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Digestion
n/a
42
Other
Undergraduate 2
02/05/2013

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Term
appetite
Definition
influenced by food preferences and psychological stimulation
may eat without being hungry or needing nourishment
Term
aromas
Definition
detected by olfactory cells in the nasal cavity as food odors
enter both the nose and mouth
Term
flavor
Definition
refers to both taste and aroma
example: Chocolate tastes sweet but its flavor is "chocolate"
Term
digestion
Definition
a multi-step process of breaking down foods into absorbable components using mechanical and chemical means in the gastrointestinal (GI) tract
Term
mechanical digestion
Definition
chewing, grinding food to aid swallowing
Term
peristalsis
Definition
part of mechanical digestion
the forward, rhythmic (wavelike) muscular contraction that moves through GI tract
Term
chemical digestion
Definition
digestive juices and enzymes break down food into absorbable nutrients
Term
gastrointestinal tract consists of:
Definition
mouth
esophagus
stomach
small and large intestines
Term
main roles of the GI tract
Definition
break down food into smallest components
absorb nutrients, mainly in small intestines
prevent microogranism or other harmful compounds in food from entering tissues of the body
about 23 feet long with extensive surface area for nutrient absorption (cell lining is replaced every 3-5 days)
Term
what happens after digestion?
Definition
nutrients are absorbed through the walls of the intestines into body's two transport systems: circulatory system (blood) and lymph system
sent to liver for processing before delivery to the body's cells
Term
how efficient is the GI tract?
Definition
highly efficient
92-97% of nutrients from food are digested and absorbed
Term
role of saliva
Definition
softens, lubricates, dissolves food particles
Term
what does saliva consist of?
Definition
water, electrolytes, mucus, and a few enzymes
Term
where does the bolus go?
Definition
moves into pharynx, is swallowed, and then enters the esophagus by peristalsis
Term
role of epiglottis
Definition
closes off the trachea during swallowing to prevent food from lodging in the windpipe (trachea)
Term
role of esophagus
Definition
propels food into the stomach
Term
stomach's mechanical action
Definition
churning mixes food with digestive juices for several hours
Term
stomach produces two powerful digestive secretions:
Definition
1. HCl
2. mucus
3. digestive enzymes
4. Chyme
Term
HCl
Definition
activates enzyme pepsin, enhances absorption of minerals, breaks down connective tissue of meat
Term
mucus
Definition
protects stomach lining from damage
Term
digestive enzymes
Definition
intrinsic factor (for vitamin B12 absorption), stomach hormone gastrin
Term
chyme
Definition
semi-liquid substance of partially digested food and digestive juices
Term
quick overview of the process of digestion
Definition
1. begins in the mouth. chewing mixes saliva with food and begins to break it down
2. bolus travels down the mouth to the stomach through the esophagus via peristalsis
3. stomach mixes food with enzymes to break it down further
4. most digestion and absorption occurs in the small intestine
5. water, vitamins, and some electrolytes are absorbed in the large intestine. the remaining wastes are passed out of the body in stool
Term
small intestine
Definition
long, narrow, coiled
Term
three segments of the small intestine
Definition
duodenum (10 inches)
jejunum (8 feet)
ileum (12 feet)
Term
interior surface area of the small intestine is tremendously increased by
Definition
villi microvilli, circular folds
Term
what is the largest gland in the body
Definition
liver
Term
role of the liver
Definition
produces bile needed for fat digestion
metabolism of carbs, fats, and protein
stores nutrients: vitamins A, D, B12, E, copper, iron, glycogen (glucose storage form)
detoxifies alcohol
Term
gallbladder
Definition
concentrates/stores bile
released into GI tract when fat is ingested
Term
pancreas
Definition
produces hormones: insulin and glucagon, regulate blood glucose
Term
role of circulatory system
Definition
transports nutrients, oxygen, waste products through your blood
Term
role of lymphatic system
Definition
distributes fat and fat-soluble nutrients through your lymph
Term
role of excretory system
Definition
eliminates wastes from circulatory system via the urine
Term
the nutrient team
Definition
carbs
protein
fat
vitamins
minerals
water
Term
calorie
Definition
the unit used to measure energy
Term
how many calories in carbs
Definition
4 calories/gram
Term
how many calories in protein
Definition
4 calories/gram
Term
how many calories in fat
Definition
9 calories/gram
Term
how many calories in vitamins
Definition
zero
Term
how many calories in minerals
Definition
zero
Term
how many calories in water
Definition
zero
Term
total calories in all of them
Definition
0g Fat x 9= 0
11g Carbs x 4= 44
9g Protein x 4= 36
total calories= 80
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