Tag: reproductive system of human

If the ovum fails to get fertilised, then corpus luteum (source of progesterone and estrogen) will disintegrate resulting in a decrease in the level of progesterone and estrogen. Thus, the endometrial lining of the uterus sloughs off and menstruation begins, marking a new cycle.

LH is secreted by anterior pituitary which inhibits secretion of FSH, stimulate maturation and rupture of Graafian follicle and release of ovum. LH also stimulates the formation of corpus luteum (the luteal/secretory phase; days 15-28) from ovulated Graafian follicle which in turn secretes estrogens and progesterone. In absence of implantation, progesterone and estrogens exerts negative feedback control over the anterior pituitary’s secretion of LH and causes degeneration of corpus luteum in the ovary. The lower progesterone level, as caused by disintegration of corpus luteum, results in disintegration of endometrium thereby initiating the next menstrual cycle. Thus, corpus luteum activity is under the regulation of estrogen and progesterone via negative feedback control. LTH (luteotropic hormone/prolactin) is secreted by the anterior pituitary gland and targets mammary gland to stimulate breast development and milk production after baby birth. Estrogens serves to stimulate the growth of the uterus and the vagina, is necessary for egg maturation as well as for the development of the secondary sex characteristics in females. Thus, the correct answer is A. 

• LH and FSH are pituitary hormones. 
• These hormones are essential for the growth of follicle from day 1 to day 15 of the menstrual cycle.
• On the 15th day, high level of LH secretion ( known as LH surge ) causes release of the ovum from Graafian follicle.
• The release of ovum is absolutely essential for having a baby in normal adult females.

The reproductive cells contain only half the number of chromosomes as compared to the normal body cells of an organism. The human sperm and egg have 23 chromosomes each. So when they fuse together, the zygote formed has 23+23=46 chromosomes. So the required ratio is 46 : 23, i.e., 2 : 1.

In the female reproductive system, the perineum is the area that lies between the vaginal opening and the anus. It represents the most inferior part of the pelvic outlet. Thus it lies above the external genitalia.

Gonadotropin is secreted from the anterior pituitary gland and it acts on the gonads (i.e., the ovaries or testes). The anterior pituitary contains five types of endocrine cell, and they are defined by the hormones they secrete-somatotropes (GH); Lactotropes (PRL); gonadotropes (LH and FSH); corticotrophs (ACTH) and thyrotropes (TSH). Gonadotrophs, cells that constitute about 10 percent of the pituitary gland, secrete two primary gonadotropins: luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Secretion of LH and FSH is low in both males and females prior to puberty

The glans is a vascular structure of the clitoris. The clitoris is composed of multiple parts: the glans, the clitoral body, and the paired crura and vestibular bulbs. The glans clitoris is the name of the part that most people call the “clitoris.” It is the external part of the clitoris, about the size of a pea, and is located above the urethra. Because the glans is the most highly innervated area of the clitoris, it’s extremely sensitive to touch.

The cell that results from the asymmetric division of an oocyte is a polar body. In animals and humans, polar bodies are produced after every meiotic division. They are relatively smaller in size due to less cytoplasm compared to the gametocyte that will become the ovum. This is essential so that much of the cytoplasm is available and the chromosomal content is halved at the time of fertilization. The polar bodies will eventually degenerate.

Suprarenal glands secrete adrenaline, testis secrete testosterone, pitutary gand secrete oxytocin and ovaries produce estrogen.

During the follicular phase, the secretion of FSH happens and this leads to the development of a mature follicle (Graafian follicle). This process of formation of a mature female gamete is called oogenesis. The FSH level increase causes the development of follicles and secretion of estrogen by the growing follicles. Rapid secretion of LH leads to the rupture of Graafian follicle and release of ovum called ovulation. This phase is followed by the remaining parts of Graafian follicle transform into the corpus luteum.