The art of sleeping

Hello readers! Do you ever get that terrible feeling on the bus where the music in your ears have become more muffled, your eyes get heavier and heavier, eventually closing your eyes becomes out of your control, your head bobs forward, you start to stoop your shoulders...you just know you're going to sleep, coffee is far off in the distance, and the one thought that drifts across your mind about whether to risk missing your stop. That'll be any morning for me! And it gives me food for thought for this post!

Sleep is one of those essential things we just have to do as human beings. As a student that will inevitably have that all-nighter, sleep becomes not just essential but a greatly desirable thing to do. Without sleep, exhaustion, heavy eyelids, an inability to concentrate, ensues. There can be nights were you find it impossible to fall alseep, you keep waking up at night, and then there are nights when you simply drop off, and you're a log for the whole night. 

The characteristics of sleep for humans: usually, a person will lie down to go to sleep, the person's eyes are closed, the person doesn't hear anything unless it is a loud noise, the person breathes in a slow, rhythmic pattern, the person's muscles are completely relaxed and during sleep, the person will occasionally roll over or rearrange his or her body. This happens approximately once or twice an hour, which may be due to the body's way of making sure that no part of the body or skin has its circulation cut off for too long a period of time. A sleeping person is unconscious to most things happening in the environment, however, unlike someone who has fainted or is in a coma, a sleeping person can be aroused if the stimulus (shaking them, loud noises, flashing a bright light) is strong enough.

With animals, reptiles, birds and mammals all sleep - they become unconscious to their surroundings for periods of time. Some fish and amphibians reduce their awareness but do not ever become unconscious. Insects do not appear to sleep, although they may become inactive in daylight or darkness. Reptiles do not dream, birds dream a little and mammals all dream during sleep. Some animals sleep in one long session, while other animals, for example dogs, like to sleep in many short bursts.

During sleep, in the person's brainwave activity, while an awake and relaxed person will generate alpha waves which are consistent oscillations at about 10 cycles per second and the generation of beta waves that are twice as fast, two slower patterns called theta waves and delta waves take over. The brainwave patterns slow down. The slower the brainwave patterns, the deeper the sleep and so a person deep in delta wave sleep is hardest to wake up. Rapid eye movement (REM) sleep occurs at several points in the night and brainwaves during this period speed up to awake levels. REM sleep is when you dream. 

Pulling an all-nigher is not fatal; the person will usually become irritable during the next day and slow down or have some energy due to adrenalin. If a person misses two nights of sleep, concentration becomes difficult and attention spans fall, causing mistakes to increase. After three days, a person will start to hallucinate and clear thinking is impossible. A person can lose grasp of reality. Rats forced to stay away continuously will eventually die.

The importance of sleep is clear in what happens when you don't get any sleep. Additionally, a growth hormone in children is secreted during sleep, and chemicals important to the immune system are also secreted during sleep. There are many theories as to why we need sleep, including ideas that sleep gives the body a chance to repair muscles and other tissues, it gives the brain a chance to organize and archive memories, lowering our energy consumption and perhaps a way of recharging the brain.  

There are animals, including horses, donkeys and elephants, that sleep standing up because when they lie down, they put pressure on their ribs making breathing difficult. Horses are able to sleep standing up by having their legs able to lock into place, enabling them to sleep without falling over. Because they are prey animals, most of their sleeping is done during the day rather then at night when the predators are not hunting. Sometimes, horses would rest their legs during short naps lying down; they would sometimes be stretched out on its side, asleep in the sun, or laying in the ground with its legs folded under. 

Fun facts about animals sleeping

• On average, cats sleep 13 to 14 hours during the day, and mostly roam around at night, which is also true of big cats like lions
• Dolphins can slumber with just half their brains asleep: they can have the brain waves of non-REM sleep functioning in just one hemisphere while the other half remains awake. They sleep by resting on half of their brain at a time which is known as unihemispheric sleeping, which enables them to continue swimming. While they are sleeping, one eye will remain open while the other is closed (the open eye will be on the same side as the resting part of the brain) which means they can keep themselves and their young safe from predators.
• Horses and cows which sleep standing up don't experience full REM sleep unless they lie down
• Giraffes can go weeks without napping
• A desert snail can snooze for three years
• While asleep, platypuses make the same movement that they use when killing crustacean prey
• To avoid predators, African Papio baboons sleep on their heels, perched on trees
• Bats sleep upside down because it makes them less obvious to prey and allows them to take off at any moment should any threat emerge. Bats must fall into flying because their wings aren't strong enough for them to alight from a standing position.
• An albatross can sleep while it is flying
• A study on fire ants showed that the workers in the colony experienced 253 sleep episodes per day and each last about 1.1 minutes

Thanks for reading!

The Immune System

Hello readers! I've been struck with another cold, and as colds are, it decided to do so just when the weather is becoming delightfully sunny again after months of rain. Of course, the sniffing and need for tissues to be somehow on my person - meltdowns have the potential to be triggered when there are no tissues about and I've just sneezed! - this is all down to the workings of the immune system. After my last post on HIV, discussing it triggered some latent memories from my biology A-Level on the immune system and I figured it was time to brush up on that knowledge and share it with others! 

What is it?
The immune system is a network of cells, tissues, and organs that work together to protect the body from infection. The human body provides an ideal environment for many microbes, such as viruses, bacteria, fungi, and parasites, and the immune system prevents and limits their entry and growth to maintain optimal health. Currently in research, scientists continue to study how the body targets invading microbes, infected cells, and tumors while ignoring healthy tissues. New technologies for identifying individual immune cells help scientists determine which cells trigger an immune response under various circumstances. Improvements in microscopy also allow for observations of living immune cells as they interact within lymph nodes and other body tissues. Furthermore, scientists have been rapidly unraveling the genetic blueprints that direct the human immune response. This new technology and expanded genetic information promises to reveal more about how the body protects itself from disease. In turn, scientists can use this information to develop new strategies for the prevention and treatment of infectious and immune-mediated diseases.

How does it work?

• The immune system is designed to defend you against millions of bacteria, microbes, viruses, toxins and parasites.
• An example of being able to see the immune system is when you get a cut, bacteria and viruses are able to enter your body through the break in the skin. The immune system responds and eliminates the invaders while the skin heals itself and seals the puncture. In rare cases the immune system misses something and the cut gets infected. It gets inflamed and will often fill with pus. Inflammation and pus are both side-effects of the immune system doing its job.
• There are many ways that you can get sick: for example, mechanical damage when you break a bone or tear a ligament, vitamin or mineral deficiency, organ degradation when an organ is damaged or weakened, genetic disease caused by a coding error in the DNA, and cancer, where a cell will change in a way that causes it to reproduce uncontrollably.  
• In comparison, when a virus or bacteria invades your body and reproduces, it generates side effects by its presence we understand as symptoms. Strep throat bacteria releases a toxin that causes inflammation in your throat for example. Viruses and bacterial infections are the most common causes of illness for most people, causing things like colds, influenza, measles, mumps, malaria, AIDS and so on.
• The job of your immune system is to protect your body from these infections. It protects it through creating a barrier that prevents bacteria and viruses from entering your body, if it does get through this barrier, the immune system tries to detect and eliminate it before it can reproduce. If the virus or bacteria is able to reproduce, your immune system can then eliminate it. 
• The skin acts as a primary boundary between bacteria and viruses and your body; it acts as a barrier as the skin is tough and generally impermeable to bacteria and viruses. The epidermis of the skin contains cells called Langerhans cells which are an important early-warning component in the immune system. The skin also secretes antibacterial substances, causing bacteria and spores that land on your skin to die quickly.
• Your nose, mouth and eyes contain an enzyme called lysozyme, which break down the cell wall of many bacteria. Saliva is also anti-bacterial. The nasal passage and lungs are coated in mucus, causing bacteria to be trapped in the mucus and swallowed. Mast cells also line the nasal passages, throat, lungs and skin. Any bacteria or virus that wants to gain entry to your body must first make it past these defenses.
• Inside the body, the major components of the immune system are: the thymus, spleen, lymph system, bone marrow, white blood cells, antibodies, complement system and hormones.
• The thymus: it is situated in your chest between your breast bone and your heart. It produces T-cells and is especially important in newborn babies - without a thymus a baby's immune system collapses and the baby will die. 

• The spleen: it  filters the blood looking for foreign cells 
• The lymphatic system: it works by the fluids which ooze into the lymph system get pushed by normal body and muscle motion to the lymph nodes. Lymph is a clearish liquid that bathes the cells with water and nutrient, and also has blood plasma, the liquid which makes up blood without the red and white cells. Blood transfers these materials to the lymph through the capillary walls, and lymph carries it to the cells. The cells also produce proteins and waste products and the lymph absorbs these products and carries them away. Once lymph has been filtered through the lymph nodes, it re-enters the bloodstream.

• Bone marrow: it produces new blood cells, both red and white. Red blood cells are fully formed in the marrow and then enter the bloodstream. For some white blood cells, the cells mature elsewhere. The marrow produces all blood cells from stem cells which can branch off and become many different types of cells. Stem cells change into actual, specific types of white blood cells.

• White blood cells: white blood cells can ingest pathogens and destroy them, produce antibodies to destroy pathogens and produce antitoxins that neutralise that toxins released by pathogens. They can be grouped as phagocytes or macrophages and lymphocytes. Phagocytes can easily pass through blood vessel walls into the surrounding tissue and move towards pathogens or toxine. They then either ingest and absorb the pathogens or toxins or release an enzyme to destroy them. Having absorbed a pathogen, the phagocytes may also send out chemical messages that help nearby lymphocytes to identify the type of antibody needed to neutralise them. In comparison, lymphocytes work based on the fact that pathogens contain certain chemicals that are foreign to the body and are called antigens. Each lymphocyte carries a specific type of antibody - a protein that has a chemical 'fit' to a certain antigen. When a lymphocyte with the appropriate antibody meets the antigen, the lymphocyte reproduces quickly, and makes many copies of the antibody that neutralises the pathogen. Antibodies neutralise pathogens by binding to pathogens and damage or destroy them, coating coat pathogens, clumping them together so that they are easily ingested by phagocytes and they bind to the pathogens and release chemical signals to attract more phagocytes. Lymphocytes may also release antitoxins that stick to the appropriate toxin and stop it damaging the body.
• White blood cells are a whole collection of different cells that work together to destroy bacteria and viruses. Here are all of the different types, names and classifications of white blood cells working inside your body right now: Leukocytes, Lymphocyte, Monocytes, Granulocytes, B-cells, Plasma cells, T-cells, Helper T-cells, Killer T-cells, Suppressor T-cells, Natural killer cells, Neutrophils, Eosinophils, Basophils, Phagocytes and Macrophages
• All white blood cells are known officially as leukocytes and are divided in three classes: Granulocytes which make up 50 - 60% of all leukocytes, Lymphocytes which make up 30 - 40% of all leukocytes. Lymphocytes come in two classes: B cells (those that mature in bone marrow) and T cells (those that mature in the thymus). Monocyes make up 7% or so of all leukocytes which evolve into macrophages.
• All white blood cells start in bone marrow as stem cells which later will divide and differentiate into all different types of white blood cells. 
• Neutrophils, the most common form of white blood cells, work by being attracted to foreign material, inflammation and bacteria. It will be attracted by a process called chemotaxis, allowing motile cells move toward higher concentrations of a chemical. Once a neutrophil finds a foreign particle or a bacteria it will engulf it, releasing enzymes, hydrogen peroxide and other chemicals from its granules to kill the bacteria. 
• Eosinophils are focused on parasites in the skin and the lungs, while Basophils carry histamine along with mast cells to causing inflammation. It brings in more blood and it dilates capillary walls so that more immune system cells can get to the site of infection.

• Macrophages are the biggest cells, released by the bone marrow, float in the bloodstream, enter tissue and turn into macrophages. Most boundary tissue has its own devoted macrophages. They are called langerhans cells when they live in the skin. 

• The lymphocytes handle most of the bacterial and viral infections. They start in the bone marrow. B cells develop in the bone marrow before entering the bloodstream while T cells starts in the marrow but then migrate through the bloodstream to the thymus and mature there. T cells and B cells are often found in the bloodstream but tend to concentrate in lymph tissue such as the lymph nodes, the thymus and the spleen. There is also quite a bit of lymph tissue in the digestive system. B cells and T cells have different functions.

• B cells mature into plasma cells which produce antibodies. A specific B cell is tuned to a specific pathogen, and when the pathogen is present in the body, the B cell will then clone itself and produce millions of antibodies designed to eliminate the pathogen.
• T cells will bump up against cells and kill them. They are known as Killer T cells which can detect cells in your body that are harboring viruses, and when it detects such a cell, it kills it. Two other types of T cells, known as Helper and Suppressor T cells, help sensitize killer T cells and control the immune response.

Thanks for reading!

HIV

Hello readers! Today, I was reading an intriguing article about a radical treatment in HIV gene therapy, replacing immune cells with genetically modified versions, using GM cells which has been hailed a success after its trial. Great news all around! It certainly poses as a possible alternative treatment method, as it has been declared by scientists as a success after the first clinical trial. The tests on people enrolled in the trial found that the disease-resistant cells (the GM versions) multiplied in their bodies. The trial poses as a potential new therapy for HI; as a few shots of the modified immune cells can become an alternative for HIV patients who currently spend the rest of their lives on antiretroviral drugs - issues of which can results in side effects, people missing days and drug-resistance. From this, I'll move my post into its topic of the day, HIV, where I will be outlining what it is and how it occurs.

HIV
What is it?
It stands for human immunodeficiency virus. The virus attacks the immune system, which in turn weakens your ability to fight infections and disease. AIDS is the final stage of HIV infection, which the stage where your body can no longer fight life-threatening infections. However, with early diagnosis and treatment, most people will HIV will not reach this stage. However, without treatment, a person with HIV's immune system will become seriously damaged, and will develop life-threatening illnesses such as cancer.
It was first discovered in 1981 in a remote area of central Africa, and since then, swept across the globe, infecting millions in a relatively short period of time. AIDS has killed more than 28 million people, with up to 3.6 million people dying in 2005 alone.  

How does it occur?
HIV is spread most commonly by having sex with someone who has HIV without a condom. However, it can also be passed on by oral sex, sharing sex toys, sharing infected needles and other injecting equipment and from an HIV-positive mother to her child during pregnancy, birth and breastfeeding. This is because HIV is found in the body fluids of an infected person; which includes semen, vaginal and anal fluids, blood and breast milk. It is a fragile virus so cannot live very long outside the body and cannot be transmitted through sweat or urine. Ninety-five percent of those diagnosed with HIV in the UK has acquired HIV as a result of sexual contact.
One of the big issues with HIV is that a person can carry and transmit the HIV virus for many years before any symptoms show themselves. So a person can be contagious for a decade or even longer before any signs of disease become apparent. The issue at hand is, for example, for ten years, a promiscuous HIV carrier can potentially infect dozens of people, who can then in turn each infect dozens of people, and so on. 

What happens?
HIV invades the cells of our immune systems, and reprograms the cells to become HIV-producing factories. The number of immune cells in the body begins to dwindle and then AIDS develops. Once it manifests, a person is susceptible to many infections, and due to the weak immune system, it cannot fight back effectively. HIV has also been shown to be able to mutate, which makes treating the virus nearly impossible. HIV is therefore a disease which both invades and destroys the immune system which normally can protect the body from a virus. It paradoxically corrupts and disables a system that should be guarding against HIV, making it both a prevalent and successful disease. 
Like all viruses, HIV requires a host cell to stay alive and replicate. In order to do so, the virus creates new virus particles inside a host cell, and those fragile particles carry the virus to new cells. Made up of genetic instructions wrapped inside a protective shell, an HIV virus particle, called a virion, is a spherical cell. It infects something called the T-helper cells (one of the cells that works in the immune system) and once infected, the T-helper cells turns into an HIV-replicating cell. HIV will slowly reduce the number of T-cells until the person develops AIDS.
HIV is a retrovirus; it has genes composed of ribonucleic acid (RNA). Like all viruses, HIV, when replicating inside host cells, is considered a retrovirus because it used an enzyme, called reverse transcriptase, which converts RNA into DNA. 
The HIV virus, once it enters the body and heads for the T-helper cells it:

• Binds to the immune cell, where a protein of the HIV virus binds with a protein of the T-helper cell. The viral core enters the T-helper cell and the virion's protein membrane fuses with the cell membrane
• Reverse transcription then occurs - the viral enzyme, reverse transcriptase, copies the virus's RNA into DNA
• Integration - the newly created DNA is then carried into the cell's nucleus by an enzyme called viral integrase which then binds with the cell's DNA. HIV DNA is called a provirus
• The transcription occurs where the viral DNA in the nucleus seperates and creates messenger RNA (mRNA), which uses the cell's own enzymes. The mRNA contains the instructions for making new viral proteins.
• Translation - the mRNA is then carried back out of the nucleus by the cell's enzymes, and the virus uses the cell's natural protein-making mechanisms to create long chains of viral proteins and enzymes
• Assembly - RNA and viral enzymes then gather at the edge of the cell while an enzyme called protease cuts the polypetides (the chains of proteins) into viral proteins
• Budding - the new HIV virus particles come out from the cell membrane and break away with a piece of the cell membrane surrounding them. And so this is how the enveloped viruses leave the cell. This way, the host cell is not destroyed.

The virions will infect other T-cells and causes the person's T-helped cell count to fall. The lack of them compromises the immune system, and after a certain number of them fall, the person infected is considered to have AIDS. An AIDS-infected person dies from infections as a result because their immune system has been dissipated. An AIDS patient could die from the common cold as easily as he or she could from cancer because the person's body cannot fight off the infection. 

What treatments are currently available?
There is currently no cure for HIV, however there is a lot of treatments at hand which can enable a person living with HIV to live a long life, without HIV developing into AIDs. There is an emergency anti-HIV medication called PEP (post-exposure prophylaxis) which may stop you from becoming infected, but treatment must be started within three days of coming into contact with the virus. This is a treatment that would work well especially with HIV-positive mothers giving birth, as a prevention technique to stop their child from contracting HIV. Medication, known as antiretrovirals, works by slowing down the damage the virus does to the immune system, which come in the form of tablets that must be taken every day. Someone with HIV will be encouraged to take regular exercise, eat healthily, stop smoking, have yearly flu jabs and pneumococcal vaccinations to minimize the risk of getting serious illnesses.

Thanks for reading

    

Mysterious Mitochondria

Hello readers! I read an interesting piece today on the Guardian about the consultation on babies with three people's DNA, a controversial technique that is currently banned but could prevent women from passing mitochondrial diseases on to their children. The reason that this technique is currently controversial is due to the fact that the procedure lead to babies with DNA from three people. Mitochondrial transfer has never been tried in humans and is prohibited in Britain due to the law that bans the placing of an egg or embryo into a woman if the DNA has been altered. However, scientists working on the technique states that it offers hope of preventing life-threatening diseases for which there were no cures. At the moment, about 1 in 200 children born in the UK have some form of mitochondrial disorder. This is, despite being a slow progress, a great step into the direction of preventing such diseases as the government announced last June that it intends to allow the procedure, although regulations must be finalized, debated and approved by Parliament before clinics can offer the treatment. It also leads to today's post piece, on...the title may allow for a guess...mitochondria!

  

What is it?

Mitochondria is an organelle found in  large numbers in most cells, where in them, the biochemical processes of respiration and energy production to occur. The cytoplasm of nearly all eukaryotic cells contain mitochondria and they are especially abundant in cells associated with active processes, for example, in flagellated protozoa or in mammalian sperm. This is because they are involved in energy production. Multicellular organisms probably could not exist without mitochondria. The inability to remove electrons from the system and the buildup of metabolic end products restrict the utility of anaerobic metabolism. Through oxidative phosphoryation mitochondria make efficient use of nutrient molecules. They are the reason that we need oxygen at all.

What is it made up of?

Here is a diagram below of the organelle:

In the structure of a mitochondrion, it has two membranes, unlike other organelles. The outer membrane covers the organelle and contains it and the inner membrane folds over many times, these folds known as cristae. This folding over increases the surface area inside the organelle which speeds up reactions. Many of the chemical reactions happen on the inner membrane of the mitochondria, therefore the maximum amount of 'work' happens in the organelle. The fluid inside the mitochondria is called the matrix. The matrix is filled with water and proteins, which are enzymes that speed up the generated energy in order for reactions to take place at a quicker amount of time. These proteins take food molecules and combine them with oxygen. The mitochondria are the only place in the cell where oxygen can be combined with food molecules. Once this occurs, the material can be digested. So, in more specific terms, the enzymes in the matrix break down carboydrates and sugars to produce adenosine triphosphate (ATP). ATP molecules store the chemical energy required by the cell to carry out its metabolic functions. Other functions of the mitochondria include controlling the cell cycle - signaling, differentiation, growth and death - and assisting with cellular aerobic respiration. A mitochondrion may also be involved in controlling the concentration of calcium within the cell.

Mitochondrion disease

Mitochondrial diseases result from failures of the mitochondria. As they are responsible for creating more than 90% of the energy needed by the body to sustain life and support growth, when they fail, less energy is generated within the cell. This causes cell injury and even cell death follow. If this process is repeated throughout the body, whole systems begin to fail, and the life of the person in whom this is happening is severely compromised. The disease primarily affects children, but adult onset is becoming more and more common.This diseases appear to cause the most damage to cells of the brain, heart, liver, skeletal muscles, kidney and the endocrine and respiratory systems. Symptoms may include loss of motor control, muscle weakness and pain, gastro-intestinal disorders and swallowing difficulties, poor growth, cardiac disease, liver disease, diabetes, respiratory complications, seizures, visual/hearing problems, lactic acidosis, developmental delays and susceptibility to infection.

Thanks for reading