Lung cancer

What is cancer of the lung?
Cancer of the lung, like all cancers, results from an abnormality in the body's basic unit of life, the cell. Normally, the body maintains a system of checks and balances on cell growth so that cells divide to produce new cells only when needed. Disruption of this system of checks and balances on cell growth results in an uncontrolled division and proliferation of cells that eventually forms a mass known as a tumor.
Tumors can be benign or malignant; when we speak of "cancer," we refer to those tumors that are considered malignant. Benign tumors can usually be removed and do not spread to other parts of the body. Malignant tumors, on the other hand, grow aggressively and invade other tissues of the body, allowing entry of tumor cells into the bloodstream or lymphatic system and then to other sites in the body. This process of spread is termed metastasis; the areas of tumor growth at these distant sites are called metastases. Since lung cancer tends to spread or metastasize very early in its course, it is a very life-threatening cancer and one of the most difficult cancers to treat. While lung cancer can spread to any organ in the body, certain organs -- particularly the adrenal glands, liver, brain, and bone -- are the most common sites for lung-cancer metastasis.
The lung is also a very common site for metastasis from tumors in other parts of the body.

The principal function of the lungs is the exchange of gases between the air we breathe and the blood. Through the lung, carbon dioxide is removed from the bloodstream and oxygen from inspired air enters the bloodstream. The right lung has three lobes, while the left lung is divided into two lobes and a small structure called the lingula that is the equivalent of the middle lobe. The major airways entering the lungs are the bronchi, which arise from the trachea. The bronchi branch into progressively smaller airways called bronchioles that end in tiny sacs known as alveoli where gas exchange occurs. The lungs and chest wall are covered with a thin layer of tissue called the pleura.
Lung cancers can arise in any part of the lung, but 90%-95% of cancers of the lung are thought to arise from the epithelial, or lining cells of the larger and smaller airways (bronchi and bronchioles); for this reason, lung cancers are sometimes called bronchogenic carcinomas or bronchogenic cancers. Cancers can also arise from the pleura (the thin layer of tissue that surrounds the lungs), called mesotheliomas, or rarely from supporting tissues within the lungs, for example, blood vessels.

General symptoms of lung cancer

* Having a cough most of the time
* A change in a cough you have had for a long time
* Being short of breath
* Coughing up phlegm (sputum) with signs of blood in it
* An ache or pain when breathing or coughing
* Loss of appetite
* Fatigue
*Losing weight

Less common symptoms of lung cancer

There are other symptoms of lung cancer that are less common. They are usually associated with more advanced lung cancer. You may have
* A hoarse voice
* Difficulty swallowing
* Swelling of the face caused by a blockage of a main blood vessel from the head (SVCO)
* Swelling in the neck caused by enlarged lymph nodes
* Pain or discomfort under your ribs on your right side (from the liver)
* Shortness of breath caused by fluid around the lungs (called pleural effusion)
* Swollen face caused by superior vena cava obstruction (SVCO)The vena cava is a large vein that carries blood from the brain and head back to the heart. If it is blocked, there is a build up behind the blockage causing fluid to seep out from the bloodstream and collect in the tissues of the face, causing swelling. This is called superior vena cava obstruction or SVCO for short.All of these symptoms can be caused by other diseases apart from lung cancer. So, you should always see your doctor if you are worried about any symptoms. You may have a chest infection, or other illness that is easily treatable. If you do have lung cancer, the earlier it is diagnosed, the easier it is to treat it.

Causes
Lung cancer most commonly begins in the cells that line your lungs. Smoking causes the majority of lung cancers — both in smokers and in people exposed to secondhand smoke. But lung cancer also occurs in people who never smoked. In these cases, there may be no clear cause of lung cancer. Doctors have identified factors that may increase the risk.
How smoking causes lung cancer Doctors believe smoking causes lung cancer by damaging the cells that line the lungs. When you inhale cigarette smoke, which is full of cancer-causing substances (carcinogens), changes in the lung tissue begin almost immediately. At first your body may be able to repair this damage. But with each repeated exposure, normal cells that line your lungs are increasingly damaged. Over time, the damage causes cells to act abnormally and eventually cancer may develop.
Your lungs are full of blood vessels and lymph vessels, giving lung cancer cells easy access to travel to other parts of your body. For this reason, lung cancer may spread to other parts of your body before you experience any signs or symptoms. In many cases, lung cancer may spread before it can even be detected in the lungs.

Epidermolysis bullosa (EB)

Epidermolysis bullosa (EB)

Definition

Epidermolysis bullosa is a group of skin conditions whose hallmark is blistering in response to minor injury, heat, or friction from rubbing or scratching. There are three main types of epidermolysis bullosa, with numerous subtypes. Most are inherited. Most types of epidermolysis bullosa initially affect infants and young children, although some people with mild forms of the condition don't develop signs and symptoms until adolescence or early adulthood. Some infants are born with blisters. Mild forms of epidermolysis bullosa may improve with age, but severe forms may cause serious complications and can be fatal. There's no cure for epidermolysis bullosa. Treatment depends on the severity, but often is aimed at preventing pain, infection and other complications.

Symptoms

The primary indication of epidermolysis bullosa is the eruption of fluid-filled blisters (bullae) on the skin, most commonly on the hands and feet in response to friction. Blisters of epidermolysis bullosa typically develop in various areas, depending on the type. In mild cases, blisters heal without scarring. Depending on the type of the condition, blistering may be present at birth, appear during infancy or occur during adolescence or early adulthood. The three main types are:

• Epidermolysis bullosa simplex, which usually begins at birth or in early infancy.
• Junctional epidermolysis bullosa, which generally begins at birth and is usually severe.
• Dystrophic epidermolysis bullosa, which generally begins at birth or in early childhood.
  

Causes

Your skin comprises an outer layer (epidermis) and an underlying layer (dermis). The area where the layers meet is called the basement membrane zone. Where blisters develop depends on the type of epidermolysis bullosa. In most cases, epidermolysis bullosa is inherited. Researchers have identified more than 10 genes involved with skin formation that, if defective, may cause a type of epidermolysis bullosa. It's also possible to develop epidermolysis bullosa as a result of a random mutation in a gene that occurred during the formation of an egg or sperm cell.
Epidermolysis bullosa simplex

In epidermolysis bullosa simplex, the most common and generally mildest form, the faulty genes are those involved in the production of keratin, a fibrous protein in the top layer of skin. The condition causes the skin to split in the epidermis, which produces blisters. If you have epidermolysis bullosa simplex, it's likely you inherited a single copy of the defective gene from one of your parents (autosomal dominant inheritance pattern). If one parent has the single faulty gene, there's a 50 percent chance their offspring will have the defect.

Junctional epidermolysis bullosa

In this usually severe type of the disorder, the faulty genes are involved in the formation of thread-like fibers (hemidesmosomes) that attach your epidermis to your basement membrane. This gene defect causes tissue separation and blistering in your basement membrane zone. Junctional epidermolysis bullosa is the result of both parents carrying and passing on the defective gene (autosomal recessive inheritance pattern), although neither parent may have the disorder (silent mutation). If both parents have the faulty gene, there's a 25 percent chance their offspring will have the defect and develop the disorder.

Dystrophic epidermolysis bullosa

In this type, whose subtypes range from mild to severe, the faulty genes are involved in the production of a type of collagen, a protein in the fibers that attach your epidermis to your dermis. As a result, the fibers are either missing or nonfunctional. Dystophic epidermolysis bullosa can be either dominant or recessive.

HIV

AIDS - Definition of AIDS - Acquired Immune Deficiency Syndrome Video - About.com

AIDS is one of the most serious, deadly diseases in human history.
AIDS is caused by the human immunodeficiency virus (HIV). HIV destroys a type of defence cell in the body called a CD4 helper lymphocyte. These lymphocytes are part of the body´s immune system, the defence system that fights infectious diseases. But as HIV destroys these lymphocytes, people with the virus begin to get serious infections that they normally wouldn´t - they become immune deficient. The name for this condition is acquired immunodeficiency syndrome (AIDS)


Where did HIV come from?
Quite simply, HIV was probably a mutation of an African monkeys virus. The presence of related retroviruses in African monkeys and apesand the close relationship of HIV to a Chimpanzee Immunodeficiency virus all suggest that Central Africa may have been the site of evolution of HIV.
Some people think that there are other possible origins of HIV. One of these is the suggestion that HIV was a deliberate or accidental productof biological warfare research. That's not possible, since the technology and the basic knowledge that would have been necessary to create such a virus had not been developed in 1975, when the epidemicbegan to grow.

Acquisition of Infection
The major routes of transmission of HIV are sexual contact, parenteral exposure to blood and blood products and transmission during pregnancy.
HIV is spread when blood, semen, or vaginal fluids from an infected person enter another person's body, usually in one of the following ways:
* Sexual Contact: any type of sexual contact - anal, vagina, or oral.
* Drug addicts sharing needles.
* Tattooing and body piercing by un sterilized needles. Getting injected by un sterilized needles by quacks (especially in the underdeveloped countries.)
* Accidental needle pricks to health workers or doctors.
* Unsafe Blood or blood products.
* Born to HIV positive mother. Pregnant female can transmit the virus to the newborn during pregnancy or during delivery or when she feeds her baby breast milk.

ORGAN SYSTEMS

ORGAN SYSTEMS

DIGESTIVE
Major Roles: To breakdown and absorb nutrients that are necessary for growth and maintenance.
Major Organs: Mouth, esophagus, stomach, small and large intestines.

REPRODUCTIVE

Major Roles: To manufacture cells that allow reproduction. In the male, sperms are created to inseminate egg cells produced in the female.
Major Organs: Female: ovaries, oviducts, uterus, vagina and mammary glands.
Male: testicles, seminal vesicles and pennies.

RESPIRATORY
Major Roles: To provide gas exchange between the blood and the environment. Primarily, oxygen is absorbed from the atmosphere into the body and carbon dioxide is expelled from the body.
Major Organs: Nose, trachea and lungs.

CIRCULATORY
Major Roles: To transport nutrients, gases (such as oxygen and CO2), hormones and wastes through the body.
Major Organs: Heart, blood vessels and blood.

LYMPHATIC
Major Roles: To destroy and remove invading microbes and viruses from the body. The lymphatic system also removes fat and excess from the blood.
Major Organs: Lymph (fluid), lymph nodes and vessels, white blood cells, T- and B-cells.

EXCRETORY
Major Roles: To filter out cellular wastes, toxins, and excess water or nutrients from the circulatory system.
Major Organs: Kidneys, ureters, bladder and urethra, skin.

NERVOUS
Major Roles: To relay electrical signals through the body. It directs behavior and movement and, along with the endocrine system, control psychological processes such as digestion, circulation, etc.
Major Organs: Brain, spinal cord and peripheral nerves.

MUSCULAR
Major Roles: To provide movement. Muscles work in pairs to move limbs and provide the organism with mobility. Muscles also control the movement of materials through some organs, such as the stomach and intestine, and the heart and circulatory system.
Major Organs: Skeletal muscles and smooth muscles throughout the body.

SKELETAL
Major Roles: To provide support for the body, to protect delicate internal organs and to provide attachment sites for the organs.
Major Organs: Bones, cartilage, tendons and ligaments.

ENDOCRINE
Major Roles: To relay chemical messages through the body. In conjunction with the nervous system, these chemical messages help control physiological processes such as nutrient absorption, growth, etc.
Major Organs: Ovaries and Testicles, Pancreas, Parathyroid glands, Pineal body, Pituitary Gland, Thymus Gland, Thyroid Gland, Adrenal Glands, Hypothalamus.

The Internet

• What is the Internet?
  The Internet is a worldwide system of computer networks, a network of big and small, in which users at any one computer can, if they have permission, get information from or communicate directly with any other computer. In fact, the term ‘Internet’ is derived from the idea of interconnected networks.
  Using the Internet, students and teachers worldwide can source and exchange information speedily and economically, as well as communicate directly with each other. The Internet facilitates collaboration on projects between individuals and schools across the globe. The skills acquired by students during such projects prepare them for a future in which ICT is an integral component of their lives.


• What are the different purposes you may use the Internet for?
  There are three strands of Internet usage relevant to schools — it can be used to communicate with others, it can be used to source information, and it can be used to publish or share information. Some of the activities include:

Communication
• Electronic mail (e-mail)
• Discussion groups
• Internet 'chat' sessions
• Voice and video links
• Social networking sites
• Voice Over Internet Protocol calls (VoIP)
Information Retrieval
• World Wide Web (WWW)
• File Transfer Protocol (FTP)
• Social Bookmarks
• Really Simple Syndication (RSS)
Publishing of Information
• Web site development
• WebLogs (Blogs)
• Wikis
• Podcasts
Educational Uses
One of the most compelling aspects of the Internet is the fact that it facilitates two-way information flow. This has opened up exciting new learning opportunities for schools by providing access to a seemingly limitless library of information and providing opportunities to work with others around the world. You can:

Use e-mail to communicate with other teachers and students
• Research and gather information using the World Wide Web
• Participate in collaborative school projects, both nationally and internationally
• Publish curriculum resources and school information online
• Join groups with shared goals, expectations and needs
• Work with mentors and subject matter experts
• Access professional development information and peer support for teachers
• Promote links between students with special needs with similar disabilities/difficulties

Cytoplasm

Cytoplasm

All of the substance of a cell outside of the nucleus of a membrane bound cell. The cytoplasm contains a number of different types organelles such as the mitochondria and it also includes fluid (the cytosol). The cytoplasm is clear in color and has a gel-like appearance. It is composed mainly of water and also contains enzymes, salts, organelles, and various organic molecules. The cytoplasm helps to move materials around the cell and also dissolves cellular waste. ( biology.about.com) Most, but not all, cells have cytoplasm. Mature sperm are essentially devoid of cytoplasm. The word "cytoplasm" was compounded from two Greek roots -- "kytos," a hollow vessel + "plasma," plasm. From "kytos" came the prefix "cyto-," cell. Cytoplasm is literally cell plasm. (medterms.com).

Mitochondria

Mitochondria

Second largest organelle with unique genetic structure.- Double-layered outer membrane with inner folds called cristae.- Energy-producing chemical reactions take place on cristae- Controls level of water and other materials in cell.- Recycles and decomposes proteins, fats, and carbohydrates, and forms urea.

Structure:

Composed of modified double unit membrane (protein, lipid)- inner membrane infolded to form cristae Function - site of cellular respiration ie. the release of chemical energy from food Glucose + Oxygen -> Carbon Dioxide + Water + Energy (ATP)