The ___________ is not an organ of the urinary system.

A. The endometrium is the inner lining of the uterus that supports the embryo after implantation, but it does not provide direct fetal nutrition or secrete hormones for fetal development.

B. The placenta is the organ that provides fetal nutrition, gas exchange, and waste removal. It also secretes hormones such as human chorionic gonadotropin (hCG), progesterone, and estrogen, which are essential for maintaining pregnancy and supporting fetal development.

C. The blastocyst is the early stage of the embryo that implants into the endometrium, but it does not provide fetal nutrition or secrete pregnancy-regulating hormones.

D. The myometrium is the muscular layer of the uterus responsible for contractions during labor, but it does not provide fetal nutrition or secrete hormones.

A. Tubuloglomerular feedback involves the macula densa sensing changes in sodium chloride concentration and adjusting the glomerular filtration rate (GFR) via the juxtaglomerular apparatus.

B. Renal autoregulation includes mechanisms like the myogenic mechanism and tubuloglomerular feedback that maintain stable GFR despite blood pressure changes. This option is too broad and not specific to the mechanism described.

C. The myogenic mechanism refers to the smooth muscle's tendency to contract when stretched, helping to stabilize GFR by adjusting the diameter of the afferent arterioles. This is the correct answer.

D. Sympathetic control influences renal blood flow and GFR through hormonal and nervous system regulation, but it is not the specific mechanism described in the question.