digestive system. processing food 4 phases 1.ingestion = food enters the mouth
TRANSCRIPT
Digestive System
Processing Food
• 4 Phases
1. Ingestion = food
enters the mouth
Processing Food
• 4 Phases
2. _________ =
process that breaks
food down into small
molecules
Processing Food
• 4 Phases
2. Digestion =
process that breaks
food down into small
molecules
Processing Food
• 4 Phases
2. Digestion = process that breaks food down into small molecules
2 types:• Mechanical digestion =
food is chewed and mixed in the mouth, churned in stomach and acted on by bile
Processing Food
• 4 Phases
2. Digestion = process that breaks food down into small molecules
2 types:• Chemical digestion =
breaks down large food molecules into smaller molecules that can be absorbed by cells; happens in mouth, stomach & small intestine
Processing Food
• 4 Phases
3. Absorption = small
molecules of food
are taken into the
body cells
Processing Food
• 4 Phases
4. Elimination =
wastes made of
unabsorbed food
molecules pass out
of the body
Major Organs of Digestive Tract (food passes through)
• Mouth = digestion starts here
Major Organs of Digestive Tract (food passes through)
• Mouth = digestion starts here1. Tongue & teeth mechanically break food
up
Major Organs of Digestive Tract (food passes through)• Mouth = digestion starts here
1. Tongue & teeth mechanically break food up
2. Saliva chemically digests food• Saliva = mostly made of water, also contains
mucus & ptyalin (an enzyme)
Major Organs of Digestive Tract (food passes through)
• Mouth = digestion starts here3. Food is now a soft mass & is moved to
the back of tongue and is swallowed• When swallowing,
a small flap of tissue called the epiglottis automatically closes over the trachea (windpipe)
Major Organs of Digestive Tract (food passes through)
• Mouth = digestion starts here3. Food is now a soft mass & is moved to
the back of tongue and is swallowed• When swallowing, a small flap of tissue called
the epiglottis automatically closes over the trachea (windpipe)
4. Food enters the food tube (esophagus)
Major Organs of Digestive Tract (food passes through)
• Esophagus
Major Organs of Digestive Tract (food passes through)
• Esophagus1. Smooth muscles force food into the
mucus-lined esophagus
Major Organs of Digestive Tract (food passes through)
• Esophagus1. Smooth muscles force food into the
mucus-lined esophagus
2. Rhythmic muscular
contractions (peristalsis)
push food downward
Major Organs of Digestive Tract (food passes through)
• Stomach
Major Organs of Digestive Tract (food passes through)
• Stomach1. Food enters stomach
2. Cells in stomach release
gastric juice that contains
pepsin, hydrochloric acid
(HCl) and mucus
Major Organs of Digestive Tract (food passes through)
• Stomach3. Food undergoes mechanical digestion when
stomach muscles churn the food
Major Organs of Digestive Tract (food passes through)
• Stomach3. Food undergoes mechanical digestion
when stomach muscles churn the food
4. Chemical digestion
happens when hydrochloric
acid (HCl) and pepsin break
down the complex proteins
Major Organs of Digestive Tract (food passes through)
• Stomach3. Food undergoes mechanical digestion when
stomach muscles churn the food
4. Chemical digestion happens when hydrochloric acid (HCl) and pepsin break
down the complex proteins
3. Peristalsis pushes the food
toward stomach’s exit
Major Organs of Digestive Tract (food passes through)
• Small Intestine (6 meters long)1. Most digestion
happens here
Major Organs of Digestive Tract (food passes through)
• Small Intestine (6 meters long)1. Most digestion
happens here
1. Intestinal juice
(full of enzymes)
breaks down food
Major Organs of Digestive Tract (food passes through)
• Small Intestine (6 meters long)3. Digestive Helpers
a) Liver = bile is produced here
b) Gall bladder = bile is stored here, then is released through the bile duct into the small intestine• Bile breaks up fats (like dish detergent breaks up
grease)
c) Pancreas = produces pancreatic
juices that are released into the
small intestine to break down
proteins, starches, & fats
Major Organs of Digestive Tract (food passes through)
• Small Intestine (6 meters long)4. Digested food is absorbed through the
villi into a network of blood vessels that carry the
nutrients to all parts
of the body
Major Organs of Digestive Tract (food passes through)
• Small Intestine (6 meters long)4. Digested food is absorbed through the
villi into a network of blood vessels that carry the nutrients to all parts of the body
5. By the time food leaves the small intestine, it is empty of all nutrients except water
Major Organs of Digestive Tract (food passes through)
• Large Intestine (1.5 meters long)
Major Organs of Digestive Tract (food passes through)
• Large Intestine (1.5 meters long)1. Undigested food spends 18-24 hours
here & most of the water is absorbed
Major Organs of Digestive Tract (food passes through)
• Large Intestine (1.5 meters long)1. Undigested food spends 18-24 hours
here & most of the water is absorbed
2. Helpful bacteria
living in large
intestine make
vitamins K & B
Major Organs of Digestive Tract (food passes through)
• Large Intestine (1.5 meters long)3. Materials not absorbed form into solid
waste
Major Organs of Digestive Tract (food passes through)
• Large Intestine (1.5 meters long)3. Materials not absorbed form into solid
waste• Solid waste = made of dead bacteria, some
fat & protein,
undigested food, dried
out parts of digestive
juices & old intestinal
cells
Major Organs of Digestive Tract (food passes through)
• Large Intestine (1.5 meters long)3. Materials not absorbed form into solid waste
• Solid waste = made of dead bacteria, some fat & protein, undigested food, dried out parts of digestive juices & old intestinal cells
4. Solid waste passes into
the rectum and is stored
until it is eliminated from the
body through the anus
Digestive System
• Salivary Glands (yellow)Salivary Glands (yellow)• Esophagus (pink)• Stomach (purple)• Liver (red)• Small Intestine (green)• Large Intestine (blue)