ArticlePDF Available

Structure and function of vulture pecten.

Authors:
S R Bawa
S R Bawa
S R Bawa
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Rakesh Yashroy at Home
Rakesh Yashroy
  • Home
Download full-text PDFDownload full-text PDF
Read full-text
Download citation

Abstract

Earlier name of journal was then 'Acta Anatomica'
Acta Anatomy 1974 vol 89 473-4
80.pdf
Content uploaded by Rakesh Yashroy
Author content
All content in this area was uploaded by Rakesh Yashroy
Content may be subject to copyright.
Acta Anatomy 1974 vol 89 473-4
80.pdf
Content uploaded by Rakesh Yashroy
Author content
All content in this area was uploaded by Rakesh Yashroy
Content may be subject to copyright.
... Their adventitial layer was well defined and has got surrounded in areolar connective tissue network wherein few melanocytes were also observed. The smaller melanin granules were there but its presence was showing the supportiveness toward performance of overall function of the pectin [14,[23][24][25]. ...
... Pectineal folds have been profoundly shown the varied density and shape of blood capillaries.The nucleated erythrocytes had evidence there and distinct distribution of leucocytes as to heterophils, monocytes and even thrombocyte were also been demonstrated. Erythrocytes at luminal component of pectineal capillary were commonly reported by researchers [9,23], but the other constituents of blood viz. heterophil, monocytes and thrombocyte were not reported earlier. ...
... The detection of pectineal capillaries has revealed [6,23], which were in similarity with present revelations wherein the luminal surface of pectineal blood capillaries had tightly interconnected endothelial cells with its substantial prominent nuclear region. The pericytes had also shown their existence which were surrounded by the thick basal lamina. ...
Gross, Histomorphological, Histochemical and Ultrastructural Studies of Pecten Oculi in Guinea Fowl (Numida Meleagris)
Article
Full-text available
  • Jun 2019
Pecten Oculi of Guinea fowl (Numida meleagris) was studied on their 18 eyes for gross, histological, histochemical and ultrastructural observations. The pecten oculi has 13 to 17 number of accordion (pectineal) folds. These accordion folds were initiated from cauda of optic nerve and travelled via fundus distally into the vitreous humour as an undulated pathway as snake. The shape of pecten oculi was not different than the water floating sail board. The maximum average length and height of pecten oculi was found on the tune of 3.378±0.061 mm and 5.913±0.074 mm respectively. Microscopically the pecten oculi showed an organization as the festoon of blood capillaries with their elastic, collagen and reticular fibers that were corresponding with the structure of spring diving board, which works after the Hook’s law. Melanocytes, melanosomes and melanin granules were observed in and around blood capillaries of pecten oculi. It has divided into three parts apex, middle one third and base. The highest concentration of melanin was observed in the apex. Histochemically the pecten oculi was shown very weak activity of acid and alkaline phosphatase. It had shown a strong activity of glycogen at optic nerve and collagen fibers of pectineal capillaries. Ultrastructurally, the nucleated erythrocytes were witnessed at luminal area of pectineal blood capillary with the tight intercellular endothelial junction. The primary and secondary lamellae were observed in the luminal region of pectineal capillary with pigment depositing globules. Pecten oculi of Guinea fowl has shown various anatomical features thereby it performs various functions as the organ of haemostatic utility, phagocytosis, providing source of energy to vitreous after the diffusion, protecting eye from ultraviolet sunlight radiation, supplementation of nutrition and provide oxygen to the retina to have visual acuity.
View
... Their adventitial layer was well defined and has got surrounded in areolar connective tissue network wherein few melanocytes were also observed. The smaller melanin granules were there but its presence was showing the supportiveness toward performance of overall function of the pectin [14,[23][24][25]. ...
... Pectineal folds have been profoundly shown the varied density and shape of blood capillaries.The nucleated erythrocytes had evidence there and distinct distribution of leucocytes as to heterophils, monocytes and even thrombocyte were also been demonstrated. Erythrocytes at luminal component of pectineal capillary were commonly reported by researchers [9,23], but the other constituents of blood viz. heterophil, monocytes and thrombocyte were not reported earlier. ...
... The detection of pectineal capillaries has revealed [6,23], which were in similarity with present revelations wherein the luminal surface of pectineal blood capillaries had tightly interconnected endothelial cells with its substantial prominent nuclear region. The pericytes had also shown their existence which were surrounded by the thick basal lamina. ...
Gross, Histomorphological, Histochemical and Ultrastructural Studies of Pecten Oculi in Guinea Fowl (Numida Meleagris)
Article
Full-text available
  • Jun 2019
Pecten Oculi of Gunia fowl (Numida meleagris) was studied for its gross, histological, histochemical and transmission electron microscopical (TEM) observations. A total of 18 eyes were studied which were collected from the identified meat shop located in the vicinity of City of Udaipur. The study revealed that dark black velvety pecten oculi has 13 to 17 number of accordion (pectineal) folds which initiated from cauda of optic nerve and travels via fundus distally into the vitreous humour travelled as an undulated natured pathway as snake. Macroscopically the shape of pecten oculi was not different than sail board. In gross study maximum average length and height of pecten oculi found 3.378 ± 0.061 mm and 5.913 ± 0.074 mm respectively. Histomorphologically the pecten oculi shows an organization as the festoon of blood capillaries with their elastic, collagen and reticular fibers which correspond with the structure of spring diving board. Its working principle is also getting matched with Hook’s law, how the diving spring board works. Melanocytes, melanosomes and melanin granules were observed in and around blood capillaries of pectin oculi. The highest concentration of melanin was observed in the apex. Histochemically the pecten oculi shows very weak activity of acid phosphatase and alkaline phosphatase. It shows a strong activity of glycogen at optic nerve and collagen fibers of pectineal capillaries. Transmission electron microscopically, the nucleated erythrocytes were witnessed at luminal area of pectineal blood capillary and the endothelium was elaborating tight intercellular junction. The primary and secondary lamellae were observed in the luminal region of pectineal capillary wherein pigment depositing globules were discovered. Pecten oculi of Guinea fowl (Numida meleagris) has performed various functions which are well established and also it identified as the organ of hemostatic function, support system to retina to get visual acuity, phagocytic, immunity and the source of energy for vitreous humour by way of diffusion.
View
... It also functions in maintaining the acid base balance and constant intraocular temperature (Brach, 1975(Brach, , 1977. Plenty of pigment cells are located there in pecten oculi which performs to perform as the functional ability while absorbing the heat and thereby it also functions as the organ of homeostasis (Bawa and Roy, 1974). ...
... The smaller melanin granules were there but its presence was showing the supportiveness towards overall function of the pecten. These findings were identical to the findings of Mann (1924) who was observed the pecten oculi without restrictions of species, Bawa and Roy (1974) The retinal epithelium was discovered after single cell layer wherein the melanin pigments were packed. The adventitial layer was also there as the supporting structure to epithelial layer, in combine that function as outer barrier for retina while supporting its function for capturing the image. ...
... The nucleated erythrocytes were had evidenced there but the distinct distribution of heterophils, monocytes and even thrombocyte 1067 were also been demonstrated. The detection of erythrocytes at luminal component of pectineal capillary was the common feature by researchers as Bawa and Roy (1974) in vulture and Onuk et al. (2013) in stork but the other constituents of blood viz. heterophil, monocytes and thrombocyte were not reported earlier. ...
SCIENTIFIC PERSPECTIVE ON MORPHOLOGICAL FEATURE OF PECTEN OCULI AND THEIR FUNCTIONAL PRINCIPLES ON APPARATUS OF VISION IN GUINEA FOWL (NUMIDA MELEAGRIS) BIRDS
Article
Full-text available
  • Apr 2019
The study was conducted on 18 eyes, which revealed that dark black velvety pecten oculi has 13 to 17 number of accordion (pectineal) folds. These accordion folds were initiated from cauda of optic nerve and travelled via fundus distally into the vitreous humour in the manner of undulated natured pathway of snake. Macroscopically the shape of pecten oculi was observed without much difference of the sail board. The maximum average length and height of pecten oculi was found on the tune of 3.378±0.061 mm and 5.913±0.074 mm respectively. Histomorphologically the pecten oculi showed an organization as the festoon of blood capillaries with their elastic, collagen and reticular fibers which correspond with the structure of spring diving board. Its working principle was also being matched with Hook’s law, how the diving spring board work. Melanocytes, melanosomes and melanin granules were observed in and around blood capillaries of pecten oculi. The highest concentration of melanin was observed in the apex. Histochemically the pecten oculi was shown very weak activity of acid phosphatase and alkaline phosphatase. It has shown a strong activity of glycogen at optic nerve and collagen fibers of pectineal capillaries. Ultrastructurally, the nucleated erythrocytes were witnessed at luminal area of pectineal blood capillary and the endothelium was elaborating tight intercellular junction. The primary and secondary lamellae were observed in the luminal region of pectineal capillary wherein pigment depositing globules were discovered. Pecten oculi of Guinea fowl (Numida meleagris) perform various functions, after which it is identified as the organ of haemostatic function, support system to retina to get visual acuity, phagocytic, immunity shield and the source of energy for vitreous humour by performing process of diffusion.
View
... It also functions in maintaining the acid base balance and constant intraocular temperature (Brach, 1975(Brach, , 1977. Plenty of pigment cells are located there in pecten oculi which performs to perform as the functional ability while absorbing the heat and thereby it also functions as the organ of homeostasis (Bawa and Roy, 1974). ...
... The smaller melanin granules were there but its presence was showing the supportiveness towards overall function of the pecten. These findings were identical to the findings of Mann (1924) who was observed the pecten oculi without restrictions of species, Bawa and Roy (1974) The retinal epithelium was discovered after single cell layer wherein the melanin pigments were packed. The adventitial layer was also there as the supporting structure to epithelial layer, in combine that function as outer barrier for retina while supporting its function for capturing the image. ...
... The nucleated erythrocytes were had evidenced there but the distinct distribution of heterophils, monocytes and even thrombocyte 1067 were also been demonstrated. The detection of erythrocytes at luminal component of pectineal capillary was the common feature by researchers as Bawa and Roy (1974) in vulture and Onuk et al. (2013) in stork but the other constituents of blood viz. heterophil, monocytes and thrombocyte were not reported earlier. ...
SCIENTIFIC PERSPECTIVE ON MORPHOLOGICAL FEATURE OF PECTEN OCULI AND THEIR FUNCTIONAL PRINCIPLES ON APPARATUS OF VISION IN GUINEA FOWL (NUMIDA MELEAGRIS) BIRDS.
Article
Full-text available
  • May 2019
The study was conducted on 18 eyes, which revealed that dark black velvety pecten oculi has 13 to 17 number of accordion (pectineal) folds. These accordion folds were initiated from cauda of optic nerve and travelled via fundus distally into the vitreous humour in the manner of undulated natured pathway of snake. Macroscopically the shape of pecten oculi was observed without much difference of the sail board. The maximum average length and height of pecten oculi was found on the tune of 3.378?0.061 mm and 5.913?0.074 mm respectively. Histomorphologically the pecten oculi showed an organization as the festoon of blood capillaries with their elastic, collagen and reticular fibers which correspond with the structure of spring diving board. Its working principle was also being matched with Hook?s law, how the diving spring board work. Melanocytes, melanosomes and melanin granules were observed in and around blood capillaries of pecten oculi. The highest concentration of melanin was observed in the apex. Histochemically the pecten oculi was shown very weak activity of acid phosphatase and alkaline phosphatase. It has shown a strong activity of glycogen at optic nerve and collagen fibers of pectineal capillaries. Ultrastructurally, the nucleated erythrocytes were witnessed at luminal area of pectineal blood capillary and the endothelium was elaborating tight intercellular junction. The primary and secondary lamellae were observed in the luminal region of pectineal capillary wherein pigment depositing globules were discovered. Pecten oculi of Guinea fowl (Numida meleagris) perform various functions, after which it is identified as the organ of haemostatic function, support system to retina to get visual acuity, phagocytic, immunity shield and the source of energy for vitreous humour by performing process of diffusion.
View
... The vitreous body of raptors is typically rather rigid and typically does not touch the central retinal surrounding a vascular pecten oculi to which it is attached. The pecten oculi of raptors is of the pleated type (Yilmaz et al. 2017, Braekevelt 1991, 1993a, Gultiken et al. 2012, Martin Roldan and Blanquez Layunta 1979, Kiama et al. 1994, 1998, Murphy and Dubielzig 1993, Smith et al. 1996, Bawa and YashRoy 1974, Williams 2012, Seaman and Himelfarb 1963, Tucker 1975, Rahman et al. 2010).). The optic nerve sits posterior to the pecten oculi and is not visible in normal eyes (although note that with pecten tears and optic neuritis, the margins may become visible), although a small amount of white sclera is commonly visualized (Fig. 20.42a). ...
Ophthalmology of Accipitrimorphae, Strigidae, and Falconidae: Hawks, Eagles, Vultures, Owls, Falcons, and Relatives
Chapter
  • Apr 2022
Birds of prey, also collectively known as raptors, consist of the Falconiformes (falcons and caracaras), Accipitriformes (eagles, buzzards, hawks, kites, and Old World vultures), Cathartiformes (New World vultures), Cariamiformes (seriemas), and Strigiformes (true owls Strigidae, and barn owls Tytonidae) (del Hoyo et al. 1999; Jarvis et al. 2014; McClure et al. 2019). Although grouped together as key apex predators, raptors are phylogenetically heterogenous assimilation with many morphological and ecological differences. Perhaps a most obvious example is revealed in their activity patterns, where most raptors are considered diurnal, except the owls, which are considered nocturnal, a habit they share with two other avian orders for which we have genome sequences (Caprimulgiformes and Apterygiformes) (Martin 1990; Mikkola 1983; Martin 2017; Zhan et al. 2013). However, the ferruginous pygmy owl Glaucidium brasilianum maintains some activity during the day and the snowy owl Bubo scandiacus hunts during the daytime, the American barn owl Tyto furcate is most active in twilight, the burrowing owl Athene cunicularia is cathemeral, and the stripped owl Asio clamator is crepuscular and nocturnal (del Hoyo et al. 1999; Martins and Egler 1990; Motta-Junior 2006; Motta-Junior et al. 2004; Sarasola and Santillan 2014; Martin 1986). Overall, as a group, owls actually exhibit a broad range of activity patterns and habitats (Bowmaker and Martin 1978; Braga 2006). Additionally, nearly one-third of falconiform species, as well as some accipitriformes species, maintain activity during the crepuscular period (Mitkus et al. 2018).
View
... Diurnal raptors have thicker retinae than other birds, including owls ( Fig. 5; e.g. [43][44][45][46][47]). For example, the central retina of the Short-toed snake eagle can be as thick as 630 μm [46,48], significantly thicker than that of the Eurasian eagle-owl (Bubo bubo; 360 μm; [48]) or non-raptorial species such as the chicken (Gallus gallus; < 200 μm; [49]), or Turquoise-fronted parrot (Amazona aestiva; 280 μm; [50]). ...
Visual adaptations of diurnal and nocturnal raptors
Article
Full-text available
  • Jul 2020
Raptors have always fascinated mankind, owls for their highly sensitive vision, and eagles for their high visual acuity. We summarize what is presently known about the eyes as well as the visual abilities of these birds, and point out knowledge gaps. We discuss visual fields, eye movements, accommodation, ocular media transmittance, spectral sensitivity, retinal anatomy and what is known about visual pathways. The specific adaptations of owls to dim-light vision include large corneal diameters compared to axial (and focal) length, a rod-dominated retina and low spatial and temporal resolution of vision. Adaptations of diurnal raptors to high acuity vision in bright light include rod- and double cone-free foveae, high cone and retinal ganglion cell densities and high temporal resolution. We point out that more studies, preferably using behavioural and non-invasive methods, are desirable.
View
... This result would corroborate the suggestion that the pecten has a sunlight absorption function 7 which is especially important in birds that fly. Moreover, pigmented stromal cells have been linked to the following functions: detoxification of the retina 33 because of abundant peroxisomes; a role in the conversion of light to metabolic energy 34 ; the regulation of eye temperature 35 ; and the flow of oxygen and carbon dioxide between the capillaries and the vitreous body. 36 On the other hand, the origin of pigmented stromal cells is controversial. ...
A comparative ultrastructural study of the pecten oculi in adult, juvenile, and nestling yellow‐legged gulls, Larus michahellis (Naumann, 1840)
Article
  • Jul 2019
This study aimed at examining the histological structure of the pecten oculi in the adult yellow‐legged gull, Larus michahellis, and at two moments of postnatal development: during the posthatch (nestling) and juvenile periods. Particular attention was paid to differences in the diameter of vessels, the thickness of the basement membrane, and ultrastructural features of endothelial and pigmented stromal cells. Capillary endothelial cells displayed numerous microvillous‐like folds projecting from their internal and external surfaces. Intercellular spaces between capillaries were occupied by pigmented stromal cells. The ultrastructure of pecten oculi underwent noticeable changes during postnatal development. The examination of the capillaries in nestlings, juveniles, and adults revealed that the formation process of vessels and pigmented stromal cells did not complete itself in the posthaching phase. The prominent feature of endothelial cells of capillaries in nestlings was that the microvilli were longer than in juvenile and adult cells, and the capillary lumen was therefore reduced. In this sense, their pigmented stromal cells showed fewer melanosomes, lacked intercellular spaces, and cellular junctions could still be observed. These results provide evidence that the pecten oculi during the posthatching phase maintains immature morphological features consistent with a role of pigmented stromal cells in the blood‐retina barrier.
View
Validierung von OCT - Befunden am hinteren Augensegment von Greifvögeln mittels Konfokalmikroskopie
Thesis
Full-text available
  • Feb 2020
Optical coherence tomography (OCT) has proven to be an indispensable tool in human ophthalmology for the diagnosis of eye diseases and is regarded as the gold standard for the detection of retinopathies. In recent years, the use of OCT gained increasing popularity in veterinary medicine. Especially in birds, where the eye is the most important sensory organ, the use of this technique is of great diagnostic and experimental interest. The aim of the study was to validate OCT images of the retina in avian ophthalmology. To achieve this, a point-to-point measurement and comparison of OCT with histology was performed for the first time. 50 eyes of 27 birds of prey were included in the OCT examination. The patients were wild birds of prey who were admitted to an avian clinic from November 2017 to December 2018. The OCT images were taken with a SPECTRALIS® HRA+OCT (Heidelberg Engineering, Heidelberg, Germany) and measured with the Heidelberg Eye Explorer 1.10.2.0 software. The animals were euthanized due to an infaust prognosis and for reasons of animal welfare. In those cases the eyes were removed for histological examination. For histological examination, the retina was immunohistochemically labelled and confocally imaged with an OLYMPUS BX51WI microscope and an OLYMPUS BX-DSU (Olympus; Tokyo, Japan) confocal microscope. The images were evaluated with the Stereo Investigator Software 11.02.01 (MBF Science, Williston, USA). In both OCT and confocal microscopy, the depth of the foveae and the layer thicknesses of the Internal Limiting Membrane + Nerve Fiber Layer + Ganglion Cell Layer, the Inner Plexiform Layer, the Inner Nuclear Layer + Outer Plexiform Layer + Outer Nuclear Layer + External Limiting Membrane, the Inner Segment of the cone layer as well as the total thickness of the retina (Internal Limiting Membrane to Inner Segment) were measured. The fovea centralis served as an orientation point in both images. The OCT examination was performed on the awake patient without sedation. In individual cases, pain medication with butorphanol (4mg/kg KM) was administered. To determine the reproducibility of the OCT, two images were measured, resulting in excellent reproducibility for OCT (total retinal thickness 1.3%). To compare OCT with histology, a total of 319 measurements from 30 healthy eyes of four different bird species were obtained. The comparison showed a low agreement between the two methods. The main reason causing this poor agreement is the fundamentally different technique of both methods. OCT represents the optical properties of cellular structures, whereas immunohistochemistry visualizes individually labelled cells. The relationship between individual cellular structures and their optical properties is largely unknown and further studies are necessary. The birds eye also has numerous special features compared to the human eye. Despite the low agreement of the values achieved by OCT and histology, the visible changes and trends in OCT were reliable and corresponded with histological findings. OCT provides a safe and reliable method to detect pathological abnormalities. This study was the first to show a follow up examination in three forest owls (Strix aluco) and one buzzard (Buteo buteo) that demonstrated the benefits of OCT for monitoring and investigating retinal alterations. Based on the results, optical coherence tomography is an important diagnostic tool in avian ophthalmology. It enables the reliable detection of abnormalities, an improved understanding of pathological processes and their trends over a period, as well as a better evaluation of prognoses. It is necessary to describe further pathological alterations visible in OCT in future studies, especially their impact and importance for visual acuity. In the future, more abnormalities should be compared with histology in order to understand ultrastructural mechanisms and their relevance for vision. For this purpose, the study provides a basic protocol for the immunohistochemical labelling of the avian retina in diurnal and nocturnal birds. Future studies should also include OCT-investigations of infectious diseases and their ocular manifestations (e.g. West-Nile-Virus or Bornavirus). Cases of light-induced glaucoma as a relevant animal welfare subject could also be investigated by OCT in further studies.
View
The Avian Eye and its Adaptations
Chapter
  • Jan 1977
The avian eye is considered to be “supreme amongst all living creatures” and capable of attaining “an order of excellence unmatched in any other species not excepting man” (Duke-Elder, 1958). Many structural and functional adaptations have become involved in the perfection of visual processes in birds which, according to Pumphrey (1948a) represent the culmination of phylogenetic development toward diurnal vision. This chapter is concerned with several of these adaptations, the most obvious of which are the oil droplet inclusions and glycogen deposits within their photoreceptors, the well-developed areae and foveae within their retina and the highly vascularized pecten within their vitreous body. A detailed description of the avian eye is not intended; excellent sources are available on this subject: Wood (1914), Slonaker (1918), Franz (1934), Walls (1942), Rochon-Duvigneaud (1943), Polyak (1957), Duke-Elder (1958), and Hodges (1974)
View
Comparative morphological and histological study of the pecten oculi in two species of Iraqi birds (Falco tinnunculus L. and Streptopelia decaocto F.)
Article
  • Mar 2015
Study showed structure of pecten oculi in the Kestrel Falco tinnunculus L.was Pleated type and consisted of 17 folds which were thick. While in the Collared Dove Streptopelia decaocto F. was Vaned type and consisted of 13 folds and it described thin. The illustrated histological study of pecten oculi folds in the Kestrel and the Collared Dove was composed of large number of capillaries, large blood vessels and pigment cells which were few in Kestrel compare with the Collared Dove. The bridge in the Kestrel and the Collared Dove pecten oculi was consisted of connective tissue, many pigment cells, and contains on little capillaries and it linked the membrane to the internal limiting membrane of the retina in the Kestrel. Key words: birds, pecten oculi, morphology, histology
View
ResearchGate has not been able to resolve any references for this publication.