10.3 Hunger Flashcards
The ____ ____ function is to break food into smaller molecules that the cells can use.
digestive systems
Humans eat more than we ____ for today. Choosing which food to eat and how much is an important decision.
need
Digestant begins in the mouth, where enzymes in the saliva breakdown ____.
carbohydrates
Swallowed food travels down the oesophagus to the stomach, where it mixes with hydrochloric acid and enzymes that digest ____.
proteins
The stomach stores food for a time, and then around sphincter muscle opens at the end of the stomach to release food to the ____ ____.
small intestine
The small intestine has enzymes that digest proteins, fats, and carbohydrates. It is also the site for absorbing digestive materials into the ____.
bloodstream
The blood carries chemicals to ____ ____ that either use them or store them for later use.
body cells
The ____ intestine absorbs water and minerals and lubricates the remaining material to pass as faeces.
large
____ ____ survive at first on mothers milk. As they grow older, they stop nursing for several reasons: the milk supply declines, the mother pushes them away, and they begin to eat other foods.
Newborn mammals
Most mammals about the age of weaning lose the intestinal enzyme ____, which is necessary for metabolising lactose, the sugar in milk. From then on, milk consumption causes stomach cramps and gas.
lactase
Humans are a partial exception to this rule. Many adults have enough lactase levels to consume milk and other ____ ____ throughout life.
dairy products
People who are ____ ____ can consume a little milk, and larger amounts of cheese and yoghurt, which are easier to digests. If they overeat dairy products, the result depends on the type of bacteria they have in their digestive system, but it often includes diarrhoea, cramps, and gas pains.
lactose intolerant
Presumably the belief that _______ is an illusion based on people’s tendency to remember the observations that fit their expectation and disregard the others.
sugar causes hyperactivity
Eating is far too important to be entrusted to just one mechanism. Your brain gets messages from your ____, ____, ____, ___ ____, and elsewhere to regulate your eating.
mouth, stomach, intestines, fat cells
People like to eat. In fact, many people like to ____ and ____ even when they are not hungry.
taste and chew
In ____ experiments, everything an animal swallows leaks out of a tube connected to the oesophagus or stomach. In short, taste and other mouth sensations contribute to satiety but they are not sufficient.
shame-feeding
Ordinarily, we end a meal before the food reaches the blood, much less the muscles or other cells. Usually, the main signal to end a meal is ____ of the stomach.
distension
Stomach distension is sufficient to produce ____.
satiety
People who had the stomach ____ ____ (because of stomach cancer or other disease) still report satiety, so stomach distension is not necessary for satiety.
surgically removed
Later researchers found that meals end after distension of ____ the stomach or the duodenum.
either
The ____ is part of the small intestine joining the stomach. It is the first digestive site that absorbs a significant amount of nutrients.
duodenum
Fat in the duodenum releases a hormone called oleoylethanolamide (ODA), which stimulates the ____ ____, sending a message to the hypothalamus that delays the next meal.
vagus nerve
Any kind of food in the duodenum also releases the hormone ____ (CCK), which limits the meal size in two ways.
cholecystokinin
First, CCK constricts the sphincter muscle between a stomach and duodenum, causing the stomach to hold it contents and fill more quickly than usual. Second, CCK stimulates the vagus nerve to send signals to the ____, causing cells there to release the neurotransmitter that is a shorter version of the CCK molecule itself.
hypothalamus
Much digestant food enters the bloodstream as ____, an important source of energy throughout the body and nearly the only fuel of the brain.
glucose
When the brains glucose level is high, liver cells convert some of the excess into ____, and fat cells convert some of it into fat.
glycogen
