Download Human Digestion

Objective: You will be able to identify
the structures of the digestive system.
Do Now:
• Read all of page 978
• Give the function of the digestive system
Figure 41.12 The four stages of
food processing
Small
molecules
Pieces
of food
Mechanical
digestion
Chemical digestion
(enzymatic hydrolysis)
Nutrient
molecules
enter body
cells
Undigested
material
Food
1 INGESTION
2 DIGESTION
3 ABSORPTION
4 ELIMINATION
Purpose of Digestive System
• Food is moved along a tube by muscular
contractions.
• Food never actually enters body tissues
until it is broken down
• The food has to be small enough to diffuse through
the cell membrane
• Remember the State Diffusion lab?
Figure 41.13 The human digestive system
Objective: You will be able to provide
the functions of each digestive organ.
Do Now:
• Read “The Stomach” which includes
“chemical digestion” on p. 980
• List the 2 chemicals released into the stomach
• What organic compound begins its digestions here
in the stomach?
Oral Cavity
• Mechanical digestion breaks food into
smaller pieces
– Increases surface area for chemical digestion
• Chemical digestion of starch occurs here
– Done by salivary amylase
– NOTE: Carbohydrate digestion begins here
Esophagus
• No digestion occurs here
• It moves food from oral cavity to stomach
by using muscles
• Called peristalsis
Stomach
• Mechanical digestion occurs by the
grinding of the stomach’s muscles
• Chemical digestion of proteins begins here
Liver
Bile
Gallbladder
Stomach
Acid chyme
Intestinal
juice
Pancreatic juice
Pancreas
Duodenum of
small intestine
Small Intestine
• Most of the chemical digestion occurs here
– Intestinal glands and the accessory organs
help to digest food
• Liver, gall bladder and pancreas
• All of the absorption of food into the body
occurs here
• No food is digested AFTER it leaves the
small intestine
Liver
Bile
Gallbladder
Stomach
Acid chyme
Intestinal
juice
Pancreatic juice
Pancreas
Duodenum of
small intestine
Accessory organs
• The liver makes the bile but it stores it in
the gall bladder
• It’s the gall bladder that actually secretes
bile into the small intestine
– Bile emulsifies fats (breaks them down)
• The pancreas secretes digestive enzymes
Liver
Bile
Gallbladder
Stomach
Acid chyme
Intestinal
juice
Pancreatic juice
Pancreas
Duodenum of
small intestine
Large Intestine
• This organs main function is to absorb
water
• It does NOT absorb food nor does it digest
food!!!!
End of the line
• Strong peristaltic action from the rectum
pushes waste out of the anus
Objective: You will be able to explain how the
digestive system is similar to organelles found within cells.
Do Now:
– Take out the frog dissection lab from yesterday.
– Begin to finish answering the questions on the lab
Villi increase the surface for more food
absorption.
• Which organelle(s) in a cell carry out
similar function to the following organs:
– Stomach
– Small Intestine
– Rectum
– Anus
Chemical Digestion
• Carbohydrates
Simple sugars (Glucose)
• Proteins
Amino Acids
• Nucleic Acids (DNA)
Nucleotides (A, G, C, T)
Objective:
You will be able to provide the
functions of each digestive organ.
Do Now:
• Read “Absorption in the Small Intestine”
on p. 982-983
• Describe the structure of the villi
• Where does food go that gets absorbed by the
villi?
Group Roles
• Leader – keeps the group focused and on
task
• Recorder – Writes down the work for the
group
• Reporter – Informs the class/teacher
about the work done by the group
• Noise monitor – Makes sure that the
group works quietly
Activity
• Create story about the digestive canal
of horrors where a group of teenage
worm friends enter a tunnel but end up
being digested by enzymes
• Remember that only some of the carbohydrate and
protein digestion happens outside intestines
• Be sure to include each structure and describe in full
detail what they do.
Figure 41.13 The human digestive system