Morphologic stages of the equine embryo proper on days 17 to 40 after ovulation

Acker, Denise A.; Curran, Sandra; Bersu, Edward T.; Ginther, O.J.

doi:10.2460/ajvr.2001.62.1358

Cited by 21 publications

(23 citation statements)

References 10 publications

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“…Previously, Franciolli et al () applied this technique on the same material to describe the overall development of the main organ system. Other studies in horses have used other methods to determine embryonic age, including Acker et al (); however, these authors used small horses (ponies). For other large and precocial mammals, Morini () also reported the importance of crown‐rump length in the buffalo for determining the age of embryos and fetuses, and Assis Neto et al () referred to morphological characteristics in cattle for age determination.…”

Section: Discussionmentioning

confidence: 99%

Prenatal Development of the Digestive System in the Horse

Rodrigues

Carvalho

Franciolli

et al. 2014

The Anatomical Record

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Since the horse has a highly precocial reproductive strategy, most organs are functionally well developed at birth and thus, embryonic and fetal life is interesting. Data on the development of important organs are very limited. Here, we detailed macroscopically and histologically the equine digestive system, focusing on the first third of gestation. At 21 days, the oral cavity was an empty space, and the liver contained proliferating endodermal cells. At 25 days, a fusiform stomach and the pancreatic bud were present. At 28 days, a small tongue and the esophagus occurred. At 30 days, primary and secondary palates were developed, the liver contained cords of hepatocytes, and the pancreas was triangular. At 40 days, crypts had formed in the intestinal loops, cell differentiation was observed in the hepatic parenchyma, and the pancreas was elongated. Pancreatic acini and islets were observed in fetuses of 50 days and intestines were highly convoluted. Three segments of the pharynx were distinguishable at 75 days. At 105 days, the intestinal villi were wide with round tips; especially, the liver, stomach, and oral cavity showed key steps of anatomical and cellular differentiation in early fetuses, whereas other areas, such as pancreas or pharynx were still immature in the investigated phase. Pluripotency analysis using Oct4 showed initial intense staining in all of the digestive system tissues and a later decreased becoming restricted to specific cell layers. In conclusion, our data may contribute to perform a chronological reference of developmental events for approaches predicting pregnancy disorders in horses.

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Section: Discussionmentioning

confidence: 99%

Prenatal Development of the Digestive System in the Horse

Rodrigues

Carvalho

Franciolli

et al. 2014

The Anatomical Record

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“…Interestingly, as also noted by Acker et al ., equine embryos reached the various developmental milestones defining the Carnegie stages (Table ) at a younger gestational age than human embryos, despite the longer total gestation time of the horse . Even compared with other precocial species, such as pigs and sheep, equine embryos reach the Carnegie stages at a smaller percentage of the total gestational length . Embryo sizes (crown–rump length) were very similar to those of human embryos at equivalent Carnegie stages.…”

Section: Discussionmentioning

confidence: 87%

“…Using MRM instead of light microscopy, the staging is not as exact, but it is possible to estimate the embryonic stages by comparing the external form of the body and the limbs, as has been described also for ultrasound‐based staging . Interestingly, as also noted by Acker et al ., equine embryos reached the various developmental milestones defining the Carnegie stages (Table ) at a younger gestational age than human embryos, despite the longer total gestation time of the horse . Even compared with other precocial species, such as pigs and sheep, equine embryos reach the Carnegie stages at a smaller percentage of the total gestational length .…”

Section: Discussionmentioning

confidence: 98%

“…The crown-rump length of all conceptuses was measured on calibrated sagittal photographs using Fiji software. All embryos were staged according to the Carnegie staging criteria for human embryos, modified by O'Rahilly and Müller in 1987 and adapted for the horse by Acker et al [5,11]. Prior to MRM, the conceptuses were immersed in MRI-invisible medium (Fomblin) d and degassed in a vacuum for 20 min to remove any air bubbles.…”

Section: Methodsmentioning

confidence: 99%

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Magnetic resonance microscopy atlas of equine embryonic development

Jenner

Närväinen

Ruijter-Villani

et al. 2013

Equine Veterinary Journal

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“…6) emergen en una dirección cráneo -caudal durante la ontogenia (Grevellec & Tucker, 2010). El primer arco faríngeo se observa al día 17 de gestación en porcinos; al día 18 en ovinos (Orzag, 1985) y en equinos (Acker et al, 2001), y en el humano a partir del día 24 son evidenciables.…”

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Desarrollo de Cara y Cuello en Vertebrados

2012

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RESUMEN: El desarrollo embrionario de las regiones facial, del cuello, cavidades nasales y oral en conjunto con las glándulas asociadas, involucra el crecimiento y fusión tridimensional de múltiples procesos. Existe participación de elementos derivados de las 3 capas embrionarias locales y adicionalmente de células derivas de la cresta neural, procedentes de los rombómeros vecinos. Estas últimas se ven involucradas en la formación del esqueleto local, entre otras estructuras. El estudio evolutivo desde los vertebrados sin mandíbula nos enseña como se expresan los genes Hox en las diferentes especies, y como esto determina la formación de diferentes estructuras. En la siguiente revisión contemplamos algunos aspectos morfológicos, moleculares y evolutivos básicos del desarrollo facial y cervical, con énfasis en mamíferos con un epílogo referente a las malformaciones de la región en humanos.PALABRAS CLAVES: Cara; Cuello; Arcos faríngeos; Crestas neurales; Malformaciones.Desarrollo inicial de la región cefálica y del cuello. La región craneal de los vertebrados consta de 3 elementos principales que fusionados forman una estructura armoniosa. El elemento más antiguo en la filogenia es el viscerocráneo o esplacnocráneo identificado desde los protocordados, se compone de una serie de arcos branquiales o faríngeos asociados a las regiónes oral y faríngea; está compuesto de ectomesénquima derivado de la cresta neural. El condrocráneo o neurocráneo rodea y da soporte al encéfalo en conjunto con los principales órganos de los sentidos, está compuesto por cartílago o hueso endocondral. El tercer elemento es el dermatocráneo que constituye el "envoltorio" externo del cráneo en la mayor parte de los vertebrados, se compone de huesos dérmicos.El estomodeo o cavidad oral primitiva en conjunto con la faringe embrionaria, que corresponde a la región cefálica del intestino anterior, se relacionan con el desarrollo del esplacnocráneo. Durante las etapas iniciales del desarrollo de los cordados las paredes de la faringe desarrollan hendiduras, que en muchos cordados primitivos constituyen aberturas a través de las cuales se podían alimentar mediante un flujo unidireccional de agua, que entra por la cavidad oral y sale a través de éstas. En peces y anfibios estas hendiduras se asociaron a branquias (Fig. 1), en la cuales existe un flujo sanguíneo a través de capilares que permiten el intercambio respiratorio. En los vertebrados terrestres estas hendiduras no se abren y por lo tanto no constituyen ningún derivado del adulto, sino que formarán la región del cuello. Los elementos esqueléticos de los arcos faríngeos son derivados exclusivamente del ectomesénquima procedente de las crestas neurales, no del mesodermo. Las células de la cresta neural al dejar su localización inicial, próxima al tubo neural, contribuyen en la formación del mesénquima que se diferenciará en células nerviosas craneales, hueso y cartíla-go entre otras estructuras. Sólo los vertebrados poseen estas células, sin embargo su origen es incierto. Al parecer evolucio...

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Morphologic stages of the equine embryo proper on days 17 to 40 after ovulation

Abstract: No embryologic structures or changes were found that could be considered unique to equine embryos on days 17 to 40 after ovulation.

Cited by 21 publications

References 10 publications

Prenatal Development of the Digestive System in the Horse

Prenatal Development of the Digestive System in the Horse

Magnetic resonance microscopy atlas of equine embryonic development

Desarrollo de Cara y Cuello en Vertebrados

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