Question

1. "compare the fate of the various reproductive tissues under the influence of testosterone or estrogen."

2. "Describe the events of lactation including roles of hormones in milk production and release."

Answer 1

1. Compare the fate of the various reproductive tissues under the influence of testosterone or estrogen?

The fate of reproductive tissues depend on the level of testosterone hormone. It is primarily released from male gonads. The undeveloped reproductive tissues are differentiated into male sexual organs under the influence of testosterone and these tissues develops into female reproductive tissues when testosterone is absent. Androgen is the major s@x hormone, synthesized in the testes and the ovaries which regulates the maintenance of male characteristics in vertebrates by binding to androgen receptors. It plays important role in development of both embryological primary s@xual characteristics and secondary s@x characteristics at puberty. Testosterone is the major male androgen but it also present in females at lower level and also acts as the precursor for estrogen, the major female s@x hormone. Estrogens is essential for female fertility because it is responsible for maturation of the v@gina, uterus, ovarian function includes maturation of ovarian follicles and regulate gonadotropin secretion.

During embryonic development, the gonads that are located inside the intermediate mesoderm is capable of becoming either ovaries or testes. The Y choromosome especially the SRY influence the development of the male phenotype by transforming the bipotential gonad into testes. Androgens play crucial role in masculinization of the developing male fetus and also suport sertoli cells for sperm production.

Tissues that produce a p@nis in males differentiated as cl!toris in females. The tissue that will become the scr0tum in male is destined to be labia in female and Hence, they are homologous structures.

2. Describe the events of lactation including roles of hormones in milk production and release.?

Lactation is a hallmark feature of female mammals and the process by which the mammary glands to begin producing milk during the postpartum is called lactation. Prolactin, secreted by pituitary gland plays central role in establishmen tof milk supply and for the transport of maternal micronutrients for breast milk. Oxytocin also plays role in the lactation process. Prolactin level found to increase to about 10–20 times to prepare breasts anatomically for the secretion of milk. The inhibition of prolactin secretion is liften once the placenta is expelled and the milk production commences.

A neuroendocrine reflex is initiated when the sensory nerve fibers in the areola triggered by infant suckling. This releases the hormone called  oxytocin to promote the squeezing of myoepithelial cells and hence the secretion of milk from the alveoli into the lactiferous ducts and further into lactiferous sinuses which is then eventually let down throught the nipple pores. Both prolactina nd oxytocin regulate via the the positive feedback loop of the let-down reflex.