digestive system. functions of the digestive system 1. ingestion = food enters the mouth
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Functions of the Digestive System
1. Ingestion = Food enters the mouth.
Functions of the Digestive System
1. Ingestion = Food enters the mouth.
2. Digestion = Process that breaks food down into small molecules
Functions of the Digestive System
1. Ingestion = Food enters the mouth.
2. Digestion = Process that breaks food down into small molecules
a) Mechanical digestion = Food is chewed and churned.
b) Chemical digestion = Breaks down large food molecules into smaller molecules to be absorbed by cells
Functions of the Digestive System
1. Ingestion = Food enters the mouth.
2. Digestion = Process that breaks food down into small molecules
3. Absorption = Small molecules of food are taken into the body cells.
Functions of the Digestive System
1. Ingestion = Food enters the mouth.
2. Digestion = Process that breaks food down into small molecules
3. Absorption = Small molecules of food are taken into the body cells.
4. Elimination = Wastes made of unabsorbed food molecules pass out of the body.
Large Intestine
Which is not a function of the digestive
system?a) Breaking down food
into molecules the body can use
b) Absorbing food molecules into the blood to deliver to the body
c) Changing waste into molecules the body can use
d) Eliminating undigested waste from the body
Organs of the Digestive Tract
1. Mouth = Digestion starts here.
Organs of the Digestive Tract
1. Mouth = Digestion starts here.
a) The tongue & teeth mechanically break food up.
Organs of the Digestive Tract
1. Mouth = Digestion starts here.
a) The tongue & teeth mechanically break food up.
b) Saliva chemically digests food.a) Saliva = Mostly made of
water, also contains mucusand enzymes
Organs of the Digestive Tract
1. Mouth = Digestion starts here.
a) The tongue & teeth mechanically break food up.
b) Saliva chemically digests food.a) Saliva = Mostly made of
water, also contains mucus and ptyalin (an enzyme)
c) When swallowing, the epiglottis (a small flap of tissue) automatically closes over the trachea (windpipe).
Organs of the Digestive Tract
2. Esophagusa) Smooth muscles force food into
the mucus-lined esophagus.b) Rhythmic muscular
contractions (peristalsis) push food downward.
Organs of the Digestive Tract
3. Stomacha) Food undergoes mechanical
digestion when stomach muscles churn the food.
b) Chemical digestion happens when hydrochloric acid (HCl) and pepsin break down the complex proteins.
c) Peristalsis pushes the food toward stomach’s exit.
Which is not an example of mechanical digestion?a) Teeth chewing foodb) Tongue breaking up
foodc) Smooth muscles in
stomach churning food
d) Hydrochloric acid breaking down proteins
Organs of the Digestive Tract
4. Small Intestine (6 meters long)
a) Most digestion happens here.b) Intestinal juice
(full of enzymes) breaks down food.
Organs of the Digestive Tract
4. Small Intestine (6 meters long)
a) Most digestion happens here.b) Intestinal juice (full of enzymes) breaks down
food.
c) Digestive Helpers• Liver = Bile is
produced here (Bile breaks up fats like dish detergent breaks up grease.).
Organs of the Digestive Tract
4. Small Intestine (6 meters long)
a) Most digestion happens here.b) Intestinal juice (full of enzymes) breaks down
food.
c) Digestive Helpers• Liver = Bile is produced
here (Bile breaks up fats like dish detergent breaks up grease.).
• Gall bladder = Bile is stored here until released into the small intestine.
Organs of the Digestive Tract
4. Small Intestine (6 meters long)a) Most digestion happens here.b) Intestinal juice (full of enzymes) breaks down food.
c) Digestive Helpers• Liver = Bile is produced
here (Bile breaks up fats like dish detergent breaks up grease.).
• Gall bladder = Bile is stored here until released into the small intestine.
• Pancreas = Produces pancreatic juices that are released into the small intestine to break down proteins, starches, and fats
Organs of the Digestive Tract
4. Small Intestine (6 meters long)
a) Most digestion happens here.b) Intestinal juice (full of
enzymes) breaks down food.c) Digestive Helpers
• Liver • Gall bladder• Pancreas
d) Digested food is absorbed through the villi in the small intestine into a network of blood vessels that carry the nutrients to all parts of the body.
Organs of the Digestive Tract
4. Small Intestine (6 meters long)
a) Most digestion happens here.b) Intestinal juice (full of enzymes)
breaks down food.c) Digestive Helpers
• Liver, Gall bladder, Pancreasd) Digested food is absorbed
through the villi into a network of blood vessels that carry the nutrients to all parts of the body.
e) By the time food leaves the small intestine, it is empty of all nutrients except water.
Where does most digestion take place?
a) Mouthb) Stomachc) Small intestined) Liver
Organs of the Digestive Tract
5. Large Intestine (1.5 meters long)
a) Undigested food spends 18–24 hours here, and most of the water is absorbed.
Organs of the Digestive Tract
4. Large Intestine (1.5 meters long)
a) Undigested food spends 18–24 hours here, and most of the water is absorbed.
b) Helpful bacteria living in the large intestine make vitamins K and B.
Organs of the Digestive Tract
4. Large Intestine (1.5 meters long)a) Undigested food spends 18–24 hours here, and most
of the water is absorbed.b) Helpful bacteria living in the
large intestine make vitamins K and B.
c) Materials not absorbed form into solid waste (dead bacteria, some fat and protein, undigested food, dried out parts of digestive juices, and old intestinal cells).
Organs of the Digestive Tract
4. Large Intestine (1.5 meters long)a) Undigested food spends 18–24 hours here, and most of the
water is absorbed.b) Helpful bacteria living in the large
intestine make vitamins K and B.c) Materials not absorbed form into
solid waste (dead bacteria, some fat & protein, undigested food, dried out parts of digestive juices, and old intestinal cells).
d) Solid waste passes into the rectum and is stored until it is eliminated from the body through the anus.