ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1988.tb01509.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1988.tb01510.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1988.tb01511.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1988.tb01512.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1988.tb01513.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1988.tb01514.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1988.tb01515.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryThe obliteration processes of the ductus arteriosus of equine foetuses and newborn foals were studied morphometrically and histologically. The length, internal and external diameters and circumference of the ductus in equine foetuses increased progressively and linearly up to 310 days with advancing foetal age, but the values, especially the internal diameter, decreased from 320 to 330 days. After birth, the ductal measurements decreased gradually and ductal closure was found in three of 14 foals examined on the first daypost partum, in two of six on the second day and in nine of nine on the third day or later, suggesting that the ductus arteriosus closes physiologically within three days after birth. Microscopical findings of the ductus arteriosus were characterised by the rearrangement of smooth muscle cells in the inner media and intimai thickening in foetuses, and by the central displacement of the intima in newborn foals. It was concluded that the ductus arteriosus begins to undergo preparatory modifications during intrauterine life, when the vessel is still functional, and that the most significant starting point of change in the obliteration processes is the rearrangement of smooth muscle cells in the inner media, which occurs during pre‐ and post natal lif

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1988.tb01516.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryHearts from 24 foals were studied; 10 were from foetuses ranging in gestational age from 230 to 322 days and 14 were from newborn and young foals aged between birth and 17 days. The foramen ovale and associated vena caval and atrial structures were examined by scanning electron microscopy. Additional observations were made by light and transmission electron microscopy. A tube‐like flap of tissue was observed, extending from the aperture in the caudal vena cava to the lumen of the left atrium. In the younger foetuses, the distal end of this tube was covered with a thread‐like network of tissue. In animals nearer to term, the network was replaced by distal fenestrations. Protrusions were seen on the rim of the opening of the tube as it entered the atrium. The role that these may play, together with the significance of cardiac muscle and non‐elastic connective tissue in the wall of the tube, were discussed with respect to possible mechanisms of closure of the foramen

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1988.tb01517.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1988.tb01518.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY