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Showing posts with label Reproduction. Show all posts
Showing posts with label Reproduction. Show all posts

Monday, May 2, 2011

Objective 71: How spermatatozoa moves through the female reproductve tract

The textbook was what I used to figure out how spermatozoa moved through the female reproductive tract. I found the picture below on a site that shows the path of the sperm as it traveled through the female reproductive tract. The textbook taught me that spermatozoa consists of a head, mid piece, and tail. The head of the sperm contains compacted DNA and an outer helmet like layer called the acrosome that helps pierce the egg for fertilization. The mid piece contains the mitochondria, which provides the ATP needed for the movements of the tail to jet the sperm along. The tail allows the sperm to move easily and help it to reach the egg.

Objective 72: Evaluate fertilization in terms of evolutionary fitness

I really do not undertand this objective but I will chime in on what I think it is about.  Women usually increase their evolutionary fitness by having children with the creme of the crop males. Men usually increase their fitness by having sex often to increase the chances that their sperm will encounter the goodies. Consequently, females have often evolved traits for choosing the fathers of their children, while males have often evolved traits for gaining access to females and their goodies.  I do not know I am just talking out my anal sphincter.

Objective 73: Compare and contrast oogenesis and spermatogenesis


Through my textbook I learned that like spermatogenesis, oogenesis involves the formation of haploid cells from an original diploid cell, called a primary oocyte, through meiosis.  But the major difference is that oogenesis leads to 1 perfect egg cell and spermatogenesis leads to 4 sperm cells.

Friday, April 29, 2011

Objective 75: Explain what happens during the 3 phases of menstrual cycle

Me being a woman I can honestly say I did not know all the things I am about to say were going on in my body.  I learned this information from my textbook and the video below.  I learned about the phases of the menstrual cycle. Basically to keep it short in sweet I learned in the follicular phase the follicles of the ovaries develop.  That was an easy conclusion to remember.  In the ovulatory phase which was the phase I knew the most about before getting in depth with the book.  In this phase a surge of luteinizing hormones (LH) starts and it stimulates the follicle to emerge from the surface of the ovary and it bursts, letting the egg go.  The last phase is the luteal phase and it follows ovulation.  I learned it lasts about two weeks, unless fertilization happens.  So after the egg is let go, the corpus luteum prepares the uterus just in case fertilization occurs.  Also the corpus luteum produces progesterone, so  the endometrium can thicken, and be filled with nutrients just in case of a fetus.In the second part of the luteal phase, the estrogen level increases, also stimulating the endometrium to thicken. In response to the increase in estrogen and progesterone levels, the milk ducts in the breasts increase. As a result, the breasts may swell and become tender.

Objective 74, 76 &77: Distinguish between diploid germ cells and haploid sex cells, Differentiate between zygote, morula, and blastocyst & Recognize that a blastocyst secretes human gonadotropin, which prolongs the life of the corpus luteum


This video basically broke down objective 76 for me.  Me being a women and having conceived twin boys I can honestly say that I had no idea that all of this goes on inside women.  I learned throughout my BIO career that a zygote is a fertilized egg.  I noticed that the above video does not state what a zygote is. What a zygote is which I have stated before is a fertilized egg.  How it becomes that way is between two haploid cells; an ovum from a female and a sperm from a male, which comes together to form a diploid cell.  Other than not explaining what a zygote was, the video did a nice job in teaching about the morula and a blastocyst.
I also thought the video delved into objective 77.  In describing how a zygote is formed I basically just answered objective 74.  How I learned to distinguish between the two is from way back in BIO 100.  I remember associating the di in diploid with two, a sperm and ovum joined.  So that is how I distinguish between haploid and diploid.



Objective 79: Locate the structures of the male and female reproductive systems



These videos and my textbook was all I needed to locate the structures of the male and female reproductive systems.  I mean this video is very cut and dry.  I do not know what else to say but to watch the videos because it is self-explanatory.