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Digestion Notes – start reading on page 602 and fill out these notes in pencil.
Don’t worry if you can’t find some answers.
We’ll review them in class.
I.
The Digestive System
A. Function: each organ and ______________________ organ helps convert
food into simpler molecules to be absorbed, delivered by the _____________
stream, and used by the target cell
B. Food is processed in humans in four phases: 1) ingestion 2) digestion
3) ______________________________ 4) ____________________________
II.
Mouth
A. Mechanical digestion: teeth and ___________________ tear, crush, and
moisten food
B. Chemical digestion
1. saliva consists of ____________________________________________
2. The ___________________ system controls the release
3. __________________________________breaks starch bonds yielding
disaccharides
C. Food passes to the back of the throat (______________________) and is
now termed "__________________"
D. _____________________________: connective tissue that covers the
________________________ to prevent the bolus from entering
III.
Esophagus - muscular food tube
A. ___________________________: smooth muscles in the esophagus
contract moving the bolus downward
B. Cardiac ___________________________: thick ring of muscles closes at
the stomach entrance to prevent stomach contents from re-opening
IV.
Stomach – large, _________________________ sac
A. Continues mechanical digestion by contractions of smooth muscle
B. Lining contains millions of _____________________________________
that secrete substances for continued chemical digestion
1. _______________________ - fluid lubricates and protects stomach wall
2. ________________ - activates the enzyme _____________________,
which begins ___________________________ digestion
C. _______________________: mixture of food and stomach fluids churned
together that remains in stomach 1-2 hours
V.
Small Intestine - adapted to absorb nutrients from chyme via active and
passive transport
A. Most of the ____________________ digestion of food and
_______________________ occurs here
B. _____________________________ - 1st of 3 parts of small intestine,
where most of the ___________________________________________ enter
C. ______________________________________________ - 2nd and 3rd part
D. __________________
1. Finger-like projections found on the inner, folded surface
2. Covered in ____________________________ that absorb nutrients
passing them onto the _______________________________ (carbs and
protein) and _______________ vessels (fatty acids and pathogens)
E. Peristalsis continues to move food into the __________________________
Effects of Digestive Enzymes
Active site
Enzyme
Effect on Food
Salivary amylase
Breaks down ________________
into disaccharides
Stomach
Breaks down _____________ into
large peptides
Small Intestine (from
Amylase
Continues _____________
_________________________)
breakdown
Trypsin
Continues _______________
breakdown
Lipase
Breaks down _______________
Small Intestine
Maltase, sucrase,
Breaks down
lactase
Peptidase
VI.
Breaks down peptides into
___________________________
Pancreas – gland (p. 519)
A. When blood sugar is high, ___________________ is released to convert glucose into
____________________________
B. When blood sugar is low, ____________________ is released to convert glycogen into
____________________________
C. Produces other enzymes for breakdown of nutrients
D. Produces ___________________________________ - base that neutralizes stomach
acids
VII.
Liver
A. produces _______________: detergent-like fluid that ____________________________
so that lipase can further break fats down
B. Bile is stored in the _____________________________ and also neutralizes stomach
acids
VIII.
Large Intestine
A. Nutrient-free chyme is left - water, cellulose, and other indigestible substances
B. Primary function is to ____________________________________
C. Rich colonies of ______________________ produce compounds the body is able to use
(vitamin K)
D. Whatever is left (_______________) passes out of the body through the __________
I.
Nutrition Notes
Food and energy
A. Cells convert the chemical energy stored in the covalent bonds in glucose and other
molecules into _________________
Label the organs of
B. The energy available in food can be measured in calories
the digestive system.
1. 1 calorie = _______________________________________________________
__________________________________________________________
2. Dietary Calories (C) = 1000 calories of 1 ________________________
C. Functions of our food
1. FUEL!!!
2. Supply raw materials used to build and repair tissues
3. Manufacture proteins
4. Supplements
II.
Nutrients – substances in food that supply energy and raw materials your body uses
(water, carbs, lipids, protein, vitamins, minerals)
A. Water – many of the body’s processes take place in water
1. Makes up the majority of blood and lymph
2. Cools body when released from sweat glands
3. Contains wastes in sweat and urine
4. Dehydration occurs if < 1L of water is consumed a day
B. Carbohydrates
1.
Starches are broken down by the digestive system and carried to the cells by
the ___________________________________
2.
Sugars not immediately used are converted to _______________ and stored in
the liver and skeletal muscles
C. Lipids
1.
Broken down into fatty acids and glycerol
2.
Deposits of fat protect body organs, insulate the body, help absorb vitamins
and store energy
3.
AHA recommends a diet with a maximum of ________% of Calories from fat
(10% saturated)
4.
High fat diets can lead to heart disease, high blood pressure, obesity, and
diabetes
D. Proteins
1.
Supplies raw materials for growth and repair of body structures
2.
Body can produce _________ of the 20 amino acids
3.
The other _____ essential amino acids must be consumed
E. Vitamins – ____________ molecules that help regulate body processes often working
with enzymes
1.
Must be consumed
2.
Fat-soluble: can be stored in fatty tissue
3.
Water – soluble: dissolve in water and can’t be stored
F. Minerals – ____________________ molecules that the body needs in small amounts
1.
____________________: major component of bones and teeth
2.
___________________: makes hemoglobin, the oxygen-carrying component in
blood
3.
____________________: needed for nerve and muscle tissue function