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Digestive System
Breaks down food into the nutrients your body needs
Mechanical– Foods are physically broken apart into smaller pieces
Chemical– Chemicals produced by your body break large
molecules into smaller ones that your body can use
What does the DS do?
Digestion – breaking down of food into nutrients
Absorption - Then the body is able to absorb and use the nutrients in food for energy, growth, and repair
Elimination - DS also eliminates undigested food from the body
Are teeth part of the DS?
Yes, very much so – They break down food so it can be swallowedIt also allows food to be mixed with saliva which acts as an enzymeEnzyme – proteins or others types of molecules that help speed up chemical processes
What path does food take?
Mouth – chewed and swallowed, moistens, saliva begins breaking down starches
Pharynx - junction b/n DT & RS, epiglottis
Esophagus – long, straight tube connects pharynx to stomach by peristalsis
cont
Stomach – – broken down by enzymes, acid– Can hold about 1 gallon of food & liquid– Churning of stomach – mechanical – Gastric juice – chemical– Lined with mucous to protect from acid– Food leaves stomach as CHYME
cont
Small intestine –– broken down, nutrients taken out
– Most chemical digestion and absorption of nutrients takes place here
– 3 organs play a role• Liver – Bile – breaks down large fat droplets
• Gallbladder – stores bile, releases it to SI
• Pancreas – triangular organ, secretes enzymes
• SI is coated with Villi– Absorb nutrients – pg 245
cont
Large intestine– 5 ft long, 3 in wide
Colon – major part of LI– Bacteria that live on undigested food make important
vitamins– These vitamins and water are taken from the undigested
food before the waste is removed from the bodyRectum – last part of LI where undigested waste is stored until in leaves the bodyThese make up the Digestive Tract
Organs of Digestive System
How does food move through the DS?
Peristalsis – waves of rhythmic motion that run through the walls of organs in the DT – push food through
Why doesn’t stomach acid burn the stomach?
Acid in your stomach is strong enough to dissolve metal
Lining of stomach secretes a coat of mucus that lines and protects stomach
Heartburn – stomach acid leaks into the esophagus which does not have protective lining
Avoid Digestive Disorders
Fiber
Limit fat
Eat moderately
Drink water
exercise
Digestive Disorders
Appendicitis– Small pouch that projects from colon
– Bacteria infects it
– Surgically removed – don’t need it
– Can rupture – serious
– Pain near naval that spreads
– Nausea
– Diarrhea
– fever
Colon cancer– Uncontrolled cell division that leads to
cancerous tumor– Change in bowel habits– Persistent gas and pain– Unexplained weight loss– Surgery, radiation, chemo
Heartburn– Acid from stomach irritates esophagus– Burning sensation in chest– OTC prescription drugs
Hemorrhoids– Veins in anus or rectum swell due to constipation,
pregnancy, and childbirth
– Sitting for long periods of time
– Heavy lifting
– Bleeding, itching, pain
– OTC treatments
– Warm bath
– surgery - minor
Crohn’s Disease – Inflammatory bowel– Chronic inflammation of DT– Diarrhea, cramping, bleeding, loss of appetite,
weight loss, fever– Anti-inflammatory drugs, surgery
Irritable Bowel Syndrome – IBS– Abnormal peristalsis in the SI leads to bouts of
diarrhea and constipation– Gas, bloating, stress may worsen symptoms– Managing stress, diet changes, drugs that affect
NS activities
Lactose Intolerance– Lack of the enzyme lactase in the SI leads to an
inability to digest lactose, a sugar in milk
– After consuming milk products• Nausea
• Cramps
• Gas
• Diarrhea
– Drink less milk, take lactose drops, drink lactose free milk
Peptic ulcer– Irritation caused by H. Pylori infection leads to
open sores in stomach lining– Burning pain b/n breastbone and navel,
especially when stomach in empty– Antibiotics, antacids, meds to protect stomach
lining and DT lining
Food Safety
Foodborne illness– Contains poison or disease causing bacteria– Undercooked– Raw– Transfer from hands, to countertops, etc– Symptoms
• Fever• Blood in stool, the runs• vomiting
Food preparation & storage
Cook meat well, cook eggs
Separate to avoid cross-contamination
Chill leftovers
Clean after touching food