ORGAN TRANSPLANTS

Tissues (cornea, bone marrow, skin...) and organs (kidneys, heart, liver, lungs, pancreas...) can be transplanted. But it has to be analysed to know that the transplant will be compatible, making sure that a transplant rejection may not happen.

There are different types of transplants, like autograft, a transplant of tissue from one to oneself, sometimes it's done with tissue that can regenerate. Or xenograft, a transplant from one species to another. The most common transplant of human tissue and organ is allograft, transplantation of an organ or tissue from a genetically non-identical member of the same species.

The first successful kidney transplant was in 1954. And the first heart transplant was in 1967. There is an urgent need for tissues and organs for transplantation. There is a person added to the donor waiting list every 12 minutes and 16 people die each day waiting for an organ transplantation.

Skin tissue that can be transplanted.

Biology- A Genetic Disorder

A GENETIC DISORDER

The human DNA has 23 pairs of chromosomes making 46 in total which carry the genes that determine our inherited characteristics. Any difference in the number of chromosomes causes a genetic disorder or possible disease for a lifetime. One example of a genetic disorder is DOWN`S SYNDROME which was discovered by John Langdon Down in 1866.

Down`s Syndrome is caused by the 21st pair of chromosomes having an extra one which can be discovered during pregnancy or at birth. These children are both physically and mentally affected. They grow less and have slightly slanted eyes. The name "mongol" probably came about due to their likeness to the people of Mongolia. They have speaking and learning difficulties and a shorter lifespan.


So far this syndrome is irreversible and a child`s development can only be improved with special education and a loving home environment. Maybe in the future with genetic engineering, the chromosomes can be manipulated and the syndrome avoided in the foetus (feto).

The cholesterol

What is cholesterol?

Cholesterol is a waxy substance our body uses to protect nerves, make cell tissues and produce certain hormones. Most of the cholesterol in our body is made by our liver. Some cholesterol also comes from foods such as eggs, meats and dairy products.

Why is a high cholesterol level unhealthy?

While some cholesterol is needed for good health, too much cholesterol in our blood can raise our risk of having a heart attack or stroke.

The extra cholesterol in our blood may be stored in our arteries (blood vessels that carry blood from our heart to the rest of our body). Buildup of cholesterol, or "plaque," in our arteries will cause them to narrow. This is called atherosclerosis. Large deposits of cholesterol can completely block an artery, so the blood can't flow through.

If the coronary artery (the blood vessel that supplies blood to the muscles in your heart) becomes blocked, a heart attack can occur. If an artery that supplies blood to your brain becomes blocked, a stroke can occur.

Cholesterol in food

• Food with a big amount of cholestherol: pork,sausages,ham,lamb,goose-pimples,yolk,seafood,bacon,croissants.
• Food with a small amount of cholestherol: hake,cod,beef,ox,horse,rabbit,milk without grass.
• Food without cholestherol:cereals,rice,sweetcorn,potatos,fruits,vegetables,oil olive,sweetcorn olive,milk,yogourt.
• Food with "good" cholestherol:nuts,olive oil, black chocolat,blue fish(sardine,mackerel).

Bulimia

Bulimia is a very serious nutritional problem..
Bulimic persons are unable to control their impulses to eat, but then the guilty feelings get them to vomit all that they ate before,to prevent rising their weight up.
Causes
In the origen of these illness there are these factors:BIOLOGIC,PSICOLOGIC,and, SOCIAL FACTORS.
This illness affect to young people generally to the females. The age is around 16-19. There are two types:
1)PURGING:the sick person use the vomit.
2)NON PURGING: in this case the ill person doesn´t eat, doing a lot of exercise.....
Bulimic persons try to hide the vomits, the selfsteem go down....
Diagnosing bulimia
The first step towards a diagnosis is to admit the existence of an eating disorder.
What are the symptoms of bulimia?
Eating incontrollably, purging, vigorous exercise, abusing of laxatives, vomiting blood, depression or swing mood, swollen glands in neck and face, irregular periods, using bathroom after eating, worrying of body weight, feeling out of control, bloodshot eyes, heart burn, bloating, indigestion, constipation, dental problem.......
What is bulimia?
Bulimia is also called nervous bulimia, is a psycological eating disorder.
What are some other symptoms of bulimia?
Persons with bulimia have depressive symptoms and unhappy feelings.
If you have bulimia:
1) Tell to someone you trust( parent, friend,boyfrien...)
2) The behavior is addictiveSome expert recomend: supportive groups, cognitive-behavior therapy.....

Anorexia

In the chapter we are going to start in Science class we will talk about nutrition and the way we eat. So I would like to talk about the problems connected with food. One of them is anorexia.

Anorexia is an eating disorder that occurs mainly in teenagers girls. But it can also occur in teenage boys, and adult women and men. Ballet dancers, models and gymnasts are more likely to be anorexic.

Anorexia is when a person loses a lot of weight because he/she thinks that is he or she is very fat and he/she doesn’t want to be fat.

Normally anorexic people start leaving carbohydrates out of his meals because people think that they are what makes you put on weight, but they are not. Then they leave out the fats, the proteins and even the liquids creating cases of dehydration. Then they start taking laxatives,vomiting, diuretics and doing a excess of sport.

Also anorexia is related with psychological problems that change the behaviour of the person.

There is a difference between anorexia and bulimia. Bulimic people eat a lot and then they punish themselves by vomiting to take out of the body the food that the ate before. And anorexic people only the loose weight by not eating.

Fashion is responible for the problem of anorexia, because people try to be a size 32 or 34 like the models. Now a days the models are putting on weight because they forced to do it.

But there are other psychological factors that make a person being anorexic like the death of a member of the family or a friend, divorce of the parents, dropping down of their marks at school, accidents…

Usually the family is the one that detect the cases of anorexia because the people who have it are always worried about the calories in food, have a constant cold sensation, have an obsession with their image and the bathroom scale, and in the women stop having periods.

The treatment of the anorexia is to make the person put on weight in a short period of time and to treat it psychologically.

If you have anorexia, bulimia or another eating disorder, tell someone about it because you are risking your life if you hide behind silence and at any moment it could be too late.

Protozoa

Protozoans are the most abundant living beings in the world having their own kingdom (protoctista) shared with sea weeds and imperfect mushrooms. Their main importance is as consumers of bacterias (prokaryotes belonging to the Monera kingdom). Bacterias play a major role in maintaining the Earth as a suitable place for inhabitation by other forms of life and protozoans play a vital role in controlling their numbers and biomass.Protozoans are defined as single-celled eukaryotic organisms, that feed heterotrophically and exhibit diverse motility mechanisms.Four major groups of protozoa are recognized and often given the status of phylum. The groups are:

• Flagellates
• Amebae
• Sporozoans
• Ciliates

Amoeba

A paramecium, the most abundant ciliate

Some cool websites for learning about protozoans

http://waynesword.palomar.edu/trnov01b.htm

http://www.uga.edu/protozoa/education/students/for_students_sop_web_ora.doc

Bacterias

This is the name that the unicellular organisms that don’t have nucleus and reproduce themselves with a simple cellular division receive.

Electron microscope image of Escherischia coli,

a bacteria thet lives in our intestine

Bacteria are very very small between 1 and 10 micrometers of length and they are very variable on the way they obtain the energy and the food.
Bacteria are all around us, they are in the air, in water; we can classify bacteria depending on shape, way of feeding, if they do the respiration or not....

Not all the bacteria have the capacity of movement but the one that have this capacity they move because they have a flagellum. Flagellum can be located in one of the extreme of the bacteria or all around its surface.

Depending on the direction that the flagellum moves, bacteria can move forward or waving to a fixed direction. Flagellum moves with a rotation movement and doing the movement of a snake.

If we look at bacteria from the outside to the interior we can find:
the capsule, cell wall, membrane, pilus, flagellum, cytoplasm, ribosomes, mesosomes, plasmids, and the DNA without nucleus, REMEMBER!!.

Inner structure of a bacteria

Some useful links to study bacterias:

• http://www.ucmp.berkeley.edu/bacteria/bacteria.html
• http://www.microbeworld.org/