What to check on the third day of menstruation

In fact, most women know that if they go to the hospital for a gynecological examination, they actually need to undergo a uterine B-ultrasound. However, because people don’t know much about B-ultrasound, they don’t know when is the most appropriate time to conduct the examination. Generally there is no time limit. So, do you know what to check during B-ultrasound on the third day of menstruation? In fact, at this time, the condition of the endometrium can be seen.

The endometrium (endometrium, uterineendome-trium) refers to the layer that makes up the inner wall of the mammalian uterus. It responds to both estrogen and progesterone and can therefore change significantly with the sexual cycle (estrus cycle, menstrual cycle).

The endometrium is divided into three layers: the compact layer, the spongy layer, and the basal layer. The dense layer and spongy layer of the 2/3 endometrial surface are collectively called the functional layer, which are shed periodically under the influence of ovarian sex hormones. The basal layer is the 1/3 of the endometrium close to the myometrium. It is not affected by ovarian hormones and does not undergo cyclical changes.

Programmed cell death (PCD), also known as apoptosis. PCD occurs in many tissues and organs including the reproductive tract. Animal experiments have observed that PCD occurs in organs such as the uterus, ovaries, fallopian tubes, testicles, and prostate. Early light microscopy and electron microscopy studies have shown that apoptotic bodies also exist in the human endometrium. When ladder-band DNA was detected through agarose gel electrophoresis and DNA chromosome technology, it was found that DNA breakage with PCD characteristics could be seen in the human endometrium in the early hyperplasia period (6-10 days), secretory period (25-28 days) and menstrual period (1-5 days); while no DNA breakage occurred in the late hyperplasia period (11-14 days), early secretory period (15-20 days) and mid-secretory period (21-24 days). The main thing is large molecular DNA. The cyclical occurrence of PCD suggests that it plays an important regulatory role in women's menstrual cycle.

The mechanism of PCD in the endometrium is still unclear, but it is related to the cyclical changes in ovarian hormones. The estrogen and progesterone receptors of the endometrium act as a transcription factor to regulate the expression of genes related to estrogen and progesterone, thereby causing proliferation and secretory changes in the endometrium. At the same time, some polypeptide growth factors and their receptors synthesized by the uterus, such as EGF, PDGF, IGF-1, IGF-2, etc., may be the mediators of the effects of estrogen, promoting cell proliferation and differentiation. Through immunocytochemistry technology, it was found that the human uterus produces cell death inhibitory factors such as BCL-2 as early as the embryonic period. The expression of BCL-2 in adult endometrium is mainly in interstitial cells and changes periodically, reaching a peak in the late proliferative stage, decreasing in the early secretory stage, and disappearing in the late secretory stage and during menstruation. Therefore, it is speculated that the disappearance of BCL-2 in the late secretory phase and menstrual period is closely related to the death of endometrial cells and the occurrence of menstruation.

Endometrial cytokines

⒈ Epidermal growth factor and its receptor: Epidermal growth factor (EGF) is mainly distributed in the uterine cavity epithelium, glandular epithelium and stromal cells, and shows periodic changes. Its physiological effects are: 1. Stimulating the proliferation of endometrial glandular epithelium and stroma, and causing stroma differentiation under the synergistic effect of progesterone; 2. Acting on receptors on the cell surface, rapidly stimulating tyrosine phosphorylation, and promoting the release of endometrial PGE2.

⒉ Platelet-derived growth factor: Platelet-derived growth factor is mainly derived from endometrial stromal cells. It can stimulate the proliferation of interstitial cells themselves or adjacent epithelial cells, thus having autocrine and paracrine effects. At the same time, PDGF can enhance the cell proliferation effect of EGF.

⒊ Insulin-like growth factor: Through in situ hybridization technology, it was found that the mRNA of insulin-like hybrid factors (IGF-1, IGF-2) is widely distributed in the endometrial epithelium, stromal and myometrial cells, and its synthesis is regulated by estrogen rather than progesterone.