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Digestive System Study Guide
Part 1
You may use the questions below as a study guide for the digestive system or you may draw out the digestive system, label each part, and list the functions. You may use your book and research on your iPad to answer the following questions.
1. What are the functions of the digestive system?
The digestive system converts food into small molecules that can be used by the cells of the body. Food is processed by the digestive system in four phases— ingestion, digestion, absorption, and elimination.
2. Food is processed in the digestive system in these 4 phases? Please be specific in outlining each of the 4 phases.
Phase 1: Ingestion: process of putting food into the mouth; opening of the digestive tract
Phase 2: Digestion: process of food being broken down 2 ways
1: Mechanical (mouth: chewing and stomach: churning)
2: Chemicals (mouth: enzymes and stomach: acids)

Phase 3: Absorption: Broken down into small molecules in the small intestine, from there it goes to through the circulatory system where the nutrients are carried throughout the body.
Phase 4: Elimination: solid and liquid wastes are separated in the large intestine; solid expelled as feces; liquid as urine
3. Do some research to see how long it takes for each phase of digestion to occur.
Ingestion: about 1 minute
Digestion: 2-4 hours
Absorption: 3-5 hours
Elimination: 10 hours - several days
4. Compare the size of the structures to the length of time spent in this phase of digestion.
(Example: The mouth is 8 cm and this phase of digestion takes approximately 5-10 seconds per bite.
You may put these results into a table).
Structure
Mouth (Ingestion)
Stomach (Digestion)
Small Intestine
(Absorption)
Large Intestine
(Elimination)
Approx. Length for an
Adult
8 cm
15 cm
4 - 6m
1.5 m
Time spent in this phase
1 min
2-4 hrs
3-5 hrs
10 hrs - several days

Part 2.
Use Quizlet to make flash cards for the following vocab terms:
1.
Enzyme: chemical that helps break down food
2.
Epiglottis: a flap of connective tissue that closes over the opening to the trachea as the bolus passes through the esophagus
3.
Bolus: clump of food formed by the tongue and throat muscles
4.
Pharynx: back of the throat
5.
Liver: part of the excretory system; it filters the blood coming from the digestive tract, before passing it to the rest of the body. The liver also detoxifies chemicals and metabolizes drugs. As it does so, the liver secretes bile that ends up back in the intestines. The liver also makes proteins important for blood clotting and other functions.
6.
Pancreas: Just behind the stomach is the pancreas,it's a gland that serves three important functions.
1. produce hormones that regulate blood sugar levels
2. produces enzymes that break down carbohydrates, proteins, lipids, and nucleic acids
3. produces sodium bicarbonate, a base that quickly neutralizes stomach acid as chyme enters the duodenum
7.
Gall bladder: squeezes stored bile into the small intestine through a series of tubes called ducts. Bile helps digest fats, but the gallbladder itself is not essential
8.
Small intestine: the part of the gastrointestinal tract between the stomach and the large intestine, and is where much of the digestion and absorption of food takes place.
9.
Large intestine: last part of the digestive system were the water and solid waste are separated in preparation for elimination
10.
Amylase: Enzyme found in saliva
11.
Peristalsis: a series of wave-like muscle contractions that moves food to different processing stations in the digestive tract. The process of

peristalsis begins in the esophagus when a bolus of food is swallowed
12.
Esophagus: the tube that carries food, liquids and saliva from your mouth to the stomach
13.
Chyme: is the semifluid mass of partly digested food that is expelled by the stomach into the duodenum (small intestine) and moves through the intestines during digestion
14. Kidneys: The kidneys are a pair of organs located in the back of the abdomen. The kidneys' function are to filter the blood. All the blood in our bodies passes through the kidneys several times a day.
The kidneys remove wastes, control the body's fluid balance, and regulate the balance of electrolytes. As the kidneys filter blood, they create urine, which collects in the kidneys' pelvis -- funnel-shaped structures that drain down tubes called 17. ureters to the 16. bladder.
15. Each kidney contains around a million units called 18. nephrons, each of which is a microscopic filter for blood. It's possible to lose as much as 90% of kidney function without experiencing any symptoms or problems.