Post on 17-Dec-2015
The Digestive System
What Happens During Digestion Three Main Processes ◊ Digestion: is the mechanical and
chemical breakdown of foods within the stomach and intestines for use by the body’s cells.
◊ Absorption: is the passage of digested food from the digestive tract into the cardiovascular system.
◊ Elimination: is the body’s expulsion of un digested food or body waste.
How Digestion Works Digestion includes two
processes Mechanical: involves chewing,
mashing and breaking down food
Chemical: involves secretions produced by digestive organs
How Digestion Works
Starts in mouth goes down the esophagus to
stomach then goes through the small
and large intestines [90% of all nutrients are absorbed]
large intestine takes care of the rest.
The Mouth & The Esophagus
Teeth- break food down with mastication (process of chewing)
Salivary Glands- produce gastric juices that help break down food
Tongue- prepares chewed food for swallow, by shaping– Uvula; small flap of tissue in the back
of the mouth helps prevent food from entering nasal passages
– Epiglottis- cover throat, prevents food from entering the respiratory system
The Mouth & The Esophagus Continued Esophagus: when food is swallowed it
enter the Esophagus. The Esophagus is a muscular tube; 10 inches long that connects to the pharynx w/stomach
Peristalsis: is a series of muscle contractions that moves food through the Esophagus. Peristalsis begins as soon as food is swallowed.
Sphincter Muscle: Is a circular muscle at the entrance of stomach. Allows food to move from Esophagus to stomach.
The Stomach
The stomach is a hollow
Sac-like organ with wall of muscles
Those muscles are flexible, allows stomach to expand when you eat
The Stomach Continued
The stomach has three tasks.1. Mixing foods with gastric juices
The hydrochloric acid kills bacteria Mucus produced by stomach protects it from the
acid Secretions from stomach lining contain hydrochloric
acid an pepsin an enzyme that digests protein
2. Storing partially digested food & liquid Holds food for further digestion before it is moved
into the small intestine
3. Moving food into the small intestine Food is covered in chyme, a creamy fluid mixture of
food & gastric juices. Peristalsis moves chyme into small intestine
The Pancreas, Liver, and Gallbladder– In small intestine chyme mix with 2
juices of 2 other organs– Pancreas produces enzymes that
breakdown carbohydrates, fats, and proteins in food.
– Liver-;other digestive juice - bile Bile- yellow-green bitter fluid; absorbs
fat. Bile is stored in the gallbladder between meals.
Large & Small Intestine
Small intestine 20-23ft. Long. &1 inch. in diameter. Small intestine has three parts.
Duodenum, jejunum, and ileun Lined with villi that absorb nutrients.
Villi are fingerlike projections
Large intestine (colon) 5-6ft. Long & 2.5 inch. in diameter. Undigested parts of food and fiber pass into the
colon. Absorbs water, vitamins ,and salts, and
eliminates waste.
Digestive System Problems
Digestive problems range from indigestion to acute conditions that require immediate medical attention.
Eat variety of low fat, high fiber foods, & wash hands before cook or eat, eat slow, drink 8,8 oz. glass of water a day.
Functional Problems Affect by illness, stress, or
eating particular food Indigestion: Discomfort in
upper abdomen Gas or Nausea Too much food Eat to fast Eat spicy/high fat Stomach disorder stress
o Constipations: feces becomes to dry & hardo Not drinking enough watero Not consuming enough fiber
o Heartburn: burning sensation in center of chesto Acid reflexo Using tobacco , alcohol,
aspirino Eating spicy or greasy food
Functional Problems Nausea: feeling of
discomfort makes vomit Motion sickness Some medication Pathogens Dehydration
Diarrhea: passage of watery fecesBacterialViral infectionChange in eating Over ate
Structural Problem Tooth decay: difficult to
chew Brush and Floss Dental Checks
Gastritis: inflammation of mucus membrane line in stomach
Gallstone: cholesterol in bile crystallizes. Blocks bile duct
Lactose Intolerance: cant digest lactose: sugar in milk
The Excretory System
How Excretory works…
Process of removing waste from body
Several organs involved
Lungs, Skin, & Large Intestine
Lungs expel carbon dioxide when breathing
Sweat is another formRemoves water & saltRegulates body’s temp.Too much = dehydration
Large intestine = solid waste
Urinary System
Uses Kidneys, bladder, ureter, urethra, & liver
Filters waste & extra fluid from bloodUrine; Liquid waste
Contains Nitrogen
Kidneys & Ureter Kidneys
Bean shape; vary in size Near middle of back Removes waste through filters
Nephrons Monitors acid-base & water
Ureter Single tube Used to travel from kidneys to bladder 8 to 10 inches long
Bladder & Urethra
Hollow & Muscular Sphincter muscle:
keep from leaks Leads to the urethra
Urethra Tube leads outside
Maintain Excretory Health
Remove waste that can become toxic
Drink at least 8 of 8 oz. of water Limit caffeine and soft drink Regular check ups Well balance eating plan
Excretory & Kidney Problems
Excretory Infection or
blockageCystilis
Inflamed bladder
Urethristis Inflamed urethra
KidneyNephris
Salts in urine crystillize to stones
Uremia Serious condition Decrease blood
filtration by kidney
Kidney Failure
Hemodialysis Machine to remove
waste Peritoneal dialysis
Use thin membrane Surround digestive
organs Kidney transplant
Replace non-working kidney