Question: Why do we itch?
Answer: No one really knows for sure. There are many theories about why this occurs though. Certain cutaneous(in the skin) nerve endings have been shown to be associated with itching, and can be stimulated by both endogenous and exogenous pruritic stimuli. This by no means accounts for all itching, however, as many pathological conditions can cause itching. The most interesting of which, in my opinion, is congestive heart failure. Congestive Heart Failure(CHF) is a condition in which the left ventricle of the heart(which normally takes blood from the left atrium and pumps it out through the aorta to the body)fails to pump properly. This causes a back up of blood flow and a build up of pressure in the heart, pulmonary circulation, and venous return to the right atrium. These things then cause a massive increase in blood pressure, as well as a decrease in oxygen perfusion of the peripheral tissues. For some reason, CHF also causes people to itch like crazy.
I wish I could give a more definitive answer...maybe something will be discovered soon and I will learn about it in immunology next quarter.
Friday, February 27, 2009
Tuesday, February 24, 2009
Reader Question #6
Question: What are allergies?
Answer: Simply put, and allergy is an inappropriate immune response to a normally benign stimulus. An allergen, such as pollen or a foodstuff of some kind, enters your system and the immune system, which should be off doing other things, attacks it. The inflammatory response associates with this immune attack is what causes most of the allergic reaction symptoms.
Immunology starts next quarter, I post a more complete answer sometime in the next few months.
Answer: Simply put, and allergy is an inappropriate immune response to a normally benign stimulus. An allergen, such as pollen or a foodstuff of some kind, enters your system and the immune system, which should be off doing other things, attacks it. The inflammatory response associates with this immune attack is what causes most of the allergic reaction symptoms.
Immunology starts next quarter, I post a more complete answer sometime in the next few months.
Sunday, February 22, 2009
Reader Question #5
Question: What exactly is a muscle "knot" and what is the best way to get rid of it?
Answer: A muscle "knot" in most cases is a discrete section of muscle fibers which is in contraction or spasm. These spasms can often occur at well described tenderpoints or trigger points. The difference between the two being that a tenderpoint will hurt when pressure is applied, while a trigger point will hurt and refer pain to another area of the body.
There are several things which can work together to release muscle knots. The first is just general soft tissue massage in the area. This can help to relax the muscle and release the contraction. The next is counterstrain treatment. The basic principle of counterstrain treatment is to approximate the origin and insertion of the muscle in spasm to allow it to relax and reset itself. This type of treatment can be done easily and very quickly. Direct inhibition (in which direct pressure is applied to the muscle knot) can also be used, but this is generally much more painful than the other techniques. Finally, if the knot will not release with physical manipulation, muscle relaxants and local anesthetic shots can be used to relax the muscle.
Answer: A muscle "knot" in most cases is a discrete section of muscle fibers which is in contraction or spasm. These spasms can often occur at well described tenderpoints or trigger points. The difference between the two being that a tenderpoint will hurt when pressure is applied, while a trigger point will hurt and refer pain to another area of the body.
There are several things which can work together to release muscle knots. The first is just general soft tissue massage in the area. This can help to relax the muscle and release the contraction. The next is counterstrain treatment. The basic principle of counterstrain treatment is to approximate the origin and insertion of the muscle in spasm to allow it to relax and reset itself. This type of treatment can be done easily and very quickly. Direct inhibition (in which direct pressure is applied to the muscle knot) can also be used, but this is generally much more painful than the other techniques. Finally, if the knot will not release with physical manipulation, muscle relaxants and local anesthetic shots can be used to relax the muscle.
Reader Question #4
Question: What's a hypotenuse? Also, what's the best way to avoid catching diabetes?
Answer: The side opposite your mom in a right triangle, or an airplane bathroom. Take your pick. As for your second question, stay the hell away from Wilford Brimley.
Real Answer: There are two major chemicals in the body which are involved in diabetes, insulin and glucagon. Insulin is the signal in the body which indicates that enough glucose is present in the system. When insulin levels are high, glucose will be packaged and stored for later use. Glucagon is the counterpart to insulin, signaling the body that glucose is low. When glucagon is high, the body will unpack stored glucose and release it to the system. These two chemicals exist in a push/pull relationship, with glucagon usually slightly dominate.
There are two major types of diabetes. Type 1 diabetes is a genetic deficiency of insulin production. In this case, the body has no signal to tell it to package and store glucose. Adding to this problem is that glucagon is now unchecked, and the body will be unpacking what glucose it does have stored and sending it out to the system. These two effects together lead to hyperglycemia. Type 2 diabetes is an acquired peripheral tissue resistance to insulin. While the body still produces insulin, the tissues which would use it to take up glucose are unable to do so. This leads to an increase in circulating glucose, and thus hyperglycemia.
The best way to avoid becoming a type 2 diabetic is simply to eat well and exercise. Adipose (fat) tissue acts as a gland within the body, and secretes substances which will either sensitize or desensitize the body to insulin. At appropriate levels, adipose serves to sensitize the tissues. In obese people, however, the opposite generally occurs. Combine these effects with a poor diet (high in fat and sugars), and your on the way to developing an insulin resistance, which can become diabetes.
A few other important factors to watch are blood lipids (cholesterol, triglycerides) and blood pressure (<120/80 is ideal, but there is much flexibility in this number). While these factors will not directly contribute to diabetes, they are all good indicators of general health and should be monitored and discussed with your doctor. Also, if you don't have a family doctor, get one. The best way to stay healthy is to catch potential problems as early as possible.
Answer: The side opposite your mom in a right triangle, or an airplane bathroom. Take your pick. As for your second question, stay the hell away from Wilford Brimley.
Real Answer: There are two major chemicals in the body which are involved in diabetes, insulin and glucagon. Insulin is the signal in the body which indicates that enough glucose is present in the system. When insulin levels are high, glucose will be packaged and stored for later use. Glucagon is the counterpart to insulin, signaling the body that glucose is low. When glucagon is high, the body will unpack stored glucose and release it to the system. These two chemicals exist in a push/pull relationship, with glucagon usually slightly dominate.
There are two major types of diabetes. Type 1 diabetes is a genetic deficiency of insulin production. In this case, the body has no signal to tell it to package and store glucose. Adding to this problem is that glucagon is now unchecked, and the body will be unpacking what glucose it does have stored and sending it out to the system. These two effects together lead to hyperglycemia. Type 2 diabetes is an acquired peripheral tissue resistance to insulin. While the body still produces insulin, the tissues which would use it to take up glucose are unable to do so. This leads to an increase in circulating glucose, and thus hyperglycemia.
The best way to avoid becoming a type 2 diabetic is simply to eat well and exercise. Adipose (fat) tissue acts as a gland within the body, and secretes substances which will either sensitize or desensitize the body to insulin. At appropriate levels, adipose serves to sensitize the tissues. In obese people, however, the opposite generally occurs. Combine these effects with a poor diet (high in fat and sugars), and your on the way to developing an insulin resistance, which can become diabetes.
A few other important factors to watch are blood lipids (cholesterol, triglycerides) and blood pressure (<120/80 is ideal, but there is much flexibility in this number). While these factors will not directly contribute to diabetes, they are all good indicators of general health and should be monitored and discussed with your doctor. Also, if you don't have a family doctor, get one. The best way to stay healthy is to catch potential problems as early as possible.
Friday, February 20, 2009
Reader Question #3
Question: "I read somewhere that tall people are more like to have bad knees and backs because they're over-nourished. That is, our bodies are over-engineered for height, and the fact that we eat well enough to grow so tall means that our size over-reaches our joints. Any thoughts?"
Answer: While there is a connection between the release of growth hormone and nourishment, I do not believe that over-nourishment will cause a person to out-grow their joints (not due to height anyway). It is true, however, that over nourishment can cause a person to grow to heavy for their joints, which can be a serious problem.
While there are some conditions which cause people to be very tall and have joint problems (i.e. Marfan's Syndrome, a genetic defect in collagen production)the back and knee problems experienced by taller people are most likely a result of musculoskeletal (somatic) dysfunction. Simply stated, taller people are required to bend down more than shorter people. This will initially cause problems in the spine. Normal physiologic motion of the spine includes three types of movement: Neutral movement(in which the spine is either flexed or extended with no side-bending), Type I movement(in which the spine is sidebent one direction and rotated the opposite), and type II movement(in which the spine is sidebent one direction and rotated in the same direction). Type II movement occurs at the extremes of physiologic range of motion, i.e. the farther you bend over the more likely you are to induce type II motion. Type II motions can lead to type II somatic dysfunctions, in which the spine gets "stuck" in a position which is flexed/extended, sidebent, and rotated relative to neutral. Type II somatic dysfunctions tend to be more damaging/painful than type I or neutral dysfunctions(Caused by Type I motion and Neutral motion respectively). Once a dysfunction is induced, this causes the person to adopt a shifted neutral standing position (often this shift is imperceptible to the person). The rest of the body will then undergo a compensatory shift, thus putting abnormal strains on other joints, specifically the knees, sacroiliac joints, and inominates(pelvis).
While I can't guarantee this is perfect (and I know its not the only possible explanation), this is what I believe to be the most likely cause of taller people being more likely to have joint problems than shorter people.
More questions?
Answer: While there is a connection between the release of growth hormone and nourishment, I do not believe that over-nourishment will cause a person to out-grow their joints (not due to height anyway). It is true, however, that over nourishment can cause a person to grow to heavy for their joints, which can be a serious problem.
While there are some conditions which cause people to be very tall and have joint problems (i.e. Marfan's Syndrome, a genetic defect in collagen production)the back and knee problems experienced by taller people are most likely a result of musculoskeletal (somatic) dysfunction. Simply stated, taller people are required to bend down more than shorter people. This will initially cause problems in the spine. Normal physiologic motion of the spine includes three types of movement: Neutral movement(in which the spine is either flexed or extended with no side-bending), Type I movement(in which the spine is sidebent one direction and rotated the opposite), and type II movement(in which the spine is sidebent one direction and rotated in the same direction). Type II movement occurs at the extremes of physiologic range of motion, i.e. the farther you bend over the more likely you are to induce type II motion. Type II motions can lead to type II somatic dysfunctions, in which the spine gets "stuck" in a position which is flexed/extended, sidebent, and rotated relative to neutral. Type II somatic dysfunctions tend to be more damaging/painful than type I or neutral dysfunctions(Caused by Type I motion and Neutral motion respectively). Once a dysfunction is induced, this causes the person to adopt a shifted neutral standing position (often this shift is imperceptible to the person). The rest of the body will then undergo a compensatory shift, thus putting abnormal strains on other joints, specifically the knees, sacroiliac joints, and inominates(pelvis).
While I can't guarantee this is perfect (and I know its not the only possible explanation), this is what I believe to be the most likely cause of taller people being more likely to have joint problems than shorter people.
More questions?
Thursday, February 19, 2009
Reader Question #2
Question: What causes a headrush?
Answer: Orthostatic Hypotension. When changing positions, your body needs to regulate cardiac output and peripheral vascular resistance in order to maintain adequate blood pressure. Specifically, the body must maintain constant blood flow to the brain. When in a sitting position (or when lounging like the ancient Greeks)the hydrostatic pressure (pressure caused by the physical effect of gravity on your blood) is much less than when you are standing (pressure is directly related to column height). The heart will therefore beat a little faster/harder and your blood vessels will constrict a little more when you are in a standing position compared to sitting. Sometimes a person will change positions faster than the body is able to adapt to the change in hydrostatic pressure, resulting in a brief period of inadequate blood flow to the brain. This causes the dizziness experienced. The heart will usually the beat a bit harder/faster, causing the blood flow to be restored. If this does not occur, the drop in blood pressure will lead to syncope(fainting).
As for the first question, I would think its because he touches himself at night (see comments to this entry ). But I don't know, I'm not a doctor...
I know someone out there has another question.
Answer: Orthostatic Hypotension. When changing positions, your body needs to regulate cardiac output and peripheral vascular resistance in order to maintain adequate blood pressure. Specifically, the body must maintain constant blood flow to the brain. When in a sitting position (or when lounging like the ancient Greeks)the hydrostatic pressure (pressure caused by the physical effect of gravity on your blood) is much less than when you are standing (pressure is directly related to column height). The heart will therefore beat a little faster/harder and your blood vessels will constrict a little more when you are in a standing position compared to sitting. Sometimes a person will change positions faster than the body is able to adapt to the change in hydrostatic pressure, resulting in a brief period of inadequate blood flow to the brain. This causes the dizziness experienced. The heart will usually the beat a bit harder/faster, causing the blood flow to be restored. If this does not occur, the drop in blood pressure will lead to syncope(fainting).
As for the first question, I would think its because he touches himself at night (see comments to this entry ). But I don't know, I'm not a doctor...
I know someone out there has another question.
Reader Question #1
The following question has been posed: What causes cramps?
The short answer is this: Muscle cramps are caused by an inappropriate shortening of muscle fibers. This can be caused by many different things, from chemical imbalances(calcium, potassium, etc...) to physical trauma. One of the more common causes of muscle cramps is a reactive shortening of muscle fibers due to a sudden stretch placed on the muscle. This can be from a hyper-extension, or when a flexed muscle is suddenly lengthened. This causes the body to reflexively shorten the muscle, to protect it from tearing. This reflexive shortening is the muscle spasm or cramp that causes pain. Often these spasms can then be held by segmental facilitation of the autonomic nervous system (over active nervous output)until some action is taken to release the muscle (stretching, counter-strain treatment, etc).
(Boosh)
The short answer is this: Muscle cramps are caused by an inappropriate shortening of muscle fibers. This can be caused by many different things, from chemical imbalances(calcium, potassium, etc...) to physical trauma. One of the more common causes of muscle cramps is a reactive shortening of muscle fibers due to a sudden stretch placed on the muscle. This can be from a hyper-extension, or when a flexed muscle is suddenly lengthened. This causes the body to reflexively shorten the muscle, to protect it from tearing. This reflexive shortening is the muscle spasm or cramp that causes pain. Often these spasms can then be held by segmental facilitation of the autonomic nervous system (over active nervous output)until some action is taken to release the muscle (stretching, counter-strain treatment, etc).
(Boosh)
Wednesday, February 18, 2009
Medical Myths
Medical Myth #42: Muscle pain during exercise is due to the build up of lactic acid.
False!
Reality: While lactic acid is a by product of anaerobic glycolysis, and muscle cells derive their primary energy from glycolysis, there is not significant lactic acid build up. Glucose, under anaerobic conditions, is converted into lactate (-ate = -ic acid in sciency speak) which is shunted from the muscle cell. The muscle soreness caused by exercise is actually the result of microscopic damage done to the myocytes (muscle cells).
Medical Myth #675: Alcohol causes frequent urination.
True!
Alcohol consumption inhibits the ability of the pituitary gland to secrete vasopressin, and anti-diuretic hormone. This results in polyuria, or frequent urination. Interestingly, this can also contribute to the dehydration that often accompanies heavy alcohol use.
Have a medical myth/question you would like me to attempt to answer? I promise to use at least 3/4 of my ass! Just post your question as a comment to this entry.
False!
Reality: While lactic acid is a by product of anaerobic glycolysis, and muscle cells derive their primary energy from glycolysis, there is not significant lactic acid build up. Glucose, under anaerobic conditions, is converted into lactate (-ate = -ic acid in sciency speak) which is shunted from the muscle cell. The muscle soreness caused by exercise is actually the result of microscopic damage done to the myocytes (muscle cells).
Medical Myth #675: Alcohol causes frequent urination.
True!
Alcohol consumption inhibits the ability of the pituitary gland to secrete vasopressin, and anti-diuretic hormone. This results in polyuria, or frequent urination. Interestingly, this can also contribute to the dehydration that often accompanies heavy alcohol use.
Have a medical myth/question you would like me to attempt to answer? I promise to use at least 3/4 of my ass! Just post your question as a comment to this entry.
Friday, February 13, 2009
The challenge, she has been accepted!
So the great push up challenge of 2009 has begun, and my arms have an odd mixed sensation of searing pain and numbness. Pain is the interpretation of afferent neural impulses, while numbness is the lack of neural conduction. Thus my current state both frightens and confuses me. On the plus side, I did complete my initial test, and surprised the hell out of myself in the process. Apparently, I can do 30 proper form push ups. I would say this puts me at an early advantage, but I notoriously suck at keeping up with anything even remotely resembling exercise...
On another note, I too have recently acquired Wii Fit. Could someone please explain to me why 50+ people feel that gathering in an auditorium and watching step aerobics is a worthwhile use of their time?
On another note, I too have recently acquired Wii Fit. Could someone please explain to me why 50+ people feel that gathering in an auditorium and watching step aerobics is a worthwhile use of their time?
Thursday, February 12, 2009
Push ups! (not that kind)
Have at ye Kurt! After reading your post I too feel inspired to aspire to pushing up glory! And so I challenge you to a push up off...er...push off...a contest in which we see who can make it to the goal of one hundred push ups (and certainly not a shameless stunt to attempt to draw traffic to my blog)! What sayeth thee?
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