TOPICS
1. Human Life Cycle: Mitosis and Meiosis
1. Human Life Cycle: Mitosis and Meiosis
2. Male/Female Reproductive Systems
3. Fetal Development and Birth
4. HIV/AIDS
Let me begin by saying that reproduction is the process of a sperm and a fertilized egg joining together, and forming a miraculous new little individual. In this section I will be discussing the above topics in a more detailed fashion. To begin, I would like to discuss the 2 different cell divisions in the human cycle: Mitosis and Meiosis. Next I will review the Male and Female reproductive systems that aid in the development of a new organism which leads into the next topic: Fetal development and Birth. Lastly I will go over a few of the common STD's. The beginning life of a fetus is an absolute miracle, that I myself am blessed with right now.
HUMAN LIFE CYCLE: MITOSIS AND MEISOSIS. We learned in prior chapters of the 2 different phases associated with the human life cycle: Mitosis and Meiosis. Glance at a scanner and then at the finished picture, this "duplication division" is known as Mitosis (Mader 320). This process occurs throughout the cell development. Recall that this process goes through 4 different phases: Prophase, Anaphase, Metaphase, and Telephase. The second process is Meiosis: " A specialized process of cell division that produces gametes(eggs and sperms)" (ref article). It is also known for reducing its diploid cells to haploid cells. In number sense; a sperm and egg both carry 23 chromosomes, therefore when fertilized the new cell has 46 chromosomes. "The first cell of a new human being is called the zygote" (Mader 320). During this step, the offspring gets a copy of each parents 
chromosomes. And the sex of the baby and hair color is determined at this point. The picture to the right is the process of the haploid cells(egg and sperm) joining together to form the zygote. To lead into the next topic I would like to mention where the production of sperm takes place in the male and females. Most of us have studied this before, but in review the males produce in the testes and the females in the ovaries. Now that we have a general idea of the egg being fertilized, I would like to discuss the male and female reproductive systems.
chromosomes. And the sex of the baby and hair color is determined at this point. The picture to the right is the process of the haploid cells(egg and sperm) joining together to form the zygote. To lead into the next topic I would like to mention where the production of sperm takes place in the male and females. Most of us have studied this before, but in review the males produce in the testes and the females in the ovaries. Now that we have a general idea of the egg being fertilized, I would like to discuss the male and female reproductive systems.MALE REPRODUCITVE SYSTEM: Testes, Epididymis, Vas deferens, seminal vesicles, Prostate gland, Urethra, Bulbourethral glands, and Penis. To begin this system, once the sperm has begun production in the testes, the epididymis is the actual site where it matures. The traveling sperm enters a long narrow tube, vas deferens, which is also a storage organ. This leads to the ejaculatory ducts, which enters into the urethra. The seminal vesicles "contribute nutrients and fluid" (Mader 321). The other glands that are helpful in providing fluid for the sperm are the prostate and bulbourethral glands. The testis have seminiferous tubules, which are packed with little cells going through spermatogenesis "the production of sperm" (Mader 323). Hormones play a big role in the sexual drive, gonoadotropin-releasing hormone(GnRH), release 2 well known hormones: follicle-stimulating hormone(FSH) and lutenizing hormone(LH). "FSH promotes the production of sperm, LH controls the production of testosterone" (Mader 324). This occurs in the males.
FEMALE REPRODUCTIVE SYSTEM: Ovaries, Oviducts, Uterus, Cervix, and Vagina. Again, the ovaries are the site of egg production. The 2 hormones in the female system are estrogen and progesterone. To start the cycle, the oviducts most commonly known as the fallopian tubes, is the spot of fertilization. During ovulation, the little egg is guided to the fallopian tubes from 2 different sweeping actions, fimbria and cilia. "A developing embryo normally arrives at the uterus after several days, and then implantation occurs" (Mader 324). The uterus is where the developing fetus lives. This organ is very muscular and durable, just think, the average 7 pound baby kicks around inside of this structure!!! The vagina has 2 different functions: penis enters during intercourse, and it is the pathway canal during delivery. The females also release the FSH and LH, as do males. These hormones are important during the ovarian cycle. Fertilization occurs when the sperm travels its course towards the fallopian tubes. This is the beginning stage of Pregnancy. The next topic will describe the fetal development process.
FETAL DEVELOPMENT: At this point, the developing baby is known as an embryo. The development is divided into 3 different stages: Pre-embyonic(which is mentioned above- takes place during fertilization), embyonic(week 2-2 months), and fetal development(3 months-9th month). Ther
e is so much information during each week of pregnancy, that it's hard to know where to start! During the embryonic development, the embryo implants itself to wall of the uterus, its home for 10 months! I remember looking at these pictures when I first found out I was pregnant thinking, WOW, these structures are forming into my little baby! The picture to the right shows the 1st week, not yet pregnant, but the conception stage. During the embryonic development, the hormone secreted is HCG, which helps distinguish pregnancy if a pregnancy test were taken. The book describes this tiny embryo as being the size of a"period at the end of this sentence" (Mader 357)!!!! Organ systems begin to develop later in th
is stage and by the 8th week the embryo looks more human-like. The picture to the right is an embryo at 8 weeks. As pregnancy progresses, the uterus grows as well. The fetal development is also an interesting part because the fetus's heartbeat can be heard with a doppler, starts its first awakening flutter sensation, the mothers belly is growing, and all of the systems are fully developed. As the months go on, the baby's body slowly forms into a proportional size. The picture below is a fetus at 23 weeks. 
There are obviously changes that occur in the mother during pregnancy. The book states the following changes: "Energy level fluctuates, uterus relaxes, and pulmonary valves increase" (Mader 368). Aside from those changes, the mother also experiences hormonal changes, body changes, and feelings of sickness. In the end these changes will be worth the miracle baby!
e is so much information during each week of pregnancy, that it's hard to know where to start! During the embryonic development, the embryo implants itself to wall of the uterus, its home for 10 months! I remember looking at these pictures when I first found out I was pregnant thinking, WOW, these structures are forming into my little baby! The picture to the right shows the 1st week, not yet pregnant, but the conception stage. During the embryonic development, the hormone secreted is HCG, which helps distinguish pregnancy if a pregnancy test were taken. The book describes this tiny embryo as being the size of a"period at the end of this sentence" (Mader 357)!!!! Organ systems begin to develop later in th
is stage and by the 8th week the embryo looks more human-like. The picture to the right is an embryo at 8 weeks. As pregnancy progresses, the uterus grows as well. The fetal development is also an interesting part because the fetus's heartbeat can be heard with a doppler, starts its first awakening flutter sensation, the mothers belly is growing, and all of the systems are fully developed. As the months go on, the baby's body slowly forms into a proportional size. The picture below is a fetus at 23 weeks. There are obviously changes that occur in the mother during pregnancy. The book states the following changes: "Energy level fluctuates, uterus relaxes, and pulmonary valves increase" (Mader 368). Aside from those changes, the mother also experiences hormonal changes, body changes, and feelings of sickness. In the end these changes will be worth the miracle baby!BIRTH. The first sign of labor, is the strength and timing of the contractions. "True labor is marked by uterine contractions that occur regularly every 15-20 minutes and last for 40 seconds or longer" (Mader 368). There are times that the mother may think she is having a contraction near the end of her pregnancy but is in fact known as, 'false labor.' The 3 stages of birth are: Stage 1 (dilation of cervix) Stage 2(child is born) and Stage 3(placenta expelled). There is much more emotional and physical details that could be added, but for this review I feel that the point is clear.
HIV/AIDS. "No war, natural disaster, or terrorist attack has ever killed more people than HIV/AIDS" (Mader 352)! That is absolutely sad, I wasn't aware of that fact. "World wide, an estimated 38.6 million people(36.3 million adults and 2.3 million children) are now living with HIV infection" (Mader 344). Scientists have been struggling to find a vaccine to prevent the spread of this horrific disease. There are many important factors that they need to study, such as: is the vaccine a short term protection and would it make the individual more vulnerable to the disease? HIV travels into the body and destroys the immune cells. Mainly the Helper T cells which are used to help destroy the body from infections. Many of the individuals living with this disease are those living in poor to low income countries. At the the top of the list is Africa and Asia, Latin America and Caribbean, North America, Europe and Central Asia, and final North Africa and the Middle East. As we are aware the transmission of HIV is through sexual contact, and sharing of needles with an infected person. There are drug therapies available, but it does not cure AIDS, it is used as treatment to help stop the spread into the cells of the body. Hopefully scientist will find a vaccine to help control this deadly disease. STDs caused by viruses are : HIV, genital warts, genital herpes, and Hepatitis. STDs caused by bacteria are: Chlamydia, Gonorrhea and Syphilis. Antibiotics are a way to cure the bacteria STDs. Again, hopefully the spread of these STDs will decrease as individuals avoid the chain of transmission.
In conclusion, I discussed the human cycle and how amazing it is to look at pictures of the process of the unborn baby. Meiosis is the process of game production, it reduces its diploid cells to haploid cells. Making a total of 46 chromosomes when the new cell is fertilized. I also reviewed both the male and female reproductive organs. Next I reviewed the process of fetal development, and how amazing each day the embryo/fetus grows! I actually go into more detail in the lab section, so I did not repeat myself in this review. Since I am pregnant, I feel its natural to be a little nervous that for some reason something may go wrong. Obviously there are babies born with certain deformities, and diseases, I just continue praying I will be blessed with a healthy baby. The last thing I discussed was STDs and HIV/AIDS. I will just repeat that hopefully individuals will think before the act, to help stop the spread of these horrific diseases!! I hope this review was worth while.Works Cited:
Mader, Sylvia S. Human Biology. Boston:McGrawHill Companies, Inc. 2006.
quotes
http://www.americanpregnancy.org
first picture
http://www.med.upenn.edu/meded/public/berp/overview/BV-1.html
picture of embryo at 8 weeks
http://www.pregnancy-calendars.net
picture of fetus at 23 weeks
http://www.-ref.usc.edu
quote, picture of meiosis
1 comment:
Good words.
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