Early Development, Devel. Physiol., Dr. D. Penney




Table 2.06 - Some Human Heart Facts from a Cellular Point of View:

DNA:

  • Concentration highest at birth, decreases with growth.

  • At birth - 1/2 in muscle cells, 1/2 in fibroendothelial cell nuclei.

  • By childhood - 2/5 in muscle cells, 3/5 in fibroendothelial cell nuclei

  • Adult - less than 1/3 in myocytes, 2/3 in fibroendothelial cell nuclei

    Cell Numbers:

  • Myocyte nuclei double in LV after birth; also in RV but occurs a little later.

  • Myocyte numbers in human heart 2,000,000,000; at birth 7-9000,000,000, and in childhood 1- 2,000,000,000.

  • There are an equal number of fibroblasts at birth, later 4-6,000,000,000.

    Capillary Density:

  • 4,000 per mm2 in infants, 3,342 per mm2 in adults

  • Faster proliferation of capillaries relative to myocytes occurs during postnatal development

  • Mean intercapillary distance decreases from 31-18 um.



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