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