Transcript Body Systems - mrhebert.org

Body Systems
The Digestive System
The Basics
• We all need energy to live
• We get it from different sources
– Carbohydrates (sugars/starches)
– Lipids (fats/oils)
– Proteins (meat/lentils/beans)
• The Digestive system takes these sources
and makes them useable to the body
Types of Digestion
• Two Types…
• Mechanical: physical breakdown of food
– Chewing/mixing
– Teeth/jaw & tongue
• Chemical: breaking down
large particles into smaller
particles using enzymes
Teeth – Cool Photo
Step 1: Mouth & Esophagus
• Food enters our body through our mouth
• We chew and grind it down
• It also mixes with saliva which comes from
3 different saliva glands
• They release the
Why is saliva important?
enzyme amylase
• Starch molecules
into sugar
molecules
Aside - Carbohydrates
• Why are they important? What do they do?
– They are the main fuel source for our body
– The energy that gets used first
– Recommended that 45-60% is
carbohydrates
• Where do they come from?
– Vegetables, grains, low-fat dairy, fruits
Step 1: Mouth & Esophagus
• When ready to swallow food tongue
pushes the food back
• Flap of skin called epiglottis moves
across your windpipe
• Into the esophagus it goes
• It is pushed down your throat by the
muscles that line the esophagus … this
is peristalsis
– Chewed food is known as bolus
– Swallowing is known as delutition
Esophagus
Swallowing Video
Step 2: The Stomach
• A little history …
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•
•
•
•
Alexis St. Martin & Dr. William Beaumont
Alexis had big wound in his left side
Could not be repaired entirely
What did they do?
As if you
are
Dr. Beaumont put food on a string and letting
dangled it into the stomach to see what me do
this! Lol!
happened – lol science history!
Step 2: The Stomach - Cont
Step 2: The Stomach
• Food enters the stomach through a
sphincter (esophageal)
• Muscular wall of the stomach mixes it around
with the gastric juices
• What is that?
– Water
– Mucus
– Hydrochloric Acid
– Digestive Enzymes
Step 2: The Stomach
• The acid, enzymes and water liquefy the
food and break it down chemically
• It passes into the small intestine through
another sphincter (pyloric)
• Why do we need mucus in the stomach?
– So acid does not burn a hole thru the stomach!
– The acid in the stomach is hydrochloric acid
Acid Video
Step 2: The Stomach
Step 3: Gastrointestinal Tract
• The pancreas, a large gland in the back of the
stomach, helps break down food, sends
digestive enzymes into the small intestine
• Enzymes complete the
breakdown of starches
and proteins into small
particles which are more
easily absorbed by the
body
Step 3: Gastrointestinal Tract
Step 3: Gastrointestinal Tract
• The liver produces a substance called bile
(which is stored in the gall bladder)
• The gall bladder sends bile into the small
intestine, where it breaks up large amounts of
lipids into small drops
Step 3: Gastrointestinal Tract
• When food is broken down into smaller particles,
the small intestine absorbs these particles.
• The inner surface of the small intestine contains
villi (small, finger like objects)
– Villi increases the
surface area of the
intestine to help absorb
nutrients.
– Villi is covered with epithelial
tissue & food molecules get
absorbed by this tissue.
Bacteria … Can Be Good?
Step 4 – The End of the Road
• Food then passes from the small
intestine to the large intestine
• Key part here is that water is absorbed in
the large intestine
• When it hits the end of the road …
washroom break!
Summary Video
Digestive
System