A rare genetic disease that resembles a sped-up aging, progeria, may point to one of the keys to longevity for humans. Similar to normal aging, about which we know so little, it causes deterioration of blood vessels, resulting in major lethal cardiovascular diseases. The skin of children with progeria becomes less elastic, their joints become stiffer, and bones weaker, but they do not develop dementia.
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Some useful information for future parents.
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Our regulation of eating depends upon a complex accord of signaling chemicals - hormones.
The main trigger of appetite is ghrelin, which has acylated form and unacylated, the latter acts as an abolisher to the first. But there are about two dozen chemicals that play a supporting role, and about the same number of appetite suppressants like insulin (produced in the pancreas), leptin (in fat cells), and PYY and oxyntomodulin (in the digestive system). Such hormones suppress ghrelin release. If anything is wrong in this regulative system, overeating can be expected.
All these hormones travel through the liquids of the body with these messages and provide communication between the brain and the digestive system and its microbiome. If the main messengers are in low concentrations, others take their role.
Compared to other micronutrients, fats are less effective in suppressing hunger. Sugar and protein cause fast 70-percent drop in ghrelin both in rodents and humans, and fat reduces it much slower and only by half. Background ghrelin concentrations, pre-breakfast, rise as most people lose weight. But after several months of a weight-reducing low-fat diet, the levels remained unchanged. Simple sugars, particularly in isolated form, can affect choices of food and its amount, even for the next day. After a drink high in fructose, people may choose fattier foods than after one glucose-sweetened.
Heavy people misread or ignore hunger and satiety signals. Obese individuals usually have the lowest ghrelin levels, and anorexics very high. By normal-weight, more ghrelin production is suppressed while consuming more calories. When overweight, ghrelin drops the same after all meals - the same as in regular-weight people after a 1,000-calory meal.
Food preferences, feeding-regulating hormones, and gut-brain signaling depend on sleep too.
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Hormones are chemical messengers that manage processes in an organism.
Tissues of human and animal bodies secrete hormones into fluids to travel until they reach specific cells and attach to the right receptors, which play a role of gatekeepers. A hormone can have many roles.
Environmental hormones, or hormone mimics, or endocrine disruptors, are the growing number of chemicals that the body may mistake for hormones.
Some plants, fungi, and bacteria have compounds that resemble human hormones well enough that it allows them to attach to some receptors, which would keep the body's genuine hormones from connecting to the cell and transferring the message. Pesticides and chemicals used in plastics can do this as well.
The human body makes about 50 different hormones, which orchestrate cells in the the body.
Most known hormones, their function area, production place, and some characteristics:
- Adrenaline (stress), by adrenal glands above the kidneys;
- Ghrelin (hunger), mostly in the stomach - low energy signals;
- Insulin (metabolic) - helps the body move sugar;
- Leptin (satiety), by fat cells - "enough to eat" signals or whether the energy should be burned or stored as fat.
- Melatonin (sleep ), by the brain’s pineal gland;
- Thyroxine (growth), by the thyroid;
- Estrogen (sex);
- Testosterone (sex), by the testes in males, by the ovaries and adrenal glands in females - tells the male body to develop masculine characteristics, such as facial and body hair, a deep voice and muscle strength; in female body promotes such traits as axillary and pubic hair growth, regulate sexual desire, vaginal lubrication, mood, and muscle development;
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New science suggests that overeating is less a product of lacking willpower or the hormonal imbalance, but rather an addictive behavior triggered by the combinations of ingredients in modified foods, especially with specific proportions of certain fats and sugars.
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Melinda W. Moyer starts and ends her article on causes and treatments of obsessive-compulsive disorder (OCD) for Scientific American Mind with a description of progress of a person with OCD, one of ten most disabling conditions: from obsession with one number and endlessly performing repetitive rituals seemingly cause by fear, to her academic and social success after an exposure and response prevention therapy.
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If you are expecting a birth of the first child, or if you would like to be helpful to a pregnant friend of a family member, here are a few basic things you should know about the prenatal care that would benefit the mother and the future child.
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New class, sixteen,
up-fashioned, lemon-clean.
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A note to a professor who defined "critical thinking" his own way.
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To what extent does human behavior is affected by biology? A summary of an article.
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Today, on May 20, seven of us, including the five participating artists, installed our works in the gallery for the opening on Monday and the reception on Tuesday, May 24.
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On May 24, I will have a group exhibition in a local art gallery, with four artist colleagues.
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