Question

List the anatomical pathway a ripe ovum takes from the ovary until it exits the body.

Answer 1

The exact path of the egg : during ovulation the egg leaves the ovary and is guided by fimbriae into the fallopian tube . it travels down the fallopian tube and into the uterus. it will leave via the cervix and vagina if not fertilized.

The fallopian tube is made up of three divisions : THe infundibulum,(funnel shaped with the fimbriae attached, this is the section closet of the ovary) , the ampulla (mid point of the fallopian tube and is also the widest . fertilization normally occurs here.) and finally the isthmus (section closet to the uterus, and is the narrowest section )

once it exists the fallopian tube it enters the uterus . if fertilization occurs it will be implanted into uterine wall ( the endometrium) and remain here.where as if fertilization did not occur , it will leave by a mensuration out through the cervix and then the vagina.

eggs are produced before birth and complete production once fertilized . THe production of an egg is called oogenesis.in the early weeks of embryonic life germ cells (which will eventually becomes the egg ) move from the yolk sac to the ovary . here they undergo mitosis ( I.e. increase in no. but keep the same no. of chromosomes 46 )

THese cells are differentiate into primary oocytes in the ovaries ( By differiantiation, i mean the cell undergo meiosis 1 which stops at prophase 1) .This happens before birth and will remain at this stage until puberty. So, a female is born with her lifetime supply of primary oocytes.

At puberty, under the influence of hormonal signal , meiosis 1 goes to completion . this therefore forms two haploid (23 chromosomes ) cells, A secondary oocyte and first polar body.

The secondary oocyte undergoes the 2meiotic division at ovulation. This division stops at metaphse 2 . meiosis 2 resumes when the sperm penetrates the ovum at fertlization. This is when it finally forms the mature ovum . If it is not fertilized , it will never form a mature ovum as it will not complete meiosis.