Showing posts with label blood. Show all posts
Showing posts with label blood. Show all posts
Tuesday, March 17, 2015
Insulin Blood Sugar
Insulin is a hormone, that means it is a chemical secreted into the blood by an endocrine organ and carried around the body to a target organ. Insulin helps to control the amount of glucose dissolved in the blood. Insulin prevents the blood sugar level from rising too high. It is also necessary to have insulin in your blood for respiration to take place. Without insulin cells can only get energy from fat and this causes serious problems. The control of blood sugar level is a homeostatic mechanism.
The Explanation:
- Insulin is secreted by the Islets of Langerhans which are special groups of cells in the pancreas. The Islets (little islands) are endocrine organs.
- If you have a large carbohydrate meal, the level of glucose in the blood will start to rise as your digestive system turns all the starch and sugars in your food into glucose.
- If you have not had a meal for several hours your blood sugar level will fall because your cells use up the glucose in aerobic respiration.
- When your blood sugar level rises, the Islets of Langerhans secrete MORE insulin.
- When your blood sugar level falls, the Islets of Langerhans secrete LESS insulin.
- The main target organ for insulin is the liver. It is the liver which removes glucose from the blood by turning it into glycogen.
- All other tissues in your body need insulin to help then respire glucose, so in a way they are also target organs.
- If you eat, and eat, and eat, and eat, never mind how little exercise; there will come a time when there is no more room for glycogen in your liver. High levels of insulin will make you start to turn the excess glucose into FAT. Please balance your diet!!!!!
- When you fast for more than two days, your liver will run out of glycogen, so you will have to use fat and protein to get energy.
- When your blood sugar level falls too low, not only does the pancreas make less insulin, but another endocrine gland, the adrenal gland, starts to make adrenalin and glucocorticoids.
- Adrenalin and glucocorticoids are hormones which have the opposite effect to insulin, i.e. they help to raise blood sugar level.
- The hypothalamus detects the conditions in your blood. It measures many things including blood sugar level. The hypothalamus is connected to the pituitary gland which is yet another endocrine gland.
- Negative feedback is the special mechanism for turning the hormones off after they have done their job. So when your blood sugar level drops, the amount of insulin produced also falls, and when your blood sugar level has risen back to normal, the amount of adrenalin and glucocorticoids falls.
Definitions
Hormone: this is a chemical secreted directly into the blood by an endocrine organ, it carries a message to a target organ. A hormone is a chemical messenger. | |
Endocrine Organ: this is an organ which secretes a chemical messenger or hormone directly into the blood. (c.f. an exocrine organ.) Endocrine organs make hormones. | |
Target Organ: this is any organ which is affected by a hormone. Almost every organ in the body is affected by one or more hormones. Target organs ar controlled by hormones. | |
Hypothalamus: this is a region at the base of the brain which monitors the conditions of your blood. It measures how much water, salts, bicarbonate ions and sugar is present; it also measures blood temperature. The hypothalamus helps to control the pituitary gland. | |
Pituitary Gland: this is the Master Endocrine Gland. It secretes hormones which control other endocrine glands. | |
Homeostasis: this is the mechanism for keeping your internal conditions constant. Blood sugar control is one example of homeostasis/a homeostatic mechanism. The other important ones are: osmoregulation, & thermoregulation. | |
Negative feedback: this is exactly the opposite of positive feedback! Another page in this Web Site to explain it. It is a switching off mechanism. |
Monday, March 9, 2015
Dark chocolate may lower blood pressure
There may be good news for people looking for an excuse to munch on a couple of squares of chocolate after a review showed the treat could reduce blood pressure.
An analysis of 20 studies showed that eating dark chocolate daily resulted in a slight reduction in blood pressure.
The Cochrane Groups report said chemicals in cocoa, chocolates key ingredient, relaxed blood vessels.
However, there are healthier ways of lowering blood pressure.
The theory is that cocoa contains flavanols which produce a chemical in the body called nitric oxide. This relaxes blood vessels making it easier for blood to pass through them, lowering the blood pressure.
Continue reading the main story
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The 100g of chocolate that had to be consumed daily in a number of the studies would also come with 500 calories - thats a quarter of a womans recommended daily intake”
Victoria Taylor British Heart Foundation
However, studies have thrown up mixed results. The Cochrane analysis combined previous studies to see if there was really an effect.
There was a huge range in the amount of cocoa consumed, from 3g to 105g a day, by each participant. However, the overall picture was a small reduction in blood pressure.
A systolic blood pressure under 120mmHg (millimetres of mercury) is considered normal. Cocoa resulted in a 2-3mmHg reduction in blood pressure. However, the length of the trials was only two weeks so the longer term effects are unknown.
Lead researcher Karin Ried, from the National Institute of Integrative Medicine in Melbourne, Australia, said: "Although we dont yet have evidence for any sustained decrease in blood pressure, the small reduction we saw over the short term might complement other treatment options and might contribute to reducing the risk of cardiovascular disease."
High blood pressure is both common and deadly. It has been linked to 54% of strokes worldwide and 47% of cases of coronary heart disease.
However, chocolate packs plenty of fat and sugar as well as cocoa so is not the ideal way of lowering blood pressure.
Dark or milk?
There has also been a warning in the Lancet medical journal that dark chocolate may contain fewer flavanols than you might think. Dark chocolate contains a higher cocoa count than milk chocolate so should contain more flavanols, however, they can also be removed as they have a bitter taste.
Victoria Taylor, of the British Heart Foundation, said: "Its difficult to tell exactly what sort of quantities of flavanol-rich cocoa would be needed to observe a beneficial effect and the best way for people to obtain it.
"With most of the studies carried out over a short period of time its also not possible to know for sure whether the benefits could be sustained in the long term. The 100g of chocolate that had to be consumed daily in a number of the studies would also come with 500 calories - thats a quarter of a womans recommended daily intake.
"Beans, apricots, blackberries and apples also contain flavanols and, while containing lower amounts than in cocoa, they wont come with the unhealthy extras found in chocolate."
Source : bbc
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