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

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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

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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

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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