Biology Journal

2008-07-28T19:02:00.000-07:00

E-learning Day 18: 28 July 2008

This will be the the final biojournal entry on this blog, and will also conclude the two-part segment related to the Issues on Sex topic, Abortion.

What is abortion and what are the consequences of carrying out abortion? Part 2

Now, I will describe some issues that come with abortion. Of course, abortion is sometimes an easy way out for pregnant women who do not feel like having children or have some simply inexplicable reasons for not wanting babies. However, abortion comes with some prices to pay.

For this entry, I have decided to try using the search engine http://cuil.com/ to search for materials instead of the commonly used http://google.com.sg/. I have also used the trusted site, http://wikipedia.org/ to look for some resources.

There are of course, a few health problems that may come, and these are subjected to the type of abortion carried out. Normally, non-surgical abortions tend to have a higher chance of triggering serious complications. The chance of complications also vary according to the progression of the pregnancy. For surgical abortions, risks are less common but some can occur, such as death due to general anaesthesia or minor pain that surpasses headaches but is milder than toothaches can be experienced.

Improper administration of abortion pills can also lead to freak accidents. In a article found on the Washington Times webpage, a teenager was reported to have lost her life due to improper administration of abortion pills that resulted in her entering a shock.

Emotionally, a person who has undergone abortion may also suffer emotional setbacks. Sometimes, women who have undergone abortion suffer from Post-Abortion Syndrome (PAS) which causes them to feel guilt and other negative feelings etc. after an abortion. Suicides among pregnant women are also found to be rare, but suicide figures for women who have undergone abortion are considerably higher.

Finally, there is also the ethicality issue. Many arguments are often issued, such as how abortion is related to the murder of a life, while some feminists view denial of abortion as oppression and injustice. Furthermore, controversies such as women undergoing abortion just to have a chance at having a child of a certain gender are not unheard of. It can be concluded that abortion is a process fraught with controversies, occasional breach legal ramifications and social debates.

Thus ends the concluding entry to my biojournal project.

Sources:
http://en.wikipedia.org/wiki/Abortion
http://www.washingtontimes.com/news/2003/sep/22/20030922-105418-2823r/
http://www.abortionfacts.com/PAS/PAS.asp

2008-07-28T18:37:00.000-07:00

E-learning Day 17: 28 July 2008

This marks the final entry I shall be writing with regards to the topic of digestion.

What are the basic functions of the large intestine, rectum and anus in the digestion of food?

For this entry, I used the search engine http://google.com.sg/ to look for materials regarding these organs, and utilized http://wikipedia.org/ to look for an article related to each individual organs.

After looking through my previous entries, I realized I have summarized the functions of the colon/large intestine prior to today. However, I will recap the functions of the organ in a few points.

Functions of the large intestine:
-no digestive enzymes produced
-bacteria present break down the cellulose/glucose
-remaining water is removed from the chyme (food "mush")
-chyme is mixed with mucus and bacteria and forms feces
-dietry fibre and waste products of the above process are used as nutrition

The rectum is about 8 inches (12cm) long and is a "warehouse" for waste products to be excreted. Folds in the rectum known known as transverse folds keep the waste in place till they are ready to be discharged.

The anus is an opening through which feces passes out from. Pressure builds up in the rectum. This pressure is increased by abdominal and pelvic floor muscles. The internal anal sphincter (a ring of muscle surrounding the anus) relaxes. The rectum shortens as the feces enter the anal canal and the relaxed sphincters (both internal and external) allows the feces to exit the anus.

This ends my final post on digestion. I have enjoyed researching on the digestive system for the past few weeks, and have gained some knowledge on the digestive system of humans and also birds. I have also learnt some other facts such as how vomiting occurs.

Sources:
http://en.wikipedia.org/wiki/Rectum
http://coloncancer.about.com/od/faqs/f/Rectum.htm
http://www.gesa.org.au/digestive-system/anus.cfm
http://en.wikipedia.org/wiki/Anus

2008-07-27T19:20:00.000-07:00

E-learning Day: 27 July 2008

Today, I shall be writing about a topic related to the subject on Issues of Sex. The final two posts relating to Issues on Sex, which will consist of this post and the post after the next post, will be discussing abortion, morality and health issues concerned.

What is abortion and what are the consequences of carrying out abortion? Part 1

Today, I will be using the search engine http://google.com.sg. I will also be using http://wikipedia.org.

I will also be mainly focusing on the definition of abortion and the procedures taken for this entry.

Firstly, abortions and miscarriages must not be mistaken for the same thing. Abortions are voluntarily induced expulsions of fetuses from the uterus surgically or medically due to psychological or other reasons. However, miscarriages are spontaneous and sometimes without warning. However, both result in the deaths or are caused by the death of the embryo.

Abortion is sometimes also known as the termination of a pregnancy. Sometimes, it is confusing as abortion simply refers to this termination, and this can be either spontaneous. Therefore, the term miscarriage is provided for the expulsion of babies before the twentieth week of pregnancy to disambiguate these two terms. Miscarriage can refer to any spontaneous expulsion, while abortion can refer to induced expulsion through abdominal pressure, the use of sharp tools or botanical abotifacients.

Botanical abotifacients refer to substances that can be used to induce abortions.

There are three main ways abortion can be carried out.

The first method is surgical abortion. There are a few different methods to carry out surgical abortion. The first two are known as MVA (Manual Vacuum Aspiration), which involves the removal of the fetus/embroyo with the use of a manual syringe, while the other is known as the EVA (Electric Vacuum Aspiration) and is carried out with an electric pump. These procedures can only be carried out before the first twelve weeks of conception is over. From the 15th week onwards, until roughly around the 26th week, a combination of the suction and surgical instruments will have to be used in a procedure known as D&E (dilation and evacuation)(D&E, not D&T). The cervix of the uterus is opened and emptied using the above the above instruments.

The second most common method is known as D&C (dilation and cutterage). A curette (spoon-shaped surgical instrument) is used to clean the walls of the uterus. However, this procedure is more uncommon and is used to examine the uterine lining for medical reasons. It is declining in use as heavy sedation is required and complications arise more often in these surgeries. The World Health Organization also only recognizes D&C as a viable form of abortion if MVA is not available.

However, abortions in the second trimester (4th-6th months of pregnancy) have to be done in a different way. Prostaglandin is injected with other medical fluids to induce premature delivery. The fetus is then removed through IDX (intact dilation and extraction or intrauterine cranial decompression) which involves the decompression of the fetus's head before removal or hysterotomy abortion where a procedure similar to caesarean section is performed under the patient's heavy sedation). However,IDX is banned by the government in U.S. If the patient is in the 20th to 23rd week of pregnancy, an injection to cease the heartbeat is included in the first part of the procedure to ensure the fetus is not born alive.

Abortions can also be carried out as non-surgical procedures. These are known as medical abortion and work within the first trimester of pregnancy. Combinations of drugs such as methotrexate or mifepristone are used, followed by a dose of prostaglandin. However, these abortions a riskier and sometimes require surgical intervention if gone wrong.

There are other methods of abortion, but these are often unorthodox, dangerous or potentially lethal.

Thus concludes the first part of two entries related to abortion. After doing this first part of research, I was very much more aware of how much suffering women must go through to undergo abortion. I cringed at some text I came across, such as how the fetus's head is decompressed in IDX, or when I came across slightly disturbing pictures of abortion being carried out. Thus, I decided not to include any images for this post in fear of more frightening pictures appearing if I utilize search engines.

Sources:
http://en.wikipedia.org/wiki/Abortion
http://en.wikipedia.org/wiki/Miscarriage
http://www.hpb.gov.sg/hpb/default.asp?pg_id=3279

2008-07-26T18:46:00.000-07:00

E-learning Day 15: 26 July 2008

What is the function of the pancreas in the digestive system? Part 2

Today, I will be focusing on the functions of the secretions of the exocrine and endocrine tissues of the pancreas.

The exocrine tissue secretes digestive enzymes. These digestive enzymes are relatively inactive as they travel through the pancreatic duct down the common bile duct into the duodenum. Upon entering the small intestine, they are activated and help to process and break down carbohydrates, fats, proteins, and acids. Furthermore, the exocrine tissue also excretes a bicarbonate to neutralize stomach acids in the duodenum, which are harmful and potentially damaging to the organ. Bicarbonates performs a task of a physiological pH buffering system.

Meanwhile, the endocrine tissue or Islets of Largenhans secretes the hormones insulin, glucacon and somatostatin. Glucose levels in the bloodstream is regulated and kept in check by insulin and glucacon, while somatostatin controls and prevents the previous two hormones from being secreted.

Sources:
http://en.wikipedia.org/wiki/Bicarbonate
http://en.wikipedia.org/wiki/Pancreas
http://www.stjohnsmercy.org/healthinfo/adult/liver/pancreas.asp

2008-07-25T18:18:00.000-07:00

E-learning Day 14: 25 July 2008

After some brainstorming, I was able to come up with a topic that was not too controversial on Issues on Sex.

How is pregnancy confirmed?

For a change, I decided to not use http://wikipedia.org/ but instead make use of http://google.com.sg/ solely for this research.

Pregnancy can easily be confirmed through a test that measures levels of pregnancy hormone, known as Human Chorionic Gonadotrophin (HCG), in a woman's urine by a doctor or a personal testing kit. This test is carried out on the day where a woman's monthly menstruation period is due about 2 weeks after conception. However, higher accuracy can be obtained after four weeks instead. Higher concentration of HCG in urine are usually present during early periods of the morning.

Besides, HCG can also be detected in the bloodstream by a doctor two weeks after conception when the menstruation period of the woman arrives.

Ultrasound after the twelfth week of pregnancy can also be used to detect the presence of a fetus in the mother's womb.

Sources:

http://huggies.com.au/BecomingAParent/YourPregnancy/ConfirmingPregnancy.asp

http://www.depression-guide.com/baby-care-guide/pregnancy/confirming-pregnancy.htm

2008-07-23T17:59:00.000-07:00

E-learning Day 13: 23 July 2008

Research for the topic of the functions of the pancreas will be carried out over 2 days in 2 parts.

What is the function of the pancreas in the digestive system? Part 1

The pancreas is an organ located across the abdomen across the stomach. It is an elongated and "fleshy" or homogeneous appearance. The pancreas shares close links to the liver, gallbladder and duodenum as discovered in past studies. It has both exocrine and endocrine tissues that serve to functions.

The exocrine tissue secretes pancreatic juice which contains digestive enzymes. They travel along the pancreatic duct, which runs along the pancreas and joins the common bile duct.

The endocrine tissue produces several hormones into the bloodstream. These include insulin and somatostatin. The endocrine tissue consists of the islets of Langerhans, which are groups of endocrine cells that provide the hormones. About a million islets are distributed throughout the organ. They form about a 1-2% of the total mass of the pancreas.

Sources:
http://en.wikipedia.org/wiki/Islets_of_Langerhans
http://en.wikipedia.org/wiki/Pancreas
http://www.stjohnsmercy.org/healthinfo/adult/liver/pancreas.asp

2008-07-19T17:16:00.000-07:00

E-learning Day 12: 19 July 2008

The second and final part to the definition of homosexuality.

What is the definition of homosexuality? Part 2

In history, homosexuality has been accepted yet rejected in different societies. In some societies, same-sex behaviour is allowed. In the Ancient Roman Empire, kings were known to have young male lovers whom would serve them as concubines, until Christian emperor Theodosius abolished this custom and condemned all of such male lovers to be burned to the stake due to religious reasons.

Many nations have different stances on homosexuality rights. Liberal countries such as the United States do not ban same-sex unions, and some states even legalize gay-marriages. However, some countries such as Iran go as far as to enforce the death penalty to people who engage in homosexual activities due to religious issues.

Violence against homosexuals are often more common. In the United States, notorious cases of violence against homosexuals have been reported. In fact, a large percentage of about 15% of hate crimes reported by the FBI were based on perceived sexual orientation.

In some nations, adoption of children by same-sex couples are legal, such as member nations of the European Court of Human Rights and the U.S. These governments believe that homosexual parenting does not affect a child's development and should be legalised.

It is also reported that homosexuality is not permanent. Cases of individuals leaving homosexuality and becoming heterosexuals are evidence.

Sources:
http://www.conservapedia.com/Homosexuality
http://en.wikipedia.org/wiki/Homosexuality

2008-07-17T16:35:00.000-07:00

E-learning Day 11: 17 July 2008

Digestive system.

What are the functions of the gallbladder and the duodenum in the digestive system?

Basically, the gallbladder's function is to store bile produced by the liver which are sent through miniature ducts and canals and assist the digestive process. The gallbladder is located somewhere behind the liver on the right-side of the rib-cage.

The gallbladder is a pear-shaped organ of minimal function. It stores bile produced by the liver and over a period of time, the bile increases in potency and intensity. This bile is provided to the duodenum, which is largely responsible for digestion in the small intestine. The bile travels in and out the gallbladder through the cystic duct. The latter is connected to the common bile duct, which is common to the pancreas, liver and gallbladder.

The duodenum produces hormones which cause the liver and gallbladder to produce bile, amid other effects such as the release of digestive enzymes from the pancreas. The duodenum also regulates the emptying of the stomach.

The gallbladder is only present in vertebrates, as vertebrates consume food as boluses and these require greater digestive secretions to be digested.

Sources:

http://www.gallbladderattack.com/gallbladder.shtml

http://en.wikipedia.org/wiki/Gallbladder

http://en.wikipedia.org/wiki/Duodenum

2008-07-14T21:10:00.000-07:00

E-learning Day 10: 14 July 2008

Today, I will be writing an entry based on the topic Issues On Sex. This is the first part two-parts regarding the subject on homosexuality.

What is the definition of homosexuality? Part 1

This post will mainly be devoted to the definition of homosexuality.

Nowadays, homosexuality is often portrayed in modern media freely. In the past, people were sometimes condemned as homosexual, due to the fact that this opposed by many religions such as Christianity and Islam etc.

The definition of homosexuality is the sexual behaviour or orientation that results in attraction to people of the same sex. A person's identity or personality is largely connected to his sexual preferences. Sexual preferences can be classified into mainly three categories.

They are:

-homosexuality
-bisexuality
-heterosexuality

Heterosexuality is also sometimes labelled as "straight", and refers to people who are attracted to people of the opposite sex. Bisexuality refers to the sexual behaviour where a person is attracted to people of both genders.

The inclination towards homosexuality is undefined. Scientific studies are conducted to find out if genetics play a role in homosexuality, but other scientists believe that culture, societal factors and religion may also have a role in derivation of homosexuality. However, it is agreed that if genes could be found to influence homosexuality, society would come to better accept "gay rights".

Many people argue over whether genetics play an important role in homosexuality. Books have been published arguing the case. Numerous of such books counter that scientific studies have failed to show that genetics have a role in inclination towards homosexuality. Studies have shown that many homosexuals have experienced abuse as children. Furthermore, if genetics played a role, it would not be incorrect to deduce that homosexuals of many different cultures and religions are present. However, further research has shed light that in certain cultures, homosexuality is either rare or completely absent. This would be another piece of evidence that homosexuality could be a personal choice and has nothing to do with genetics.

However, the issue is still being debated, so it is unwise to make any presumptions.

Sources:
http://en.wikipedia.org/wiki/Homosexuality
http://www.conservapedia.com/Homosexuality

2008-07-13T19:11:00.000-07:00

E-learning day 9: 13 July 2008

From today onwards, almost all digestion topics will be focusing on parts of the digestive system that play important roles in digestion.

What is the liver's function in the digestive system?

The liver is the largest internal organ and gland in the human body. An adult human's liver can weigh up to 1.4-1.6kg. It has a length of 20cm horizontally, 17cm vertically and is 12cm thick.

The liver plays a number of roles in the human digestive system.

Firstly, it is able to store and process/metabolize this fats. It creates bile, a greenish alkaline liquid that causes fats and vitamins such as vitamins A,D,E and K to be reduced into a form of milky fluid. This milky fluid (emulsion) can then be absorbed by the intestines.

Next, the liver can metabolize carbohydrates for storage. Metabolized carbohydrates in storage is a main source of glucose for the brain and the red blood cells to engage in routine activities.

Other functions of the liver:

"Cleansing" the body- detoxification, by metabolizing and/or secreting substances such as drugs, alchohol and environmental toxins.

Destroy, by metabolizing and/or secreting harmful biochemicals produced by the body such as ammonia which breaks down proteins.

Synthesizes proteins which affect blood clotting conditions and volume of blood in the body.

Sources:
http://en.wikipedia.org/wiki/Liver

http://ourworld.compuserve.com/homepages/sbrillanti/liver2.jpg

http://www.medterms.com/script/main/art.asp?articlekey=4179

2008-07-12T19:17:00.000-07:00

E-learning Day 8: 12 July 2008

Decided to form a question related to the topic Issues on Sex and the following explanation.

Initially, I was unable to formulate a question, as I did not have the necessary creativity to come up with one. So, I decided to surf the biology-journal blogs of my other classmates for inspiration (xD).

What is the current progression in the search for a cure for Aids?

I decided to visit heavily frequented http://wikipedia.org/ and http://google.com.sg/ to research for materials.

Background Information on AIDS: Acquired Immune Deficiency Syndrome. The syndrome appears as a series of infections and symptoms that result because of damage to the immune system. This damage to the immune system is caused by Human Immunodeficiency Virus (HIV). Highly transmittable, more than 33 million live in the world with AIDS, with more than 2 million deaths resulting from the condition.

Currently, there is only one form of treatment of AIDS, and even though it can prevent people from falling ill for many years, it is not a cure and the person infected by AIDS will have to take the medication/drugs for the rest of his or her life.

This form of treatment is known as HIV antiretroviral treatment. These drugs work by slowing down the replication of HIV in the body. Multiple antiretroviral drugs have to be taken to slow down this replication. This is because HIV replicates in many different forms. Thus, there could be several strains of HIV in a single person's body at any one time. As such, a combination of three or more drugs will have to be taken to effectively counter HIV. This combination is known as HAART (Highly Active Antiretroviral Therapy). There are many forms of antiretroviral drugs. They are categorized into five main groups.

The first group is Nucleoside/Nucleotide Reverse Transcriptase Inhibitors (NRTIs). They restrict the replication of HIV and were the first type of drugs used to treat AIDS. They are an essential drug of HAART and two or more types of drugs categorized in this group is often used.

The second group is known as Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs). They are also known as non-nukes, while NRTIs are known as nukes. They work in a similar fashion as the NRTIs, which intefere with the activities of reverse transcriptase, a form of HIV protein that is needed by the virus to replicate itself.

The third form of drugs are known as Protease Inhibitors (PIs). As the name suggests, PIs restrict the functions of protease, a protein involved in HIV replication.

Fusion or Entry Inhibitors are the fourth type of drugs. Fusion inhibitors prevent HIV from fusing with cells of the immune system, while Entry inhibitors prevent HIV from entering these immune system cells.

The final and fifth group is known as Integrase Inhibitors. The group consists of the drug raltegravir, which restricts the functions of integrase, a enzyme needed by HIV to inject its genetic material into human cells.

HAART is rather exorbitant, and is costly for most people to utilize. People who have no access to HAART are only able to receive treatment for infections they are likely to contract with AIDS. These infections are known as Opportunistic Infections. These are not very effective as they provide short-term benefits but do not actually address AIDS.

Sources:
http://en.wikipedia.org/wiki/AIDS
http://www.avert.org/introtrt.htm

2008-07-10T09:06:00.000-07:00

E-Learning Day 7: 10 July 2008

Formulated a question based on Digestion.

What is the scientific explanation for vomiting in humans?

Research on this rather "gross" topic was done by sourcing the Internet. Mainly by visiting my preferred choice of sites, http://wikipedia.org/ and http://answers.com/. The search engine http://google.com.sg/ may also have been used.

http://answers.com/ did not appear to have a scientific explanation for vomiting. However, http://dictionary.reference.com/ had a short definition on the action of vomiting, which is to "eject the contents of the mouth; regurgitate; throw up". My previous knowledge of vomiting consisted of little, except the lingering sour taste in one's mouth after doing so and the susceptibility of vomiting when suffering from motion sickness etc. Therefore, I sought a satisfactory explanation to vomiting.

For a start, there are numerous causes for vomiting. They include migraines, pregnancy, excessive alcohol, motion sickness and many other causes. The vomiting I was striving to research on involved the one that had a sour taste that lingered in one's mouth, and not one where blood is regurgitated etc.

There is a part of the brain identified as the vomiting centre. The vomiting centre is located in the pons (an area located in the brain stem). The fourth ventricle of the brain is actually a receptor or trigger zone, and stimulating it could either inhibit or cause vomiting.

When the process of vomiting occurs, contents of the stomach are usually regurgitated, sometimes even including the acidic contents of the stomach. Therefore, saliva is produced excessively and subconsciously to ensure the protection of the enamel of the teeth. Excessive vomiting can lead to dental erosion. Contents of the digestive tract are swept into the stomach, abdominal muscles contract and contents of the stomach rushes to the oesophagus, which is relaxed. Retching, or release of gastric gases usually accompany vomiting. Also, sweating and an increased heart rate are induced.

I was able to dicover why there is a lingering sour taste in the mouth after vomiting as the acid passes through the mouth to be discharged. I also learnt the process the body undergoes when vomiting occurs.

No images were included as they are not appropriate for faint-hearted audiences.

Sources:

http://dictionary.reference.com/browse/vomit
http://www.wrongdiagnosis.com/sym/vomiting.htm
http://en.wikipedia.org/wiki/Vomiting

2008-07-05T20:14:00.000-07:00

E-Learning Day 6: 5 July 2008

Q & A with the question relating to Issues on Sex.

How are twins formed?

To conduct research based on the question, I decided to make use of http://answers.com/ to find the relevant background information.

However, there was plenty of scientific terms that were rather unexplained. Therefore, I decided to use http://wikipedia.org/ as well to search for additional materials with possibly simplified scientific terms.

Simplistically, twins can be categorized into two different groups. There are Monozygotic twins, which are generally more rare and have higher probability of being "identical" in appearance and Dizygotic twins, of which are more common and do not necessarily look "identical" in appearance. Both types of twins are formed in different ways.

Monozygotic twins are formed when a single egg cell is fertilized by a single sperm and the fertilized egg cell (also known as a zygote) splits into two. This process of splitting into two is a genetic anomaly that happens randomly and occurs in birthing at a rate of 3 in every 1000 deliveries worldwide, regardless of racial background. If the splitting of the zygote occurs after the seventh of eighth day after fertilization, mirror-reversal may occur in certain traits, for example handedness. Zygotes separated in the earlier days have their own separate placenta and sac (fetal membrane). Zygotes that separate after two days share the same placenta but have different sacs. These form the majority of monozygotic twins.

However, dizygotic twins are formed when two separate egg cells implanted in the uterine wall are fertilized by two separate sperm cells. The two different zygotes then develop. Dizygotic twins are more likely to not look identical, but merely similar as they do not share the same amount of chromosome profile. They share 50% of genes and look similar to each other as ordinary siblings resemble each other, and can also be described as siblings that happen coincidentally to be the same age.

I managed to learn more about how twins are formed and how fraternal twins are actually like siblings except of the same age.

Sources:

http://www.answers.com/twins?cat=health
http://en.wikipedia.org/wiki/Twins

2008-07-03T21:56:00.000-07:00

E-Learning Day 5: 3 July 2008

Today, I will be posting an answer to a question related to Digestion.

How do birds digest food?

Initially, from the little I knew about digestion in birds, I knew that birds did not have teeth and thus were not able to masticate their food before swallowing. I also knew that birds swallowed stones to aid their digestion, but did not know how it aided this process. Therefore, I decided to utilise the search engine http://google.com.sg/ and http://wikipedia.org/ to source for information on the subject.

On Google, I managed to find a website describing the digestion process for birds. Digestion starts from the beak, where the food first enters. The bird's beak varies on its diet. Most birds also have saliva to help make swallowing easier for birds. The bird uses the tongue and beak to manipulate the food for swallowing.

The food then travels down the oesaphagus before coming to the stomach, or else known as the proventriculus in birds. The oesaphagus has an enlarged area in most brids known as the crop, which allows for the storage of food. The birds sometimes use the crop for the food to soften before entering the stomach. Other birds, for example the osprey, regurgitates softened food from the crop to feed their young. The stomach consists of two parts, namely the proventriculus and the gizzard (also known as the ventriculus or muscular stomach). Cells in the proventriculus are able to produce special digestive enzymes, hydrochloric acid and mucus to digest the food. The partly broken down food materials then proceed to the gizzard, which grinds and breaks the food down. This is to allow the enzymes to break down the food more easily. Furthermore, small stones or grains of sand that were swallowed by birds are stored in the gizzard, and these help to grind the food. The food can be passed back to the proventriculus and vice versa for more complete digestion. The gizzard is also lined with a tough layer of keratin, which is a type of protein, to protect the muscles responsible for the grinding.

The small intestine absorbs water and nutrients from the food and digests the food. The pancreas develops enzymes that break down protein and fats in the small intestine. The bloodstream receives nutrients that are absorbed by the intestinal membrane. The remaining waste products are transferred to the cloaca, which is somewhat an avian equivalent of the human rectum, through the largely featureless large intestine before being expelled at the right time.

From this, I finally understood the reason why birds are said to swallow small rocks and grains of sand and have learnt more about the digestive system of birds, which appear to be slightly similar to that of the human's.

Avian digestive system:

Sources:

http://fsc.fernbank.edu/birding/digestion.htm
http://en.wikipedia.org/wiki/Gizzard
http://www.helium.com/knowledge/8061-why-a-bird-would-eat-stones

2008-07-01T05:55:00.000-07:00

E-learning Day 4: 1 July 2008

Based on a alternating pattern, I'll be writing an entry based on a question created according to the topic, Issues On Sex.

How do contraceptive pills work?

From the word "contraceptive", I am able to more or less deduce that contraceptive pills prevent preganancy despite sexual contact. They are probably used as a means of family planning, for young couples who are not ready to have children due to lack of financial means.

To find information related to the question, I decided to use the search engine http://google.com.sg/ to search for articles related to how contraceptive pills work.

The use of contraceptive pills is closely tied to the menstrual cycle. Thus, it is necessary to explain the menstrual cycle briefly. At the beginning of the menstrual cycle, estrogen levels begin to rise. Estrogen is a form of hormone that is responsible for the development and growth of the woman's reproductive system. The lining of the uterus is thickened in preparation of a fertilized egg. An egg is released when estrogen levels peak, which occurs around halfway through the cycle and this is called ovulation. This occurs once a month. After ovulation, progesterone, another hormone, prepares the endometrium (lining of the uterus) for fertilized egg. When a fertilized egg implants itself in the uterine lining, conception or pregnancy begins.

Menstruation begins when conception does not occur. The thickened uterine lining is shed and menstruation takes place. Estrogen and progesterone levels drop.

The contraceptive pill acts as artificial estrogen and progesterone. They regulate these levels so the ovary does not receive the signal to release an egg. As such, fertilization and pregnancy is rendered impossible without an egg. Furthermore, the sperm is unable to reach the egg as the cervical mucus is thickened and the uterus becomes unreceptive to the implantation of the fertilized egg.

There are several types of contraceptive pills. Some examples are Progestine-only pills (POP). These are ideal for breastfeeding women as less estrogen lower the amount of breastmilk produced and these pills do not have estrogen.

The contraceptive pill is also sometimes known as the brith-control pill or simply "the Pill".

Contraceptive pills:

Sources:

http://www.healthywomen.org/healthtopics/birthcontrolpills
http://www.healthywomen.org/healthtopics/estrogen
http://en.wikipedia.org/wiki/Contraceptive_pill
http://www.dkimages.com/discover/previews/825/30012714.JPG

2008-06-29T20:52:00.000-07:00

E-learning Day 3: 29 June 2008

Greetings. Once again, I will be writing an entry on a digestion-related topic which is derived from a question formulated.

How is it possible for a person to swallow food even in space despite the lack of gravity?

First, I decided to search http://wikipedia.org/ for an article relating to how the oesophagus, or else known as the gullet, manages to allow a person to swallow food. Basically, according to Wikipedia, the oesophagus (American spelling: esophagus) is an organ in vertebrates that consists of a muscular tube through which food travels from the pharynx (part of the throat directly behind the mouth and nasal cavity) to the stomach. From this, I am able to make a vague guess that gravity is not required in the process of swallowing since the oesophagus is a muscle and is able to make use of muscular effort to transport food.

However to be sure, I decided to research on the process of swallowing. To obtain the relevant information, I referred to http://wikipedia.org/ and http://answers.com/. Firstly, the food which enters the mouth is masticated into small chunks by the teeth and mixed with saliva to form a food bolus. This is then transferred to the oesophagus when modified to an appropriate size through movement of the tongue and the chewing of the jaw.

The food bolus is pushed backward by the tongue against the roof of the mouth. The kinetic energy forces the bolus into the pharynx. Circularly-arranged muscles in the pharynx contract repeatedly, causing the food bolus to travel down the oesophagus into the stomach for digestion.

However, swallowing is complicated by the position of the airway leading from the nose to the larynx within the pharynx. Therefore, human adults are unable to inhale or exhale at exactly the same time they swallow and have to time these properly.

Above, gravity was not listed as a factor that would affect swallowing. Therefore, it is safe to conclude that swallowing food in space is possible, which explains how astronauts eat in space.

However, oesophagus of most birds are merely "chutes" that rely on gravity to transport the food to the stomach. In fish, water is utilised to pump food towards the pharynx and the water is transferred out of the gills.

Therefore, it is inadvisable for birds or fish to swallow food in outer space as it is impossible for them to do so.

Oesophagus (including other organs of the body):

Sources:

http://en.wikipedia.org/wiki/Esophagus
http://en.wikipedia.org/wiki/Swallowing
http://www.answers.com/swallowing?cat=health
http://www.sts.org/graphics/patientinfo/colorstomach-esophagus.jpg

2008-06-27T21:00:00.000-07:00

E-Learning Day 2: 27 June 2008

First post related to the second topic selected for the biology journal project, Issues On Sex. Once again, I shall begin with a question created.

What are general hazards that accompany lack of consideration to the consequences of unprotected sex?

First, I decided to utilise the search engine http://google.com.sg/ to find the consequences of unprotected sexual intercourse. Based on a question posted on http://au.answers.yahoo.com/ on what three consequences of having unprotected sex were, many replies were posted in reply. Some of the most common consequences listed were unwanted pregnancies, STDs and emotional conflicts. Some other consequences listed included AIDS, but since AIDS is categorised as an STD, I will touch on it when approaching the general topic.

Firstly, I decided to research on how pregnancies would be considered "unwanted". I once again used http://google.com.sg/ to search for articles pertaining to the definition of an "unwanted pregnancy". According to an article found, an unwanted pregnancy is different from a mistimed pregnancy in the sense that pregnancies are actually "counted as 'unwanted' when the mothers who underwent birth (or suffered a miscarriage) made it clear that they did not want the child at the time of conception, 'or ever in the future.' "However due to a lack of further resources on the topic, I had to use my knowledge on the subject to give a clearer picture. Based on past lessons regarding "Issues on Sex" conducted by the schools I had attended, unwanted pregnancies are usually unplanned and may be the result of various reasons such as unsatutory rape etc. Therefore, it can be said that this is linked to the sensitive issue of emotional conflict, as in the case of such extreme corruption of morality as rape, victims are normally traumatised by the violence and cruelty. Furthermore, most unwanted pregnancies are considered "unwanted" as the mothers are usually young (in the teenage years) and do not have the financial nor emotional means to support the baby. Thus, such a consequence is definitely not a viable consequence of unprotected sex.

Finally, the last consequence of unprotected sex is the risk of transmission of STDs (Sexually Transmitted Diseases). According to http://answers.com/, the definition of a sexually transmitted disease is a disease that has a high probability of being spread through sexual contact etc. Highly dangerous, they have many consequences on a sufferer. There are numerous forms of sexually transmitted diseases, and some examples include Herpes simplex, Pubic lice or Syphilis. Many STDs have greatly undesirable consequences, and some include brain damage, heart ailments or even death in unfortunate cases. One very commonly known disease contracted through unsafe sex is AIDs (Acquired Immune Deficiency Syndrome). The disease has devastating effects on the sufferer as there is no available cure or vaccine for the disease. Furthermore, the disease weakens the immune system of the body considerably, causing the person to become greatly susceptible to viruses or even cancer. Therefore, prevention is vital in countering the contraction of STDs.

Prevention involves lifestyle changes and certain practices. For example, non-monogamous people are often susceptible to STDs as they run the risk of acquiring diseases from their partners if not regulated. One method of prevention is the usage of condoms properly. Another is to have regularly health check-ups to check for possible existence of sexual diseases one may possess and prevent the spread of the related disease. Also, there is one alternative which is celibacy or the abstinence of sex before marriage. Such measures can lower the risk of sexual infection.

In conclusion, there are many consequences of unsafe sex. Therefore, one must take the necessary steps to avoid the above mentioned consequences.

Sources:

http://au.answers.yahoo.com/question/index?qid=20080223162938AAPwn5f
http://en.epochtimes.com/news/7-5-13/55246.html
http://en.wikipedia.org/wiki/Sexually_transmitted_disease
http://www.answers.com/AIDS
http://www.answers.com/sexually%20transmitted%20diseases
http://en.wikipedia.org/wiki/Safe_sex

E-Learning Day 1: 25th June 2008

2008-06-25T19:50:00.000-07:00

E-Learning Day 1: 25th June 2008

Today, I decided to start off the bio-journal learning journey process with a question formulated on the topic of digestion.

What is the colon and what are it's functions in the digestive system?

First, I went to the website http://wikipedia.org/ to find the general function of the colon and find out if there was any alternative names to it. According to the site, the colon is also known as the large intestine and is located above the small intestine. It is between 1.2 metres-1.8 metres in length according to http://answers.com/ and primarily stores water, reclaims water, maintains the water balance in the body and absorbs some vitamins from partly undigested food (also known as chyme) such as vitamin K, a derived vitamin that is produced by bacteria in the large intestine.

In the colon, no digestive enzymes are secreted. Instead, bacteria present in the colon such as Escherichia coli digest most of the food i.e. cellulose, which is defined as glucose. At the stage where chyme arrives at the colon, roughly ninety-percent of water and almost all nutrients have been absorbed by the body. Remaining components include electrolytes like sodium, magnesium, chloride and indigestible carbohydrates known as dietary fibre. Most of the remaining water is removed and the chyme is mixed with mucus (slippery secretion of the lining of the mucous membranes in the body) and bacteria to become feces. Some of the dietary fibre is broken down by the bacteria and utilised for nourishment while waste products created as a result of this process are used by the cell lining of the colon for nutrition.

The feces is then passed on to the rectum for storage before exiting the body through the anus.

Images of the colon:

Sources:

http://home.earthlink.net/~cybernrse/colon.jpg
www.colonpalooza.com/
http://en.wikipedia.org/wiki/Colon_(anatomy)
http://www.answers.com/colon?cat=health