Download HBS Lesson 2 - terms and def

Human Body Systems
Lesson 2 Terms and Definitions
Major Organs of the
Digestive System
1.
2.
3.
4.
5.
6.
7.
Mouth
Esophagus
Stomach
Small intestine
Large intestine
Rectum
Anus
http://www.pediatricfeeding.org/images/gi_anatomy/A_digestive_system.png
Accessory Organs of the
Digestive System
1.
2.
3.
4.
5.
6.
Tongue
Teeth
Salivary glands
Liver
Gallbladder
Pancreas
Accessory Organs are
important for
mechanical and
chemical digestion
produce or store
enzymes
What is the purpose of
Digestion?
Digestion
Purpose – break foods down into a form
that can be absorbed into the bloodstream
and transported to the cells of the body.
Digestion is NOT a single activity BUT a
series of processes. (Mechanical and
Chemical)
Mechanical Digestion
Mechanical Digestion – The physical
breaking down, tearing, and mashing of
food from large to small pieces.
Example: Teeth tearing, tongue mashing,
churning of food by muscles that line the
digestive tract.
Chemical Digestion
Chemical Digestion – Breakdown of the
chemical bonds in nutrients so that they
can be absorbed into the bloodstream.
Example: Enzymes breaking down
carbohydrates, fats, and proteins.
Fun Facts…
Digestive Tract – Single convoluted tube
8-10 meters long
Muscle Activity in the digestive
tract
Peristalsis –wave like motions, caused by
the muscles in the digestive tract, that
move food slowly through the digestive
tract.
Crazy! – Peristalsis
contractions are so strong
that food would continue to
move through your
digestive system if you
stood on your head!
http://z.about.com/d/gymnastics/1/0/B/4/-/-/Step7.jpg
Muscle Activity in the digestive
tract
• Sphincters – rings of thickened muscle
that control the passage of food from one
organ to another
– Keeps food moving in the same direction
(Down! Not back up!)
Example – lips and anus, but also between
organs.
Mucus
• Mucus – slippery secretion that coats the
inner walls of the digestive tract and helps
facilitate the movement of food.
Also coats the lining
of the stomach and
small intestine to
prevent acidic
gastric juices from
eating away at the
stomach lining.
http://www.thethinkingblue.com/pics/Stomachabc.jpg
Small Intestine…
• Small Intestine (SI)
– Where most nutrient absorption occurs in
duodenum (first 25 cm of SI)
– Entire SI – 6-8 meters long
http://cache3.asset-cache.net/xc/85824240.jpg?v=1&c=IWSAsset&k=2&d=C82013BE001AABCB31C0B7E4AA7CE1E8
Large Intestine
• Food – all that’s left is waste or Feces!
What is a FART?
A fart is…
• Flatus – intestinal gases produced
bacteria feeding on undigested wastes.
Digestive Timeline!
6 seconds
2 hrs
4 ½ hours
4-12 hours
18 hours
12-24 hours