. Analysis of development. Embryology; Embryology. Ontogeny of Endocrine Correlation _ _o _o .2 - e 1-1 »j c V r^ V iu tj H c B c 3 C rn C fa S 'o G w < Q M O 11 JS 6 .^8 581 in pig fetuses of 46 to 50 days of age, thy- roxine and di-iodotyrosine are first detected a little later, , in 52-day-old fetuses (Ran- kin, '41). The stage at which the amount of organic iodine compounds becomes promi- nent is apparently correlated with the ap- pearance of acini and colloid. Moreover, the first appearance of organic iodine is accom-. Fig. 208. Section of thyroid of a normal 11-day chick embryo sh
. Analysis of development. Embryology; Embryology. Ontogeny of Endocrine Correlation _ _o _o .2 - e 1-1 »j c V r^ V iu tj H c B c 3 C rn C fa S 'o G w < Q M O 11 JS 6 .^8 581 in pig fetuses of 46 to 50 days of age, thy- roxine and di-iodotyrosine are first detected a little later, , in 52-day-old fetuses (Ran- kin, '41). The stage at which the amount of organic iodine compounds becomes promi- nent is apparently correlated with the ap- pearance of acini and colloid. Moreover, the first appearance of organic iodine is accom-. Fig. 208. Section of thyroid of a normal 11-day chick embryo showing marked sinusoidal vascular- ity at time of rapid formation of discrete follicles with colloid. Carotid artery to the left. Initial X 135. panied by marked increase in vascularity of the gland (cf. Fig. 208). In the bovine fetus from 53 days to term there is a progressive increase in thyroxine-like compounds of iodine and non-thyroxine iodine. These io- dine fractions increase proportionately with increasing fetal size and age (Wolff et al., '49). The rate at which each of these sub- stances accumulates in the fetal thyroid shows an exponential relationship to body weight and length as well as to age of the fetus. Moreover, the increase in their ac- cumulation cannot be accounted for solely on the basis of increase in thyroid growth, since the percentage growth rate of the thyroid declines steadily with increasing age. Apparently as the growth rate declines with age there is a progressive increase in the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Willier, Benjamin H. (Benjamin Harrison), b. 1890. Philadelphia, Saunders
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Keywords: ., bookcentury1900, bookpublisherphiladelphi, booksubjectembryology
