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Greenhouse Effect

What is the Greenhouse Effect?


Life on earth depends on energy from the sun. About 30 percent of the sunlight that beams toward Earth is deflected by the outer atmosphere and scattered back into space. The rest reaches the planet's surface and is reflected upward again as a type of slow-moving energy called infrared radiation.
The heat caused by infrared radiation is absorbed by "greenhouse gases" such as water vapor, carbon dioxide, ozone and methane, which slows its escape from the atmosphere.
Although greenhouse gases make up only about 1 percent of the Earth's atmosphere, they regulate our climate by trapping heat and holding it in a kind of warm-air blanket that surrounds the planet.
This phenomenon is what scientists call the "greenhouse effect." Without it, scientists estimate that the average temperature on Earth would be colder by approximately 30 degrees Celsius (54 degrees Fahrenheit), far too cold to sustain our current ecosystem.
How Do Humans Contribute to the Greenhouse Effect?
While the greenhouse effect is an essential environmental prerequisite for life on Earth, there really can be too much of a good thing.
The problems begin when human activities distort and accelerate the natural process by creating more greenhouse gases in the atmosphere than are necessary to warm the planet to an ideal temperature.
  • Burning natural gas, coal and oil -including gasoline for automobile engines-raises the level of carbon dioxide in the atmosphere.
  • Some farming practices and land-use changes increase the levels of methane and nitrous oxide.
  • Many factories produce long-lasting industrial gases that do not occur naturally, yet contribute significantly to the enhanced greenhouse effect and "global warming" that is currently under way.
  • Deforestation also contributes to global warming. Trees use carbon dioxide and give off oxygen in its place, which helps to create the optimal balance of gases in the atmosphere. As more forests are logged for timber or cut down to make way for farming, however, there are fewer trees to perform this critical function.
  • Population growth is another factor in global warming, because as more people use fossil fuels for heat, transportation and manufacturing the level of greenhouse gases continues to increase. As more farming occurs to feed millions of new people, more greenhouse gases enter the atmosphere.
Ultimately, more greenhouse gases means more infrared radiation trapped and held, which gradually increases the temperature of the Earth's surface and the air in the lower atmosphere.

The Average Global Temperature is Increasing Quickly

Today, the increase in the Earth's temperature is increasing with unprecedented speed. To understand just how quickly global warming is accelerating, consider this:
During the entire 20th century, the average global temperature increased by about 0.6 degrees Celsius (slightly more than 1 degree Fahrenheit).
Using computer climate models, scientists estimate that by the year 2100 the average global temperature will increase by 1.4 degrees to 5.8 degrees Celsius (approximately 2.5 degrees to 10.5 degrees Fahrenheit).


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12 “Superfoods” You Should be Eating Now


"Superfoods” are foods packed with nutrients that offer various health benefits, and have few if any negative properties. It’s not a medical term, but one that’s emerged more popular culturally. Since it’s best to load up on your vitamins through diet rather than through expensive vitamins, it’s always a great idea to reach for “superfoods,” and we’ve outlined the ones that are particularly good for women in their 20s and 30s. While these multitasking foods won’t make your Spidey senses tingle (or, maybe they will: read below about edamame), they may help to ward off diseases such as cancer, heart disease, Alzheimer’s and osteoporosis.    


Apples


Fiber-rich apples are a great food to help you feel fuller longer while providing you with a necessary dose of pectin, a soluble fiber. It’s believed that pectin reduces blood pressure, cholesterol, and the risk of colon cancer, breast cancer, and diabetes.    


Cranberries


You may know to gulp down cranberry juice if you’re suffering from a urinary tract infection (as a compound in cranberry juice helps to flush bacteria from the urinary tract), but did you know that cranberries also help to reduce cholesterol? Eat them dry, fresh, ground, as a salad topping, in a smoothie, or drink natural cranberry juice. Now that’s what we call versatility.       


Tomatoes


Tomatoes are loaded with the antioxidant lycopene, and they’re thought to play a role in protecting the skin against damage that leads to skin cancer--cases of which have soared recently in young women. Apart from that, tomatoes are rich in vitamin C, which can give your immune system a boost.    


Kale


While the research is still developing, kale may help to prevent breast and ovarian cancers. Researchers think that kale’s phytonutrients may cause the body to make enzymes that combat cancer-causing substances. If you need further evidence to try out this multi-purpose green, it’s also great for providing you with vitamin C, potassium and calcium. Remember, in your 20s and 30s you still need lots of calcium to build your bone mass to prevent osteoporosis.      


Blueberries


Blueberries aren’t just delicious, they may protect you against cancer and dementia, and can even neutralize free radicals that cause cell damage. That is, the nutrition in blueberries can help to protect the skin against prematurely aging (we knew that would perk you up!).    


Turkey


While it’s the showstopper at Thanksgiving, consider eating turkey regularly year round. In terms of superfood criteria, the selenium in lean turkey breast meat will help boost your immune function. Need more reason? It contains niacin and vitamins essential for energy production.    


Eggs


Women in their 20s and 30s disproportionately suffer from low iron levels that can lead to anemia, which can leave you feeling tired and low energy. Eggs are not only a great source of protein to start your day off right, but they also combat anemia because they are rich in iron. An added bonus: eggs have biotin and vitamin B-12, which can help make your mane lovelier by strengthening your hair.     


Spinach


Popeye was on to something with his obsession with this superfood, which is rich in vitamin K, vitamin A, magnesium, folate, manganese, iron, calcium, vitamin C, vitamin B2, potassium, and vitamin B6. Spinach also provides antioxidants (via flavonoids), is anti-inflammatory, aids digestion, and helps lower the effects of stress in the body (via magnesium). Perfect, since being in your 20s and 30s may be fun, but it’s a crazy stressful time of life.    


Quinoa


Quinoa is a whole grain that’s an excellent source of fiber and even has protein, so it’ll help you feel fuller for longer. Quinoa’s fiber and whole grain helps to prevent high cholesterol, and since it’s also rich in zinc, it’s thought to protect against stroke and cancer.     


Salmon


While salmon has omega-3 fatty acids, the key ingredient here is the DHA (docosahexaenoic acid). Your body can use DHA to protect its cellular membranes, which can help combat depression, cardiovascular disease, strokes, hypertension, and Alzheimer’s. And did you know taht omega-3 fatty acids are great for keeping mucous membranes in tip top shape--dry eyes remedy, anyone?     


Pistachios


Pistachios pack a wop of antioxidants your body needs to reduce cholesterol and even help reduce stress in some situations. In addition, they’re a great source of iron, calcium and potassium. If you’re looking to meet protein needs, pistachios will give you more than any other nut (apart from almonds). At snack time, go for unsalted in shells. And those shells are actually a good thing, since the time it takes to crack and eat each pistachio will make you more conscious of portion size (probably why we’ve heard pistachios be referred to as “the skinny nut”).    


Edamame


Folate isn’t just important for expectant mothers, but for all women of childbearing age. It’s even been shown to ward off grey hair in some cases. For a healthy folate-rich snack, steam edamame or sprinkle it onto a salad. Some have even pointed to edamame as something of an aphrodisiac. Looks like you may want to head to a sushi restaurant for your next date night…    

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Why is Smoking is Bad for Health?

"Smokers never become old because they die younger."

This saying reveals a harsh fact about the hazardous effects of smoking. There are millions of people who are addicted to cigarette smoking throughout the world. Why do people start smoking? Well, there are several different reasons for smoking. Some people start smoking in their teens just for the sake of the thrill and sometimes, it's peer pressure. Eventually, they become addicted to the nicotine present in cigarettes. Some people smoke to get relief from stress.

People with low self-esteem become more addicted to smoking. Whatever the reason, once a person gets addicted to smoking, he/she has to face a number of serious health problems. Let's take a look at what are some of the health complications that an average smoker is exposed to.

Diseases Caused Due to Smoking

There are several harmful health effects of cigarette smoking. A person addicted to smoking may suffer from a number of serious and fatal diseases. Smokers are more likely to suffer from respiratory infections and several minor complaints such as coughand cold. Smokers may suffer from some dreadful diseases such as cancer, heart, cardiovascular and lung diseases. Also caused, are respiratory problems and several other problems related to the kidneys, liver and pancreas.

Cancer: Smokers are at a higher risk of getting cancer than non-smokers. Carcinogens, such as tar, present in tobacco smoke, can cause cancer of the lungs, mouth, throat and gullet. Mouth cancer, which is a highly common occurrence among smokers, starts off usually on one's lips or underneath the tongue. About 90% of lung cancer cases are due to smoking. Female smokers are at a greater risk of getting cervical cancer. Smokers can also develop other types of cancers such:

  • Larynx cancer
  • Acute myeloid leukemia
  • Stomach cancer
  • Kidney cancer
  • Lung cancer
  • Pharynx cancer
  • Esophagus cancer
  • Oral cavity cancer
  • Bladder cancer
  • Pancreatic cancer
It has been observed that smokers who've smoked earlier in life, and light up many times in a single day, are at a higher risk of getting lung cancer. A startling yet interesting fact, is that ex-smokers have about 15 years before they are cleared from the high risk of getting lung cancer.

Cardiovascular Diseases: These are diseases of the heart, its blood vessels, and other related organs. Coronary disease is a major cause of death related to smoking. Nicotine present in tobacco, increases cholesterol levels in the blood, getting clogged within the arteries; causing a hardening in the arteries. The arteries become narrow, rigid, or blocked.

Due to atherosclerosis (narrowing of arteries), blood clots are formed, thus increasing the risk of having a cardiovascular disease. Common cardiovascular diseases found in smokers are coronary thrombosis, cerebral thrombosis, coronary heart diseases, blockage in the legs (peripheral vascular disease) and cerebrovascular diseases such as stroke. Smoking can also cause what is called abdominal aortic aneurysm, which is a condition where the aorta swells up or weakens; this is a major artery in the body.

Respiratory Conditions: COPD or Chronic Obstructive Pulmonary Disease, is a group of health conditions that block airflow, thus making it difficult to breath. It causes health problems such as emphysema and chronic bronchitis. Emphysema is breathlessness caused by damage to the alveoli (air sacs). Chronic bronchitis causes frequent coughing with a lot of mucus.

Smoking increases the rate of decline in lung function to three times its usual rate. Breathlessness starts due to regression of lung functions. For runners who smoke, this habit can cause breathlessness and difficulty in breathing, since the lungs have to work harder than usual. This can cause one to run out of air within minutes, not making it as effective if one were a non-smoker.

Other Conditions Caused by Smoking
  • Smoking causes an acidic taste in the mouth. It can increase the risk of developing mouth ulcers.
  • The chemicals present in tobacco damage the lining of the blood vessels and affect the levels of fat in the bloodstream. It increases the risk of atheroma, which is the main cause of heart disease, strokes, and aneurysms.
  • Smoking deteriorates oral health, leading to stained teeth and gums. Smoking can give rise to various health problems of the gums and teeth, such as swollen gums, loose teeth, and bad breath.
  • Smoking can give rise to various sexual problems. People addicted to smoking are more likely to face fertility and sexual performance issues.
  • Smoking increases the risk of high blood pressure which is a risk factor for stroke and heart attacks.
  • Smoking worsens asthma in patients who smoke, increasing the inflammation of the airways.
  • Smoking can cause premature aging. Due to smoking, the blood supply to the skin is reduced, thus reducing the levels of vitamin A. Hence, smokers have paler skin and more wrinkles.
  • Women who smoke, increase the chances of suffering from hip fractures, than non-smoking women. This is because women who smoke have a lower bone density, like in postmenopausal women.
  • Heavy smoking causes macular degeneration which results in gradual loss of eyesight. Smokers are also at a higher risk of cataract.
  • Some other conditions caused by smoking are chest infections, diabetic retinopathy, tuberculosis, multiple sclerosis and Crohn's disease.
  • There are even passive effects of smoking, which can be quite dangerous to the non-smokers in the company of smokers. If babies and kids come in contact with smokers, they are highly prone to asthma and infections of the ear, nose, and chest. They are also at a high risk of Sudden Infant Death Syndrome (dying while asleep).
Effects of Smoking During Pregnancy

A pregnant woman who frequently smokes is at a higher risk of a miscarriage and other complications such as bleeding, detachment of placenta, and ectopic pregnancy. There is a possibility of giving birth to a baby with a low birth weight, or a stillborn baby. There may be some congenital defects in the baby (for instance, a cleft palate). Mothers who smoke can also suffer from preterm delivery and infertility issues.

Summary of Why Smoking is Dangerous

It is estimated that every minute about 7 people die due to tobacco use. According to researches, tobacco in a cigarette contains more than 400 toxic substances and 4,000 chemical compounds. Let us see how harmful smoking such substances can be.
  • The most hazardous substances in cigarettes are tar (which is a carcinogen), nicotine (which increases cholesterol levels in the body) and carbon monoxide (which decreases the amount of oxygen within the body).
  • Nicotine is the most addictive substance in tobacco. Smoking decreases the level of oxygen from reaching the tissues, giving rise to different health problems such as strokes, heart attacks or miscarriages.
  • It increases cholesterol levels in the blood, thus increasing the risk of heart attacks.
  • Smoking causes damage and constriction of blood vessels, leading to various diseases of blood vessels.
  • Smoking also causes chronic coughing, shortness of breath, premature aging, recurrent infections and reduced overall fitness.
  • Smoking-related deaths are mainly because of heart diseases, cancers and COPD (chronic obstructive pulmonary disease).
Smoking adversely affects the health of a smokers and of those around them. The only way to prevent these health hazards is to quit smoking. It's never too late to stop smoking. It could protect you and your family from many fatal diseases. After all, health is wealth, isn't it?



 
 
 
 
 

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6 Reasons to Avoid Soy Milk

The soybean is a rich form of protein and other nutrients that has been the basis of several Asian dishes for thousands of years. It wasn’t a big stretch for the industry to claim that, if a whole food is so good, then surely the concentrated juice of this food must be even better. It certainly caught the imagination of many of the baby boomer generation and they enthusiastically embraced the new “milk without guilt”. Soy growers contribute a substantial levy which is used to market soy products and the marketing has been a major success story with soy milk sales in the US rising from two million dollars in 1980 to 300 million dollars last year. The problem was that no one told the health-minded consumers that the Asians wouldn’t touch soy milk with a barge pole. They understood that there were some problems with this legume so they only ate it in fermented form, i.e. lacto-fermentation neutralises the negatives associated with soy products. So what is wrong with this ‘miracle health food’? Let’s look behind the big budget advertising.

A beautiful soy crop - Ready for harvest
A beautiful soy crop - Ready for harvest

Six Serious Soy Problems

I) Soy milk is one of the highest known
sources of phytates.

Phytic acid is a natural acid found in cereal grains and legumes which inhibits the uptake of important minerals like zinc, magnesium and calcium. The body contains relatively large amounts of magnesium and calcium but very low stores of the trace mineral, zinc. The vast majority of us are deficient in zinc and yet this is the main mineral involved in the health of the prostate gland and prostate cancer is set to become the largest killer of Australian men. Zinc is also linked to breast health and it is essential for the thymus gland and the associated production of killer T cells for the immune system. Zinc is often called “the intelligence mineral” because it also plays a major role in the development and health of the brain and central nervous system. Phytates form insoluble zinc phytates so it is always best to supplement your zinc directly before bed. This ensures that it doesn’t conflict with phytic acid in your breakfast cereal or your lunchtime sandwich.

2) Soy milk contains huge amounts of
enzyme inhibitors.

If Dr Edward Howell is correct then we are born with a certain capacity to produce enzymes and when we have exhausted our enzyme capacity then we die. Every time we eat cooked food we withdraw from this bank account, as opposed to consumption of raw food which contains the enzymes which help to digest it. Every function from breathing to thinking to digesting is enzyme-dependent. If we over-stress the digestive system then metabolic enzymes from the immune system or detox system, for example, are directed to help out with digestion. The very worst thing we can do is to speed up the ‘use by’ date of our enzyme capacity by consuming foods or taking drugs which inhibit this precious workforce. Aspirin is a serious enzyme inhibitor, for example, even when it is taken at low doses to thin the blood. The soya bean contains very high levels of enzyme inhibitors to help prevent premature germination. The most important enzyme affected is trypsin which is involved in the digestion of protein. As a result, soy products can lead to gastric distress, reduced protein digestion and serious deficiencies in amino acids. Animal research has shown that diets high in trypsin inhibitors are linked to serious pancreatic disorders, including cancer. Soy milk effectively concentrates the enzyme inhibitors found in the bean.

3) Soy milk contains haemagglutinin which
compromises delivery of cellular oxygen.



Haemagglutinin is a clot-promoting substance which causes red blood cells to clump together. This, in turn, limits the capacity of these cells to absorb oxygen for delivery around the body and can compromise heart health. Haemagglutinin and enzyme inhibitors are both growth depressors so it is incomprehensible that infant formulas are so often based on soy milk. It becomes blatant stupidity when you understand that soy milk is also a goitrogen (causing enlargement of thyroid gland).

4) Soy milk negatively affects the health
of the thyroid gland.

Soy milk contains genistein which can do irreversible damage to the enzymes that synthesise thyroid hormones. In 1991 Japanese researchers found that as little as 30 grams of soy beans per day for one month resulted in a significant increase in the thyroid stimulating hormone. In fact, several of their subjects developed diffuse goitre and hyper thyroidism and complained of constipation, fatigue and lethargy, even though their intake of iodine was adequate.

5) Soy milk contains unacceptably high
levels of aluminium.



The soy bean is an aluminium accumulator and as a result soy milk contains 100 times more aluminium than cow’s milk. Aluminium has been heavily implicated in the current plague of Alzheimers Disease. Alzheimers now affects one person in four, over the age of 65. Unlike cow’s milk, soy milk is a highly processed material. Soybeans are first mixed with an alkaline solution to remove fibre, then precipitated and separated using an acid wash and, finally, neutralised in an alkaline solution. Acid washing in aluminium tanks leaches aluminium into the end-product. Soy-based formula contains over 1000% more aluminium than conventional, milk-based formula due to the concentrating effect of the powdering process. During the spray drying process, used to create the high protein powder, unacceptable levels of nitrates are formed and a toxin called lysinoalanine is also formed during the alkaline stage of the processing. In the US, if you are unlucky enough to live there, 99% of the soy is genetically modified and it is also one of the most chemical intensive of the broadacre crops in that country. You wouldn’t think that the soy milk formula vs. the breast milk debate would be too hard considering these facts.

6) Soy milk features high levels of phytoestrogens which are proven endocrine disruptors.

Soy contains isoflavones which are currently being researched in relation to treatment for osteoporosis, relief of menopausal symptoms, cancer prevention and heart disease. It sounds an impressive list and you might argue that ‘what could be wrong with consuming these compounds every day in your food?’. The problem relates to balance, a key factor influencing the health of plants, animals and humans. While isofavones are powerful compounds with undeniable medicinal potential, like any medicine, they should only be used for short periods to address specific issues. When we consume them, in concentrated form, on a daily basis, they can become both disruptive and dangerous. When toxicologist, Dr Mike Fitzpatrick, conducted an extensive literature review of soy research, he was shocked to find that consumption of this vegan “wonder food” has been linked to numerous disorders. He found that the phytoestrogen, genistein, had been linked to endocrine disruption in animals, in studies dating right back to the 1950′s. He also discovered research confirming links to infertility, increased cancer and infantile leukemia. Some US commentators are even suggesting that soy has the potential to become the next asbestos. In a recent New York Times feature article, the author, a previous soy supporter, begrudgingly admitted that “not one of the 18 scientists interviewed for this article was willing to say that taking isoflavones was risk free”.

In Conclusion

Both margarine and soymilk are examples of the opportunistic bastardisation of whole foods in pursuit of profit. There has never been a single example where industrial manipulation of whole foods has not seriously compromised the nutritional integrity of that food. At some point, perhaps, we will finally recognise that science cannot improve on the original when it comes to food. Food has been sacred in every society prior to ours and the bombarding of our food with massive amounts of radiation is about as far removed from sacred appreciation as is possible. Removing margarine, soymilk and microwaves from your kitchen is a good start to reclaiming vitality in your diet.

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Cytokinesis


Cytokinesis

Cytokinesis is the process by which a cell divides its cytoplasm to produce two daughter cells. As the final step in cell division after mitosis , cytokinesis is a carefully orchestrated process that signals the start of a new cellular generation. The separation of one cell into two is accomplished by a structure called the contractile ring. The contractile ring is a structure believed to operate in a way similar to muscle. A molecular motor, myosin, contracts the actin filaments that form the contractile ring tighter and tighter until the cell is pinched in two. The contraction of the contractile ring has been likened to tightening a purse string to close the top of a pouch. The furrow created by this pinching process is also called the "cleavage furrow," as it is the site at which cleavage of one cell into two cells occurs.
Cytokinesis consists of four major steps. The first step is to define the position at which the contractile ring will form. The spindle, the structure responsible for segregating the chromosomes into what will become the daughter cells, also appears to be responsible for defining where the contractile ring forms. The contractile ring forms perpendicular to the long axis of the spindle at its midpoint. Components of the spindle that come in contact with the plasma membrane, called astral microtubules, are believed to transmit a signal to the cell periphery that tells actin and other components of the contractile ring to assemble at that location. Actin and microtubules are both part of the cytoskeleton .
The second step in cytokinesis is to assemble the actin filaments that form the contractile ring. Additional proteins , including the molecular motor myosin, which powers contraction, also assemble in this same domain. The third step is the actual contraction of the contractile ring. In this step, the myosin motor, powered by adenosine triphosphate, moves the actin filaments past each other, much in the same way as myosin interacts with actin to power the contraction of muscle. This step also requires the removal of actin subunits to allow the ring to decrease in size. The final step, breaking and refusion of the plasma membrane, occurs once the ring has contracted to its minimum size. This breaking and fusion finally separates the two daughter cells from each other.
As with each of the steps in mitosis, cytokinesis is highly regulated. If the cell were to divide its cytoplasm prior to the completion of duplication and segregation of the chromosomes, it is unlikely that each of the progeny cells would receive the proper genetic information. Thus the cell employs several regulatory mechanisms to assure that cytokinesis occurs only after all of the chromosomes have been properly segregated. There is, for example, a "spindle checkpoint" that assures that each and every chromosome has attached to the spindle. The entire process of cell division waits at the checkpoint until the conditions of the checkpoint have been satisfied. Once they have been, the process continues and concludes with cytokinesis.

Cytokinesis in Animal Cells

The first step in cytokinesis in animal cells is the contractile ring positioning. The difference between cytokinesis in plants and animals arises from this stage itself. Animal cell cytokinesis begins just after the onset of sister chromatid separation in the anaphase of mitosis. A contractile ring that is made of non-muscle myosin II and actin filaments, assembles equatorially, that is, in the middle of the cell, at the cell cortex. The cell cortex is adjacent to the cell membrane. Myosin II uses the free energy released when ATP is hydrolysed to move along these actin filaments, thus, constricting the cell membrane to form a cleavage furrow towards the middle. The continuing hydrolysis causes this cleavage furrow to ingress, that is, move inwards. This process is visible with the help of a light microscope. Ingression continues until a midbody structure that is composed of electron-dense, proteinaceous material is formed and the process of abscission then physically cleaves this midbody into two.

The abscission depends on septin filaments beneath the cleavage furrow, which provides a structural basis to ensure completion of cytokinesis. After cytokinesis, non-kinetochore microtubules reorganize and disappear into a new cytoskeleton as the cell cycle returns to the interphase. The position at which the contractile ring assembles is dictated by the mitotic spindle. Simultaneous with contractile ring assembly during prophase, a microtubule based structure called the central spindle forms when non-kinetochore microtubule fibers are bundled between the spindle poles. Cytokinesis must be a controlled procedure so as to ensure that it occurs only after sister anaphase separation during normal proliferative cell divisions. To achieve this purpose, many components of the cytokinesis machinery are highly regulated so as to ensure that they are able to perform a specific function at only a specific stage of the cell cycle.

 


Cytokinesis in Plant Cells

As mentioned earlier, cytokinesis in plants and animals is basically different from each other due to the presence of cell wall, which is one of the plant cells parts. Rather than forming a contractile ring, plant cells form a cell plate in the middle of the cell. The Golgi apparatus releases vesicles that contain cell wall materials. These vesicles fuse at the equatorial plane to form the cell plate. The cell plate initially begins as a fusion tube network, which then becomes a tubulo-vesicular network as more and more components are added.

There is only one exception to the process of cytokinesis, which is in the case of oogenesis, which is the process where an ovum is created in the ovarian follicle of the ovary. Here, the ovum takes up almost all the cytoplasm and organelles, thus, leaving very little for the resulting polar bodies which eventually die. Thus, there is no division of the cytoplasm per se. However, in all other cells, irrespective of whether they are plant cells or animal cells, cytokinesis is the method by which the cell divides into two.
 

 
 
 
 
 
 


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Tissue Culture


Tissue culture is a process that involves exposing plant tissue to a specific regimen of nutrients, hormones, and light under sterile, in vitro conditions to produce many new plants, each a clone of the original mother plant, over a very short period of time. AgriForest's tissue culture plants are characterised by disease free growth, a more fibrous, healthier root system, a bushier branching habit, and a higher survival rate.
There are three main steps to the tissue culture process:


STAGE I is the initiation phase. It concerns the establishment of plant tissue in vitro by sterilising the material and initiating it into culture.


STAGE II is the multiplication phase. At this stage, the in vitro plant material is re-divided and placed in a medium with plant growth regulators that induce the proliferation of multiple shoots. This process is repeated many times until the number of plants desired is reached.


STAGE III is the root formation phase. It involves the introduction of hormones to induce rooting and the formation of complete plantlets.

Following these three stages, the plants are then moved from the laboratory to the greenhouses for acclimatisation and further development.



 
 
 
 

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Phagocytosis Process In Amoeba

Phagocytosis

Phagocytosis is a process used by certain cells to engulf and ingest solid particles. The particles engulfed and ingested can be nutrient particles or bacteria. The cells capable of ingesting in such a manner, by the phagocytosis process, are known as phagocytes. The phagocytes can be free living unicellular organisms, such as amoeba, or they can be part of the body cells of a multicellular organism. Phagocytes belongs to the family of processes, that are collectively referred to as 'endocytosis', consisting of all the processes that involve ingestion of material by cell.

What is the Process of Phagocytosis :

Phagocytosis process is a specific type of endocytosis, that involves vesicular internalization of solid particles, such as bacteria, unlike other endocytosis process that involve vesicular internalization of liquids. Certain unicellular organisms, such as the protists, use this particular process as means of feeding. It provides them part or all of their nourishment. This mode of nutrition is known as phagotrophic nutrition. In amoeba, phagocytosis takes place by engulfing the nutrient with the help of pseudopods, that are present all over the cell, whereas, in ciliates, a specialized groove or chamber, known as the cytostome, is present, where the process takes place.

Other examples of phagocytosis include some immune system cells, that engulf and kill certain harmful, infectious micro-organisms and other unwanted foreign materials. Mammalian immune system contains certain phagocytes that helps them to destroy and get rid of pathogenic bacteria and other infectious organisms. In these cells, the engulfment of foreign material is facilitated by actin-myosin contractile system. It allows the cell membrane to expand in order to engulf the particle and then contract immediately, ingesting it.

Phagocytosis Steps :
It is quite fascinating to watch the process under a microscope. One can actually see the phagocyte engulfing the foreign particle. There are several distinct steps involved in the process of phagocytosis. Let us have a look at them.

In case of unicellular organisms, the process of phagocytosis takes place when the organism comes in contact with the nutrient particles. The phagocytes in the immune system are activated in the presence of certain bacterial cells, inflammatory cells or other foreign bodies. Let us talk about the general steps involved in the process.

Step 1: The phagocytes get activated by the presence of certain particles around them. As soon as they detect a foreign particle, the phagocytes produce surface glycoprotein receptors, that increase their ability to adhere to the surface of the particle.

Step 2: The phagocyte slowly attaches to the surface of the foreign particle. The cell membrane of the phagocyte begins to expand and forms a cone around the foreign particle.

Step 3: The cell membrane surrounds the foreign particle from all sides to create a vacuole, known as phagosome or food vacuole. The phagosome is then passed into the cell for absorption.

Step 4: Now comes the role of the lysosomes, which are cell structures, that are specialized in digesting the particles that enter the cell through the cell membrane. The lysosomes break the food vacuole or phagosome, into its component materials. The essential nutrients, if any, are absorbed in the cell, and the rest is expelled as waste matter. In case of the immune system, the cell creates a peroxisome, a special structure that helps the body to get rid of the toxins.

In unicellular organisms like amoeba, phagocytosis is necessary for survival, as they are totally dependent on it for nutrients. Some of these organisms have adapted special traits which enable them to locate and keep a track of the food particles.
 
 
 
 
 
 
 
 
 
 
 
 
 


 

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Healthy Eating

Eating Based on Food Pyramid


Healthy Eating Pyramid  Guidelines :

 
Daily Exercise & Weight Control
 
The Healthy Eating Pyramid has a picture of “Daily Exercise and Weight Control” on its base, showing that these two related elements strongly influence your chances of staying healthy. They also affect what you eat and how your food affects you. Exercise and weight control are also linked through the simple rule of energy balance; that you will gain weight if you eat more than you burn. By exercising regularly it will help you control your weight and it is the key part of any weight loss effort.

Vegetables and Fruits

Vegetables and fruits take up a big section of the food pyramid, showing their importance. Vegetables and fruits are rich in colour and taste. They add variety to your diet and are a feast for the eyes, but they can do even more for you. By eating a lot of vegetables and fruits everyday you will gain the possibility to stay healthy throughout your life. You will create a beneficial habit that may: lower your blood pressure, reduce your risks of having cardiovascular diseases and cancer, protect you from losing your vision when you are getting older and also help you from having diverticulitis (intestinal ailment).

Healthy Fats and Oils

The Healthy Eating Pyramid puts the fats and oils near the base which is a bit different and unconventional if you compare to other food pyramids, but it makes sense. They are inline with the evidence: unsaturated fats are healthy fats. They don’t improve cholesterol levels and they can protect against heart problems. Putting the fats and oils near the base is also in line with common eating habits since the average American gets about one-third of its daily calories from fat. This is why it is so important to eat healthy fats. Healthy fats can be found in vegetable oils, nuts, seeds, avocados and fatty fish like salmon.

Whole Grains

You need carbohydrates for energy and whole grain is the best source, which the food pyramid illustrates. Research suggests that we should eat a diet rich in whole grains because it helps controlling our blood sugar and insulin levels from rising and falling too quickly. The reason for this is that the body can’t digest whole grains as quickly as with processed carbohydrates such as white bread. By eating whole grains you won’t feel hungry that often, which will have a positive effect on your weight. It may also prevent the development of type 2 diabetes and protect you against heart diseases. Whole grains can be found in oatmeal, whole bread and brown rice.

Nuts, Seeds, Beans and Tofu
The Healthy Eating Pyramid shows the importance of eating nuts, seeds, beans and tofu. They are all rich in protein, fibre, vitamins and minerals. Many kinds of nuts contain healthy fats and vitamin E. Research has even suggested that they are good for your heart especially: almonds, walnuts, pecans, peanuts, hazelnuts, and pistachios.

Fish, Poultry and Eggs

Fish, poultry and eggs are included in the food pyramid because they are rich in protein. Chicken and turkey are also good sources of protein and are low in saturated fat. Research suggests that you can reduce the risk of heart disease if you eat fish rich in omega-3 fats. Salmon, trout and herring are especially high in omega-3 fatty acids. Eggs have been said to be bad for your health because they are high in cholesterol, but if you compare it to a doughnut made from refined flour and cooked in oil (rich in trans fat), eating an egg for breakfast is a much healthier alternative. If you have diabetes or heart disease you should not eat more than 3 eggs (egg yolk) a week. The egg whites are fine though; they are rich in protein and a fine substitute in omelettes and baking.

Dairy (1 to 2 servings per day) or Vitamin D/Calcium Supplements

If you want to grow and have strong bones you need Vitamin D, Calcium and exercise, according to the Healthy Eating Pyramid. You will get most of vitamin D and Calcium from your dairy but sometimes it’s not enough. For example: If you drink one glass of milk you will get 100 IU (International Units) of vitamin D but you need at least 1,000 IU every day. The answer to that problem should logically be to drink more milk or eat more dairy products, but if you drink three glasses of whole milk you will get as much saturated fat as 13 strips of cooked bacon! So what is the solution if you want to stay healthy and in control of your weight? How can you get enough vitamins and minerals without getting too much of the unhealthy saturated fat? The solution to this dilemma is to stick to no- or low-fat dairy products. If you don’t get enough vitamin D and Calcium from the dairy products, you should consider taking vitamin D and calcium supplement, according to Healthy Eating Pyramid.

Use Sparingly: Red Meat and Butter

To the left at the top of the Healthy Eating Pyramid you will find red meat and butter. It has the smallest section of the food pyramid because you should eat less red meat and butter. Red meat and butter contain lots of saturated fat and may increase your risk of colon cancer. Instead, if you switch to eating fish, chicken or beans more often and switch from butter to olive oil, it can improve your cholesterol levels as well as the overall condition of your heart health, according to Healthy Eating Pyramid.

Use Sparingly: Refined Grains (White Bread, Rice, Pasta), Potatoes, Sugary Drinks, Sweets, Salt

The reason why refined grains, potatoes, sugary drinks, sweets and salt are placed at the top of the Healthy Eating Pyramid (together with red meat and butter), is that you should eat/drink very little of this kind of products. They increase blood sugar levels, making you feel hungry quickly with the results that you eat more and gain more weight. It may also cause diabetes and other chronic disorders. A new addition to the Healthy Eating Pyramid is that it says “Use Sparingly” next to the salt shaker. Research has found that high-sodium diets increase risk of health problems causing heart attack and stroke.

Multivitamin with Extra Vitamin D (for most people)

If you look to the left of the Healthy Eating Pyramid you will find a bottle of multivitamin and multimineral supplement, emphasizing vitamin D. It is not suggested to replace a healthy diet, rather fill in the nutrient holes that sometimes occur.
There are supplements that don’t cost a lot of money that will do just fine. Look for a multivitamin that meets the requirements of the USP (U.S. Pharmacopeia), an organization that sets standards for drugs and supplements. Then look for the standard RDA-level (Recommended Dietary/Daily Allowance) which will be enough for most nutrients, except for perhaps vitamin D. Vitamin D is important for your bones and new research even suggest that some extra vitamin D (1,000 IU per day) can help lower the risk of colon and breast cancer. People who live in the northern parts during winter or have darker skin will need extra vitamin D (3,000-4,000 IU per day). If you are unsure, ask your doctor to check your blood level.

Optional: Alcohol in Moderation (not for everyone)

A bottle of wine is placed next to the food pyramid to point out that consumption of alcohol is optional. According to studies the risk of heart diseases may reduce if you have a moderate amount of alcoholic drink. In general however, the risks of drinking, even in moderation, exceed benefits until middle age. Women should avoid alcohol during pregnancy.



 

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The Different Types of Relationships Among the Living Organisms in Biosphere

Type of Organisms and their Relationships

Many ecosystems have different types of Species those have different manners of interrelationship among them. These species interact with each other to establish a stable ecological balance. These types of relationships may be of interspecific or intraspecific categories. Different types of associations are discussed below :

a) Saprotropism: In this type of association one type of organism is living, where other is dead organic matter. Living organisms grow on the dead and decaying organic bodies like wood, bread, lemon etc. and take their nutritive elements from those dead organic materials. Saprophytic nutrition is found in non-green plants which draw their nourishment from dead matters. Saprophytes may be of two types : Total and Partial.
Total saprophytic plants completely depend on the dead and decaying substances for nutrition. E.g. Mucor, Agaricus.

b) Antagonism: In this type of interaction either one or both type of organisms are harmed. This association is subdivided into following categories :

1. Parasitism: In this type of relationship one type of organism is benefited and other is harmed. In this category of heterospecific association one organism (Parasite), lives at the expense of other associated organism (Host). Among plant kingdom Dodder (Cuscuta reflexa) collects its nutritive elements fro the host plant with the help of sucking root called Haustoria. Among kingdom Animalia two types of parasites are found : Ectoparasite (living outside the host body) and Endoparasite (living inside the host body). Round worm is an ectoparasite living inside the human small intestine and draw nutrition as endoparasite but Louse is an ectoparasite at it lives outside the human body i.e. on the outer body surface.

2. Exploitation : In this type of relationships one organism enslaves the other organism.

3. Predation : In this type of association one organism catches and kills the other type of oraganism and take it as food. As Tiger catches deer, Pitcher plant catches insects for their food, Human catches fishes.

4. Ammensalism or antibiosis : In this type the chemical secretion of organism's body harms the another but no nutrition takes place. The chemical secretion is called Antibiotic. Penicillin is an antibiotic produced from the fungus Penicillium notatum that kills the bacterium Staphylococcus bacterium.

5. Competition : In this type of nutrition two organisms when living in a specific ecosystem compete with each other for food and shelter.

6) Symbiosis : In this type of relationship living organisms live together and help one another. It is mainly of three categories :

1. Commensalism : In this type of association one organism may be benefited and other may remain neutral but no one is harmed. Fireasfer fish lives inside the cloacal cavity of Sea cucumber to protect itself from the attack of predators. Here no one is harmed, but Fireasfer fish is protected. So, it is an example of commensalism relationship between them.

2. Mutualism : It is an obligatory relationship between two organisms where both of the individuals are benefited by each other and they are physiologically inter-dependant with each other. The association between the algae Zoochlorella and Hydra is an example of mutualism where both are benefited by each other. Lichen is the result of a union between a green alga and a fungus. The fungus gains oxygen and carbohydrates from the alga and the alga obtains water carbon dioxide and mineral salts from the fungus.

3. Protocooperation : this is an facultative relationship between two organisms where both the individuals are benefited by each other but they can also live independently. Association between hermit crab and sea anemone is an example of  Protocooperation.

4) Neutralism : This is one type of relationship between/among two or more type/types of organism/organisms where they live together but neither they are benefited nor harmed. In the freshwater bodies this type of relationship is found between Hydra and Phytoplankton.

GLOSSARY FOR HELPING THE READERS :
1. Intraspecific : between/among same species.
2. Interspecific : between /among different species.
3. Organic : related to living body.
4. Nutritive elements : substances required for the purpose of nutrition of organisms.
5. Heterospecific : between/among different organisms.
6. Kingdom Animalia : animal kingdom.
7. Pitcher plant : an insectivorous plant.
8. Cloacal cavity : a part of alimentary canal contains faecal elements.
9. Alga : singular form of algae.

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Reproductive System

Reproductive system in Animals

Animals’ reproductive systems can be divided into the internal reproductive organs and the external genitalia. The gonads are the actual organs that produce the gametes. In the male, testes (singular = testis) produce sperm, and in the female, ovaries make eggs.
In most animals, individuals are either definite males or definite females. However, in some species, individual organisms are both male and female. Hermaphroditism is when one organism has both sexes. Earthworms and garden snails always have both male and female organs, and when, for example, two earthworms mate, they fertilize each other. A special variation on the theme is sequential hermaphroditism, in which an organism changes sex during its life. If an organism is female first and later changes to male, that organism is protogynous, and if the organism is male first and changes to female, it is said to be protandrous. In different species, sequential hermaphroditism can be influenced by the organism’s age or size or by various environmental/climatic factors.
While most higher animals reproduce sexually, there are some species in which the females can, under certain conditions, produce offspring without mating. Parthenogenesis is the ability of an unfertilized egg to develop and hatch. This seems to be especially prevalent among insects. Some of the giant walkingsticks at the Zoo are females who, without mating, lay eggs that hatch into more females generation after generation. Other insects, like some aphids, have complicated life cycles that involve sexually-reproducing generations alternating with parthenogenically produced generations. In honeybees, fertilized eggs turn into females (workers and queens), while unfertilized eggs, which are only produced in the spring, turn into males.
In sexual reproduction, there must be some way of getting the sperm to the egg. Since sperm and eggs are designed to be in a watery environment, aquatic animals can make use of the water in which they live, but terrestrial animals must, in some way, provide the wet environment neeeded for the sperm to swim to the egg. There are, thus, two major mechanisms of fertilization. In external fertilization, used by many aquatic invertebrates, eggs and sperm are simultaneously shed into the water, and the sperm swim through the water to fertilze the egg. In internal fertilization, the eggs are fertilized within the reproductive tract of the female, and then are covered with eggshells and/or remain within the body of the female during their development.
In species with external fertilization, at an appropriate developmental stage, the eggs hatch, and the new young simply swim away. However, females of species with internal fertilization must, at some point, expel the growing young. There are three general ways of doing this:

  • Oviparous organisms, like chickens and turtles, lay eggs that continue to develop after being laid, and hatch later.
  • Viviparous organisms, like humans and kangaroos, are live-bearing. The developing young spend proportionately more time within the female’s reproductive tract, portions of which are specially-modified for this purpose. Young are later released to survive on their own.
  • Ovoviviparous organisms, like guppies, garter snakes, and Madagascar hissing roaches, have eggs (with shells) that hatch as they are laid, making it look like “live birth.”

Reproductive System in Humans :

1. Male Reproductive System :

The male reproductive system is illustrated to the right. Sperm are produced in the testes located in the scrotum. Normal body temperature is too hot thus is lethal to sperm so the testes are outside of the abdominal cavity where the temperature is about 2° C (3.6° F) lower. Note also that a woman’s body temperature is lowest around the time of ovulation to help insure sperm live longer to reach the egg. If a man takes too many long, very hot baths, this can reduce his sperm count. Undescended testes (testes are supposed to descend before birth) will cause sterility because their environment is too warm for sperm viability unless the problem can be surgically corrected.
From there, sperm are transferred to the epididymis, coiled tubules also found within the scrotum, that store sperm and are the site of their final maturation.
In ejaculation, sperm are forced up into the vas deferens (plural = vasa deferentia). From the epididymis, the vas deferens goes up, around the front of, over the top of, and behind the bladder. A vasectomy is a fairly simple, outpatient operation that involves making a small slit in each scrotum, cutting the vasa deferentia near where they begin, and tying off the cut ends to prevent sperm from leaving the scrotum. Because this is a relatively non-invasive procedure (as compared to doing the same to a woman’s oviducts), this is a popular method of permanent birth control once a couple has had all the children they desire. Couples should carefully weigh their options, because this (and the corresponding female procedure) is not designed to be a reversible operation.
The ends of the vasa deferentia, behind and slightly under the bladder, are called the ejaculatory ducts. The seminal vesicles are also located behind the bladder. Their secretions are about 60% of the total volume of the semen (= sperm and associated fluid) and contain mucus, amino acids, fructose as the main energy source for the sperm, and prostaglandins to stimulate female uterine contractions to move the semen up into the uterus. The seminal vesicles empty into the ejaculatory ducts. The ejaculatory ducts then empty into the urethra (which, in males, also empties the urinary bladder).
The initial segment of the urethra is surrounded by the prostate gland (note spelling!). The prostate is the largest of the accessory glands and puts its secretions directly into the urethra. These secretions are alkaline to buffer any residual urine, which tends to be acidic, and the acidity of the woman’s vagina. The prostate needs a lot of zinc to function properly, and insufficient dietary zinc (as well as other causes) can lead to enlargement which potentially can constrict the urethra to the point of interfering with urination. Mild cases of prostate hypertrophy can often be treated by adding supplemental zinc to the man’s diet, but severe cases require surgical removal of portions of the prostate. This surgery, if not done very carefully can lead to problems with urination or sexual performance.
The bulbourethral glands or Cowper’s glands are the third of the accessory structures. These are a small pair of glands along the urethra below the prostate. Their fluid is secreted just before emission of the semen, thus it is thought that this fluid may serve as a lubricant for inserting the penis into the vagina, but because the volume of these secretions is very small, people are not totally sure of this function.
The urethra goes through the penis. In humans, the penis contains three cylinders of spongy, erectile tissue. During arousal, these become filled with blood from the arteries that supply them and the pressure seals off the veins that drain these areas causing an erection, which is necessary for insertion of the penis into the woman’s vagina. In a number of other animals, the penis also has a bone, the baculum, which helps to stiffen it. The head of the penis, the glans penis, is very sensitive to stimulation. In humans, as in other mammals, the glans is covered by the foreskin or prepuce, which may have been removed by circumcision. Medically, circumcision is not a necessity, but rather a cultural “tradition”. Males who have not been circumcised need to keep the area between the glans and the prepuce clean so bacteria and/or yeasts don’t start to grow on accumulated secretions, etc. there. There is some evidence that uncircumcised males who do not keep the glans/prepuce area clean are slightly more prone to penile cancer.


 
 
 
2. Female Reproductive System

The female reproductive system is illustrated to the right. “Eggs” are produced in the ovaries, but remember from our discussion of meiosis, that these are not true eggs, yet, and will never complete meiosis and become such unless/until first fertilized by a sperm. Within the ovary, a follicle consists of one precursor egg cell surrounded by special cells to nourish and protect it. A human female typically has about 400,000 follicles/potential eggs, all formed before birth. Only several hundred of these “eggs” will actually ever be released during her reproductive years. Normally, in humans, after the onset of puberty, due to the stimulation of follicle-stimulating hormone (FSH) one “egg” per cycle matures and is released from its ovary. Ovulation is the release of a mature “egg” due to the stimulation of leutenizing hormone (LH), which then stimulates the remaining follicle cells to turn into a corpus luteum which then secretes progesterone to prepare the uterus for possible implantation. If an egg is not fertilized and does not implant, the corpus luteum disintegrates and when it stops producing progesterone, the lining of the uterus breaks down and is shed.
Each “egg” is released into the abdominal cavity near the opening of one of the oviducts or Fallopian tubes. Cilia in the oviduct set up currents that draw the egg in. If sperm are present in the oviduct (if the couple has recently had intercourse), the egg will be fertilized near the far end of the Fallopian tube, will quickly finish meiosis, and the embryo will start to divide and grow as it travels to the uterus. The trip down the Fallopian tube takes about a week as the cilia in the tube propel the unfertilized “egg” or the embryo down to the uterus. At this point, if she had intercourse near the time of ovulation, the woman has no idea whether an unfertilized “egg” or a new baby is travelling down that tube. During this time, progesterone secreted by the corpus luteum has been stimulating the endometrium, the lining of the uterus, to thicken in preparation for possible implantation, and when a growing embryo finally reaches the uterus, it will implant in this nutritious environment and begin to secrete its own hormones to maintain the endometrium. If the “egg” was not fertilized, it dies and disintegrates, and as the corpus luteum also disintegrates, its progesterone production falls, and the unneeded, built-up endometrium is shed.
The uterus has thick, muscular walls and is very small. In a nulliparous woman, the uterus is only about 7 cm long by 4 to 5 cm wide, but it can expand to hold a 4 kg baby. The lining of the uterus is called the endometrium, and has a rich capillary supply to bring food to any embryo that might implant there.
The bottom end of the uterus is called the cervix. The cervix secretes mucus, the consistency of which varies with the stages in her menstrual cycle. At ovulation, this cervical mucus is clear, runny, and conducive to sperm. Post-ovulation, the mucus gets thick and pasty to block sperm. Enough of this mucus is produced that it is possible for a woman to touch a finger to the opening of her vagina and obtain some of it. If she does this on a daily basis, she can use the information thus gained, along with daily temperature records, to tell where in her cycle she is. If a woman becomes pregnant, the cervical mucus forms a plug to seal off the uterus and protect the developing baby, and any medical procedure which involves removal of that plug carries the risk of introducing pathogens into the nearly-sterile uterine environment.
The vagina is a relatively-thin-walled chamber. It servs as a repository for sperm (it is where the penis is inserted), and also serves as the birth canal. Note that, unlike the male, the female has separate opening for the urinary tract and reproductive system. These openings are covered externally by two sets of skin folds. The thinner, inner folds are the labia minora and the thicker, outer ones are the labia majora. The labia minora contain erectile tissue like that in the penis, thus change shape when the woman is sexually aroused. The opening around the genital area is called the vestibule. There is a membrane called the hymen that partially covers the opening of the vagina. This is torn by the woman’s first sexual intercourse (or sometimes other causes like injury or some kinds of vigorous physical activity). In women, the openings of the vagina and urethra are susceptible to bacterial infections if fecal bacteria are wiped towards them. Thus, while parents who are toilet-training a toddler usually wipe her from back to front, thus “imprinting” that sensation as feeling “right” to her, it is important, rather, that that little girls be taught to wipe themselves from the front to the back to help prevent vaginal and bladder infections. Older girls and women who were taught the wrong way need to make a conscious effort to change their habits.
At the anterior end of the labia, under the pubic bone, is the clitoris, the female equivalent of the penis. This small structure contains erectile tissue and many nerve endings in a sensitive glans within a prepuce which totally encloses the glans. This is the most sensitive point for female sexual stimulation, so sensitive that vigorous, direct stimulation does not feel good. It is better for the man to gently stimulate near the clitoris rather than right on it. Some cultures do a procedure, similar to circumcision, as a puberty rite in teenage girls in which the prepuce is cut, exposing the extremely-sensitive clitoris. There are some interesting speculations on the cultural significance of this because the sensitivity of the exposed clitoris would probably make having sexual intercourse a much less pleasant experience for these women.




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Importance of Water in Diet

Water

Water.  Most of us take it for granted.  But have you every taken a moment to stop and think just how important water is to you?  For the human body, water is truly a vital resource.  You can go weeks without food but only 5-7 days without water.  When the water in your body is reduced by just 1 percent, you become thirsty.  At 5 percent, muscle strength and endurance declines significantly and you become hot and tired.  When the loss reaches 10 percent, delirium and blurred vision occur.  A 20 percent reduction results in death. 
 
There is no more important nutrient for our bodies than water.  No other substance is as widely involved in the processes and make up of the body.  A man's body is about 60 percent water, and a woman's is approximately 50 percent.  Did you know that the human brain is about 75 percent water? 
 

TissuePercent Water
Blood83.0
Heart79.2
Muscle75.6
Brain74.8
Skin72.0
Bone22.0
 
Every day, we lose 2-3 quarts of water through urination, sweating and breathing.  Since many of the processes within the body rely greatly on water, it is important we replace our fluids regularly to compensate for this loss. 

Importance of Water :

Water as a Solvent:  Water is the fundamental solvent for all biochemical processes in our bodies.  Because water is highly polar (has an unequal distribution of charge), it is an excellent solvent for other charged and polar molecules.  Haemoglobin, carbonates, various proteins, and many other molecules in the body use water as a solvent.

 
Water as a Transporter:  Once a substance is dissolved in water, water becomes very important for transporting it throughout the body.  Blood, which is 83 percent water, transports oxygen, CO2, nutrients, waste products, and more from cell to cell.  Urine is also mostly water. Another very important transporter, urine removes waste products from the body.  If we don't get enough water and can't produce enough urine, toxic levels of wastes build up in the body and we can become very sick or even die. 

Protection:    Water is needed for protection as well.  It keeps your mouth moist and washes away dirt and grim on your eyes.  Water even lubricates our joints, keeping them from getting stiff and making sure motion is smooth. 

  Chemical Reactant:   As a chemical reactant, water is involved in many processes and pathways of the body.  We use it to digest food in the gastrointestinal tract, to access stored energy for muscles and organs, and for countless other reactions.  Next, we will examine one of these reactions in detail and see how water helps regulate pH in the body.

pH regulation:    Our bodies must maintain a very specific pH level of 7.4.  pH values less than 6.9 and greater than 7.6 are life threatening so it is essential that we have ways to keep pH from deviating too far from normal.  Water is a reactant in a very important reaction that maintains pH at 7.4. 
Example:
This reaction takes place in the blood: 
CO2 + H20 <==> H2CO3< ==> H+ + HCO3
Can you see water's role?  If pH is too high (too few H+ ions), water reacts with carbon dioxide to create more H+ ions, lowering the pH.  A pH lower than 7.4 shifts the above reaction to the left, using up H+ ions, creating CO2 and H2O and raising pH.   It is important that this reaction go back and forth to maintain equilibrium.

 
Electrolyte Balance:    Water is very important in maintaining electrolyte balance within our bodies.  Electrolytes are charged ions (such as Na+ or Cl-) which must be kept at certain levels to maintain the proper amount of water in our cells.  Electrolytes transmit all sorts of information to our brains in the form of nerve impulses and are important in muscular activity as well.  To maintain electrolytes at the proper level in our cells, water flows in and out of the cell to make sure that these ions remain in balance.


Temperature Regulation  In our homes, the air conditioner keeps things cool.  But how does our body stay cool?  Well, we actually have our own natural air conditioning system.  Bet you can guess what it is...  That's right, water!  The most important way water regulates our body temperature is through sweat.  Our normal body temperature is 98.6 degrees Fahrenheit.  When you go outside in the sun, you'll probably begin to sweat in no time, especially if you're active.  But why does the body need to sweat?  Sweat is a way for the body to cool itself down.  When we sweat, it evaporates on our skin, drawing heat away from the body and cooling us down.

Exercise and Water:   When we exercise, water loss through sweat can reach 1-2L per hour!  If you are exercising in warm weather, water should be replenished every 15 minutes in order to keep muscles strong and body temperature down.  This is especially crucial for long endurance events, which is why cyclists (who strip away every unnecessary ounce of equipment) still carry water with them.  Water is vital in delivering oxygen to muscles and helps the body perform physical labour more efficiently.  Here are some graphs showing the effects of fluid replacement during exercise.  Can you guess which lines represent the people who were given water and which represent those who went without it?


 
 
 
 

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