plica.