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Study Guide Answers
organ: a group of different tissues that work together to perform a
specific function ; examples include the heart, liver, and brain
body system: a group of organs that work together to perform a
specific function; the organs of the digestive system process food and
prepare it for delivery to the body’s cells.
Food moves through the digestive tract using peristalsis.
Digestive enzymes help to speed up chemical reactions in the digestive
system. They help to break down nutrients into smaller particles.
 amylase – breaks down starch into sugars
 pepsin (with the help of HCl) – breaks proteins into amino acids
 pancreatic juices/bile – Finishes breaking down remaining
nutrients (starch, protein, and fat), breaks down fat into fatty
acids and glycerol
Food sources:
a. protein – meat, eggs, milk, fruit
b. carbohydrates – whole-grain breads, cereal, candy, potatoes
c. fats – fish, avocado, meat, cheese, butter, cookies, cake
The body needs proteins to help with building and repairing tissue,
and to make substances such as hemoglobin.
Carbohydrates are important for energy sources.
Fats are important for energy sources, to insulate your body, and to
provide padding for internal organs.
Sphincter muscles are located at the beginning and the end of each
organ (where they connect). They function to limit the passage of food
through the organs of the digestive system.
Mucus is a thick, sticky substance that lines and protects the inner
walls of the digestive organs. It helps the passage of food through the
digestive tract and helps protect the walls of the digestive tract from
being digested (since they are made of protein). If there is too little
mucus, ulcers can occur.
Diffusion is the process by which molecules move from places where
they are more concentrated to places where they are less concentrated.
It is considered a form of passive transport because it does NOT
require energy, so the molecules must be small. Examples include
food coloring in a glass of water, perfume sprayed out of a bottle, and
sugar solution moving through a membrane into distilled water.
Active transport is the process by which materials, using energy
supplied by the cell, are moved across a membrane.
All nutrients except for water and minerals are absorbed in the small
intestine. The nutrients then are transported by the bloodstream to
the rest of the body allowing us to live!
The small intestine has a large internal surface area in order to allow
the greatest amount of absorption possible. This is accomplished
using the villi and the microvilli in the small intestine.
The large intestine’s main job is to help the body reabsorb water and
minerals into the bloodstream. By doing this, any undigested food
begins to “dry out” in preparation for elimination of feces. If the feces
moves too quickly through the large intestine, diarrhea occurs. If the
feces moves too slowly through the large intestine, too much water is
reabsorbed and constipation occurs.
7.
MOUTH
ESOPHAGUS
STOMACH
pancreas
liver
gall bladder
SMALL INTESTINE
LARGE INTESTINE
RECTUM/ANUS
Mouth: chemical –the enzyme amylase in saliva breaks down starch
into sugar
mechanical – teeth and tongue tear food into smaller pieces
and move the food around in the mouth until it
makes a bolus
Esophagus: NO digestion takes place, simply peristalsis to move the
food to the stomach
Stomach: chemical – gastric juice (pepsin + hydrochloric acid) break
down proteins into amino acids
mechanical – 3 layers of muscle (circular, longitudinal, and
diagonal) churn the nutrients around and
break them down using peristalsis; the food is
now known as chyme
Small Intestine: chemical – pancreatic juices and bile (from the gall
bladder) break down fats into fatty acids
and glycerol (in the duodenum)
mechanical – peristalsis helps move food through
*** MAJOR digestion and absorption takes place here***
Large Intestine: NO digestion takes place here; reabsorption of
water is the main function