The Epididymis: Embryology, Structure, Function And Its Role In Fertilization And Infertility

Abstract

Embryology is a branch of science concerned with the morphological aspects of organismal development. The genomic and molecular revolution of the second half of the 20th century, together with the classic descriptive aspects of this science have allowed greater integration in our understanding of many developmental events. Through such integration, modern embryology seeks to provide practical knowledge that can be applied to assisted reproduction, stem cell therapy, birth defects, fetal surgery and other fields. This book focuses on human embryology and aims to provide an up-to-date source of information on a variety of selected topics. The book consists of nine chapters organized into three sections, namely: 1) gametes and infertility, 2) implantation, placentation and early development, and 3) perspectives in embryology. The contents of this book should be of interest to biology and medical students, clinical embryologists, laboratory researchers, obstetricians and urologists, developmental biologists, molecular geneticists and anyone who wishes to know more about recent advances in human development.

The Expression Patterns of Connexin Isoforms in the Rat Caput Epididymis During Postnatal Development

“…However, the number of narrow cells in the total epithelial cell population increases along the epididymis from 3% in the initial segment to 6% in the corpus epididymis (Arrotéia et al, 2012). In addition, each cell type in the epididymal epithelium has different roles that influence overall epididymal functions.…”

“…During embryonic development, under the influence of androgens secreted from the male gonad, the Wolffian ducts develop into a number of male reproductive organs, such as the epididymis, vas deferens, and seminal vesicles (Hannema and Hughes, 2007). In general, the differentiation of epididymal epithelial cells appears in two developmental phases during postnatal development a first phase in the early neonatal period, in which halo cells appear from undifferentiated cells, and a second phase, in which there is a sequential differentiation of other cell types until adulthood (Arrotéia et al, 2012). It is believed that a number of lumicrine factors produced by the testis, such as androgens, growth factors, and other secretory molecules, play important roles in the differentiation of the epithelium (Hinton et al, 2011).…”

“…Each epididymal segment is confined by connective tissue septa to functionally separate the epididymal regions (Cornwall, 2009). The epithelium of the epididymis is composed of several cell types, including principal, basal, apical, narrow, clear, and halo cells (Arrotéia et al, 2012). Each region of the epididymis has a different cellular organization with distinct cell populations, although the principal cell is the most abundant cell type throughout the entire epididymal duct (Arrotéia et al, 2012).…”

“…The epithelium of the epididymis is composed of several cell types, including principal, basal, apical, narrow, clear, and halo cells (Arrotéia et al, 2012). Each region of the epididymis has a different cellular organization with distinct cell populations, although the principal cell is the most abundant cell type throughout the entire epididymal duct (Arrotéia et al, 2012). For example, the number of principal cells decreases from 80% of the total epithelial cell population in the initial segment to 65% in the cauda epididymis (Robaire and Hermo, 1988).…”

Differential Expression of Multiple Connexins in Rat Corpus and Cauda Epididymis at Various Postnatal Stages

“…These Cxs include Cx26, Cx30.3,Cx31,Cx31.1,Cx32,Cx37,Cx40,Cx43,and Cx45. Comparison analyses of Cx genes expression between the head and tail part of the epididymis from 7 to 91 days of postnatal age conducted by Dufresne et al (2003) demonstrated segmental-specific and postnatal age-differentiated expression patterns of Cx genes in the epididymis. The epididymis is divided into an initial segment (IS), caput epididymis (head), corpus epididymis (body), and cauda epididymis (tail) based on morphological and functional aspects (Arrotéia et al, 2012). Because the head of the epididymis used in Dufresne's research includes the IS, caput epididymis, and corpus epididymis, it is difficult to determine whether their findings truly represent segmentspecific expression of Cx genes.…”