10.3.1 Hunger 2 Flashcards
When the blood glucose level starts to fall, the ____ converts some of its glycogen back to glucose. In this way blood glucose levels stay fairly steady for most people most of the time.
liver
To pancreatic hormones, insulin and ____, regulate the flow of glucose.
glucagon
____ enables glucose to into the cells, except for brain cells, where glucose does not need insulin to enter. When insulin levels are high, glucose enters cells easily.
Insulin
When someone is getting ready for a ____, insulin levels rise, letting some of the blood glucose into the cells in preparation for the rush of additional glucose about enter the blood.
meal
Insulin continues to increase during and after a meal. In general, high levels of insulin ____ appetite, because insulin enables so much glucose to into the cell. When much glucose is already entering the cells, you don’t need to eat more.
decrease
As time passes after a meal, the blood glucose level falls. Therefore, insulin levels drop, glucose injures the cells more slowly, and ____ increases.
hunger
____ stimulates the liver to convert some of it stored glycogen into glucose to replenish low supplies in the blood.
Glucagon
If the insulin level stays constantly ____, the body continues moving blood glucose into the cells, including the liver cells and the fat cells, long after a meal.
high
Before too long, ____ ____ drops, because glucose is leaving the blood without any new glucose entering. In this case, despite the high insulin level, hunger increases.
blood glucose
If the insulin level remains low, as in people with ____, blood glucose levels may be three or more times the normal level, but little of it enters the cells.
diabetes
People and animals with diabetes eat more food than normal because their cells are starving, but they excrete most of the glucose, and they ____ ____.
lose weight
Note that either prolonged high or prolonged low insulin levels ____ ____, but for different reasons and with different effects on body weight.
increased eating
If you consistently eat either a little more or less than necessary, eventually, you would be much too heavy or much to thin. The body needs to compensate for day-to-day mistakes by some sort of long-term regulation. It does so by monitoring ___ ____.
fat supplies
____ signals your brain about your fat reserves, providing a long-term indicator of whether you have been overeating or undereating. Each meal also releases leptin, so the amount of circulating leptin indicates something about short-term nutrition as well.
Leptin
If you have enough fat supplies, you can afford to devote energy to your immune system. If you have no fat, you are starving and you have to ____ ____ whenever you can.
conserve energy
Researchers soon discovered that almost all ____ people already produce plenty of leptin. The problem is that they have become less sensitive to it.
overweight
Leptin sensitivity declines during ____ and in animals preparing for hibernation.
pregnancy
Unfortunately, leptin sensitivity also declines as a result of ____.
obesity
When consistent overeating leads to obesity, it damages the ____ ____ (a cell constituent) in the neurons of the hypothalamus, setting in motion a series of outcomes that lead to decreased leptin sensitivity.
endoplasmic reticulum
So far, the only way to undo that effect is ____ ____, which increases production of certain chemicals of the immune system. Those chemicals help repair the endoplasmic reticulum.
physical exercise
____ depends on the contents of your stomach and intestines, the availability of glucose to the cells, and your body’s fat supplies, as well as your health and body temperature.
Hunger
The key brain areas in hunger include several nuclei of the ____.
hypothalamus
Many kinds of information impinge onto two kinds of cells in the arcuate nucleus of the hypothalamus, which is regarded as the master area for ____ of ____. Axons extend from the arcuate nucleus to other areas of the hypothalamus
control of appetite
The ____ ____ of the hypothalamus has one set of neurons sensitive to hunger signals and a second set sensitive to satiety signals.
arcuate nucleus
The hunger-sensitive cells receive input from the ____ ____, and you have surely noticed that good-tasting foods stimulate your hunger. Another input to the hunger-sensitive cells comes from axons releasing the neurotransmitter ghrelin.
taste pathway
The stomach releases ____ during a period of food deprivation, where it triggers stomach contractions. Ghrelin also acts on the hypothalamus to decreased appetite and acts on the hippocampus to enhance learning.
ghrelin
Where is the digestive system secretes several hormones that signal satiety, ghrelin is the only known ____ ____.
hunger hormone
____ has become a serious problem in more and more countries. Simultaneously, other people suffer from ____, in which they refuse to eat enough to survive, or ____, in which they alternate between eating too much and eating too little.
Obesity : anorexia : bulimia
