MCN (Lesson 2) "Normal Pregnancy" Exam

What are the phases of menstrual cycle? - menstruation, follicular phase, ovulation, luteal phase, and ischemic phase. How many hours does an ovum need to be capable of fertilization? - 24 hours. (48 hours the most). Total critical span during sex must occur for fertilization to be successful is - 72 hours or 48 hours before ovulation, plus 24 hours afterward. Eggs are propelled into fallopian tubes (ampulla) by: - fimbriae, peristalsis of tube, and cilia of tube. What is the zona pellucida? - it is the "ring of mucopolyssacharide fluid" and is surrounded by "circle of cells". What is corona radiata? - it is what you called "circle of rings" which surrounds the Zona pellucida. How many minutes does a sperm need to be able to reach the ovum after deposition? - 5 minutes. What final process does a sperm undergo inside the uterus? - Capacitation. What is capacitation? - they undergo this process to be ready for fertilization. as sperm move towards the ovum they will develop a "sperm binding receptor site" or sticker-like attached to their head.Sperm contains a head anf tail that is called? - Flagella. How does a sperm travels? - They have a tail. And because of the cervical mucus they are now able to swim well. There are also uterine contractions that help them as they travel towards the egg as they meet in the ampulla. (Flagella, Thin Cervical Mucus, Uterine Contractions). What is proteolytic enzyme? - "Hyaluronidase" - enzyme that will dissolve layets of the ovum, specifically the outer layer which is the Corona Radiata. (an ejaculation must contain many sperm to be able to fertilize an egg). Product of fertilization - zygote. What is the difference of fraternal and identical twins? - Fraternal - 2 or 3 mature eggs then a mature sperm will fertilize that 2 or 3 ovums that will develop a twins or triplets. Identical - one egg plus one sperm unite then they will divide to form twins. What are the chromosomes of female zygote? - XX What are the chromosomes of male zygote? - XYThree important factors necessary for fertilization - 1. Maturation of the ovum and sperm. 2. Ability of the sperm to reach the ovum. (ampulla) 3. Ability of the sperm to penetrate. (hyaluronidase) Components of implantation - zygote, morula, blastocyst (embryoblast & trophoblast). How does implantation occur? - "Zygote" that is in the ampulla after 3-4 days will now travel towards the uterus and as it travels it also undergo mitosis that is why it will divide its parts into 16-50 cells which is now called "Morula". Then after 3-4 days it will form a different shape that has an inner circle "embryoblast" and outer fluid "trophoblast" that forms a "blastocyst". Embryoblast - The inner cell mass of the blastocyst, which is the developing human organism. "embryo". Trophoblast - outer cells of the blastocyst that secrete enzymes that allow implantation. "Placenta, Umbilical cord, Membranes and other products of conception".