Thursday 22 March 2012

what are they RSS feeds


You must have come across this term and it is obvious to wonder what are RSS feeds exactly. The answer is not as obvious as you think. Here is an attempt to explain, what are RSS feeds and how do they work. This article on 'RSS Feeds: What are They' will share some interesting concepts with you.


RSS stands for "Really Simple Syndication". RSS is a format, which does the job of distributing web content and news. When you put a feed on RSS, you are basically sending content to other websites and many people as well. Well, feeds are considered very powerful, because they attract interest of Internet Search Engine and a large audience as well. This was only a partial answer to the question, RSS feeds, what are they? Read on for a detailed answer...

Various commercial websites such as Twitter, Myspace and many blogging websites use RSS feeds. Social media such as Facebook are also not behind in this trend of using RSS feeds, they use it very zealously. From a user's point of view, RSS feeds help him to stay connected and the feeds are doing a very good job of getting him better visibility.

Some FAQs on RSS Feeds

What goes on in an RSS feed??
First of all, I must tell you that RSS feeds are not restricted to any media. You can add text, audio or video to the feeds. RSS feeds look like a list of items that contain a title and description. This list is indexed and is identified by the link to your respective website. It is expected that the title is catchy and its description is very interesting, so that the targeted user may visit your website.

What do these RSS feeds do?
Once you subscribe to RSS feeds, the content will come to you rather than you visiting every website. From a publishers point of view, this seems a bad idea, but it is in fact a good way to publicize. Consider this example, when you are browsing through Internet, there are many websites which you intend to revisit. But you rarely do revisit that particular website (maybe you forget to do so or maybe you just don't remember the name of the website). This pattern of not visiting, is true for many news websites as well. A stale news is of no use to the reader, as well as the publisher. Through RSS feeds, at least the news is reaching to the reader and there is a chance that the reader may visit the news website, once he has had a chance to read the RSS feed. RSS feeds are great tools for attracting many users.

How to read the RSS feeds?
Reading this RSS feed is like listening to the radio. The station sends out the signals and we listen to the songs. With RSS you send out the content and the user reads the content through 'newsreader' (its an application that was used previously). These days RSS comes built in the browser. Typically a tab is placed below the browser's address bar with an orange colored logo. Click on it and you can see a list. This is one of the many ways to go about RSS feeds. You can also use the RSS feeds with iGoogle and MyYahoo page.

How do RSS feeds improve the search engines visibility?
Search engines use a program called crawlers. These crawlers are programmed to search new as well as updated content on the Internet. Fresh and updated content is by far the most effective way of search engine optimizing (SEO) of your website. Now, how is this relevant to RSS feeds? You know, instead of going to the website and searching for the content, RSS feeds bring the content to the search engine (just the way it brings to the user). This way a crawlers job is simplified. This is also a way of increasing the publishers visibility. Improved visibility means improved search engine optimization and improved ranking means more visitors. When the number of visitors to your website increases, you get more advertising revenue. Well, RSS feeds have become a fantastic tool for website owners.

The experience of using RSS feeds is absolutely delightful. Almost every one who uses RSS Feeds has fallen in love with it. Hope this article on 'RSS Feeds – What they are' helps you in solving all your queries regarding the same.

water model in software engineering


Waterfall model in software engineering' is a highly popular topic among software engineering students as well as others. Here is some information about the role of the waterfall model in SDLC (software development life cycle).
Waterfall Model in Software Engineering

The waterfall model is probably the oldest and the best-known model as far as software developement process models are concerned. The role of the waterfall model in software engineering is as important as its role in software testing. Of course, over the years, there are a number of other software process models which have been designed and implemented, but what is true is that a lot of them are based (in some way or the other) on the fundamental principle of the waterfall model. On that note, let us examine the waterfall model in detail.Waterfall Model in Software Engineering
The waterfall model is so named because it employs a 'top down' approach regardless of whether it is a waterfall model in testing, or a waterfall model in
SDLC. Now I won't sit and draw an artistic waterfall model diagram, but what I will do, is illustrate and explain the different waterfall model phases and the overall waterfall model life cycle.Phases of the Waterfall Model in Software Engineering
To put it in my own words, the waterfall model is nothing but common sense. Assuming that writing a piece of code for a small project is your objective, what the waterfall model suggests, is nothing but what one would do in real life (using his or her common sense).

First and foremost, you need to completely analyze the problem definition and all the various project requirements. This phase is commonly referred to as 
'Requirement Analysis'. Once you have thoroughly and exhaustively identified and understood all the project requirements, they are to be properly documented, after which you move onto the next phase, which is known as 'System Design'. This involves specifying and designing the project's hardware and software requirements, and their inter-relation. The entire software aspect of the project is broken down into different logical modules or blocks which are identified and systematically documented. 'System Implementation' is the next phase which involves nothing but writing software code and actually implementing the programming ideas and algorithms which have been designed or decided upon in the 'System Design' phase. Once the coding and implementation phase has been completed, it is now time to test the code. This is precisely what happens in the next phase which is known as 'System Testing'. The code that has been written is subjected to a series of tests and test cases to detect and determine whether there are any bugs, errors or software failures. Once all the repair work, i.e. correcting and re-writing every piece of erroneous or flawed code is completed, you then move to the next and last phase titled 'System Deployment and Maintenance'. As the name suggests, the last phase is nothing but handing over the completed project to the client or customer, and subsequently performing maintenance activities on a periodic basis.Waterfall Model Advantages and Disadvantages
Let us now examine the pros and cons of the waterfall model in software engineering as well as in software testing.
Pros
  • It is the simplest software process model in terms of complexity and ease of implementation. As I said before, it is nothing but common sense.
  • This model is extremely easy to understand and therefore, is implemented at various project management levels and in a number of fields (not just software development).
  • It employs a systematic, orthodox method of project development and delivery.
Cons
  • Since it is not an iterative model, it has its fair share of shortcomings and drawbacks.
  • Being a strictly sequential model, jumping back and forth between two or more phases is not possible. The next phase can be reached only after the previous one has been completed.
  • Due to this, bugs and errors in the code cannot be discovered until and unless the testing phase is reached. This can lead to a lot of wastage of time and other precious resources.
  • This process model is not suitable for projects wherein the project requirements are dynamic or constantly changing.
Well, this was a short overview of the role of the waterfall model in software engineering. I hope it has managed to enhance your software engineering knowledge.

Genetically Modified Organisms Pros and Cons


Genetically Modified Organisms Pros and Cons

The issue of genetically modified organisms is drawing unprecedented media attention due to its potential of bringing about fundamental changes in the genetic make up of living beings. The genetically modified organisms pros and cons discussed in the following paragraphs throw some light on this controversial subject.What are Genetically Modified Organisms
The genetically modified organisms or GMOs are the animals and plants that are genetically modified in order to develop the useful or desired traits. The techniques used to carry out genetic modification are known as 
genetic engineering techniques. The recombinant DNA technology is used for creating a new set of genes by combining the DNA molecules from different sources. The DNA is transferred into the organism in question and it results into the formation of two different types of GMOs (transgenic and cisgenic) based on the origin of the DNA being used. Transgenic organisms are formed by inducing exogenous genes called transgenes in an organism. In the process of cisgenesis or the creation of cisgenic organisms, the genes are transferred between organisms that are compatible in terms of breeding.Genetically Modified Organisms Pros and Cons
The idea of modifying an organism genetically sounds exciting however, the genetically modified organisms pros and cons have not been studied on a long term till date. Let us understand the pros and cons of genetically modified organisms with the help of the following information.
Pros of Genetic Engineering
Genetic engineering has many applications in different fields such as the medical, agricultural, pharmaceutical, etc. Let us have a look at the pros of genetic engineering.
Production of Human Insulin: The patients suffering from diabetes are not capable of producing enough insulin. So, there arises a need for such people to obtain insulin from external sources. With the help of genetic engineering, human genes could be transferred into other mammals for the production of insulin. The mammals like sheep and goat are used as a medium with human genes acting as the 'software' or the 'brain' containing the necessary genetic information to produce insulin.Use in Gene Therapy: The GMOs like some viruses are used in gene therapy. Gene therapy can be used in the treatment of various genetic disorders and diseases like sickle cell anemia, muscular dystrophy and cystic fibrosis.Creation of Neo-organs: The unavailability of organs for transplants is a big problem in the US. The creation of neo-organs in order to increase the supply of desired organs is possible with the help of genetic engineering. The regeneration of new tissues is carried out by the injection of a growth factor by means of a tissue injector. There is another procedure of creating new organs, in which a scaffold made from biodegradable polymers is used to place the plant cells in it. The scaffold is placed in a position where the new growth is expected. Eventually the scaffold breaks down or dissolves and a completely new organ is formed.Usage in Agriculture: The genetically modified plants have many applications in the field of agriculture. Genetic modification or engineering is used for increasing the production of crops, pest control, weed management, etc. The genetically modified foods are also produced to make them more nutritive. For example, the incorporation of digestible iron in the genetically modified crops influences the health in a positive way.Cons of Genetic Engineering
The main argument made against the activity of genetic modification is that it leads to unpredictable outcomes or side effects. Genetic modification is considered to be unnatural and doesn't fit in the context of natural way like breeding/crossing the plants and animals for bringing out the best in them. Thus, unpredictable alterations in the genetic make-up of organisms is the biggest cause of worry among scientists regarding the whole issue of genetic modification.
Harmful Effects on Crops: The genetically modified crops which the farmers plant in their fields have the same genetic make-up. Any viral or bacterial attack would thus, affect all the plants present in the field. Moreover, the cross-pollination of such plants with other plants increases the risk of contamination. The 'Bt' (Bacillus thuringiensis) genes present in the GM crops kill the insects like bees, ladybird beetles, butterflies, etc. Thus, helpful organisms too are affected along with the pests.GM Animals: Genetic modification in animals is carried out for the production of pharmaceuticals, human proteins and in therapies. The activity of animal cloning leads to deformities at the time of birth and many of such animals die while they are still young. Genetic engineering is also used for creating organs by means of animals for implanting them in human beings. For example, pig's heart could be transplanted in a human being if the human is facing the danger of heart failure. However, the pig's heart if infected with a disease, it might spread to the human beings.Unnatural Methods Being Used: In order to carry out genetic engineering/modification, the methods being used are artificial and thus, the natural reproductive barriers of organisms are breached.Risk of Misuse: The risk of the information regarding these techniques falling into wrong hands should be considered while studying the pros and cons of genetic engineering. Mindless cloning of animals and plants for commercial purposes would definitely have adverse effects on the gene pool we have today. The process of genetic erosion might accelerate with increase in the number of genetically modified organisms.Disruption of Natural Genetic Information: It is argued that in genetic engineering, the insertion of genes is done precisely in living cells. However, it cannot be decided where exactly in the DNA sequence, the gene is to be inserted. There is a risk of the disruption of gene expression and the genetic information present in the DNA.Preliminary Stage of Research: Most of the research in the field of genetic engineering is in its preliminary stages. The tests are generally conducted on animals and very little of the research is reviewed by scientists. Moreover, the research methodology used by these companies is not reviewed by the FDA (Food and Drug Administration).Genetically Modified Organisms List
Here is a list of some genetically modified organisms.
  • Glo Fish: The GloFish is a genetically modified form of the zebra fish. Yorktown Technologies from Austin, Texas brought the GloFish into the US market in the year 2003.
  • Graisin: It is a variety of raisin which is genetically modified in order to make it grow to a large size. The National Institute of Genetics, Japan carried out this genetic modification.
  • Grapple: The grapple is a genetically modified fruit which has the size of an apple and the texture of grapes. The taste/flavor of both the fruits could be found in this GM food. The purpose behind creation of the grapple was to incorporate a high vitamin C dose in it, in order to provide the third world population with a nutritious diet.
  • Umbuku Lizard: Creation of the Umbuku lizard was an experiment carried out by scientists from Zimbabwe. In this experiment, the scientists were able to successfully unlock/decode a strand of DNA which is necessary for flying.
  • Rubber Cork Tree: The rubber cork tree has qualities of both the cork and rubber tree.
  • Tiney Piney: It is pine tree with 2 cm height.
  • Fern Spider: It is the first genetically modified organism which is a cross between a plant and animal i.e. the Ponga fern and Italian Wolf spider.
  • Dolion: As the name suggests, dolion is a cross between the lion and dog.
  • Paper Tree: This tree is genetically modified to produce square shaped leaves. These leaves can be directly used for writing.
The genetically modification of living beings is becoming controversial with the scientist community being divided over this issue. The genetically modified organisms pros and cons need to be studied properly before carrying out the process of altering the genetic constitution of any living being.

Potassium Nitrate Uses


Potassium Nitrate Uses
Potassium nitrate (KNO3) is a naturally occurring mineral that contains three basic chemical elements. It contains potassium that is a soft, light, silver metal, nitrogen a colorless odorless gas and oxygen, the most essential element for life. The combination of these three elements forms potassium nitrate, also known as saltpeter or nitre. It is found as a thin white crust on rocks, caves and soils that are rich in organic mater. It is abundantly found in India, Spain, Egypt and Italy.

Potassium nitrate is soluble in hot water and slightly soluble in cold water. When the compound is heated or on decomposition, it releases 
oxygen. It is a strong oxidizing agent that burns and explodes on reaction with other organic compounds. The melting point of potassium nitrate is 334º C and the boiling point is 400º C. Let us know more about potassium nitrate uses. Read more on history of potassium.Uses of Potassium Nitrate

There are many uses of potassium nitrate. The following points will help explain the various potassium nitrate uses:
Potassium Nitrate Fertilizer
Potassium nitrate fertilizer is the most widely used application of the compound. It contains all the macro nutrients needed for growth of plant species. It has potassium that is vital for growth of plants. Nitrogen helps the crops to fully mature, rather than delaying their growth.
Food Preservative
Use of potassium nitrate as food preservatives was commonly seen during the Middle Ages. Today, it is used in many processes like curing meat, production of brine and making corned beef.
Potassium Nitrate for Explosives
According to the ancient Chinese firecracker invention history, the Chinese had accidentally stumbled upon one of the greatest discoveries of all time. The mixture of 15% carbon, 10% sulfur and 75% potassium nitrate resulted in the "Chinese Snow" or " Devil's Distillate". This black power is now commonly known as gunpowder. It has been used to make 
fireworks, grenades, bombs, etc. It is also used as an ingredient for amateur solid-rocket propellant.

During the initial years of discovering gunpowder, the ingredients of gunpowder were carefully hand mixed and broken into small pieces. Today, charcoal and sulfur are mixed using a tumbling action with the steel balls rotating in a hollow cylinder. Potassium nitrate is powdered separately and mixed and grounded along with other ingredients. Then it is pressed into cakes and re-broken and separated into grains of standard sizes. Then the grains are tumbled in wooden cylinders to make the edges smooth. Graphite is added to give a moisture resistant and friction reducing film on the cake.
Potassium Nitrate Uses in Cigarettes
Potassium nitrate is a frequently used ingredient in cigarettes. It is used during the production and manufacturing of cigarettes. It helps in burning the tobacco evenly. (
Statuary Warning: Cigarette Smoking is Injurious to Health).Other Potassium Nitrate Uses
Potassium nitrate is used as a diuretic in medicine. Potassium nitrate uses also include its use as an ingredient in toothpastes. It makes the teeth less sensitive to pain, by interfering with the transmission of pain signals in the nerves of teeth. It is also added to drugs for 
back pain andjoint pain. It is also used to produce kinescope, optic glass, high grade craft glassware, etc. Uses of potassium nitrate also include its use in metalworking as a flux and in the preservation of hides.

These were some of the potassium nitrate uses in many fields and industries. It has also been famous for generations among the male population, due to a myth that claims potassium nitrate to be a great aphrodisiac. Myth or fact, the other uses of potassium nitrate are a reality, making the saltpeter, one of the most useful compounds on Earth.

Levels of Biological Organization

Levels of Biological Organization

Our environment is a bag full of components which are different from each other, yet are mutually dependent on each other. The components are both living and non-living and they play vital roles in their own domain. With anyone of the components being absent, the so called biological organization will suffer in more than one way. In all the levels of biological organization, the individual components are responsible for everything which make life possible. It would be unfair to establish a distinction between each of these components, regarding their level of importance. As said, each component holds its own importance in its own place and it is equally dependent on the other components, which again are important to the biological organization. So here is a description of each of the components which make up the levels of biological organization.Levels of Biological Organization from Smallest To Largest
Levels of Biological Organization - Subatomic Particles
These particles are smaller than the atom of a substance. Protons, neutrons and electrons are the main subatomic particles which reside in a substance. Protons are positively charged particles and neutrons are charge-less. These reside inside the nucleus of the atom. Electrons are negatively charged particles and revolve around the nucleus in certain energy levels or shells. Photon is also a subatomic particle. A photon is a quantum of electromagnetic energy, posses zero mass and rest energy and moves with the speed of light. Know more on 
what are subatomic particles?Levels of Biological Organization - Atoms
Atoms are defined as the the smallest unit or the basic building blocks of matter which make up all objects. Atoms are made up of equal number of protons and electrons. However, there might be a difference in the number of neutrons between two atoms of the same element. The center of the atom is occupied by what is known as the nucleus; consisting of the protons and neutrons. Electrons, as mentioned above, keep orbiting around the nucleus. More on the 
structure of atomic nucleus.Levels of Biological Organization - Small Molecules
Larger molecules are made up of some building blocks and these blocks are attributed as small molecules. Examples of such molecules are amino acids, fatty acids, glucose, etc.
Levels of Biological Organization - Macromolecules
Consisting of many subunits, macromolecules are defined as large or gigantic molecules which populate a cell and render the important functions of life. Examples are carbohydrates, lipids, proteins, nucleic acids, etc.
Levels of Biological Organization - Molecular Assemblies
These assemblies are organized sets which comprise one or more molecular entity. The microtubule (conveyer belts inside the cells) and the cell membrane (plasma membrane) are a typical example of organized molecular assemblies.
Levels of Biological Organization - Organelle
The term 'organelle' means little organs and it is a specialized part of a cell. Just like the human body which has organs such as heart, liver, etc., a cell also has them in the form of organelle. Examples are the nucleus, endoplasmic reticulum, mitochondria, etc. Know more on 
plant cell organelles.Levels of Biological Organization - Cell
All living organisms in the levels of biological organization consist of structural and functional units called cells. For example, bacteria, amoeba, archaebacteria, etc, are all single-celled organisms. Humans and many other organisms are multicellular, which may have around 100,000,000,000,000 cells!
Levels of Biological Organization - Tissue
A group of cells which may or may not have similar characteristics is termed as a tissue. Each tissue is attributed with a particular set of functions in the body of the living organism. Connective tissue, muscle tissue, nervous tissue and epithelial tissue are the tissues in animals, while meristematic tissues and permanent tissues are those of the plants. Know more on 
nervous tissues.Levels of Biological Organization - Organ
Now when the different types of tissues are organized or grouped together, they form what is known as an organ. These tissues enable a particular organ to carry out its own specific task. Examples are heart, lungs, kidneys, stomach, etc.
Levels of Biological Organization - Organ System
An organ system consists of a groups of organs which are meant for performing a broad set of functions, particularly in multi-cellular organisms. A number of organs in a system work together as a single unit. For example, the circulatory system works with the help of heart, blood and blood vessels.
Levels of Biological Organization - Organism
Plants, animals, humans, bacterium, etc., and any form of life is known as an organism. It can be regarded as the complete framework of organ systems, organs, organelle and all other components which work in their own specific way in order to carry out the various processes of life.
Levels of Biological Organization - Population
Now we come to a broader part in the levels of a biological organization. A group of inter-breeding organisms of the same species inhabiting a defined area is termed as a population. For example, the population of mice in a barn.
Levels of Biological Organization - Species
We come to the fourth-last of the levels of biological organization. Species is merely a defining term given to a specific kind of organism. For example, humans are a kind of species who are different from the other species of animals or plants. Learn more on 
animal species.Levels of Biological Organization - Community
A group of interacting organisms of different species living in a given area is termed as a community.
Levels of Biological Organization - Ecosystem
An ecosystem is made up of both biotic or abiotic components of the environment such as the climate, landscape, animals and plants; interaction of a group of organisms and their environment, to be precise! For example, ponds, rivers, forests, an estuary and a grassland. Here's more on 
pond ecosystem, as an example.Levels of Biological Organization - Biosphere
Here we come to the last of all levels of biological organization known as the biosphere. It is simply defined as the regions on, below, and above the surface, and atmosphere of the Earth where living organisms exist. The biosphere can range from the atmosphere to very cold environments and from the deep-sea vents of the ocean depths to very hot environments.

Starting right from the subatomic particles to the organism level, is what comprises the levels of biological organization within an organism. So these were the levels of biological organization in order. As you can see and as it was mentioned earlier, each and every component in the level is linked with the other in the next level and so on. It can be referred to as a biological chain where in all the factors are interdependent on each other.

Levels of Organization of Living Things


Levels of Organization of Living Things

Levels of Organization of Living Things

The study of different levels of organization of animate or living things helps us gain insights into the complexities of their structure and functioning. Let us try to understand what are the levels of organization in living things.Life on Earth
The life present on earth is complex and varied in its form. The living beings have evolved from their single celled or unicellular forms to complex and giant multicellular bodies. In the process of development, their body systems and mechanisms became specialized in nature. Thus, in the course of evolution, different levels were formed. Let us understand these levels of organization of living things.
Levels of Organization of Living Things
There are in all five levels of organization of living things. The levels of organization of living things in sequence are the cells, tissues, organs, organ systems and organisms.
Cell: The cell is considered to be the basic unit of life. It is also known as the building block of life. A cell is bound by the cell membrane and has a nucleus which acts as the brain of the cell. Cytoplasm which surrounds the nucleus, contains the cell organelles like the mitochondria, ribosomes, vacuole, endoplasmic reticulum, chloroplasts, peroxisomes and ventricles. The number of cells in human beings is approximately 100 trillion. Cells bring about the conversion of nutrients into energy, reproduce (cell division) as the need arises and carry out specialized functions. The cells are of 2 types, i.e. prokaryotic and eukaryotic. Prokaryotic cells which are smaller and simpler in form lack a nucleus and many of the cell organelles that are found in the eukaryotic ones. The eukaryotic cells are more specialized in their structure than the prokaryotic cells. Moreover, they are greater in size (by almost 15 times) than the prokaryotic cells. Read more on plant cell structure and parts.Tissue: The tissues are a collection of cells which perform specialized functions. The cells which form a tissue need not be identical but have the same origin. The different types of tissues which form organs are the nervous, muscle, connective and epithelial tissues. The connective tissues are fibrous in nature and are made up of cells separated by the extracellular matrix. Muscle tissues, which are the active contractile tissues of the body, are useful in producing force and motion. Skeletal, cardiac and smooth muscles are the three types of muscles. The nervous tissues form organs, like, brain, spinal cord, etc. The epithelial tissues cover the surface of body organs.Organ: An organ is the next level in the organization of living things. It performs certain functions with the help of different tissues. The various organs of animals include the lungs, brain, liver, etc. Roots, stem and leaves, etc. are different organs of the plants. The organs could be classified on the basis of the functions they perform. For example, in case of animals, tongue, ears, eyes, skin and nose form the sensory organs. Flowers and seeds are the reproductive organs in plants. The organs are formed of tissues which serve a common function. There are two types of tissues that form an organ: the main and sporadic tissues. For example, in the heart, myocardium is the main tissue while blood, nerves and connective tissues are the sporadic ones.Organ System: The organ systems are complex mechanisms which carry out important functions of the body. For example, the circulatory system in animals and vascular system in plants. The organ systems of an organism are interdependent, i.e. they take each others' help to carry out various functions of the body. For example, the digestive system which carries out the process of digestion is formed of salivary glands, stomach, esophagus, gallbladder, liver, intestines, pancreas, rectum and the anus.Organism: Amongst the different levels of organization of living things, this is the highest level. An organism could either be unicellular or multicellular. The organisms that are closely related are grouped together under a single species.

Read more on:
The levels of organization of living things mentioned in the above article present before us the systematic structure and functioning of various components of this organization.

Endocrine System Function


Endocrine System Function

Every reaction in your body, from breaking down food into energy, the mood swings that you have, physiological development of your body, development of your reproductive system, etc. are all carried out by certain chemicals. These certain chemicals are known as hormones in your body. These slow processes that take time to develop are a part of the endocrine system functions. Breathing, body movement, sudden reaction to the surroundings are a part of the nervous system functions.

The endocrine systems consists of hormones and glands. The hormones are the chemical messengers of the body that travel down to the various body parts concerned transferring information. There are many hormones secreted by the endocrine system, and each individual type of hormone affects only those body cells that have a genetic program that allows them to react only to those hormones that are related to them. The hormones influence the body to react according to the changes in the balance of fluids and minerals in blood, stress, infection, etc. Let us understand more on how does the endocrine system function.
How Does the Endocrine System Function?
Endocrine system is a collection of 'glands' that produce hormones. These hormones are very important for regulating 
metabolism process, growth of the body and sexual development. The glands release the hormones into the blood stream and are transported to the various cells and body parts. When the hormones reach the target site, they bind to the receptor cells with a lock and key mechanism. The hormone may be present within the nucleus or on the surface of the cells. Once bound to the receptor, the hormones transmit a signal that triggers an action by the site. Hormones control the organs function and affect the growth and development of the organs. It is due to the hormones that the sexual characteristics of the organs develop and act accordingly. They also determine the use and storage of energy in the body, regulate the fluid, salt and sugar levels in the blood. Minute amount of hormones trigger large reactions within the body. All hormones are proteins, but all proteins are not hormones. Steroids are not derived from proteins, but from the fatty substances from cholesterol.

The body has a well-controlled feedback system that manages the on/off button of the endocrine gland. When the chemical level or the nutrient level in the body is abnormally high or low, the endocrine glands secrete the hormones. Once the levels of the body fluids are normal the hormones secretions is shut down. When the glands receive information to secrete hormones, it is a positive feedback mechanism. When the glands receive information to stop the secretions of the hormones, it is known as negative feedback.
Functions of Endocrine System
The endocrine system is a collection of glands that secrete different hormones for the various functions and chemical reactions occurring within the body. The main function of the endocrine system is to maintain a stable environment within the body or homeostasis. For example, maintaining the blood sugar levels according to changes  occurring in the body is homeostasis. The major function of the of the endocrine system is promoting the structural changes of the body. For example, the permanent changes occurring in the body over the period of time like height, development of sexual organs, etc. is a part of the structural changes.

There are 8 major glands that help in the endocrine system functions. These major endocrine glands are as follows:
  1. Hypothalamus
  2. Pituitary gland
  3. Parathyroid gland
  4. Thyroid gland
  5. Adrenal glands
  6. Pancreas
  7. Ovaries (in female body)
  8. Testes (in male body)
Let us know more about the various endocrine system functions with the help of the above mentioned endocrine glands.
  • Hypothalamus: A collection of specialized cells that are located in the lower central part of the brain is called the hypothalamus. The hypothalamus is the main link between the endocrine system and the nervous system. The nerve cells of the hypothalamus control the pituitary gland by stimulating or suppressing the hormone secretions.
  • Pituitary Gland: The pituitary gland is located at the base of the brain just below the hypothalamus. The pituitary gland is the most important part in the endocrine system. The pituitary gland secrete hormones on the basis of the emotional and seasonal changes. The hypothalamus sends information that is sensed by the brain to pituitary triggering production hormones. The pituitary gland is divided into two parts: the anterior lobe and the posterior lode. The anterior lobe of the pituitary gland regulated the activity of the thyroid, adrenals, and the reproductive glands. The anterior lobe also produces hormones like:
    • Growth Hormone: To stimulate the growth of the bones and tissues. It also plays a role in the body's absorption of nutrients and minerals.
    • Prolactin: To activate the production of milk in lactating mothers
    • Thyrotropin: To stimulate the thyroid gland to produce thyroid hormones
    • Corticotropin: To stimulate the adrenal glands to produce certain hormones.
    Endorphins are also secreted by the pituitary that acts on the nervous system and lower the feelings of pain. The pituitary glands produces hormones that signal the reproductive organs to secrete sex hormones. The menstrual cycle and ovulation in women is also controlled by the pituitary gland. The posterior lobe of the pituitary gland produces antidiuretic hormone that helps to control the water balance in the body. Oxytoxins that trigger the contractions of the uterus in a woman who is in labor is secreted by the posterior lobe.
  • Thyroid Gland: The thyroid gland is situated in the front part of the lower neck that is shaped like a bow tie or butterfly. The production and secretions of the hormones of the thyroid glands are controlled by thyrotropin secreted by the pituitary gland. Thyroid produces thyroxine and triiodothyronine, that control the rate at which the cells use up energy from food for production of energy. The thyroid hormones are very important a they help in growth of bones and the development and growth of the brain and nervous system in children. Over or under secretion of thyroid hormones leads to a number of thyroid problems in the body.
  • Parathyroids: These are four tiny glands that are attached to the thyroid gland. They release the parathyroid hormone that helps in regulating the level of calcium in blood along with another hormone produced by thyroid called as calcitinin.
  • Adrenal Glands: On each of the two kidneys, there are two triangular adrenal glands situated. The adrenal gland is divided into two parts. The outer part called the adrenal cortex produces corticosteroids, that influence and regulate the salt and water levels. They are also helpful in the body's response to stress, metabolism, immune system and the function and development of sexual organs. The inner part called as the adrenal medulla, secrete catecholamines like epinephrine. This hormone is also called the adrenaline, it increases the blood pressure and heart rate when the body is under stress. Know more on Adrenal problems.
  • Reproductive Glands or Gonads: The gonads are present in males and females and are the main organs producing sex hormones. In men, the gonads are related to testes. The testes are located in the scrotum and secrete androgens. The most important hormone for men testosterone is secreted from the testes. In women, ovaries are the gonads that are located in the pelvis region. They produce estrogen and progesterone hormones. Estrogen is involved during the sexual maturation of the girl, that is, puberty. Progesterone along with estrogen are involved in the regulation of menstruation cycle. These hormones are also involved during pregnancy.
  • Pancreas: These glands are associated with the digestive system of the human body. They secrete digestive enzymes and two important hormones insulin and glucagon. These hormones work together to maintain the level of glucose in the blood. If these hormones are not secreted in the required levels, it leads to development of diabetes. Know more on pancreas problems.
  • Pineal: The pineal gland is located in the center of the brain. Melatonin is secreted by this gland that helps regulate the sleeping cycle of a person.
Thus, the endocrine system fact is the organ that regulates metabolism, growth, development, tissue functions, puberty and even moods. These are are the basic endocrine system functions that help keep our bodies in working condition. Any kind of problem in the endocrine system function will result in many disorders and abnormalities in the body. Thus, maintain a healthy diet so that the endocrine system functions in optimum conditions. Just as the car needs engine oil to run smoothly, our bodies require hormones secreted by the endocrine system to continue working efficiently.