Glider

Hydroponics doesn't necessarily mean the roots of the plant are constantly immersed in water. Usually, there is an inert medium like expanded fired clay granules that the plants root into. Water and nutrients are pumped through this medium at regular intervals.

'Spoildley'? I'm sure I never said 'spoildley'.

You have nothing to apologise for. You haven't said anything bad. I only presented some information on phobias for clarity, so people could tell the difference between 'normal' fear and a phobic response. You are right, there is a certain area of the brain that accounts for fear. It is a large area though, and no one 'part' is responsible for fear. Fear is an extreme emotion, and emotion is a product of circuitry rather than the function of any single part. In other words, there is no 'fear centre' as such, but the combined activity of many 'parts' of the brain (e.g. amygdalae, anterior cingulate gyrus, hypothalamus, reticular system etc.) can result in fear. The general area is known as the limbic system.

My 'special effort' was referring to the formation of phobias, not the 'curbing' of phobias. As mentioned above, fear of (e.g.) snakes and spiders can be passed between individuals, phobias can't. It requires a 'special effort' to form a phobia. Phobias are generally a result of the formation of an association between a severely traumatic/aversive event or state and an innocuous (often non-related) stimulus. Phobias can be defined as an extreme and irrational fear response to an innocuous stimulus. You aren't born with them, nor can you learn them from other peoples' reaction to stimuli. They are very subjective and personal percepts. PS. There is no such thing as a 'fear receptor'.

Red meat is only one source of iron and iron deficiency is only one cause of anaemia. Rather than just looking at the colour of your lips (which can change according to temperature and other factors influencing peripheral vasodilation), pull your lower eyelid down and check the colour of the sclera underneath. It should be bright red. If the sclera appears very pale/light pink, it suggests you are anaemic. In any event, I agree with blike, you should go and see your doctor. There are several possible causes of anaemia, and if you are anaemic, it would be as well to find out why sooner rather than later.

When in the process of developing a phobia, and in the absence of any obvious cause of their distress or trauma, people will often (on a non-conscious level) 'search' for something to associate with their extreme negative state. If they already have have something in their memory to which they are 'sensitive' and which evokes fear in them (albeit not to phobic levels), they will 'attach' their state to it. In other words, in the absence of an obvious thing to blame for their trauma, they will attach the blame to something that already makes them uncomfortable. These are more likely to be things that evoke a similar response in most people (e.g. spiders, snakes, needles etc.) and so are the more common phobias. However, people often form such associations with whatever is prominent in the environment at the time of their distress. I know someone who has a phobia of moths. In this case, there just happened to be a moth present during an extremely distressing experience. The association was formed, and the subsequent exposure to moths re-evoked the emotions associated with the experience. However, because the details of the experience had been forgotten (this happened in childhood), the person could provide themselves with a rational explanation for their response to the moth. Because of this, the fear became irrational and grew (unchecked by a rational explanation) into a full blown phobia. The person has been phobic towards moths for over 18 years now, and is only just beginning to deal with it.

The defeat of the Luftwaffe in the Battle of Britain and the German defeat in Lenningrad.

It's true. The 'learning' of fears and fear responses is a known phenomenon. It has been demonstrated in lower primates and in humans. Not only between adults and infants, but between adults too. It's an adaptive feature. Again though, phobias are different and require a special effort.

We didn't really. Phobias have to be learned. Our ancestors evolved a 'healthy respect' for certain things (e.g. snakes and spiders), i.e anything that we evolved alongside which has the potential for harm. To turn that 'discomfort' at their proximity into a phobia takes a special effort though.

It's definitely patients who are strongly religious. The theory (from a psychoneuroimmunological perspective) is that patients who place their faith in God, engender a kind of passive "it is in the hands of God" or "Whatever God wills" state. They have, in effect, abdicated personal control The less (or not) religious tend to take on more personal responsibility for the probable outcome; more a kind of "If anything is going to happen, it's me who will make it happen" approach. The former is more passive, and whilst it can be beneficial emotionally, those who fight and rage stand a better chance physically. State of mind is a factor in cancer prognoses. Those who fight tend to do better, live a bit longer and stand a slightly greater chance of going into remission. Not a huge effect, but statistically significant. The irony is that type A personalities (who are at a generally higher risk of heart attacks, strokes and other stress-related ilnesses than other types) actually have quite a favourable prognosis in cases of cancer. They will get angry and fight it all the way.

If you're stupid enough to actually imagine you're thundering across the Serengeti with the last of the rhino whilst sitting in traffic for three hours at apex corner like everyone else, you need one of these! : Land Rover Freelander

Here's an interesting (empirically based) statistic: In cases of serious illness (e.g. cancer), patients who are strongly religious have a poorer prognosis than those who are not; a higher mortality rate and a shorter life expectancy.

Exogenous pyrogens are introduced into the body from the ouside (e.g. bacteria etc.), or produced within the body by organisms that came from the outside (e.g. bacterial toxins). Either way, the original source is outside the body. Endogenous pyrogens are produced inside the body, by the body (monocytes and macrophages).

You answered your own question (what is a pyrogen?) in your post. The answer to question 1. is in the first paragraph of the above post. The answer to question 2. is in the second paragraph. Endogenous pyrogens are not released to combat bacteria or other 'invaders'. They are released to re-set the neural 'thermostat' to a higher level to help the body combat the infection by elevating metabolism (faster healing and antibody production). The elevation in core temperature can also inhibit bacterial growth in some cases. One of the mechanisms of inhibition is that fever and the elevation in metabolism causes certain minerals (particularly iron) that bacteria need for reproduction to be locked up in the liver.

There are no loopholes. No metabolism = no life. Life support machines would be irrelevant, as these machines only ..er..support life.

The term Pyrogen refers to any substance that causes an elevation in core temperature. There are exogenous (exo = outside; gennan = to produce) pyrogens and endogenous (endo = within) pyrogens. The most common cause of fever (pyrexia) are exogenous pyrogens, which are usually toxins (particularly bacterial toxins) and those produced as a result of bacterial and viral infection. However, other causes of fever can include heart attacks, tumours, tissue trauma, reaction to vaccines and so-on. The way it works is this: exogenous pyrogens cause monocytes and macrophages (both are kinds of white cell called phagocytes) to synthesise and release endogenous pyrogens, which are small proteins. These circulate to the anterior hypothalamus (the area responsible for the homoeostatic maintenance of body temperature), and cause cells in the preoptic area to release substances called prostoglandins, which re-set the hypothalamic 'thermostat' (internal comparator) to a higher level. Neither condition is a disease, but they can be chronic. However, you should note that Hyperpyrexia and hyperthermia are terms used to indicate fever above 40 degrees C. Prolonged hyperthermia is harmful (particularly in children), and can result in febrile seizures, tissue damage and death. So hyperthermia per se cannot be chronic, pyrexia can. On the other hand, hypothermia simply means a subnormal body temperature and is encountered (as a result of pathology) much less frequently than fever. What we are talking about here is Pyrexia, which indicated temperatures above 38 degrees C, but below 40 (104F). All these terms refer to body temperature (i.e. changes in core temperature), not changes in peripheral temperature. We are very much more tolerant of changes in temperature of, for example, skin, limbs hands and feet than we are of changes in core temperature, which must be maintained very closely around 38 degrees Celsius. There are conditions which upset the hypothalamic 'temperature control'. For example, Hypo- and Hyperthyroidism. One of the symptoms of hyperthyroidism is heat intolerance. Hyperactivity of the thyroid results in an elevated metabolism, weight-loss, an elevated core temperature, profuse sweating and feeling uncomfortably hot in conditions that are comfortable to everyone else. There are also psychological effects, nervousness, anxiety and emotional lability (instability) are also manifest. The symptoms of hypothyroidism (also known as myxedema) are more or less the opposite of these; i.e. mild hypothermia and cold intolerance, reduced metabolism, weight gain sluggish mental processes, tiredness and flattened emotional responses. Lesions (damage) to the hypothalamus can also cause long-term temperature dysregulation. They are. And phagocytes are a kind of white cell. White cells are the immediate defence, and directly attack the pathogens. They also release endogenous pyrogens. Partially right. A pyrogen is not a cell. It is a small protein released by cells, but it is not released to kill bacteria and viruses (see below). Quite right. The increase in core temperature does not help kill bacteria and viruses to any significant extent. Bacteria are not viruses; bacteria are alive and capable of reproduction, viruses are not alive (they are 'viable') and are incapable of independent reproduction. They require a host cell to produce more of themselves. In some cases, fever can inhibit the rate of bacterial reproduction, but many bacteria can live in temperatures higher than those that would kill us very quickly (a core temperature of around 110 - 112 Fahrenheit, 43.3 - 44.4 Celsius is fatal to us). Viruses can exist in very high temperatures. Even the HIV virus (which, as viruses go, is quite pathetic outside of a host) requires temperatures of at least 60 degrees Celsius to destroy it. Many viruses can cope easily with temperatures in excess of 100 degrees Celsius. A core temperature sufficient to kill most pathogens would kill us instantly. There are a very few exceptions, for example, the causative organisms in gonorrhea and neurosyphilis don't like heat, but even then, the temperature required to wipe them all out would also severely damage us, if not kill us. As for viruses, they can't reproduce on their own. They insert their RNA into our cells and our own cells begin producing new viruses, so the only way to kill them would be to kill our own cells. The principal benefit of fever is the elevated metabolism. This means our own chemical process are occurring at a higher rate, which means we heal faster (repairing and replacing damaged cells more quickly) and we produce more white cells and antibodies faster. 102 Fahrenheit is about 39 degrees Celsius. For more detailed information see: Kandel, E.R., Schwartz, J. H., & Jessell, T. M. (1991). Principles of Neural Science. International: Prentice-Hall international Inc. Tortora, G. J. and Anagnosticos, N. P. (1987). Principles of Anatomy and Physiology (5th Ed.). New York: Harper and Row. Watson, J. E., (1979). Medical-Surgical Nursing and Related Physiology (2nd Ed.). London: W.B. Saunders.

Is it...indeed. Well, there you go then.

...er...what?

Well put sir!

It's a nice idea, but I'm afraid your teacher is wrong. Whilst the gyri and sulci do increase the area of the cortex, cortical area is a poor correlate of intelligence. Your socioeconomic status to a large extent determines your social environment, which, in turn determines to a large extent the type of things you will be exposed to as you grow up. Of course, SES is not the rigid barrier it used to be. People have much more choice concerning what they experience now. But if all you know is TV soap, computer games and the pub, it's less likely you will search out more stimulating things.

Metabolism is the term given to the balance between catabolism (the breaking down of substances for energy, waste, etc.) and anabolism (the creation of new substances, for repair, growth etc.). For example, catabolic processes are what happen when you break down animal protein into amino acids that you can rebuild into your own proteins. Anabolic processes are what happen when you create new actin and myacin from these amino acids to build muscle. Anabolism and catabolism are usually in balance. This balance is called metabolism. The rate at which anabolic and catabolic processes happen is called the matabolic rate.

Depends how hungry you are. You'd have to have been fasting for some time to become ketotic. The body produces ketones as a byproduct of metabolising fat for energy in the absence of glucose (or if your insulin levels ore too low to utilise the glucose that is present). If you've eaten a poor breakfast (stuffed full of sucrose) you could suffer a fast drop in glucose levels before lunch. This will lead to feelings of hunger. How does being hungry disrupt they way you think? It does so in two ways; 1) Physiologically: As has already been said, the brain uses glucose as fuel. If you are low on glucose, the brain will be affected. 2) Psychologically: When you are hungry, your subconscious begins the search for food, whether you are otherwise occupied or not. Environmental stimuli pertaining to food, or the source of food become much more salient and your brain will begin to focus on these and bring them to your attention, where previously, you might not have noticed them. Example: A study was done on the effects of fasting on perception. Participants were shown a large board on which were presented a large number of images. Amongst these images were images of food (banana, apple, egg and so-on). Participants were allocated to two groups. One group fasted for 12 hours. The other ate as normal. The task was to find all the food items that were hiddden amongst all the distractor items in the shortest possible time. Those that had fasted found these items in a significantly shorter time than those who had eaten normally. Eat a good breakfast; lots of complex carbohydrates that will last until lunch. Do not eat just before an exam. If you do this, the body diverts resources from your brain to your gastrointestinal tract to assist with digestion (the reason you sometimes feel drowsy after a meal), and you won't be able to concentrate in the exam. If you need to eat, have a light snack at least an hour beforehand.

Syringes do contain air. You can see the bubble when you draw a sample. Syringes designed to take arterial blood-gas samples have a plunger which is designed to eliminate that air bubble (which is enough to change the sats values significantly). The plunger has a projection which fits into the leur cone, eliminating that space. Normal syringes don't have this. The best way to see the colour of venous blood is to take the sample directly into an oxygen free container, e.g. an anaerobic blood culture sample.

I agree, though there is a degree of subjectivity involved, I would have to say that venous blood is more blue than red (i.e. if you were to mix blue and red to get the purple of venous blood, it would take more blue than red). If you look at somebody who is cyanotic, they have a general blue tinge and bright blue lips too.

Does blood flow from any finger to the nose? Well, yes...eventually. There is no direct connection though. Starting at the heart (right ventricle) blood flows from there to the lungs via the pulmonary artery. From the lungs it flows back to the left atrium, and into the left ventricle (the heart is a double pump). The blood leaves the left ventricle via the aorta. The first branches from the aortic arch are the brachiocelphallic (which in turn splits into the right subclavian and the right common carotid), then the left common carotid, then the left subclavian. The subclavian arteries turn into the Axillary arteries at the shoulders and become the brachial arteries as they descend into the medial aspect of the upper arms. These arteries supply the arms (and by extension, the hands and fingers). The left and right common carotids split at the neck (about the point where the lower jaw meets the neck) into the internal and external carodid arteries. The internal carotid feeds into the circle of Willis and supplies the brain. The external carotid branches into the lingual artery (supplying areas under the lower jaw) the facial artery (supplying the outer lower jaw and front of the face - outside the skull) and the maxillary artery, which supplies the inside of the face (inside the skull) and the maxillary sinus. This is the one that supplies blood to the the membranes that bleed in nose bleed. So, whilst arguably the entire circulatory system is connected, the direct connection between blood supply to the fingers and the nose stops at the aorta, and don't rejoin again until the superior vena cava (the venous equivalent of the aorta). In short, no. Blood does not flow from your finger to your nose. To get from any finger to the nose, blood has to go back to the heart (right atrium - right ventricle - lungs - left atrium - left ventricle - common carotid) and then to the nose.