Transcript Disorders and Diseases of the Digestive System

13
The Digestive System
and Nutrition
Lesson 13.1: Nutrition
Lesson 13.2: Anatomy and Physiology
of the Digestive System
Lesson 13.3: Disorders and Diseases
of the Digestive System
Chapter 13: The Digestive System and Nutrition
Lesson 13.1
Nutrition
Nutrition
• Energy
– The ability of physical systems to do work
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Heat
Chemical
Kinetic
Potential
– Metabolism = the sum of all chemical & physical
activities in an organism.
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Energy
• measuring the body’s energy use
– Calorie (used to measure food’s potential energy)
– Kilocalories (kcal)
• Calorie is the unit used to measure the potential energy in
foods
• The amount of heat required to raise the temperature of
1 kcal of water by 1°C
• basal metabolic rate (BMR)
– energy required for one day at rest
– varies by individual
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Macronutrients, Vitamins, and Minerals
• nutrients
– substances needed for
• energy
• growth
• maintenance
• Water is a nutrient.
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Nutrients
• Macronutrients
– carbohydrates
– proteins
– fats (lipids)
• Essential Nutrients (micronutrients)
– vitamins
– minerals
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Nutrients
• Essential Nutrients
– Vitamins
• Organic chemicals needed by the body for
normal functioning & good health
• Certain health problems occur without them
– Minerals
• Elements that the body needs in relatively
small amounts
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Carbohydrates
• Sugars (fruit, table sugar, sodas)
• Starches (bread, pasta, cereal)
• 1 gram supplies 4 Calories
• 50% of daily caloric intake should
be from carbohydrates
– No more than 25% should come
from sugar
• (such as in candy & sodas)
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Proteins
• made of amino acids
• essential amino acids
– must be part of diet
• nonessential amino acids
– body can make
• one gram supplies 4 Calories
• 25% of daily caloric intake from
proteins
• Meats (vegetarians eat beans,
peas, or soy)
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Fats
• Lipids (includes oils & solid fat)
• saturated fats (most solid at room temp.)
– Most come from animals (meat & dairy)
– Some oils (coconut & palm oil)
• unsatuated fats (most come from plants)
• 3 types
– monounsaturated fats
– polyunsaturated fats
– trans-unsaturated fats (trans fats)
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Unsaturated Fats
• monounsaturated fats (liquid)
– Canola & Olive oils
• polyunsaturated fats (liquid)
– Corn & Soybean oils
• trans-unsaturated fats (trans fats)
– artificially produced
– Solid at room temp
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Fats
• one gram supplies 9 Calories
• less than 25–35% of total calories from fat
• minimize trans and saturated fat intake
– Especially bad for cardiovascular health
• Everyone is recommended to restrict fats in your
diet.
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Vitamins
• Only small amounts are needed for proper metabolism
• types of vitamins
– fat-soluble
• may be stored in the body’s fat
• Aren’t easily excreted so they can be toxic
– water-soluble
• are not stored in the body
• Excess is expelled with urine
• Most are COENZYMES – combines with protein to make a
working enzyme
• vitamin deficiency- long term lack of a particular
vitamin (usually causes disease)
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Water-Soluble Vitamins
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Fat-Soluble Vitamins
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Minerals
• elements needed for proper body function
• examples
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calcium
potassium
iron
phosphorus
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Minerals
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Chapter 13: The Digestive System and Nutrition
Lesson 13.2
Anatomy and Physiology
of the Digestive System
Activities of Digestion
• (1) ingestion
– getting food into the body
• (2) propulsion
– moving food along GI tract
• a) swallowing
• b) peristalsis   
• c) mass movements
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Activities of Digestion
• (3) mechanical breakdown
– breaks food into smaller pieces
– increases surface area of food
• a) chewing w/teeth & tongue
• b) churning of stomach
• c) segmentation of intestines
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Activities of Digestion
• (4) chemical breakdown
–also known as digestion
–enzymes
• Mouth – salivary amylase
• Stomach – pepsin, gastrin & HCl
• Small Intestine – pancreatic amylase,
nuclease, lipase & trypsin
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Activities of Digestion
• (5) absorption
–digested food particles moved into
blood
• (6) defecation
–Release of indigestible remains &
dead bacteria bodies
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Activities of
Digestion
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Layers of the Alimentary Canal (GI tract)
• Mucosa (mucus membranes)
– innermost layer – epithelial cells
– adjacent to lumen
– often secretes mucus
• Submucosa
– below mucosa
– Lymphatic tissue & glands secrete substances that aid
in digestion & absoption
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Layers of the Alimentary Canal
• muscularis externa (causes peristalsis)
– circular muscle
– longitudinal muscle
• serosa (serous membrane)
– outermost layer
– peritoneum
• visceral
• parietal
• Mesentery
– Holds abdominopelvic organs
in place (especially Sm. Int.)
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Digestive Organs and Their Functions
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the oral cavity
the nasal cavity
teeth and gums
salivary glands
pharynx
esophagus
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Digestive Organs and Their Functions
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stomach
small intestine
liver and gallbladder
pancreas
large intestine
rectum
anal canal
anus
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The Oral Cavity
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lips
tongue
cheeks
palate
– hard
– Soft
• Ingestion, chemical & physical digestion,
and propulsion
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The Nasal Cavity
• passageway for air (while you chew)
• uvula
– hangs from soft palate
– keeps food out of nasal cavity when swallowing
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Teeth and Gums
• gum
– gingiva
• teeth
– deciduous
– permanent
• incisor
• canine
• molar
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Salivary Glands
• parotid
• submandibular
• Sublingual
• saliva
– Water, enzymes, mucus & antibodies
• Moistens & lubricates food, protects against
bacteria, and starts chemical digestion
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Pharynx
• Nasopharynx
– Only air
• Oropharynx
– Food & air
• laryngopharynx
– Glottis
• Opening for
larynx
– epiglottis
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Esophagus
• connects pharynx to stomach
• peristalsis
– muscle contraction changes size of
tube
– food is moved through GI tract
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Stomach
• regions
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cardia
fundus
body
pyloric region
• three layers of
muscle
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Lining of the Stomach
• gastric gland
– mucus-secreting cells
– parietal cells
• Secrete HCl
– chief cells
• Produce pepsin
– enteroendocrine cells
• Produce gastrin
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Chemical Reactions in the Stomach
• protein-digesting enzymes secreted
• chyme formation
– Acidic gastric juices mixed w/food
• stomach contractions
– Rugae flatten to allow more volume
– 3 muscle types churn
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Small Intestine
• segments
– duodenum
– jejunum
– Ileum
• 6-8 yards long
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Small Intestine
• lining
– villi
– intestinal crypts
(similar to gastric
pits in stomach)
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Small Intestine
• chemical breakdown
– Fat emulsification by bile
– break down by nuclease
• absorption into the blood
– from capillaries to the
blood
– lacteal to lymph
– vitamin B12
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The Liver
• functions of the liver
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maintains nutrients in blood
converts one nutrient to another
stores nutrients
inactivates toxins
• hepatic portal vein
– Deoxygenated
blood is diverted
• parts of the liver
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lobules
hepatocytes
blood vessels
bile canaliculi
bile salts
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The Gallbladder
• functions of the gallbladder
– stores bile produced by liver
– releases bile when fat-containing chyme is in duodenum
– Chemically breaks down fat
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Pancreas
• pancreatic juices
– contain digestive enzymes
• Amylase, nuclease, lipase, trypsin
• Released into duodenum
• glucose regulation
– beta cells–insulin
• Lowers blood glucose levels
– alpha cells–glucagon
• When glucagon reaches it, the liver then breaks down
stored glycogen into glucose, which is released into blood
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Large Intestine
• regions
– Cecum (w/appendix)
– colon
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ascending
transverse
descending
Sigmoid
5’ long – larger diam.
Absorption:
– water, electrolytes
– vitamin K
– Mass movements
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Rectum, Anal Canal, and Anus
• rectum
• anal canal
• anus
– sphincters
• internal
• External
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Chapter 13: The Digestive System and Nutrition
Lesson 13.3
Disorders and Diseases
of the Digestive System
Disorders and Diseases of
the Digestive System
• gingivitis and periodontal disease
– plaque forms tarter
• cardiovascular disease
• gastroesophageal reflux
disease (GERD)
– heartburn
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Disorders and Diseases
of the Digestive System
• Ulcers
– Stomach or duodenum
– Helicobacter pylori
• gastroenteritis
– inflammation of stomach
or intestine
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Disorders and Diseases of the Digestive
System
• inflammatory bowel disease
– chronic inflammation
– ulcerative colitis
– Crohn’s disease
• constipation and diarrhea
– infrequent or too frequent defecation
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Disorders and Diseases of the Digestive
System
• hepatitis
– inflammation of liver
• pancreatitis
– inflammation of pancreas
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Disorders and Diseases of the Digestive
System
• gallstones
– bile forms crystals
– Cholecystectomy
• cancer
– digestive system cancers
are common
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