Transcript Digestion and Nutrition

Digestion and Nutrition
Introduction
 Digestion: mechanical and
chemical breakdown of food
into forms the cell membrane
can absorb

Alimentary canals: extends from
the mouth to the anus
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Mouth, pharynx, esophagus,
stomach, small intestine, large
intestine, and anal canal
Several accessory organs: release
secretions into the canal
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Salivary glands, liver, gallbladder,
and pancreas
General Characteristics
 9-meter muscular tube
 Structure of the Wall
 Mucosa: mucous membrane
Inner most layer
 Protects the underlying tissue
 Carries out secretion and absorption
 Epithelium, connective tissue, and smooth muscle
 Tiny folds and projection in the lumen, passageway
 Increase absorption through increased surface area
 Glands: secrete mucus and digestive enzymes

Structure of the Wall
 Submucosa
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Loose connective tissue, glands, blood vessels, lymphatic vessels, and
nerves organized into plexus
Vessels nourish surrounding tissue and carry away absorbed
nutrients away
 Muscular Layer
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Moves the tube
Smooth muscle tissue and some nerves organized into a plexus
 Serosa: serous layer
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Visceral peritoneum: outer covering of the tube
Protect underlying tissue
Secrete serous fluid

Moistens and lubricates the tube’s outer surface
Layer of Digestive Tract
Tube Movement
 Mixing Movement
 smooth muscles in small segments of the tube contract
rhythmically
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Full stomach: movement mixes the food and digestive juices
 Propelling Movement
 Peristalsis: wave-like motion
Ring of contraction
 Push food along the tube
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Mouth
 Receives food
 Begins digestion
 mechanically reducing the size
of solid particles
 mixing particles with saliva
 Oral Cavity: chamber
between palate and tongue
 Vestibule: narrow space
between the teeth, cheeks,
and lips
Cheeks and Lips
 Cheeks
 outer layers of skin
 pads of subcutaneous fat
 muscles associated with expression and chewing
 inner linings of moist stratifies squamous epithelium
 Lips: highly mobile structures that surround the
mouth opening
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Skeletal muscles
Sensory receptors: temperature and texture

Red color: due to abundance of blood vessels near their surface
Tongue
 Covered with mucous membranes
 Frenulum: connects the midline of the tongue to floor of
the mouth
 Skeletal Muscle
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Mix food particles with saliva
Move food toward the pharynx
 Papillae: rough projections on
surface
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Provides friction to handle food
Contain taste buds
 Root: posterior region
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Connected to hyoid bone
Lingual tonsils: rounded masses of lymphatic tissue
Palate
 Roof of oral cavity
 Hard plate: anterior part
 Soft plate: muscular arch, which extends downward to coneshaped projection, the uvula
During swallowing, drawn upwards
 Action closes the opening between the nasal cavity and pharynx
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Palatine Tonsils: back of mouth, on either side
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Tonsils of tonsillectomy
Pharyngeal Tonsils: adenoids
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Posterior wall of pharynx
Tonsils and Adenoids
Teeth
 Primary Teeth: 20 deciduous teeth
 6 months to 2 or 4 years
 Secondary Teeth: 32 permanent teeth
 6 years to 17 or 25 years
 Break pieces of food into smaller pieces
 Increases surface area  digestive enzymes
Teeth
 Crown: projects beyond the
gum
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Enamel: covers the crown
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Ca salts; hardest substance in
the body
Dentin: beneath the enamel;
bone like
 Root: anchored to the jaw
Teeth
 Incisors: chisel-shaped
 Bit off large pieces of food
 Cuspids: cone-shaped
 Grasp food and tear
 Bicuspids and Molars
 somewhat flattened surface
 Grinding food particles
Salivary Gland
 Secrete saliva
 Moistens food particles, helps bind them, and begins the
chemical digestion of carbohydrates
 Solvent allowing food to be tasted
 Helps cleanse the mouth and teeth
Salivary Secretions
 Serous Cells: water fluid that contains amylase
 Splits starch and glycogen molecules
 Mucous Cells: thick liquid called mucus
 Binds food particles
 Lubricated during swallowing
 Parasympathetic Nerves secrete watery saliva
 see, smell, taste, or think about food
 Food that looks, smells, or tastes unpleasant inhibits this
Major Salivary Glands
 Parotid Glands: largest, anterior to each ear
 Secrete a clear, watery fluid rich in amylase
 Submandibular Gland: floor of the mouth on the
inside surface of the jaw
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Predominantly serous and some mucous
 Sublingual Gland: floor of the mouth, inferior to the
tongue
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Smallest
Primarily mucous
Pharynx, Esophagus, Stomach,
and Pancreas
Pharynx
 Cavity posterior to the mouth from which the tubular
esophagus leads to the stomach
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Pharynx nor esophagus digests food
Pharynx
 Structure of Pharynx: connects the nasal and oral
cavities with larynx and esophagus
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Nasopharynx: provides a passage way for air during breathing
Oropharynx: passageway for food moving downward from
mouth and for air moving to and from the nasal cavity
Laryngopharynx: passageway to esophagus
Swallowing Mechanism
 1st stage: voluntary
 food is chewed and mixed with saliva
 Tongue rolls mixture into a mass, bolus and forces it into the
pharynx
 2nd stage: food stimulates sensory receptors around
the pharyngeal opening
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Triggers swallowing reflex
Epiglottis: flap-like structure that closes the tops of the trachea
 3rd stage: peristalsis transports the food in the
esophagus to the stomach
Epiglottis
Esophagus
 Straight, collapsible tube about 25 cm long
 Food passageway from the pharynx to the stomach
 Mucous Glands: secretions moisten and lubricate the tube’s
inner lining
 Lower esophageal sphincter: close the entrance to the stomach
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Prevents regurgitation of stomach contents
Stomach
 J-shaped, pouch-like organ
 inferior to the diaphragm
 upper left portion of abdominal cavity
 1 L capacity
 Functions:
 Receives food from the esophagus
 Mixes food with gastric juices
 Initiates protein digestion
 Carries limited absorption
 Move food into small intestine
Parts of the Stomach
 Cardiac: small area near the
esophageal opening
 Fundic: balloons above the
cardiac portion
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Temporary storage area
 Body: main part
 Pyloric: narrows as it
approaches the sm. Intestine
 Pyloric sphincter: muscle valve
controlling gastric emptying
Gastric Secretions
 Mucous Membrane of stomach contains many gastric
pits, ends of gastric glands
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Mucous cells: large quantities of thin mucus
Chief cells: digestive enzymes
Parietal cells: HCl
Gastric Secretions
 Digestive Enzymes
 Pepsin: protein
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Mucus and other alkaline
secretions prevent pepsin from
digesting the stomach itself
Intrinsic Factor: need for B12
absorption
Regulation of Gastric Secretions and Absorption
 Gastric juices are continuously produced, but the
rate varies
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Parasympathetic impulses and the hormone gastrin enhance
gastric secretion
Food moving into the sm. intestines inhibits secretions
 Gastric absorption: only a few substances in small
quantities
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Water, certain salts, alcohol, and some lipid-soluble drugs
Mixing and Empting Actions
 Chyme: mixture of food particles and gastric juices
 Production aided by movement of stomach
 Peristaltic waves push chyme toward pyloric sphincter
 Stomach relax with accumulation of chyme, a little at a time, is
pushed into the small intestines
Mixing and Empting Actions
 Liquid pass quite rapidly
 Solid remain until they are well mixed
 Fatty foods remain 3-6 hours
 Proteins: quicker
 Carbohydrates: faster than protein and fats
 As food enters the duodenum, accessory organs add
their secretions
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Pancreas, liver and gallbladder
Pancreas
 Secretes pancreatic juice into the duodenum
 Contains enzymes to digest carbohydrates, fats, nucleic acids,
and proteins
Pancreatic amylase: carbohydrate digesting enzyme
 Pancreatic lipase: fat digesting enzyme
 Nucleases: nucleic acid digestion enzyme
 Trypsin, chymotrypsin, and carboxypeptidase: protein digesting
enzymes
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Pancreas Regulation
 Stimulation the release of pancreatic juices
 Nervous and endocrine system
 Food in duodenum
 Pancreatic juices are high in bicarbonate ions
 Neutralizes chyme
 Intestinal contents to be alkaline
Liver, Small Intestines, and
Large Intestines
Liver
 Located in the upper right quadrant
of the abdominal cavity
 Fibrous capsule encloses the liver
 Connective tissue divides the organ
into a large right lobe and a smaller
left lobe
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Each lobe is separated into tiny hepatic
lobules
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Liver’s functional units
Bile canals carry bile from hepatic lobules
to hepatic ducts
Liver Function
 Metabolizes carbohydrates, lipids, and proteins
 Stores some substances
 Filters blood
 Destroys toxins
 Secretes bile
 Important in digestion
Bile
 Bile salts, bile pigments, cholesterol, and electrolytes
 Only bile salts have digestive functions
 Bile salts emulsify fats and aid in the absorption of fatty acids,
cholesterol, and certain vitamins
 Gallbladder stores bile between meals
 Cholecystokinin from the small intestine stimulates
bile’s release
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Enters the duodenum
Small Intestine
 Receives secretions from the pancreas and liver
 Completes nutrient digestion
 Absorbs the products of digestion
 Transports the residues to the large intestine
 Parts
 Duodenum
 Jejunum
 Ileum
Small Intestine
 The wall is lined with villi
 Increase in surface area
 Aid in mixing and absorption
 Intestinal glands are located between the villi
 Secretions of the small intestine
 Mucus and digestive enzymes
 Digestive enzymes split sugars,
proteins, and fats
 Gastric juice, chyme, and reflexes
stimulated by distention of the small
intestine wall stimulate secretion
Absorption
 Microvilli: absorb monosaccharides, amino acids,
fatty acids, and glycerol
 Fat molecules with long chains enter the lacteals of
the villi
 Fatty acids with short chains enter blood capillaries
in villi
Movement
 Mixing and peristalsis
 Ileocecal sphincter: controls movement between
small and large intestines
Large Intestines
 Parts
 Cecum, colon, rectum, and anal canal
 Colon is divided into ascending, transverse, descending, and
sigmoid portions
 Unique layer of longitudinal muscle fibers arranged
in distinct bands
Large Intestines
 Functions:
 Little or no digestive function
 Secretes mucus
 Absorbs water and electrolytes
 Forms and stores feces
 Movement: similar to small intestine
 Mass movement occurs two to three times a day
 Feces: water, undigested material, electrolytes,
mucus, and bacteria
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Color is due to bile salts that have been altered by bacteria
Nutrition
Nutrition
 Process of ingestion and utilization
of necessary food substances, or
nutrients
 Carbohydrates: organic
compounds that primarily supply
cellular energy
 Sources: starch, glycogen,
disaccharides, and
monosaccharides
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Cellulose: polysaccharide that humans
cannot breakdown
Carbohydrates
 Utilized for:
 Oxidation energy release from
glucose
 Excess glucose is stored as glycogen
or converted to fat
 Most carbohydrates supply energy
 Some cells require a continuous
supply
 Requirements: humans can
survive with a wide range of
carbohydrate intake
Lipids
 Supply energy and used to build cell structure
 Sources: triglycerides from plants and animals
 Animals: most cholesterol
Lipids
 Lipid Utilization
 Liver and adipose tissue control triglyceride metabolism
 Linoleic acid: essential fatty acid
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Corn, cotton seed, and soy oil
 Lipid Requirements: amounts and types are
unknown
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Fat intake must be sufficient to carry fat soluble vitamins
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A,D,E,K
Proteins
 Serve as structural materials, function as enzymes,
and provide energy
 Sources: meats, dairy products, cereals, legumes
 Requirements
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Supply essential amino acids and nitrogen for the synthesis of
nitrogen containing molecules
Vitamins
 Essential for normal metabolic processes
 Body cells cannot synthesize adequate amounts
 Fat soluble: A, D, E, K
 Carried by lipids and affected by the same factors that
influence lipid absorption
 Resist the effects of heat; cooking has no effect
 Water-soluble: B and C vitamins
 B vitamins: oxidizes carbohydrates, lipids, and proteins
 Cooking or food processing destroys some water-soluble
vitamins
Minerals
 Elements other than carbon that are essential
 Most minerals are in the bone and teeth
 Usually in organic compounds
 Some are in inorganic compounds or free ions
 Functions: structural material, enzymes, and vital
roles in metabolic processes
 Major Minerals: Ca, P, K, S, Na, Cl, and Mg
 Trace Elements: Fe, Mn, Cu, I, Co, Zn, F, Se, Cr
Adequate Diet
 Provides sufficient energy and essential nutrients to
support optimal growth, maintenance, and repair of
tissue
 Impossible to design a diet adequate for everyone
 Malnutrition: poor nutrition due to the lack of foods
or failure to make the use of the available foods
Eating Disorders
Eating Order Statics
 8 million Americans have an eating disorder
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7 million women and 1 million men
 1 in 200 American women suffers from anorexia
 2 to 3 in 100 American women suffers from bulimia
 Nearly half of all Americans personally know someone with an eating
disorder (Note: One in five Americans suffers from mental illnesses.)
 An estimated 10 – 15% of people with anorexia or bulimia are males
ADOLESCENTS
 Anorexia is the 3rd most common chronic illness among adolescents
 95% of those who have eating disorders are between the ages of 12-25
 50% of girls between the ages of 11-13 see themselves as overweight
 80% of 13-year-olds have attempted to lose weight
MORTALITY RATES
 Eating disorders have the highest mortality rate of any mental illness
 A study by the National Association of Anorexia Nervosa and
Associated Disorders reported that
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5 – 10% of anorexics die within 10 years after contracting the disease;
18-20% of anorexics will be dead after 20 years
only 30 – 40% ever fully recover
 The mortality rate associated with anorexia nervosa is 12 times higher
than the death rate of ALL causes of death for females 15 – 24 years old.
 20% of people suffering from anorexia will prematurely die from
complications related to their eating disorder, including suicide and
heart problems
Treatment
 Only 1 in 10 people with eating disorders receive treatment
 About 80% of the girls/women who have accessed care for their eating
disorders do not get the intensity of treatment they need to stay in recovery –
they are often sent home weeks earlier than the recommended stay
 Treatment of an eating disorder in the US ranges from $500 per day to $2,000
per day. The average cost for a month of inpatient treatment is $30,000. It is
estimated that individuals with eating disorders need anywhere from 3 – 6
months of inpatient care. Health insurance companies for several reasons do
not typically cover the cost of treating eating disorders
 The cost of outpatient treatment, including therapy and medical monitoring,
can extend to $100,000 or more
 http://www.huffingtonpost.com/2010/12/29/isabelle-caro-dead-anorexicmodel_n_802424.html
Amputation Diet
Procedure
Clip finger and toenails
Haircut
Drastic Haircut / Headshave
Trim Body Hair
Remove a wart
Take a diuretic
Take a laxative
Colon Therapy / Take an Enema
Poop
Run a marathon on a hot day
Amputate your arm
Amputate your leg
Vascetomy
Take a big pee.
Take a big dump
Estimated Immediate Weight Loss
1 ounce maximum
2-6 ounces
4-12 ounces
1 oz. (ladies) 3 oz. (men) 24 lbs (Greek
men)
1 oz.
1-3 pounds (temporary)
1-2 pounds (temporary)
2-3 pounds (temporary)
0-2 pounds (temporary)
3 lbs (women), 5 lbs (men) (temporary)
10-25 lbs (way too permanent)
15-45 lbs (again, not advised)
none.
up to 1.5 pounds
up to 2.5 pounds
Amputation Diet
Procedure
Go barefoot
Go Naked
Contact lenses vs. Glasses
No liquids all day
No food all day
No salt all day
Don't wear underwear
Exfoliating face wash
Liposuction
Donate a kidney
Breast Reduction Surgery
Estimated Immediate Weight Loss
1-2 pounds
1-8 pounds (summer vs. winter)
0.3 pounds
1-2 pounds
2-3 pounds
0-1 pound
1 oz. (thong)-2 lbs. (granny panties)
nothing.
10 lbs maximum per surgery
3 pounds.
5-15 pounds typically
Things that Remind Me of My Grandmother
 1.If you eat something and no one sees you eat it, it has no calories.
 2.If you drink a diet soda with a candy bar, the calories in the candy bar are
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cancelled out by the diet soda.
3.When you eat with someone else, calories don't count if you don't eat more
than they do.
4.Food used for medicinal purposes NEVER count, such as hot chocolate,
brandy, toast and Sara Lee Cheesecake.
5.If you fatten up everyone else around you, then you look thinner.
6.Movie related foods (Milk Duds, Buttered Popcorn, Junior Mints, Red Hots,
Tootsie Rolls, etc.) do not have additional calories because they are part of the
entertainment package and not part of one's personal fuel.
7.Cookie pieces contain no fat-- the process of breaking causes fat leakage.
8.Things licked off knives and spoons have no calories if you are in the process
of preparing something. Examples are peanut butter on a knife making a
sandwich and ice cream on a spoon making a sundae.
Things that Remind Me of My Grandmother
 9.Foods that have the same color have the same number of calories. Examples
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are: spinach and pistachio ice cream; mushrooms and white chocolate. NOTE:
Chocolate is a universal color and may be substituted for any other food color.
10.Foods that are frozen have no calories because calories are units of heat.
Examples are ice cream, frozen pies, and Popsicles.
11. Foods eaten while watching a major event on television do not count. Major
events include: Superbowl, Hockey Finals, Indy 500.
12. Powerbars and other type energy bars make you thinner. In all my years of
exercising (at least three times a year) I have only seen thin people eating
energy bars. Ergo (therefore) they must make you thin.
13. Snickers is the same as an energy bar (see #12)
14. Tasting other people's food does not add to your calorie count.
15. Containers of food that list the number of servings as greater one are lying.
Every container includes one serving. Half gallon of ice cream, box of cereal,
bottle of soda, bag of chips are all one serving.